IDQP Training Manual

Effective January 2020

International Air Transport Association

Montreal—Geneva 6th Edition
 NOTICE
DISCLAIMER. The information contained in this
publication is subject to constant review in the light
of changing government requirements and regula-
tions. No subscriber or other reader should act on
the basis of any such information without referring
to applicable laws and regulations and/or without
taking appropriate professional advice. Although
every effort has been made to ensure accuracy, the
International Air Transport Association shall not be
held responsible for any loss or damage caused by
errors, omissions, misprints or misinterpretation of
the contents hereof. Furthermore, the International
Air Transport Association expressly disclaims any
and all liability to any person or entity, whether a
purchaser of this publication or not, in respect of
anything done or omitted, and the consequences
of anything done or omitted, by any such person or
entity in reliance on the contents of this publication.

© International Air Transport Association. All

Rights Reserved. No part of this publication may
be reproduced, recast, reformatted or trans-
mitted in any form by any means, electronic or
mechanical, including photocopying, record-
ing or any information storage and retrieval sys-
tem, without the prior written permission from:

Senior Vice President

Safety and Flight Operations
International Air Transport Association
800 Place Victoria
P.O. Box 113
Montreal, Quebec
CANADA H4Z 1M1

IDQP Training Manual, 6th Edition

ISBN 978-92-9264-048-4
© 2020 International Air Transport Association. All rights reserved.
Montreal—Geneva
 Training Manual

Table of Contents

Record of Revisions ...................................................................................................................................................... v

Section 1— General ....................................................................................................................................................... 7

Section 2— Legal Basics .............................................................................................................................................. 8

Section 3— IDQP and Drinking Water for Aircraft Standards ............................................................................. 9

Section 4— Potable Water on Board Aircraft ........................................................................................................ 10

Section 5— Chemical Additives ................................................................................................................................ 11

Chlorite ............................................................................................................................................................................................... 11
Chlorine .............................................................................................................................................................................................. 11
Free Chlorine ................................................................................................................................................................................... 11
Total Chlorine .................................................................................................................................................................................. 11
Water Additive and Water Treatment ................................................................................................................................ 12
Different Methods for Water Disinfection ........................................................................................................................ 13
5.6.1 Chlorine ...................................................................................................................................................................................... 13
5.6.2 Chlorine Dioxide .................................................................................................................................................................... 13
5.6.3 Ozone .......................................................................................................................................................................................... 14
5.6.4 Chloramine ............................................................................................................................................................................... 14
5.6.5 Home Filtration ...................................................................................................................................................................... 14
5.6.6 UV Radiation............................................................................................................................................................................ 14
Disinfectants Based on Silver Ions ...................................................................................................................................... 15
Schrader Trucks............................................................................................................................................................................ 15
5.8.1 Chlorine Production Via Inline – Electrolysis on GSE Drinking Water Units .......................................... 15

Section 6— Chemicals in Water Samples ............................................................................................................... 17

Chemical Aspects .........................................................................................................................................................................17
pH Definition and Measurement Units.............................................................................................................................. 18
6.2.1 pH Diagram .............................................................................................................................................................................. 18
6.2.2 pH and Water Quality ......................................................................................................................................................... 19
6.2.3 Odor and Taste...................................................................................................................................................................... 20
6.2.4 Turbidity ..................................................................................................................................................................................... 21
6.2.5 Chlorine ......................................................................................................................................................................................22
Definitions ....................................................................................................................................................................................... 23

Section 7— Microbiology ........................................................................................................................................... 27

Introduction..................................................................................................................................................................................... 27
7.1.1 General ....................................................................................................................................................................................... 27
7.1.2 Benefits ...................................................................................................................................................................................... 27
Microbial Hazards Associated with Drinking-Water ................................................................................................. 28

ii 6th Edition 2020

 Public Health Aspects ............................................................................................................................................................... 30
7.3.1 General....................................................................................................................................................................................... 30
7.3.2 The Role of Reduced Immune Function .....................................................................................................................31
7.3.3 Health Risks in Aircraft and at Airports ......................................................................................................................31
7.3.4 Sources of Contamination.................................................................................................................................................31
7.3.5 Process of Infection ............................................................................................................................................................. 32
7.3.6 Persistence and Growth in Water ................................................................................................................................ 34
Bacteria ............................................................................................................................................................................................. 34
Other Organisms and More Common Bacteria ........................................................................................................... 37
7.5.1 Micro-organisms Affecting Taste, Odor and Appearance ............................................................................... 37
Biofilms in Water Supply .......................................................................................................................................................... 38
Elimination of Harmful Microorganisms from Water ................................................................................................. 39
Microbiological Monitoring ..................................................................................................................................................... 40
7.8.1 Verification of Microbial Safety and Quality ............................................................................................................ 40
7.8.2 Microbial Indicators of Water Quality .......................................................................................................................... 41
7.8.3 Rationale for the Use of Indicator Organisms ........................................................................................................ 42
7.8.4 Methods of Detection of Faecal Indicator Bacteria ............................................................................................. 43
7.8.5 Total Coliform Bacteria ...................................................................................................................................................... 43
7.8.6 Escherichia Coli and Thermotolerant Coliform Bacteria .................................................................................. 45
7.8.7 Intestinal Enterococci ......................................................................................................................................................... 46
7.8.8 Clostridium Perfringens..................................................................................................................................................... 46
7.8.9 Colony Count Bacteria ....................................................................................................................................................... 47
7.8.10 Heterotrophic Plate Counts (HPC) .............................................................................................................................. 48
7.8.11 Other Potential Indicators of Faecal Contamination .......................................................................................... 48

Section 8— Disinfection Methods ............................................................................................................................ 50

Purification vs Disinfection ..................................................................................................................................................... 50
How disinfection works ............................................................................................................................................................ 50
Typical Agents and methods for disinfection .................................................................................................................51
8.3.1 Chlorine Disinfection ...........................................................................................................................................................51
8.3.2 Ozone ......................................................................................................................................................................................... 53
8.3.3 Hydrogen Peroxide .............................................................................................................................................................. 53
8.3.4 AnoFluid .................................................................................................................................................................................... 54
8.3.5 Ultra-Violet Light................................................................................................................................................................... 55
8.3.6 Other Methods ....................................................................................................................................................................... 55

Section 9— Drinking Water Parameters ................................................................................................................. 57

Section 10— Connectors and Hoses ........................................................................................................................ 58

6th Edition 2020 iii

 Training Manual

Connectors ..................................................................................................................................................................................... 58
Hoses ................................................................................................................................................................................................. 61
Section 11— Tanks ....................................................................................................................................................... 68
Potable Water Steel Tank ....................................................................................................................................................... 68
Potable Water Plastic Tank .................................................................................................................................................... 69
Section 12— Paperwork (Taken from AHM440 and IDQP Inspection sheet) .................................................. 71
Potable Water – Fill Point .........................................................................................................................................................71
Potable Water Servicer(S) ........................................................................................................................................................71
Miscellaneous ................................................................................................................................................................................ 72

Section 13— Aircraft Servicing ................................................................................................................................. 75

Treatment of the Drinking Water by the Airport Management ............................................................................. 75
Supply Station and Filling Points at the Airport ........................................................................................................... 76
Transport of Drinking Water to the Aircraft .................................................................................................................... 76
Supply of Drinking Water to the Aircraft ..........................................................................................................................78
Inspection and Control in the Aircraft ...............................................................................................................................78

Section 14— Waste vs. Potable Water ..................................................................................................................... 79

General .............................................................................................................................................................................................. 79
Definitions ........................................................................................................................................................................................ 79
Sanitary Practices and Procedures ..................................................................................................................................... 79

Section 15— Water Servicing .................................................................................................................................... 81

Section 16— How to Prepare for the Inspection ................................................................................................... 82

Section 17— Checklist................................................................................................................................................. 83

Checklist Structure ..................................................................................................................................................................... 83
RC – General & Airport Records ......................................................................................................................................... 86
FP – Potable Water Fill Point ................................................................................................................................................ 89
WS/WC – Potable Water Servicers / Cabinets ............................................................................................................ 96
WU – Potable Water Uplift ................................................................................................................................................... 106

iv 6th Edition 2020

Record of Revisions
Edition Number Issue Date Effective Date
1st Edition October 2013 October 2013
nd
2 Edition September 2014 September 2014
3rd Edition May 2017 May 2017
4th Edition February 2018 February 2018
th
5 Edition July 2019 July 2019
6th Edition January 2020 January 2020

6th Edition 2020 v

 Section 1—General
Potable water is one of the most precious products on earth. Wherever it is being used for human
consumption, we have to take into consideration the high requirements with regard to its transportation and in
particular to its taste and odour which must be absolutely neutral. Also any growth of microbes is not
acceptable.

WHO- World Health Organization asserts: “The safety and accessibility of drinking-water are major concerns
throughout the world. Health risks may arise from consumption of water contaminated with infectious agents,
toxic chemicals, and radiological hazards. Improving access to safe drinking-water can result in tangible
improvements to health”

How do we achieve our goal to ensure safe & clean potable water for air passengers worldwide?

▪ Standardization and Harmonization

▪ Inspection
▪ Education and Training

Benefits
▪ Better water quality control
▪ Safer water on board
▪ Reduced fuel consumption
▪ Less costs and CO2 Emissions

Roles of Different Stakeholders

World Health Organisation or local regulations

Water quality and Safety
IATA IDQP
Create Safety Standards Manual.
Harmonize the Audit /Inspection Process
Airports
Maintain Drinking Water Standards
Airport Handling Agent
Drinking Water Standards
Training their staff
Maintaining Hygiene & serviceability of all equipment.
Testing and recording.
Operator
Ensuring all above are action.
Aircraft water system is maintained to the recommended standards.

6th Edition 2020 7

 Training Manual

Section 2—Legal Basics

The most common and widespread health risk associated with drinking water is microbial contamination

▪ WHO issued in 2004 “Drinking water quality guidelines”

▪ UN declared 2005 – 2015 as the International decade for action “Water for
▪ Life” “Safe water does not represent risk to health over a lifetime of
▪ consumption” (U.N.)
▪ Europe: Historically individual countries have established their own
▪ standards. This is becoming harmonised (EU directive).
▪ UK WATER Act 2003
▪ Germany TVO (German drinking water regulations)
▪ N. America April 2008 Environmental Protection Agency (EPA)

Legislation and References

▪ 2014 – UK Water Act

▪ 2009 – Aircraft Drinking Water Rule - EPA
▪ 2009 – WHO Guide to Hygiene and Sanitation
▪ 2017 – WHO Drinking Water Quality Guidelines
▪ German TVO – German Drinking Water Regulations
▪ Commission Directive (EU) 2015/1787 & 98/83/EC
▪ Canadian Water Act R.S.C.-1985 c.C-11
▪ Other local regulations

8 6th Edition 2020

 IDQP and Drinking Water for Aircraft Standards

Section 3—IDQP and Drinking Water for

Aircraft Standards
IDQP Develops and Promotes Global Standards and Harmonization by developing the IATA IDQP
Standards as well as contributing to the AHM and IGOM Manuals.

6th Edition 2020 9

 Training Manual

Section 4—Potable Water on Board Aircraft

These are some of the uses for water uplifted in the aircrafts:

▪ Preparation of hot and cold beverages, such as coffee, tea and powdered beverages

▪ Reconstitution of dehydrated foods, such as soups, noodles and infant formula

▪ Direct ingestion from cold water taps and water fountains

▪ Reconstitution and/or ingestion of medications

▪ Brushing of teeth in lavatories

▪ Cleaning of utensils and work areas

▪ Preparation of hot, moist towels for hand and face washing

▪ Direct face washing in lavatories

▪ Onboard showering facilities

▪ Emergency medical use

▪ Hand washing in lavatories and galleys

Although some of these uses do not necessitate consumption, they involve human contact and
possibly incidental ingestion (e.g. tooth brushing.)

10 6th Edition 2020

 Chemical Additives

Section 5—Chemical Additives

Chlorite
"Chlorite" is a name used for a group of sheet silicate minerals with similar properties. They are primarily found
in weakly metamorphosed rock and form from the alteration of clay-rich sedimentary rocks. It has very few
industrial uses. It’s usually used as a filter and as a constituent of clay.

Chlorine
Chlorine is a poisonous, greenish-yellow gas described as having a choking odor. It is a very corrosive,
hazardous chemical. Usually combined with other chemicals, it is used to disinfect water, purify metals, bleach
wood pulp and make other chemicals. Because of its reactivity, Chlorine does not exist in the free elemental
state in nature, although it is widely distributed in combination with other elements. Chlorine is available in a
number of different forms. Granular, liquid or tablet for example Household bleach, is a 5% solution of a
stabilized form of chlorine.

Free Chlorine
Chlorine in water may be present in two forms, free and combined. Free chlorine does the hard work of killing
bacteria and oxidizing contaminants. When you add chlorine to water, you are actually adding free chlorine.

Total Chlorine
When the free chlorine combines with contaminants, it becomes combined chlorine, or chloramines. In water,
this form of chlorine has very little sanitizing ability, and no oxidizing ability. Total chlorine is just the sum of
both combined chlorine and free chlorine.

6th Edition 2020 11

 Training Manual

Water Additive and Water Treatment

Disinfection is an effective barrier to many pathogens (especially bacteria) during drinking water treatment and
should be used for surface water and for ground water subject to faecal contamination. Residual disinfection
is used to provide a partial safeguard against low-level contamination and growth within the distribution
system.

The use of chemical disinfectants for water treatment usually results in the formation of chemical by-products.
However, the risks to health from these by-products are extremely small in comparison with the risks
associated with inadequate disinfection.

Generally disinfection is done by adding chlorinated agents such as bleach and chlorine dioxide. The three
chemicals most commonly used as primary disinfectants are chlorine, chlorine dioxide and ozone.
Monochloramine, usually referred to as chloramine, is used as disinfectant on distribution.

Other treatments use hard UV light or ozone injection. Those two latter processes do not provide residual
disinfection.

Only products approved by the local health authority may be used for the disinfection of drinking water.

Some disinfectants such as chlorine can be easily monitored and controlled as a drinking water disinfectant,
and frequent monitoring is recommended wherever chlorination is used.

12 6th Edition 2020

 Chemical Additives

When a disinfection agent is added in the potable water servicing vehicle, this should be done immediately
after filling and the water should be circulated within the servicing vehicle during a minimum time of 30 minutes
in order to have a full dilution and to allow the disinfection agent to react.

The content of the potable water servicing vehicle must be delivered to an aircraft or drained not later than 24
hours after filling.

Different Methods for Water Disinfection

5.6.1 Chlorine

Water chlorination is the process of adding the element chlorine to water as a method of water purification to
make it fit for human consumption as drinking water. Water that has been treated with chlorine is effective in
preventing the spread of waterborne disease.

Chlorine is one of the most commonly used disinfectants for water disinfection. Chlorine can be applied for the
deactivation of most microorganisms and it is relatively cheap.

Chlorine is one of the most widely used disinfectants. It is very applicable and very effective for the deactivation
of pathogenic microorganisms. Chlorine can be easily applied, measures and controlled.

Chlorine has been used for applications, such as the deactivation of pathogens in drinking water, swimming
pool water and wastewater, for the disinfection of household areas and for textile bleaching, for more than two
hundred years.

Chlorine in water is more than three times more effective as a disinfectant against Escherichia coli than an
equivalent concentration of bromine, and is more than six times more effective than an equivalent
concentration of iodine.

Free chlorine content at the point of filling into the aircraft must be in the range of 0.3 to 0.8 mg/l (0.3 mg/l
minimum for sample taken at aircraft).

5.6.2 Chlorine Dioxide

The other option for the use of chlorine for water disinfection is chlorine dioxide (ClO 2), known for being a highly
selective and an effective biocide it is often used in Legionella control because of how potent a disinfectant it
is, sanitizing in seconds. This means ClO2 is often used in drinking water purification and is the disinfectant and
sanitizer of choice for water used in food and beverage production.

https://iaspub.epa.gov/tdb/pages/treatment/treatmentOverview.do?treatmentProcessId=-1277754943

6th Edition 2020 13

 Training Manual

5.6.3 Ozone

Ozonation is used by many European countries and also in a few municipalities in the United States. This
alternative is more cost effective and energy-intensive. It involves ozone being bubbled through the water,
breaking down all parasites, bacteria, and all other harmful organic substances. However, this method leaves
no residual ozone to control contamination of the water after the process has been completed.Due to current
regulations, systems employing ozonation in the United States still must maintain chlorine residuals
comparable to systems without ozonation.

The advantage of chlorine in comparison to ozone is that the residual persists in the water for an extended
period of time. This feature allows the chlorine to travel through the water supply system, effectively controlling
pathogenic backflow contamination. In a large system this may not be adequate, and so chlorine levels may be
boosted at points in the distribution system, or chloramine may be used, which remains in the water for longer
before reacting or dissipating.

5.6.4 Chloramine

Disinfection with chloramine is also becoming increasingly common. Unlike chlorine, chloramine has a longer
half-life in the distribution system and still maintains effective protection against pathogens. The reason
chloramines persist in the distribution is due to the relatively lower redox potential in comparison to free
chlorine. Chloramine is formed by the addition of ammonia into drinking water to form mono-, di-, and
trichloramines. Whereas Helicobacter pylori can be many times more resistant to chlorine than Escherichia
coli, both organisms are about equally susceptible to the disinfecting effect of chloramine.

5.6.5 Home Filtration

Water treated by filtration and home filtration may not need further disinfection; a very high proportion of
pathogens are removed by materials in the filter bed. Filtered water must be used soon after it is filtered, as the
low amount of remaining microbes may proliferate over time. In general, these home filters remove over 90%
of the chlorine available to a glass of treated water. These filters must be periodically replaced otherwise the
bacterial content of the water may actually increase due to the growth of bacteria within the filter unit.

5.6.6 UV Radiation

Another method which is gaining popularity is UV disinfection. UV treatment leaves no residue in the water
due to use of light instead of chemical disinfectants. However, this method alone (as well as chlorination alone)
will not remove bacterially produced toxins, pesticides, heavy metals, etc. from water. Often, multiple steps are
taken in commercially sold water.

14 6th Edition 2020

 Chemical Additives

Disinfectants Based on Silver Ions

Elsil uses new technology to adapt proven, highly effective anti-bacterial processes for use in aviation. Its key
ingredient is Hydrogen Peroxide (H2O2). This chemical is already closely related to water (H2O) and the first
thing you will notice is that Elsil is completely odour free so your potable water will taste just like fresh water,
with no chlorine taste or smell. Hydrogen Peroxide was discovered in 1818 and is widely used in both Health
Care and the water industry. Hydrogen Peroxide is supported by a trace element of Silver. Silver has been used
for medicinal purposes since ancient times when silver coins were used to protect drinking water fountains in
ancient Rome. The combination of Hydrogen Peroxide and Silver allows Elsil to attack all types of bacteria,
spores, fungi, algae and bio-film without exception. A patented process semi-stabilises Elsil for long term
effectiveness up to 7 days. This drastically reduces the volume of water used at airports as well as saving much
time in managing potable water supply.

Certisil is a disinfection product which is, similar to Elsil, based on silver ions. It is available as powder, tablets
or liquids.

If peroxide is added for disinfection result shall be 0.1 to 0.3 ml/l H 2O2.

● As these products contain silver, check operators manuals and local regulation for applicability as usage
is strongly not recommended !

Schrader Trucks
At many airports in Europe, a new generation of potable water trucks is now in use. The vehicles of the German
company Schrader are able to produce chlorine automatically. Details of this procedure is described below.

5.8.1 Chlorine Production Via Inline – Electrolysis on GSE Drinking Water

Units

An inline-electrolysis pipe section is placed in the water bearing system of the drinking water unit. While driving
or in stand-by mode the electrolysis cell witch is supplied by co current flow, produces chlorine from the salt
witch is in the drinking water.

The drinking water in the tank will be circulated permanently through the electrolysis cell, the measuring
system and all hose and pipe sections back into the tank by a water pump.

The produced chlorine will be captured by measuring and control system. The threshold for chlorine is free
selectable (e.g. 0,3 mg/l)

6th Edition 2020 15

 Training Manual

Display chlorine and pH values

The condition for working with electrolysis system is an adequate value of salt in the filled up water. This value
must not below under 20 mg/l NaCl (Salt).

The ideal value for chlorine production via electrolysis is more than 50 mg/l NaCl(Salt).

Chloride concentration mg/l Consequence of Schrader eco-clean

more > 50 mg/l Fast chlorine production
Approx. 0,3 mg/l per 0,5 hours
less < 50 mg/l Slower chlorine production
Approx. 0,15 mg/l per 0,5 hours
less < 20 mg/l No chlorine production with Schrader eco-clean possible

A continue control of the physical-chemical drinking water analysis of the local water supplier is necessary in
order to react of fluctuating salt values.

When the salt values are too low an addition of NaCl (Salt) to the water is possible. This can be through a
special adapter fitting. The right quantities in order to the tank volume and the existing values in the drinking
water has to be calculated.

Dosing of NaCl (Salt)

Max. value in the drinking water: 250mg/l
Ideal value for electrolysis: 80 mg/l

Addition of NaCl: 2,000 litre Water + 160g Salt = 80 mg/l

The shown chlorine values on the display has to be double checked by DPD-Method (Photometric measuring
system) periodically.

When there is a difference between these values the parameter has to be adjusted.

The maintenance of the electrolysis system must take place in order to the lime concentration in the drinking
water. The cleaning can be done by citric acid.

16 6th Edition 2020

 Chemicals in Water Samples

Section 6—Chemicals in Water Samples

Without human influences water quality would be determined by the weathering of bedrock minerals, by the
atmospheric processes of evapotranspiration and the deposition of dust and salt by wind, by the natural
leaching of organic matter and nutrients from soil, by hydrological factors that lead to runoff, and by biological
processes within the aquatic environment that can alter the physical and chemical composition of water.

Typically, water quality is determined by comparing the physical and chemical characteristics of a water sample
with water quality guidelines or standards. Drinking water quality guidelines and standards are designed to
enable the provision of clean and safe water for human consumption, thereby protecting human health. These
are usually based on scientifically assessed acceptable levels of toxicity to either humans or aquatic organisms.

The chemical and physical quality of water may affect its acceptability to consumers. Turbidity, colour, taste,
and odour, whether of natural or other origin, affect consumer perceptions and behaviour. In extreme cases,
consumers may avoid aesthetically unacceptable but otherwise safe supplies in favour of more pleasant but
less wholesome sources of drinking-water

Chemical Aspects
The great majority of health-related water quality problems are the result of bacteriological or other biological
contamination. Nevertheless, a significant number of very serious problems may occur as a result of the
chemical contamination of water resources. Some potentially chronic effects may occur where overuse of
agrochemicals leads to significant levels of pesticides in water sources. The presence of nitrate and nitrite in
water may result from the excessive application of fertilizers or from leaching of wastewater or other organic
wastes into surface water and groundwater. Although effects may be difficult to detect in human populations,
such contaminants may pose a risk to health.

In areas with aggressive or acidic waters, the use of lead pipes and fittings or solder can result in elevated lead
levels in drinking-water, which may, after longterm exposure, affect the mental development of children.
Exposure to high levels of chemical contamination, even naturally occurring like fluoride and arsenic, may result
in a risk to health.

More acute health effects can occur from chemical contamination due to high levels of nitrate, and accidental
and other discharges of solvents or heavy metals from mining activities.

In order to establish whether or not this type of problem exists, a selected number of physicochemical
parameters may have to be measured. However, it may be both very costly and physically impractical to cover
a large number of parameters. If certain chemical contaminants are of special local significance, the levels
should be measured and the results evaluated in the light of the guideline values and other recommendations.

6th Edition 2020 17

 Training Manual

pH Definition and Measurement Units

pH is a measure of how acidic/basic water is. The range goes from 0 - 14, with 7 being neutral. pH’s of less than
7 indicate acidity, whereas a pH of greater than 7 indicates a base.

pH is really a measure of the relative amount of free hydrogen and hydroxyl ions in the water. Water that has
more free hydrogen ions is acidic, whereas water that has more free hydroxyl ions is basic. Since pH can be
affected by chemicals in the water, pH is an important indicator of water that is changing chemically.

pH is defined as the decimal logarithm of the reciprocal of the hydrogen ion activity, aH+, in a solution.

1
pH = log 10 ( ) = −log10 (a H+ )
a H+

pH is reported in "logarithmic units". Each number represents a 10-fold change in the acidity/basic of the water.
Water with a pH of five is ten times more acidic than water having a pH of six.

Although the pH of pure water is 7, drinking water and natural water exhibits a pH range because it contains
dissolved minerals and gases. Surface waters typically range from pH 6,5 to 8,5 while groundwater ranges from
pH 6 to 8,5.

Water with a pH less than 6,5 is considered acidic. This water typically is corrosive and soft. It may contain
metal ions, such as copper, iron, lead, manganese and zinc. The metal ions may be toxic, may produce a metallic
taste, and can stain fixtures and fabrics. The low pH can damage metal pipes and fixtures.

Water with a pH higher than 8,5 is considered basic or alkaline. This water often is hard water, containing ions
that can form scale deposits in pipes and contribute to an alkali taste.

6.2.1 pH Diagram

As this diagram we can see all pH range (from 0 to 14) and examples of some materials/substances pH. Normal
rainfall has a pH of about 5,6—slightly acidic due to carbon dioxide gas from the atmosphere but as we can see
can rain can be very acidic, and it can affect the environment in a negative way.

18 6th Edition 2020

 Chemicals in Water Samples

pH diagram

6.2.2 pH and Water Quality

Excessively high and low pH’s can be detrimental for the use of water. High pH causes a bitter taste, water
pipes and water-using appliances become encrusted with deposits, and it depresses the effectiveness of the
disinfection of chlorine, thereby causing the need for additional chlorine when pH is high. Low-pH water will
corrode or dissolve metals and other substances.

The pH of water can be measured by different methods, a pH meter with a probe, a field kit, and litmus paper.

Examples of pH measurement devices

6th Edition 2020 19

 Training Manual

6.2.3 Odor and Taste

Can arise as a consequence of natural substances in surface waters. Water treatment with activated carbon or
ozone will remove these natural substances. The standard for drinking water describes as acceptable to
consumers - no abnormal change in odor or taste.

Taste and odor can enter water in a variety of manners. Surface water sources can become contaminated
through algal blooms or through industrial wastes or domestic sewage introducing taste- and odor-
causing chemicals into the water. Groundwater supplies can be afflicted with dissolved minerals, such as iron
and manganese, which enter the water when it passes through rocks underground. Tastes and odors can also
enter either type of water in the raw water transmission system and in the treatment plant due to algal growths,
accumulated debris and sludge, or disinfection byproducts.

The distribution system can have many of the same causes of taste and odor mentioned above, with the
addition of problems resulting from cross-connections and low flow zones.

A refreshing glass of drinking water requires certain chemicals be present in combination, such as calcium and
bicarbonates. A drinking water that originated from a municipal treatment plant probably made contact with
chlorine when it was added to destroy waterborne germs, such as e. coli 0157 H7 and norovirus, which are
capable of spreading disease. Chlorine disinfectants play an essential role in maintaining the public health, but
they can introduce an unpleasant odor or taste to drinking water.

Since taste and odor work together it is often difficult to distinguish the two. The table below we can see some
of the chemicals which cause the most common taste and odor problems in water.

Odor and taste chemical causes

Chemical cause Taste/odor Origin

Geosmin Earthy or grassy odors Produced by actinomycetes,
blue-green algae, and green
algae.
2-Methylisoborneol (MIB) Musty odor Produced by actinomycetes and
blue-green algae.
2t, 4c, 7c-decatrienal Fishy odor Produced by blue-green algae.
Chlorine Bleach, chlorinous, or medicinal Addition of chlorine as a
taste and odor disinfectant.
Chloramines Swimming pool, bleach, or Addition of chlorine and
geranium odor ammonia as a disinfectant.
Aldehydes Fruity odor Ozonation of water for
disinfection.
Phenols and Chlorophenols Pharmaceutical or medicinal taste Phenols usually originate in
industrial waste. Chlorophenols
are formed when phenols react
with disinfecting chlorine.

20 6th Edition 2020

 Chemicals in Water Samples

Chemical cause Taste/odor Origin

Iron Rusty or metallic taste Minerals in the ground.
Manganese Rusty or metallic taste Minerals in the ground.
Hydrogensulfide Rotten egg odor Produced by anaerobic
microorganisms in surface water
or by sulfates in the ground.
Methane gas Garlic taste Decomposition of organic matter.

6.2.4 Turbidity
Turbidity is a measure of the cloudiness of water. It can come from fairly benign sources, such as suspended
sediment in the water, or from high levels of disease-causing organisms. All are generated as water moves
through soil and into ground water supply.

Turbidity measurement is an important non‐specific water quality control parameter at water treatment works,
because it can be monitored continuously on line and alarms set to alert operators to deterioration in raw water
quality or the need to optimize water treatment.

Note: The standard at consumer’s taps is 4 NTU. IDQP has established the limit of 1 NTU.

An NTU is the measurement of light that passes through a sample of water; the more particles that are in the
water, the higher the NTU number.

Turbidity caused by high levels of organic matter can protect microorganisms from the effects of drinking water
disinfection. It can even stimulate bacterial growth. Therefore, it is critical to successful water treatment and
disinfection to keep turbidity levels low.

Higher turbidity levels are often associated with higher levels of disease-causing microorganisms such as
viruses, parasites and some bacteria. These organisms can cause nausea, cramps, diarrhea and associated
headaches.

Examples of turbidity measurement devices

6th Edition 2020 21

 Training Manual

6.2.5 Chlorine
The destruction of microbial pathogens is essential and very commonly involves the use of reactive chemical
agents such as chlorine. The use of chemical disinfectants usually results in the formation of chemical
byproducts, some of which are potentially hazardous, but the risks to health posed by these by-products are
extremely small in comparison with those associated with inadequate disinfection. It is important that
disinfection should not be compromised by attempts to control such by-products.

“The health risks from these byproducts at the levels at which they occur in drinking water are extremely
small in comparison with the risks associated with inadequate disinfection. Thus, it is important that
disinfection not be compromised in attempting to control such byproducts.” WHO

Chlorine is applied to water either as elemental chlorine (chlorine gas), or through the use of chlorinating
chemicals such as calcium hypochlorite (tablets or granules) or solutions of sodium hypochlorite (liquid
bleach). While varying in form and concentration, each produces “free chlorine” to attack germs in water. The
level of free chlorine can be easily monitored, providing an important measure of water quality. A “residual”
level of chlorine helps protect treated water treated water in the distribution system, particularly important for
older water systems.

Chlorine in one form or another is the most commonly used disinfectant worldwide.

Chlorine is produced in large amounts and widely used both industrially and domestically as an important
disinfectant and bleach. In particular, it is widely used in the disinfection of swimming pools and is the most
commonly used disinfectant and oxidant in drinking-water treatment reacting to form hypochlorous acid and
hypochlorites.

Terminal disinfection is essential for surface waters after treatment and for protected groundwater sources
when E. coli or thermotolerant (faecal) coliforms are detected.

Chlorine Added

Chlorine Demand

Total Chlorine

Residual Chlorine Combined Chlorine

22 6th Edition 2020

 Chemicals in Water Samples

Definitions

Chlorine added the amount of chlorine added to the water

Chlorine demand the amount of chlorine used up or consumed by the bacteria, algae, organic
compounds and some inorganic substances like iron and manganese

Total Chlorine = Residual total chlorine = Added – Demand

Total Chlorine the amount of chlorine remaining in the water at time of measurement

Free Chlorine the amount of HOCl (hypochlorous acid) and OCl- (hypochlorite ion) species
existing in water after chlorine addition. Killing power is more effective at
lower pH values where HOCl specie existence is higher

Cl2 + H2O HOCl + HCl

HCl H+ + Cl-

HOCl H+ + OCl-

Combined Chlorine the amount of chloramines as result of the reaction between chlorine and
ammonia or amino compounds that were present in water. These forms have
lower disinfection effectiveness.

For terminal chlorination, there should be a free chlorine residual of at least 0.5 mg/litre after a minimum
contact time of 30 minutes at a pH of less than 8.0, as for inactivation of enteric viruses.

When chlorine is used as a disinfectant in a piped distribution system, it is desirable to maintain a free chlorine
residual of 0.2–0.5 mg/litre throughout, to reduce the risk of microbial regrowth and the health risk of
recontamination.

Chlorine can be easily monitored and controlled as a drinking-water disinfectant, and regular, frequent
monitoring is recommended wherever chlorination is practiced.

Examples of chlorine measurement devices

6th Edition 2020 23

 Training Manual

Residual Chlorine

Chlorine is widely used both industrially and domestically as an important disinfectant and is the most
commonly used disinfectant and oxidant in drinking-water treatment reacting to form hypochlorous acid and
hypochlorites

pH is a measure of how acidic/basic water is. The range goes from 0 - 14, with 7 being neutral. pHs of less
than 7 indicate acidity, whereas a pH of greater than 7 indicates a base. pH is really a measure of the relative
amount of free hydrogen and hydroxyl ions in the water. Water that has more free hydrogen ions is acidic,
whereas water that has more free hydroxyl ions is basic.

24 6th Edition 2020

 Chemicals in Water Samples

PH
Blue litmus paper with a drop of acid rain

Turbidity

Turbidity, is measured by shining a light through the water and is reported in Nephelometric Turbidity Units
(NTU)

Turbidity caused by high levels of organic matter can protect microorganisms from the effects of drinking water
disinfection. It can even stimulate bacterial growth. Therefore, it is critical to successful water treatment and
disinfection to keep turbidity levels low.

Water appearance and smell

a) Sample check
Samples should be taken in a suitable, clean dry clear glass jar. It is not necessary to use a sterile bottle for
this check.
Ensure that the sample drain pipework is first flushed during 2 to 3 minutes at medium flow rate to obtain a
representative sample.
Allow the sample to settle in the container to ensure freedom from entrained air. Inspect in a good light. A
flash light beam may be used to detect colloids in suspension.

6th Edition 2020 25

 Training Manual

b) Visual check
For the water to be acceptable it should be of appropriate colour, visually clear, bright and free from solid
matter and noticeable odour.
A sample from the sump of each tank should be checked for cleanliness and pollution -, (Clear and Bright). If
visible particulates or other pollution are detected, let the water settle for 10 minutes and take another sample.
If visible particulates or other pollution are still present, the source supply shall not be used and the installation
Manager should be notified.

c) Liquid pollution
Water may be polluted by foreign liquids. Petroleum products are easily detected by an iridescent water
surface. Some heavy solvents may settle at the bottom of the sampling bottle.

d) Particulates
Particulates (solid matter) appear as flakes, specks or fibers suspended in the water or settled out at the
bottom. Examination can be facilitated by swirling the sample to form a vortex, any solid matter concentrating
itself at the centre.
Sources of solid contaminants are normally:
• rust and scale from inside pipes and tanks.
• rubber particles from hoses and gaskets.
• dust, dirt and sand drawn in through vents.
• fibers from rags and filters.
• wear particles from pumps and meters.

e) Micro-organisms
Micro-organisms may enter in improper sealed or cleaned systems. They can be detected only by specific
microbial analysis. Some portable field microbial detectors are under evaluation and not yet fully approved.

f) Chemical Checks for disinfectant content

Use test kits appropriate for the chemical that has been added for disinfection.
Note: Chlorine test result color mostly purple, Hydrogen Peroxide mostly blue or green

26 6th Edition 2020

 Section 7—Microbiology
Introduction

7.1.1 General

The great majority of evident water-related health problems are the result of microbial (bacteriological, viral,
protozoan or other biological) contamination. Microbiology is the scientific field that is occupied with the study
of microorganisms, including bacteria, fungi, protozoa, algae, parasites, viruses, nematodes, microbes or the
immune system. Some of the applied studies are food, environmental or water microbiology.

All living creatures consist of cells, the basic units of life. They are the smallest structures capable of basic life
processes, such as taking in nutrients and expelling waste. Cells can only be made visible by microscopes.
Microorganisms are organisms that usually consist of one single cell. Because of this, they are often referred
to as "single-celled organisms".

At first, microorganisms were not seen as a separate kind. Microorganisms that carried out photosynthesis
(compare to the carbon cycle) were classified in the plant kingdom, and microorganisms that ingested food
were placed in the animal kingdom. However, in the 19th century, scientists had identified a wide variety of
microorganisms with diverse cell structures, very specific internal structures, and specific reproductive patterns
that made them realize these organisms did not belong to the plant or animal kingdom. The three domains:

7.1.2 Benefits

While some fear microbes due to the association of some microbes with various human illnesses, many
microbes are also responsible for numerous processes, such as fermentation (dairy products, vinegar, alcohol)
or the production of antibiotics, amino acids or polymers (polyesters, polyamides, polysaccharides), even
cellulose and many others more.

Microorganisms are beneficial for microbial biodegradation, and symbiotic microbial communities are known
to confer various benefits to their human and animal host's health including aiding digestion, production of
beneficial vitamins and amino acids, and suppression of pathogenic microbes.

Some benefit may be conferred by consuming fermented foods, probiotics (bacteria potentially beneficial to
the digestive system) and/or prebiotics (substances consumed to promote the growth of probiotic
microorganisms).

6th Edition 2020 27

 Training Manual

Adults carry over 200 species with the weight of 1 kg of gut bacteria and excrete their own weight in faecal
bacteria every year. Some gut bacteria such as lactobacilli and bifido-bacteria are thought to confer health-
promoting properties.

These good bacteria ('probiotics') may help to maintain a healthy balance of bacteria, stimulate gut immunity
and help prevent colonisation by pathogenic organisms that cause stomach and intestinal disturbances and
diarrhoea.

Microbial Hazards Associated with Drinking-Water

Sometimes microorganisms that cause health effects can be found in drinking water. However, as drinking
water is thoroughly disinfected today, disease caused by microorganisms is rarely caused by drinking water.
People that swim in swimming pools will find that the water they swim in is disinfected with either chlorine,
ozone, UV or chlorine dioxide. But there are people that swim outside in surface water every year. Surface water
may be infected, for example with botulism.

The pathogens that may be transmitted through contaminated drinking-water are diverse. The immunity of
individuals also varies considerably, whether acquired by contact with a pathogen or influenced by such factors
as age, sex, state of health and living conditions.

Infectious diseases caused by pathogenic bacteria, viruses and parasites (e.g., protozoa and helminths) are the
most common and widespread health risk associated with drinking-water. Breakdown in water supply safety
may lead to large-scale contamination and potentially to detectable disease outbreaks.

Securing the microbial safety of drinking-water supplies is based on the use of multiple barriers, from catchment
to consumer, to prevent the contamination of drinking-water or to reduce contamination to levels not injurious
to health. Safety is increased if multiple barriers are in place, including protection of water resources, proper
selection and operation of a series of treatment steps and management of distribution systems (piped or
otherwise) to maintain and protect treated water quality.

The preferred strategy is a management approach that places the primary emphasis on preventing or reducing
the entry of pathogens into water sources and reducing reliance on treatment processes for removal of
pathogens. In general terms, the greatest microbial risks are associated with ingestion of water that is
contaminated with human or animal (including bird) faeces. Faeces can be a source of pathogenic bacteria,
viruses, protozoa and helminths. Faecally derived pathogens are the principal concerns in setting health-based
targets for microbial safety.

Microbial water quality often varies rapidly and over a wide range. Short-term peaks in pathogen concentration
may increase disease risks considerably and may trigger outbreaks of waterborne disease. The infective stages
of many helminths, such as parasitic roundworms and flatworms, can be transmitted to humans through
drinking-water. As a single mature larva or fertilized egg can cause infection, these should be absent from
drinking-water. However, the water route is relatively unimportant for helminth infection, except in the case of
the guinea worm.

28 6th Edition 2020

 Microbiology

Legionella bacteria are ubiquitous in the environment and can proliferate at the higher temperatures
experienced at times in piped drinking-water distribution systems and more commonly in hot and warm water
distribution systems. Exposure to Legionella from drinking-water is through inhalation and can be controlled
through the implementation of basic water quality management measures in buildings and through the
maintenance of disinfection residuals throughout the piped distribution system.

Public health concern regarding cyanobacteria relates to their potential to produce a variety of toxins, known
as “cyanotoxins”. In contrast to pathogenic bacteria, cyanobacteria do not proliferate within the human body
after uptake; they proliferate only in the aquatic environment before intake. While the toxic peptides (e.g.,
microcystins) are usually contained within the cells and thus may be largely eliminated by filtration, toxic
alkaloids such as cylindrospermopsin and neurotoxins are also released into the water and may break through
filtration systems.

Some microorganisms will grow as biofilms on surfaces in contact with water. With few exceptions, such as
Legionella, most of these organisms do not cause illness in healthy persons, but they can cause nuisance
through generation of tastes and odors or discoloration of drinking-water supplies. Growth following drinking-
water treatment is often referred to as “regrowth.” It is typically reflected in measurement of increasing
heterotrophic plate counts (HPC) in water samples.

Elevated HPC (heterotrophic plate counts, explained lateron) occur especially in stagnant parts of piped
distribution systems, in domestic plumbing, in some bottled water and in plumbed-in devices such as softeners,
carbon filters and vending machines.

While water can be a very significant source of infectious organisms, many of the diseases that may be
waterborne may also be transmitted by other routes, including person-to-person contact, droplets and aerosols
and food intake. Depending on circumstance and in the absence of waterborne outbreaks, these routes may
be more important than waterborne transmission.

6th Edition 2020 29

 Training Manual

The potential waterborne pathogens include:

● bacteria, viruses, protozoa and helminthes except Schistosoma, which is primarily spread by contact with
contaminated surface water during bathing and washing;

● potentially emerging pathogens, incl. Helicobacter pylori, Tsukamurella, Isospora belli and microsporidia,
for which waterborne transmission is plausible but unconfirmed;

● Bacillus, which includes the foodborne pathogenic species Bacillus cereus but for which there is no
evidence at this time of waterborne transmission; and
● hazardous cyanobacteria.

The effect on human health caused by waterborne transmission vary in severity from mild gastroenteritis to
severe and sometimes fatal diarrhoea, dysentery, hepatitis and typhoid fever.

Contaminated water can be the source of large outbreaks of disease, including cholera, dysentery or
cryptosporidiosis; for the majority of waterborne pathogens, there are other sources of infection, such as
person-to-person contact and food. Most waterborne pathogens are introduced into drinking-water supplies
in human or animal faeces, do not grow in water and initiate infection in the gastrointestinal tract following
ingestion.

Legionella, atypical mycobacteria, Burkholderia pseudomallei and Naegleria fowleri are environmental
organisms that can grow in water and soil. Besides ingestion, other routes of transmission can include
inhalation, leading to infections of the respiratory tract (e.g., Legionella, atypical mycobacteria), and contact,
leading to infections at sites as diverse as the skin and brain (e.g., Naegleria fowleri, Burkholderia pseudomallei).

Public Health Aspects

7.3.1 General

Some of the pathogens that are known to be transmitted through contaminated drinking-water lead to severe
and sometimes life-threatening disease. Examples include typhoid, cholera, infectious hepatitis (caused by
hepatitis A virus [HAV] or HEV) and disease caused by Shigella spp. and E. coli O157.

Others are typically associated with less severe outcomes, such as self-limiting diarrheal disease (e.g.,
Norovirus, Cryptosporidium). The effects of exposure to pathogens are not the same for all individuals or, as a
consequence, for all populations. Repeated exposure to a pathogen may be associated with a lower probability
or severity of illness because of the effects of acquired immunity.

For some pathogens (e.g., HAV), immunity is lifelong, whereas for others (e.g., Campylobacter), the protective
effects may be restricted to a few months to years. On the other hand, sensitive subgroups (e.g., the young, the
elderly, pregnant women and the immune-compromised) in the population may have a greater probability of
illness or the illness may be more severe, including mortality. Not all pathogens have greater effects in all
sensitive subgroups.

30 6th Edition 2020

 Microbiology

Not all infected individuals will develop symptomatic disease. The proportion of the infected population that is
asymptomatic (including carriers) differs between pathogens and also depends on population characteristics,
such as prevalence of immunity. Carriers and those with asymptomatic infections as well as individuals
developing symptoms may all contribute to secondary spread of pathogens.

7.3.2 The Role of Reduced Immune Function

Other pathogens that may be naturally present in the environment may be able to cause disease in people with
impaired local or general immune defense mechanisms, such as the elderly or the very young, patients with
burns or extensive wounds, those undergoing immune-suppressive therapy or those with acquired immune-
deficiency syndrome (AIDS). If water used by such persons for drinking or bathing contains sufficient numbers
of these organisms, they can produce various infections of the skin and the mucous membranes of the eye, ear,
nose and throat.

7.3.3 Health Risks in Aircraft and at Airports

The importance of water as a potential vehicle for infectious disease transmission on aircraft has been well
documented. In general terms, the greatest microbial risks are those associated with ingestion of water that is
contaminated with human and animal excreta. If the source of water used to replenish aircraft supplies is
contaminated, and unless adequate precautions are taken, disease can be spread through the aircraft water.

A potable water source is not a safeguard if the water is subsequently contaminated during transfer, storage
or distribution in aircraft. Airports usually have special arrangements for managing water after it has entered
the airport. Water may be delivered to aircraft by water servicing vehicles or water bowsers. Transfer of water
from the water carriers to the aircraft provides the opportunity for microbial or chemical contamination.

7.3.4 Sources of Contamination

The quality of many source waters will depend upon geology, soil type, natural vegetation, climate and run-off
characteristics. Disruption of natural geology and heavy rainfall can dramatically affect water quality. Wild
animals and birds can also be natural sources of zoonotic pathogens.

All types of water sources may be subjected to contamination by agricultural activity. Free-range animals may
excrete faeces into water, and animals like cattle have a habit of wading into water and stirring up sediments.
Rainfall can result in the run-off of faecal matter from agricultural and other rural lands into rivers, lakes,
reservoirs and springs. Much can be done to reduce the risk of water contamination from slurry spillage, or the
use of slurry on land followed by surface run-off, by the adoption of appropriate agricultural practices and
aquifer protection policies.

Recreational activity may cause pollution through direct contamination of water with faecal material or
indirectly by faulty drainage or leakage from sewers and septic tanks provided as part of public access facilities.

6th Edition 2020 31

 Training Manual

Proper control of recreational activities or treatment commensurate with the recreational use of water should
give adequate protection. Where the public has access to reservoirs, consideration should be given to the
provision of toilets and hand-washing facilities.

The discharge of effluents from sewage treatment works, septic tanks and cesspools can dramatically increase
the microbial content of surface waters. The installation of septic tanks and cesspools should be in accordance
with national standards. The discharge of industrial effluents, particularly from abattoirs and cattle markets,
may also contain large numbers of pathogenic micro-organisms which increase the risk of contamination.

Slurries and solid waste from sewage treatment and animal waste should be spread on land only with strict
control in accordance with the Code of Practice for the Agricultural Use of Sewage Sludge and The Safe Sludge
Matrix taking into accounts any protection or buffer zones.

7.3.5 Process of Infection

Most available information relates to health outcomes arising from exposure through swimming and ingestion
of contaminated water. Recreational waters generally contain a mixture of pathogenic and non-pathogenic
microbes.

These microbes may be derived from sewage effluents, the population using the water, livestock or other
animals, industrial processes, farming activities (e.g., use of animal manures as fertilizers), as well as indigenous
pathogenic micro-organisms. Bathers may succumb to infection when an organism colonizes a suitable growth
site in the body.

These sites are typically the alimentary canal, eyes, ears, nasal cavity and upper respiratory tract and may also
include opportunistic colonization of wound infections. Depending on their route of transmission, waterborne
pathogens can be classified into those that are transmitted via ingestion and those that are transmitted via
inhalation or contact.

For pathogens transmitted by the faecal–oral route, drinking-water is only one vehicle of transmission.
Contamination of food, hands, utensils and clothing can also play a role, particularly when domestic sanitation
and hygiene are poor. Improvements in the quality and availability of water, in excreta disposal and in general
hygiene are all imporant in reducing faecal–oral disease transmission.

Drinking-water safety is not related only to faecal contamination. Some organisms grow in piped water
distribution systems (e.g., Legionella), whereas others occur in source waters (guinea worm Dracunculus
medinensis) and may cause outbreaks and individual cases.

Certain serious illnesses result from inhalation of water droplets (aerosols) in which the causative organisms
have multiplied because of warm temperatures and the presence of nutrients. These include legionellosis and
Legionnaires’ disease, caused by Legionella spp., and those caused by the amoebae Naegleria fowleri (primary
amoebic meningoencephalitis [PAM]) and Acanthamoeba spp. (amoebic meningitis, pulmonary infections).

32 6th Edition 2020

 Microbiology

Schistosomiasis (bilharziasis) is a major parasitic disease of tropical and subtropical regions that is transmitted
when the larval stage (cercariae), which is released by infected aquatic snails, penetrates the skin. It is primarily
spread by contact with water.

High water temperature enhances the growth of microorganisms and may increase taste, odor, color and
corrosion problems. It is conceivable that unsafe drinking-water contaminated with soil or faeces could act as
a carrier of other parasitic infections, such as balantidiasis (Balantidium coli) and certain helminths (species of
Fasciola, Fasciolopsis, Echinococcus, Spirometra, Ascaris, Trichuris, Toxocara, Necator, Ancylostoma and
Strongyloides and Taenia solium).

However, in most of these, the normal mode of transmission is ingestion of the eggs in food contaminated with
faeces or faecally contaminated soil (in the case of Taenia solium, ingestion of the larval cysticercus stage in
uncooked pork) rather than ingestion of contaminated drinking-water.

6th Edition 2020 33

 Training Manual

7.3.6 Persistence and Growth in Water

While typical waterborne pathogens are able to persist in drinking-water, most do not grow or proliferate in
water. Microorganisms like E. coli and Campylobacter can accumulate in sediments and are mobilized when
water flow increases. After leaving the body of their host, most pathogens gradually lose viability and the ability
to infect. The rate of decay is usually exponential, and a pathogen will become undetectable after a certain
period.

Pathogens with low persistence must rapidly find new hosts and are more likely to be spread by person-to-
person contact or poor personal hygiene than by drinking-water. Persistence is affected by several factors, of
which temperature is the most important.

Decay is usually faster at higher temperatures and may be mediated by the lethal effects of UV radiation in
sunlight acting near the water surface. The most common waterborne pathogens and parasites are those that
have high infectivity and either can proliferate in water or possess high resistance to decay outside the body.

Viruses and resting stages of parasites (cysts, oocysts, ova) are unable to multiply in water. Conversely,
relatively high amounts of biodegradable organic carbon, together with warm temperatures and low residual
concentrations of chlorine, can permit growth of Legionella, V. cholerae, Naegleria fowleri, Acanthamoeba and
nuisance organisms in some surface waters and during water distribution. Microbial water quality may vary
rapidly and widely.

Short-term peaks in pathogen concentration may increase disease risks considerably and may also trigger
outbreaks of waterborne disease. Results of water quality testing for microbes are not normally available in time
to inform management action and prevent the supply of unsafe water.

Bacteria
There are various bacteria and protozoa that can cause disease when they are present in surface water.
Bacteria are not only known to cause disease when they enter a human body through food, surface water may
also be an important source of bacterial infection. In this table you can see various bacteria that can be found
in surface water, and the diseases they cause when swallowed in large amounts, along with the symptoms.

Bacteria Disease/ infection Symptoms

Aeromonas Enteritis Very thin, blood- and mucus-containing
diarrhoea
Campylobacter jejuni Campilobacteriose Flue, diarrhoea, head- and sto-
machaches, fever, cramps, nausea
Escherichia coli Urinary tract infections, neonatal Watery diarrhoea, headaches, fever,
meningitis, intestinal disease homiletic uraemia, kidney damage

34 6th Edition 2020

 Microbiology

Plesiomonas shigelloides Plesiomonas-infection Nausea, stomachaches and watery

diarrhoea, sometimes fevers, head-aches
and vomiting
Salmonella Typhoid fever Fevers
Salmonellosis Sickness, intestinal cramps, vomiting,
diarrhoea and sometimes light fevers
Streptococcus (Gastro) intestinal disease Stomachaches, diarrhoea and fevers,
sometimes vomiting
Vibrio El Tor (freshwater) (Light form of) Cholera Heavy diarrhoea

Bacteria – The Invisible Killers

Staph. aureus
Bacillus cereus Salmonella Campylobacter jejuni

Clostridium perfringens

Vibrio parahaemolyticus
Campylobacter
Shigella

Listeria
Monocytogenes

Norwalk Virus
Norwalk Virus Listeria

Clostridium botulinum

6th Edition 2020 35

 Training Manual

Streptococcus Salmonella Typhi E. Coli

Pseudomonas Aeruginosa Clostridium-Perfringens E. Coli (Strain)

Intestinal bacteria

36 6th Edition 2020

 Microbiology

Other Organisms and More Common Bacteria

Many species of bacteria occur naturally in ground and surface waters. A proportion of these may survive water
treatment or may subsequently be introduced into treated water as a result of contamination. Some of these
organisms may be able to grow if temperatures are high enough, if sufficient nutrients are available in the water,
if inappropriate construction materials are used, or as a result of poor maintenance. In many cases, this may
not be a problem; in some cases, if growth is sufficient, the result may lead to deteriorating organoleptic quality
of the water or, potentially, a risk to public health.

The Pseudomonas Group

Many are capable of growth in relatively low-nutrient environments. When the organisms gain access to treated
water they may proliferate in certain circumstances by utilizing nutrients either present in the water or derived
from unsuitable materials used in the construction of distribution systems or domestic plumbing installations.
Similarly, they may grow in water contained in bottles (particularly plastic) and on surfaces such as plastic
tubing within drinks vending machines. Some species can be pathogenic for humans and are particularly
important as a cause of nosocomial (hospital acquired) infection because of their resistance to many antibiotics
and disinfectants and their ability to colonize aquatic low-nutrient environments. Heavy colonization of water
systems with Pseudomonas species, particularly the fluorescent species Pseudomonas fluorescens and
Pseudomonas putida, can lead to taste and odor problems without any concomitant risk of disease.

7.5.1 Micro-organisms Affecting Taste, Odor and Appearance

Ideally, drinking water should be clear and acceptable to the palate. In practice, however, the aesthetic
properties of a drinking water will depend to a large extent on its source and any subsequent treatment or
microbial activity. In most instances, when there is adverse comment regarding the appearance, taste or odor
of a drinking water, the causes tend to be physical or chemical in nature rather than microbiological.

Nevertheless, musty, moldy or earthy tastes and odors may result from the growth of fungi or actinomycetes in
water pipes. These tastes and odors are primarily associated with the production of secondary metabolites or
the biomethylation of chlorinated phenols.

Other compounds, which are produced via microbial decomposition, can impart fishy, swampy or septic odors
to waters, whilst rotten-egg odors can be generated via the reduction of sulphate and sulphite to hydrogen
sulphide by some bacteria.

Micro-organisms growing in biofilms in pipes can result in the corrosion of iron pipes. A consequence of this is
the discoloration of drinking water due to elevated levels of iron in the water, or to the accumulation of (brown)
iron or (black) manganese deposits, or iron-stained material being dislodged from pipes or sediments.

6th Edition 2020 37

 Training Manual

Biofilms in Water Supply

In low-nutrient aqueous environments, micro-organisms preferentially colonize surfaces rather than grow in
the planktonic phase. Nutritional levels are higher at surfaces and bacteria are protected from adverse
environmental influences. The organisms colonizing surfaces become embedded in a matrix of extra-cellular
polymeric substances that are produced by organisms.

This layer of growth is termed a biofilm and in water distribution systems is usually quite thin, not exceeding a
few hundred micrometers. In both natural environments and water distribution systems, biofilms are usually
composed of complex mixtures of microorganisms including bacteria, fungi and protozoa.

The metabolic by-products of one organism can provide nutrients for other organisms. This enables organisms
that would otherwise be unable to grow by themselves, such as Legionella pneumophila, to proliferate. Biofilm
distribution can be patchy and can vary considerably, even over distances of a few millimeters or less. Biofilms
can also accumulate organic and inorganic debris from external sources by the adsorption of silt, sediments,
inorganic precipitates and corrosion products. These materials may provide additional nutrients for microbial
growth.

No material that comes in contact with water is immune to colonization, but some materials may support or
promote more growth than others. To maintain water quality during distribution, construction materials should
not promote growth.

Most of the growth that takes place in distribution systems probably occurs in biofilms and the majority of the
planktonic organisms may be derived from organisms leaving the biofilm or by the biofilm breaking up.
Organisms that have survived disinfection, including environmental strains of coliform bacteria, can become
attached to biofilms where they may subsequently grow. Biofilms are important because they contribute too
many causes of the problems that can occur in water distribution systems.

They may promote or cause corrosion of pipes, can be responsible for off-flavors, contribute to discoloured
water, harbor pathogens, increase the chlorine demand and provide a site for the re-growth of some strains of
coliform bacteria.

Microbial diversity in the biofilm of a drinking water biofilter

38 6th Edition 2020

 Microbiology

Source: Hammes, Frederik (2011) Drinking water microbiology, Eawag News 70/2011

Biofilms also protect organisms from disinfection. The contact time, by chlorine, required to produce a particular
degree of disinfection of the organisms in a biofilm be hundreds, or even thousands, of times greater than that
required to achieve an equivalent degree of disinfection or death for the same organisms suspended in water.

Thus, it is possible for biofilms to continue to survive and grow even when the water contains residual chlorine
at the concentrations normally used in drinking water. This reduction in disinfection efficiency is caused by the
diffusion of the disinfectant being reduced by the biofilm and alterations in the physiology of the organisms
growing in the biofilm, and is less for monochloramine than chlorine.

Enumerating the number of bacteria in a body of water in a pipe (planktonic phase) provides a poor estimate
of the total microbial activity in a water system. This is because many of the organisms in the planktonic phase
do not grow on conventional culture media. Unfortunately, it is difficult to measure the degree of biofilm
formation routinely because of problems of collecting representative samples of biofilm.

Elimination of Harmful Microorganisms from Water

Disinfection is an effective barrier to many pathogens (especially bacteria) during drinking-water treatment
and should be used for surface waters and for groundwater subject to faecal contamination. Residual
disinfection is used to provide a partial safeguard against low-level contamination and growth within the
distribution system.

Chemical disinfection of a drinking-water supply that is faecally contaminated will reduce the overall risk of
disease but may not necessarily render the supply safe. For example, chlorine disinfection of drinking-water
has limitations against the protozoan pathogens – in particular Cryptosporidium – and some viruses.
Disinfection efficacy may also be unsatisfactory against pathogens within flocs or particles, which protect them
from disinfectant action. High levels of turbidity can protect microorganisms from the effects of disinfection,
stimulate the growth of bacteria and give rise to a significant chlorine demand.

Micro-organisms differ in their susceptibility to chlorine (in decreasing order of resistance: protozoan cysts,
bacterial spores, enteric viruses and enteric bacteria). However, the combination of chlorine concentration and
contact time necessary for inactivation of enteric viruses and pathogenic bacteria can be achieved by a well-
managed water treatment works.

Nonetheless, certain incidents of water-borne disease have occurred as a result of inadequate chlorination, or
because no such facility was installed or used.

Chlorination of drinking water can impart chlorinous tastes and odors resulting in complaints from some
consumers. Additionally, concerns have been raised regarding the formation of disinfection by-products (most
notably, the trihalomethanes).

6th Edition 2020 39

 Training Manual

Microbiological Monitoring
The results of a laboratory examination of any single water sample are representative only of the water at the
time at that particular point at which the sample is taken. Satisfactory results from single samples do not justify
an assumption that the water is safe to drink at all times.

Contamination is often intermittent and may not be revealed by the examination of a single sample. The
impression of security given by satisfactory results from microbiological testing of waters at infrequent intervals
may, therefore, be false.

Indeed, the value of microbiological tests is dependent upon their frequent and regular use. It is far more
important to examine a supply frequently by a simple test than to examine a supply occasionally by a more
complicated test or series of tests.

Information gained over time through monitoring will provide a comprehensive picture of the range of quality
of any particular source of water, any deterioration from which should at once arouse suspicion. A
microbiological report based on a single sample can only indicate that, at the time of examination, certain
bacteria (either indicative of faecal contamination or general water quality) did or did not grow under laboratory
conditions from the sample of water submitted.

Sampling techniques and sample transportation can influence sample results and good practice is essential. It
should be emphasized that, when site inspection reveals obvious signs that a water supply is subject to
contamination, remedial action should be taken without waiting for, and irrespective of, the results of
microbiological examination. The protection of public health is of paramount importance.

7.8.1 Verification of Microbial Safety and Quality

Pathogenic agents have several properties that distinguish them from other drinking water contaminants:

● Pathogens are discrete and not in solution.

● Pathogens are often clumped or adherent to suspended solids in water.

● The likelihood of a successful challenge by a pathogen, resulting in infection, depends upon the
invasiveness and virulence of the pathogen, as well as upon the immunity of the individual.
● If infection is established, pathogens multiply in their host. Certain pathogenic bacteria are also able to
multiply in food or beverages, thereby perpetuating or even increasing the chances of infection.

● Unlike many chemical agents, the dose–response of pathogens is not cumulative.

Faecal indicator bacteria, including E. coli, are important parameters for verification of microbial quality. Faecal
indicator bacteria should fulfill certain criteria to give meaningful results. They should be universally present in
high numbers in the faeces of humans and other warm-blooded animals, should be readily detectable by simple
methods and should not grow in natural water.

40 6th Edition 2020

 Microbiology

The indicator organism of choice for faecal pollution is E. coli. Thermotolerant coliforms can be used as an
alternative to the test for E. coli in many circumstances. Water intended for human consumption should contain
no indicator organisms. In the majority of cases, monitoring for indicator bacteria provides a high degree of
safety because of their large numbers in polluted waters.

Pathogens more resistant to conventional environmental conditions or treatment technologies may be present
in treated drinking-water in the absence of E. coli. Retrospective studies of waterborne disease outbreaks and
advances in the understanding have shown that continued reliance on assumptions surrounding the absence
or presence of E. coli does not ensure that optimal decisions are made regarding water safety. Protozoa and
some enteroviruses are more resistant to many disinfectants, including chlorine, and may remain viable (and
pathogenic) in drinking-water following disinfection.

7.8.2 Microbial Indicators of Water Quality

The use of indicator organisms, in particular the coliform group, as a means of assessing the potential presence
of water-borne pathogens has been paramount to protecting public health.

These are based upon the principle of the detection of selected bacteria that are indicative of either
contamination or deterioration of water quality through the use of simple bacteriological tests. This has been
the foundation upon which protection of public health from water-borne disease has been developed. The
relatively rare occasions where bacterial or viral illnesses have been caused through public drinking water
supplies stand testament to the success of the indicator principle and improvements in water treatment.

The concept of using indicator organisms as signals of faecal pollution is a well-established practice in the
assessment of drinking-water quality. For many pathogens, such as viruses and protozoan parasites, reliable
indicators are not available. Even if there were, there is no absolute correlation between the number of indicator
organisms and

a) the actual presence or numbers of enteric pathogens or

b) the risk of illness occurring.

The use of indicator bacteria, in particular Escherichia coli (E. coli) and the coliform bacteria, as a means of
assessing the potential presence of water-borne pathogens has been paramount to protecting public health.
The analysis of large volumes of sample for faecal indicator bacteria using membrane filtration procedures can
be very useful in assessing water treatment efficiency at various points in the treatment process.

Many pathogens are present only under specific conditions and, when present, occur in low numbers
compared with other micro-organisms. Whilst the presence of coliform bacteria does not always indicate a
public health threat, their detection is a useful indication that treatment operations should be investigated.

6th Edition 2020 41

 Training Manual

7.8.3 Rationale for the Use of Indicator Organisms

The key criteria for ideal bacterial indicators of faecal pollution are that they should be universally present in
large numbers in the faeces of human and other warm-blooded animals. They should also be present in sewage
effluent, be readily detectable by simple methods and should not grow in natural waters. Ideally, they should
also be of exclusive faecal origin and be present in greater numbers than faecally transmitted pathogens. No
single indicator organism fulfills all these criteria, but the member of the coliform group that satisfies most of
the criteria for the ideal indicator organism in temperate climates is E. coli.

The presence of E. coli in a sample of drinking water may indicate the presence of intestinal pathogens.
However, the absence of E. coli cannot be taken as an absolute indication that intestinal pathogens are also
absent. E. coli bacteria are the only biotype of the family Enterobacteriaceae which can be considered as being
exclusively faecal in origin and it can represent up to 95 % of the Enterobacteriaceae found in faeces.

For water quality monitoring and assessment, reliance has been placed on relatively simple and more rapid
tests for the detection of faecal indicator bacteria and other coliform bacteria. These bacteria are easier to
isolate and characterize, and are, almost always, present in the faeces of humans and warm-blooded animals.

Chemical analysis is, nevertheless, an important aid to the hygienic assessment of a water supply. However,
the major role of chemical analysis is to provide process control information for water treatment and for
monitoring compliance with prescribed standards. Chemical tests that give additional information on whether
faecal contamination may be present include turbidity, color, total organic carbon, nitrate, nitrite and ammonia.

Other coliform bacteria may originate from faecal sources and possess the ability to grow inside taps and pipes,
even in the presence of high levels of residual disinfectant.

Other bacteria, which possess some of the properties of indicator organisms, include the enterococci and
spores of sulphite-reducing clostridia, typified by Clostridium perfringens. Enterococci do not multiply in the
environment and can occur normally in faeces. The enterococci are used to indicate water quality.

Clostridium perfringens are present in faeces in much smaller numbers than E. coli or enterococci. Spores of
Clostridium perfringens are capable of surviving for significantly longer periods than vegetative bacteria, such
as coliform bacteria or enterococci. These spores are also more resistant to chlorination. At present, there is
conflicting evidence regarding the correlation of the presence of spores or vegetative cells of Clostridium
perfringens with that of pathogens.

Some limited information can be provided on treatment efficiency or past faecal contamination by determining
the count of Clostridium perfringens in distribution. The main value of carrying out tests for Clostridium
perfringens more frequently at a point where water leaves the water treatment works (as permitted by
regulations) may be to provide information of the efficiency of the treatment process.

Tests for colony count bacteria growing at 37 °C and 22 °C enable a count to be determined of the heterotrophic
bacterial population of the water. The bacteria grown in these tests are not indicators of faecal contamination,
although historically, the count at 37 °C was taken to give an indication of faecal contamination.

42 6th Edition 2020

 Microbiology

7.8.4 Methods of Detection of Faecal Indicator Bacteria

Analysis for faecal indicator bacteria provides a sensitive, although not the most rapid, indication of pollution
of drinking-water supplies. Because the growth medium and the conditions of incubation, as well as the nature
and age of the water sample, can influence the species isolated and the count, microbiological examinations
may have variable accuracy. This means that the standardization of methods and of laboratory procedures is of
great importance if criteria for the microbial quality of water are to be uniform in different laboratories and
internationally.

Established standard methods are available, such as those of the ISO or methods of equivalent efficacy and
reliability. It is desirable that established standard methods be used for routine examinations.

● Immediate investigative action must be taken if E. coli are detected.

● Although E. coli is the more precise indicator of faecal pollution, the count of thermotolerant coliform
bacteria is an acceptable alternative.

● If necessary, proper confirmatory tests must be carried out.

7.8.5 Total Coliform Bacteria

Coliform bacteria belong to the family Enterobacteriaceae. Typical genera encountered in water supplies are
Citrobacter, Enterobacter, Escherichia, Hafnia, Klebsiella, Serratia and Yersinia. The total coliform group
includes both faecal and environmental species.

Faecal coliform bacteria possess the characteristics of coliform bacteria but are able to carry out lactose
fermentation at 44 °C. The term “faecal coliform” is not precise and has been used to describe coliform bacteria
thought to be of faecal origin. The term “thermotolerant coliform” has been used to describe presumptive faecal
coliform bacteria.

6th Edition 2020 43

 Training Manual

Value as indicator Total coliforms include organisms that can survive and grow in water. Hence, they are not
useful as an index of faecal pathogens, but they can be used as an indicator of treatment effectiveness and to
assess the cleanliness and integrity of distribution systems and the potential presence of biofilms.

However, there are better indicators for these purposes. As a disinfection indicator, the test for total coliforms
is far slower and less reliable than direct measurement of disinfectant residual. In addition, total coliforms are
far more sensitive to disinfection than are enteric viruses and protozoa.

Source, occurence, ways of exposure Total coliforms are not naturally found in well water or groundwater.
Many coliforms are heterotrophic and able to multiply in water and soil environments. Total coliforms can also
survive and grow in water distribution systems, particularly in the presence of biofilms.

Several members of the coliform group are known to be present in soil and other environmental materials, and
are capable of growth in nutrient-rich water and biofilms. As a result, coliform bacteria are no longer considered
to be specific indicators of faecal contamination. However, some species of coliform bacteria, although
common in the environment, can be associated with human infection but rarely with gastro-enteritis.

Relevance in potable water When coliform bacteria are isolated from drinking water supplies it is often useful
to determine which species of coliform bacteria are present, particularly if problems recur, in order to determine
the source and significance of the coliform bacteria being recovered.

The potential sources of coliform bacteria in water supplies result from sub-optimal operation of water
treatment processes or ingress of contamination from breaches in the integrity of the distribution system. These
include for example, leaking hatches on service reservoirs, contamination via air-valves and stop valves,
infiltration into mains and service reservoirs, cross connections and back-flow effects. Coliform bacteria can be
present in domestic plumbing systems with kitchen taps and sinks being recognized sources of these
organisms.

44 6th Edition 2020

 Microbiology

Total coliforms should be absent immediately after disinfection, and the presence of these organisms indicates
inadequate treatment. Wells should be tested yearly if there is a history of totalcoliform-absent
(bacteriologically safe) results or more frequently if there is a change in the water quality because of color, taste
or odor.
It is possible to detect coliform bacteria using fluorogenic or chromogenic substrates that demonstrate the
presence of the enzyme β-galactosidase. Selective media containing these substrates have been developed
which allow the presence of coliform bacteria and E. coli to be detected in a single step.

7.8.6 Escherichia Coli and Thermotolerant Coliform Bacteria

Total coliform bacteria that are able to ferment lactose at 44–45 °C are known as thermotolerant coliforms. In
most waters, the predominant genus is Escherichia, but some types of Citrobacter, Klebsiella and Enterobacter
are also thermotolerant. Escherichia coli are present in very high numbers in human and animal faeces.

E. coli is a coliform bacterium and has historically been regarded as the primary indicator of faecal
contamination of both treated and untreated water. As a coliform bacterium it is a member of the family
Enterobacteriaceae, and is capable of fermenting lactose or mannitol at 44 °C, usually within 24 hours.

Value as indicator Escherichia coli are considered the most suitable index of faecal contamination. In most
circumstances, populations of thermotolerant coliforms are composed predominantly of E. coli; as a result, this
group is regarded as a less reliable but acceptable index of faecal pollution. Escherichia coli (or thermotolerant
coliforms) is the first organism of choice in monitoring programmes for verification, including surveillance of
drinking-water quality. These organisms are also used as disinfection indicators, but testing is far slower and
less reliable than direct measurement of disinfectant residual. In addition, E. coli is far more sensitive to
disinfection than are enteric viruses and protozoa.

Practical application coli occurs in the faeces of all mammals, often in high numbers (up to more than 100 per
gram of faeces). This widespread faecal occurrence, coupled with methods that for the recovery and
enumeration of E. coli are relatively simple to conduct, has contributed to the detection of this bacterium as the
cornerstone of microbiological water quality assessment for over 100 years. Most of the E. colistrains can be
detected using specific fluorogenic or chromogenic substrates. Escherichia coli (or, alternatively,
thermotolerant coliforms) are generally measured in 100-ml samples of water. Field test kits are available.

Relevance in potable water The presence of E. coli (or, alternatively, thermotolerant coliforms) provides
evidence of recent faecal contamination. E. coli is a subset of total coliform, so if there is no total coliform
present in the water sample, there is no E. coli. The survival characteristics and susceptibility to disinfection of
E. coli are similar to those of many other bacterial pathogens, particularly Salmonella and Shigella, and it does
not multiply in temperate surface water or in treated waters. There are situations where E. coli is not a suitable
indicator of microbiological contamination (for example, disinfected surface waters exposed to
Cryptosporidium contamination), yet it still remains the best biological indicator for drinking water and public
health protection.

6th Edition 2020 45

 Training Manual

7.8.7 Intestinal Enterococci

Enterococci include a number of species that occur in the faeces of humans and warmblooded animals.
Enterococci can be found in foodstuffs, particularly plant-based products, where their presence is often
unrelated to direct faecal contamination. Intestinal enterococci are a subgroup of the larger group of organisms
defined as faecal streptococci, comprising species of the genus Streptococcus. These bacteria are relatively
tolerant of sodium chloride and alkaline pH levels. In animal faeces they are often more numerous than E. coli.

Value as indicator Enterococci of faecal origin rarely multiply in water and are more resistant to environmental
stress and chlorination than E. coli and coliform bacteria. They generally persist longer in the environment. The
intestinal enterococci group can be used as an index of faecal pollution. Important advantages of this group
are that they tend to survive longer in water environments than E. coli (or thermotolerant coliforms), are more
resistant to drying and are more resistant to chlorination.

Practical application Enterococci are detectable by simple, inexpensive cultural methods that require basic
bacteriology laboratory facilities. The main reason for their enumeration is to assess the significance of the
presence of coliform bacteria in the absence of E. coli, or to provide additional information when assessing the
extent of possible faecal contamination. As such, they are regarded as secondary indicators of faecal pollution.

Relevance in potable water It has been suggested that testing for enterococci can be a useful additional
indicator of water treatment efficiency. As these bacteria are resistant to drying, they can be of value for routine
assessment after new mains have been laid or when repairs in distribution systems have been carried out, or
for assessing pollution by surface run-off to ground or surface waters.

7.8.8 Clostridium Perfringens

The genus Clostridium contains over 100 species of bacteria. They produce spores that are exceptionally
resistant to unfavorable conditions in water environments, including UV irradiation, temperature and pH
extremes, and disinfection processes, such as chlorination. Like E. coli, C. perfringens does not multiply in most
water environments and is a highly specific indicator of faecal pollution.

Clostridium perfringens is the key species of the sulphite-reducing clostridia and is commonly found in human
and animal faeces. Clostridium perfringens produces environmentally resistant spores that survive in water
and in the environment for much longer periods than the vegetative cells of E. coli and other faecal indicators.

Value as indicator In view of the exceptional resistance of C. perfringens spores to disinfection processes and
other unfavorable environmental conditions, C. perfringens has been proposed as an index of enteric viruses
and protozoa in treated drinking-water supplies.

Source, occurence, ways of exposure Most species of Clostridium are environmental bacteria. Many are
saprophytic, normally inhabiting soil, water and decomposing plant and animal material. These bacteria will,
therefore, be present in surface derived source waters. Clostridium perfringens does not multiply in water
environments.

46 6th Edition 2020

 Microbiology

The genus Clostridium, whilst consisting mainly of saprophytes, contains some species which are regarded as
opportunistic pathogenic bacteria (for example, some clostridia are commonly associated with wound
infections in humans and animals). Growth tends to be restricted to the site of infection but a wide variety of
toxins, some of which are extremely potent, are produced dependent on the particular strain (for example,
tetanus, wound botulism and gasgangrene).

Clostridium botulinum and Clostridium perfringens have also been associated with food poisoning, and some
strains of Clostridium perfringens can produce severe but self-limiting diarrhoea in humans and animals if
ingested in large numbers

Practical application As Clostridium perfringens is generally present in faeces in much lower numbers than
E. coli and enterococci, it is less sensitive as an indicator of faecal contamination. Vegetative cells and spores
of C. perfringens are usually detected by membrane filtration techniques. These detection techniques are not
as simple and inexpensive as those for other indicators, such as E. coli and intestinal enterococci.

The presence of C. perfringens in drinking-water can be an index of intermittent faecal contamination. Filtration
processes designed to remove enteric viruses or protozoa should also remove C. perfringens. Detection in water
immediately after treatment should lead to investigation of filtration plant performance.

Low numbers may occasionally occur in water supplies, but they do not represent a risk to health. These
bacteria will not grow to significant numbers, or produce toxins, in water supplies, as conditions are usually
unsuitable. Clostridia are removed from water by coagulation and filtration, but the spores of these bacteria
can be resistant to chlorine at concentrations normally used in water treatment.

7.8.9 Colony Count Bacteria

Colony counts are enumerations of the general population of heterotrophic bacteria present in water supplies.
The enumerations may represent bacteria whose natural habitat is the water environment or those that have
originated from soil or vegetation. Historically, these bacteria have been enumerated on bacteriologically
nutrient-rich media with incubation at 37 and 22 °C.

Value as indicator It is well recognized, however, that only a small fraction of the viable bacterial population
present in water is enumerated by the procedures normally employed. Despite this, monitoring of water
supplies for colony count bacteria can be useful for monitoring trends in water quality or detecting sudden
changes in quality.

Practical application Colony counts at 37 °C, when compared with those at 22 °C can be a useful quality
indicator, in that they can provide an early indication of a significant deterioration in quality. This can often be
demonstrated before coliform bacteria or other indicator bacteria are detected (for example, due to ingress into
a distribution system).

An increase in the counts at 37 °C (compared with those normally recorded for a supply) may be an indication
of contamination, particularly if not accompanied by a similar increase in the corresponding counts at 22 °C.

6th Edition 2020 47

 Training Manual

Bacteria recovered in the colony counts at 22 °C generally represent those bacteria naturally present in water
and are not of sanitary significance, and thus, have limited public health significance. They may, however, be
of greater relevance to the food and drink industries and electronics manufacturers, where high numbers may
impact on the quality of products. These counts may be useful in assessing the efficiency of water treatment
and the cleanliness and integrity of distribution systems.

An important benefit of determining colony counts at both 37 and 22 °C, particularly if carried out regularly from
the same site and location, is that the data generated can provide an indication of seasonal and longer-term
changes in the general bacteriological quality of the water. Many heterotrophic bacteria are able to multiply
within the distribution system network by utilizing nutrients derived either from fixtures and fittings or from
assimilable or particulate organic carbon in the water. Changes in colony numbers may, therefore, be indicative
of the use of inappropriate materials or changes in the quality of the source water.

7.8.10 Heterotrophic Plate Counts (HPC)

HPC measurement detects a wide spectrum of heterotrophic microorganisms, incl. bacteria and fungi, based
on the ability of the organisms to grow on rich growth media, without inhibitory or selective agents, over a
specified incubation period and at defined temperature.

Value as indicator The test has little value as an index of pathogen presence but can be useful in operational
monitoring as a treatment and disinfectant indicator, where the objective is to keep numbers as low as possible.
In addition, HPC measurement can be used in assessing the cleanliness and integrity of distribution systems
and the presence of biofilms.

Source, occurence, ways of exposure Heterotrophic microorganisms include both members of the natural
(typically nonhazardous) microbial flora of water environments and organisms present in a range of pollution
sources. The principal determinants of growth or “regrowth” are temperature, availability of nutrients, including
assimilable organic carbon, lack of disinfectant residual and stagnation.

Practical application No sophisticated laboratory facilities or highly trained staff is required. Results on simple
aerobically incubated agar plates are available within hours to days, depending on the characteristics of the
procedure used. This test measures changes during water treatment and in a distribution system. This test is
also one of the tests used to measure the disinfection efficiency of whirlpools, pools and spas. HPC can include
potentially “opportunistic” pathogens such as Acinetobacter, Aeromonas, Flavobacterium, Klebsiella, Moraxella,
Serratia, Pseudomonas and Xanthomonas.

7.8.11 Other Potential Indicators of Faecal Contamination

E. coli and related coliform bacteria, intestinal enterococci and Clostridium perfringens are currently
recommended for use as indicator organisms of faecal contamination in water. Other micro-organisms have
been suggested for this purpose and these include the Bacteroides fragilis group, Bifidobacterium species or
Rhodococcus coprophilus. Also bacteriophages that infect the coliform bacteria (coliphages) and the

48 6th Edition 2020

 Microbiology

Bacteroides fragilis group have been used. Although some of these alternative indicator organisms have been
applied with varying degrees of success to environmental waters, they are not considered suitable for the
assessment of water treatment efficacy or treated water quality.

6th Edition 2020 49

 Training Manual

Section 8—Disinfection Methods

Purification vs Disinfection
Water Purification - "The act of cleaning by getting rid of impurities." For water treatment, this term refers to
the process of removing specified contaminants from a water source. All effective water treatment methods
will provide some amount of purification, however, only some methods will disinfect the water

Water Disinfection - "Killing or removal of microorganisms outside the body by direct exposure to chemical or
physical agents or processes." For water treatment, this term refers specifically to a purification process that
kills or removes biological contaminants (cysts, bacteria, viruses, protozoans, etc.) from a water source.

• Water that has been disinfected (by UV treatment, boiling, chlorination, micro-filtration, ozone, etc.)
may still be polluted with other contaminants that are not affected by the disinfection treatment.

• In some cases, additional contaminants may actually be added to the water by the disinfection
process. For instance, the process of chlorination adds frequently some disinfection byproducts like
trihalomethanes; Boiling water too long will concentrate inorganic contaminants.

• It is generally understood that no single disinfection technology can meet all the treatment objectives.

• Disinfectants must also have a residual effect, which means that they remain active in the water after
disinfection. A disinfectant should prevent pathogenic microorganisms from growing after disinfection,
causing the water to be recontaminated.

• Disinfection extend will depend of contact time; pH; temperature and systems condition (biofilm and
sediments increases residual disinfectant consumption in detriment of contamination control)

How disinfection works

There are five mechanisms to explain the action of disinfectants:

▪ damage to cell wall → cell lysis and death

▪ alteration of cell permeability → vital nutrients escape

▪ alteration of colloidal nature of protoplasm → coagulation of cell proteins; lethal effect

▪ alteration of the organism DNA or RNA→ disruption of replication process

▪ Inhibition of enzyme activity→ by alteration of enzyme arrangement

50 6th Edition 2020

 Disinfection Methods

Typical Agents and methods for disinfection

▪ Chlorine and Chlorine Dioxide

▪ Ozone

▪ Hydrogen Peroxide

▪ AnoFluid

▪ Ultra-Violet Light

8.3.1 Chlorine Disinfection

ClO2

▪ Easily accesibly around the world. Low cost

▪ Does not remove Biofilm from inner walls

▪ Incorrect application may create an unpleasant odour

The most common disinfection method involves some form of chlorine or its compounds such as chloramine
or chlorine dioxide. Chlorine is a strong |oxidant that rapidly kills many harmful micro-organisms. Because
chlorine is a toxic gas, there is a danger of a release associated with its use. This problem is avoided by the
use of sodium hypochlorite, which is a relatively inexpensive solution that releases free chlorine when
dissolved in water.

6th Edition 2020 51

 Training Manual

Chlorine can assume oxidation states (*) from -1 to +5. That means we can have several compounds based in
chlorine like:

Free chlorine residual - residual consisting of dissolved chlorine gas (Cl2 ), hypochlorous acid (HOCl), and
hypochlorite ions (OCl-)

▪ (*) Oxidation state shows the total number of electrons which have been removed from an element (a
positive oxidation state) or added to an element (a negative oxidation state) to get to its present state
.

Chlorine is usually added to water in the form of chlorine gas, or as a sodium or calcium hypochlorite
solution. Chlorine itself hydrolyzes quickly to hydrochloric acid and hypochlorous acid. These compounds may
dissociate, dependent on the pH of the solution. The overall reaction scheme is given in following figure.

Chlorine production via a inline-electrolysis on drinking water units

Some potable water bowsers use an inline-electrolysis method to produce chlorine by utilising the sodium
chloride that is already available in the water.
The electrolysis requires a continuous electrical power supply.
While the bowser is in motion the supply comes from the vehicle's engine, when parked in the stand will
require an external electrical power supply to keep the pump permanently circulating the water through the
electrolysis cell for the production of chlorine.
The ideal value of 50 mg/l of NaCl is required to produce sufficient chlorine via electrolysis. When NaCl
values are below 20 mg/l it is not possible to produce chlorine. Additional salt can be added to restart the
process.

Chlorine Dioxide

Powerful disinfectant and oxidizing agent. It has been used for many years in water treatment systems for
the elimination of chlorophenols, the oxidation of inorganic compounds such as iron and manganese, and in
the control of taste, odor and color. It is recognized by the EPA as a primary disinfectant and is effective
against viruses, bacteria and protozoa, including the cysts of Giardia and the oocysts of Cryptosporidium.

Does not react with ammonia to form less-active chloramines. It will not form trihalomethanes (THM’s) or
other chlorinated organic compounds, nor will it react with the many impurities that normally consume
chlorine.

52 6th Edition 2020

 Disinfection Methods

8.3.2 Ozone

Ozone is an unstable molecule which readily gives up one atom of oxygen providing a powerful oxidizing
agent which is toxic to most waterborne organisms. It is a very strong, broad spectrum disinfectant that is
widely used in Europe.
It is an effective method to inactivate harmful protozoa that form cysts. It also works well against almost all
other pathogens.
Does not leave a residual effect.

Ozone is used in the same manner as chlorine. Due to its instability, ozone must be generated before use
and the equipment and operating costs can be quite high.

Extremely active as a disinfectant without the formation of potentially harmful by-products like
trihalomethanes (THMs).

A wider range of organisms is killed by ozonation than by chlorination. It also achieves excellent removal of
taste and odors. The reactions, in general, are more rapid than that of chlorination processes.

Ozone has an active residual measured in minutes. The lack of long residual is a significant drawback for its
use in large distribution systems.

O3 Direct oxidation (acidic conditions)

Oxidation via OH. ( high pH; under UV light; presence of H2O2)

8.3.3 Hydrogen Peroxide

Hydrogen peroxide (H2O2) is rarely used in drinking water treatment as a stand-alone treatment process. H2O2
is a weak microbiocide compared to chlorine, ozone, and other commonly used disinfectants. However, there
are a number of technologies where H2O2 is used as part of the treatment program. The advanced oxidation
process (AOP) uses H2O2 in conjunction of O3 and/or UV light to generate highly reactive oxygen radicals (·OH),
without the addition of metal catalysts. This technology is being used to purify and disinfect drinking waters. Is
very effective in removing taste and odor (T&O) compounds, and inorganic and organic micropollutants.

6th Edition 2020 53

 Training Manual

When combined with metals (like silver – Ex: Elsil or Sanosil) protects water during a long time; easy to check
residual with measuring strips

Note: Silver on a constant usage can damage the human kidneys!

8.3.4 AnoFluid

The technology is named Cell Membrane Electrolysis and it uses salt, water and electrical power . Water and
salt are “activated” by an electrical current and produce an effective disinfectant, called AnoFluid, is a HOCI-
rich solution (hydrochloric acid) and contains the four performance-strongest oxidants: oxygen, chlorine-
dioxide, ozone and hydrogen-dioxide, through which bacteria and viruses, even those extremely resistant in
other sterilization processes, are destroyed. HOCI is an extremely effective disinfectant (>100 times more
effective than OCl-) AnoFluid is fed into the water stream and penetrates the cell membrane of bacteria and
virus by osmosis and destroys them. AnoFluid remains stable for an extended period of time. AnoFluid also
removes “bio-film” build up, the breeding ground for bacteria.

54 6th Edition 2020

 Disinfection Methods

8.3.5 Ultra-Violet Light

Ultraviolet radiation does not kill the micro-organisms directly, but it damages their DNA and RNA that means
that they unable to reproduce, causing the population of the organisms to become extinct.

UV radiation does not produce any known toxic byproducts does not adds chemical taste or smell to the
disinfected water and it’s effectiveness is relatively insensitive to temperature and pH differences.

Ineffective disinfection can occur by scattered UV-light due to suspended solids, turbidity, color or soluble
organic matter.

UV light does not leave any residual disinfectant in the water, which means that unless water is transported
through a micro-organism free environment there is a chance of recontamination.

8.3.6 Other Methods

Ultra filtration membrane

Use polymer membranes with chemically formed microscopic pores that can be used to filter out dissolved
substances avoiding the use of coagulants. The type of membrane media determines how much pressure is
needed to drive the water through and what sizes of micro-organisms can be filtered out.

6th Edition 2020 55

 Training Manual

Reverse osmosis
Mechanical pressure is applied to an impure solution to force pure water through a semi-permeable
membrane.

Ion exchange
use Ion exchange resin packed columns to replace unwanted ions.

Solar water disinfection

One low-cost method of disinfecting water that can often be implemented with locally available PET containers
is solar disinfection.

Boiling

Boiling water will kill bacteria as well as other disease-causing microorganisms like Giardia lamblia and
Cryptosporidium parvum which are commonly found in rivers and lakes. Water temperatures above 70ºC will
kill all pathogens within 30 minutes, above 85ºC within a few minutes, and at boiling point 100ºC most
pathogens will be killed, excluding certain pathogens and their spores, which must be heated to 118 ºC (e.g.
botulism – Clostridium botulinum).

56 6th Edition 2020

 Drinking Water Parameters

Section 9—Drinking Water Parameters

6th Edition 2020 57

 Training Manual

Section 10—Connectors and Hoses

Connectors
Hose connectors are used to attach the servicing hose from the potable water cart/truck to the aircraft potable
water fill point. Whilst there are many manufacturers worldwide, the standard and specification is similar across
airplane manufacturers and are either made of stainless steel or aluminum alloy.

The connectors are quick release type, and rotating the knurled surface will release the locking balls internally
to allow the connector to be attached to the aircraft servicing nipple. Once released, the locking balls will
permanently attach the hose to the aircraft. To remove the hose from the aircraft, repeat the operation to release
connector from the aircraft.

ISO 17775:2006 specifies the detail dimensions of the male connector interfaces, fitted to an aircraft, used for
servicing of the potable water systems, the toilet-flush water systems, and the toilet drain systems currently in
common use. ISO 17775:2006 is applicable to all commercial aircraft with water and toilet systems and is
recommended for military and private aircraft that use water and toilet systems.

ISO 17775:2006 does not include requirements for the ground half (female) couplings or protective caps, but
provides sufficient interface details for such items to be designed. It does not include any specified dimensions
for the clearance required around the connector on the aircraft body itself for either any protective caps or
ground half couplings, although general recommendations are made.

A typical stainless steel connector

A typical aluminum alloy steel connector

58 6th Edition 2020

 Connectors and Hoses

6th Edition 2020 59

 Training Manual

Some hoses are fitted with drag cushions adjacent to the connector and/or valves which prevent damage if
the hose is dragged across the ground.

If water draining is performed via coupling / hose (combined fill / drain port at aircraft):

● coupling has to be

o daily checked
o weekly disinfected

o monthly cleaned

● coupling has to be stored in a disinfecting solution

60 6th Edition 2020

 Connectors and Hoses

Hoses
Hose construction varies from country to country, and governed by standards within countries, so you will find
many hoses in use.

The main standards that are commonly found are;

● FDA – The PVC ingredients used are sanctioned for food contact use under CFR title 21, parts 170-199.
● 3-A – Sanitary Standards, Inc. (3-A SSI) is an American organisation that serves the public health by
developing standards and practices for equipment and systems and for the advancement of food and dairy
sanitation.

● NSF – The inner core tube PVC material is certified under NSF/ANSI standard 51: Food Equipment
Materials and is also certified as Potable Water Material under NSF/ANSI Standard 61: Drinking Water
System Components - Health Effects for end use not to exceed a maximum of 128.9 square inches per liter.
● RoHS – The product complies with the requirements of the EU directive 2002/95/EC which is on the
restriction of the use of certain hazardous substances in electrical and electronic equipment.

● UL – The clear PVC plastic material is certified for Flame Class HB under the Plastics - Components
category by UL with a minimum thickness of 0.8 mm.

● USDA – The PVC hose has been found chemically acceptable for use in slaughtering, processing,
transporting, or storage areas in direct contact with meat or poultry food product prepared under Federal
Inspection.

● USP – The PVC compound has been tested and meets the requirements of the USP guidelines, for Class
VI Plastics.

Generally, most hoses found on aircraft potable water servicing equipment comply with;

Working pressure: 250 psi at 70 degrees F and 150 psi at 122 degrees F. Compliance standards: 3A, FDA, NSF,
RoHS, UL, USDA, and USP.

In the United States of America for example, if you manufacture, sell or distribute water treatment or distribution
products in North America, your products are required to comply with NSF/ANSI Standard 61: Drinking Water
System Components – Health Effects by most governmental agencies that regulate drinking water supplies.
Developed by a team of scientists, industry experts and key industry stakeholders, NSF/ANSI 61 sets health
effects criteria for many water systems components including;

● Protective barrier materials (cements, paints, coatings)

● Joining and sealing materials (gaskets, adhesives, lubricants)

● Mechanical devices (water meters, valves, filters)

● Pipes and related products (pipe, hose, fittings)

● Plumbing devices (faucets, drinking fountains)

● Process media (filter media, ion exchange resins)

6th Edition 2020 61

 Training Manual

● Non-metallic potable water materials

Examples of worldwide standards you will find are;

● The CE mark, or formerly EC mark, is a mandatory conformity marking for certain products sold within the
European Economic Area (EEA) since 1985.

● EN (European Standards) can be distinguished by content, which is decisive for the purpose of the use of
terminology, basic, test, products, safety rules, procedures and standards of services, quality management
standards, interfaces, interchangeability etc.

● DVGW – (Deutscher Verein des Gas und Wasserfaches) in Germany.

● KIWA – (Keuringinstituut voor wasserleidingartikelen) in the Netherlands.

● BSI – (BSI Group) in the UK.

● ISO – (International Standards Organisation).

● AUS & NZL – Australia and New Zealand.

● GB/T – China.

● DIN – Also in Germany.

● GOST R – Russia.
● TIS – Thailand.

● JIS – Japan.

62 6th Edition 2020

 Connectors and Hoses

Examples of symbols for standards are;

6th Edition 2020 63

 Training Manual

Hose construction examples;

Food Grade Nitrile Rubber Suction and Discharge Hose.

Tube: Seamless Nitrile

Cover: Coloured Nitrile Rubber (Abrasion and oil resistant)

Reinforcement: Two polyester spirals with dual helix wire

Temperature range: -40°F to 180°F

64 6th Edition 2020

 Connectors and Hoses

6th Edition 2020 65

 Training Manual

PVC Yarn reinforced PVC Hose

66 6th Edition 2020

 Connectors and Hoses

6th Edition 2020 67

 Section 11—Tanks
A water tank is a container for storing water.

The need for a water tank is as old as civilized man, providing storage of water for drinking water, irrigation
agriculture, fire suppression, agricultural farming, both for plants and livestock, chemical manufacturing, food
preparation as well as many other applications.

Water tank parameters include:

● the general design of the tank, and

● the choice of construction materials.

Following materials can be used to design potable water tanks:

● plastics (polyethylene, polypropylene),

● fiberglass,

● stone,

● steel

Regulations to keep the compliance:

● NSF/ANSI 61
● UL-1746

● NSF, UL, AWWA

● ANSI/AWWA D102-03

Potable Water Steel Tank

The Steel Potable Water Storage Tank is an ideal way to store large quantities of drinking water.

Made in a wide range of sizes, these steel tanks feature must have an interior coating that is approved for safe
potable water storage.

Potable water tanks are available in vertical and horizontal styles depending on the site requirements and the
available space.

6th Edition 2020 68

 Tanks

Water tanks are available with multiple internal adjustments which can be used for industrial facilities, public
buildings (such as airports, schools or hospitals) or commercial resorts. These tanks can safely store potable
water.

Features:
● Vertical or horizontal construction

● Can be installed above or underground

● Small or large diameter range

Benefits:

● Longer lasting, safe and high-quality potable drinking water

Potable Water Plastic Tank

This tank is built from highly durable and resistant polyethylene. These tanks safely stores drinking water for
future use.

This plastic water tank comes with a sump located at the bottom of the tank. This sump allows an easy draining
and cleaning of the tank. Additionally, this type of tank is completely enclosed to protect the drinking water
from various outdoor conditions.

6th Edition 2020 69

 Training Manual

All plastic tanks are UV stabilized and contain built-in grooves for holding steel bands to secure the tank
outside.

Features:

● Made from Polyethylene

● Sump at bottom for draining

● UV-resistant

Benefits:

● Stores potable drinking water safely

● Resistance to rust and corrosion

● Easy to drain and clean tan

70 6th Edition 2020

 Paperwork (Taken from AHM440 and IDQP Inspection sheet)

Section 12—Paperwork (Taken from

AHM440 and IDQP Inspection sheet)
Potable Water – Fill Point
Checklist B6

● Dates of last / next inspections of the filling point shall be labeled on the outside panel of the enclosure
door.

Checklist B8

● Dates of last / next inspections and change of the filters (if any) shall be labeled on the outside panel of the
enclosure door

Checklist B11

● [insert table 5.3.5 / parameters]

● Laboratory analysis

● Filling points records

Potable Water Servicer(S)

Checklist C15a

● Daily checks ( refilled within 24 hours and chlorine or other disinfectant content)

● Free Chlorine result shall be 0.3 to 0.8 mg/l. If peroxide is added for disinfection result shall be 0.1 to 0.3
ml/l H2O2.

Checklist C15b

● Vehicles disinfection

Servicing vehicle tanks shall be disinfected at least weekly in accordance with disinfection/cleaning
procedures and the last / next cleaning disinfection dates shall be displayed.
● Vehicles cleaning

Water tank interiors shall be cleaned internally (scoured or chemically) at least once a month to remove
any scale or deposit.
Rust and lime scale inside of water bowsers can contaminate the water.

6th Edition 2020 71

 Training Manual

Visually inspect through the upper opening (if applicable) that the internal surfaces are well maintained
and clean.

Water tanks shall be designed to allow easy cleaning, de-scaling and sanitizing.

Best methods for removing scale build up are:

o Manual scraping

o Steam

o Chemical usage (Citric acid based chemicals)

Checklist C15c

● [insert table 4.3.5 / parameters]

● Laboratory Analysis

Checklist C15d

● Vehicles should be maintained to a generally accepted standard of mechanical reliability, safety and be
leak free.

This will cover all daily and weekly serviceability checks through to periodic preventative maintenance of
engine, chassis and pumping/servicing equipment.

Vehicles should be in a roadworthy condition.

Checklist C16a+b Hoses shall be of food and beverage quality, i.e. BS EN 13618; NSF/ANSI standard 61; KTW
DVGW; FDA or recognized equivalent and check for correct marking.

Checklist C17a+b

● Hose connectors have to apply to standard ISO 17775.

Miscellaneous
Checklist E1

● Service Company Quality Manual

The Service Provider should have an up-to-date Quality Manual which should include or refer to water
service procedures and should be available to all staff.

Checklist E4a-d

● Operators training records

Specific training should be provided to the operators. Training and qualified operators shall be recorded.
List of qualified operators shall be available.

72 6th Edition 2020

 Paperwork (Taken from AHM440 and IDQP Inspection sheet)

An employee training record must be maintained for every employee; that record indicates which tasks
training has been given and the date of such training, the signature of the trainer, a „yes/no“ assessment
of whether the trainee demonstrated satisfactory understanding of the training, and the signature of the
trainee.
Training should include at least:

o Hygienic principles (personnel sanitary precautions and cleaning equipment procedures),

o Water servicing and water draining procedures

o Safety and security,

o Specific equipment and individual equipment

o Fire extinguishers are needed for mobile powered servicing trucks used for water servicing. Operators
shall be trained to use them and will be aware of the fire extinguishers available on the tarmac and
their locations.

Checklist E8

● Incidents / accidents reports

Incidents and accidents should be reported immediately. This applies to:

o Major accidents

o Fatal or serious injury to personnel

o Excessive damage to property, plant and equipment including aircraft.

o Accidental contamination during water uplift.

o Major spills

o Breaches of security due to criminal or malicious action

o Minor incidents and accidents

o A near miss which might otherwise have resulted in any of the above

Detailed reporting and investigation procedures including forms for reporting and investigating incidents
should be included in the procedure manual of the operation. Forms should be readily available locally so
that staff can get familiar with accident reporting procedures.

Spillage: Under freezing temperature, any water spillage will be treated as soon as possible. A specific
procedure to dam and recover the spillage shall be provided.

If spillage is not treated, this fact shall be reported to the airline and the airport tarmac officer.

Checklist E9

● Airline notification procedure

A system should be established which ensures that airline customers are notified of any impending risk of
water supply being disrupted. Whatever the reason, be it staff industrial action, breakdown of equipment,

6th Edition 2020 73

 Training Manual

pollution, fire, financial or political, the airlines should be informed in good time to be able to make
alternative arrangements for water uplift.

In addition, if any damage to a vehicle is discovered during or after an aircraft servicing, such that there is
a possibility that parts may have entered an aircraft water system, or have damaged aircraft connectors,
the Airline should be notified immediately. This action may prevent further damage incurred to the aircraft
at the next servicing, in flight water system blockages or incident. It is important to first check that missing
parts have not fallen onto the apron, but that the Airline is notified as soon as possible and in any event, if
possible, before the next servicing on the aircraft involved in the incident. Observed damage to the aircraft
servicing connectors should also be reported to the airline.

This is done either by direct contact with the local representatives of the airlines or via the airport authority
or through the supplier.

74 6th Edition 2020

 Aircraft Servicing

Section 13—Aircraft Servicing

Aircraft portable water services ramp procedure

Treatment of the Drinking Water by the Airport Management

Drinking water supplied to the aircraft must come from the airport infrastructure in accordance with the
regulation of the World Health Organisation (WHO). Therefore, the authority responsible for managing each
airport must provide all the information necessary about the water quality to the Airline Companies / Handling
Agents that use this service.

Accordingly main characteristics to be taken into account are:

● The water supplied to aircraft must be free from pathogenic organisms, be pleasant, not cloudy, not have
a colour or odour, free from excessive amounts of chemical substances, and have a pH of between 7.0 and
8.5.

● Those airports where quality of the water is below WHO limits must take positive precautionary disinfection
actions.

● Water distribution system must be safeguarded against crossed connections and low siphon level, which
could occur when the valves are closed or during periods with low pressure.

● The frequency of bacteriological tests on the water distribution system will depend on different factors,
such as the quality of the water sources, the risk of contamination, the complexity and length of the
distribution system, the number of supplier points, the possibility of epidemics spreading, or the population
to be supplied.

● In any case, the chemical inspections of the system should be carried out with the following frequency:

o 3 months for biological factors.

o 3 months for physical-chemical factors

● Sampling must be carried out by the airport or when this is not possible by the Handling Agent.

● Filling points where water comes straight from the main infrastructure must be tested every day to
guarantee the correct levels of residual chlorine.

● Samples must be taken in properly sterilised glasses, jugs or bottles, with a glass stopper or metal screw-
on cap, and without contact with any other object.

6th Edition 2020 75

 Training Manual

Supply Station and Filling Points at the Airport

Filling points at each airport may be used by several supplier companies or airline companies. So it must be
the airport management who guarantees the control, maintenance and correct functioning of these stations or
filling points.

The main characteristics to be satisfied are:

● Main infrastructure supply point must be raised above floor level, and protected against any type of
contamination. It should also be covered with an adequate housing, and it will be at least 30 metres away
from any toilet or washroom.

● Water station connections or outlets may be connected directly to the aircraft, or to the drinking water
bowser / vehicles for subsequent transport.

● The drinking water stations will only be used for this service. The hose connections will also be situated
above floor level and protected against any type of contamination.

For this purpose, a container with hyper chlorinated water will be installed to immerse the connections when
the hoses are not operative.

● The drinking water supply station will satisfy the regulation that exists in this regard (standard ISO 450,
regulation on materials, etc.). The maintenance of this supply station will guarantee the cleanliness of the
surrounding area and regular disinfection.

Transport of Drinking Water to the Aircraft

Supply service to aircraft is responsibility of the Handling Agent. Airlines must contract drinking water transport
from the filling stations to the aircraft, using approved equipment for this service.

Airlines contracts with handling water companies must include all those clauses in the contracts that guarantee
compliance with these standards, including periodically reports to airline station managers, the results of
inspections performed and analyses carried out in the trucks.

Basic standards to be taken into account related to this part of the service are specified in the following points:

● Vehicle/Bowser/Tanks used to transport drinking water to the aircrafts will satisfy the specifications
indicated in the IATA 970 recommendation of the AHM.

● These Vehicle/Bowser/tanks must comply with the regulation on equipment used to transport food (ISO
450), whose requirements indicate that they must be clearly marked and they must not be used for other
types of tasks.

● Transferring water will be designed in such a way that between the filling point and the aircraft connection,
water cannot be into contact with any substances or be affected by human handling.
● Water inlet and outlet valves will have an automatic and hermetic seal, and will prevent the hose from
draining water from any container.

76 6th Edition 2020

 Aircraft Servicing

● When bowser/ vehicle device is not operating, all the connections will be closed with hermetic covers and
the delivery nozzle will be immersed in a container with hyperchlorinated water with WAVER-465 or any
other similar product.

● Before connecting the hose nozzle to the aircraft, it must be rinsed, letting a small amount of water pump
up and come out.

● Maintenance of the bowser/vehicle water device will be rigorous, cleaning it and disinfecting it as often as
indicated below.
● Despite the purity of the water, all the tankers that supply drinking water must be disinfected and cleaned
with the following frequency:

o External cleaning: every 15 days. The outside of the tankers must look generally clean, especially in
those areas where contamination is likely to accumulate (lower parts, containers, etc.) The tankers that
are bodied with duralumin will be decaled and polished, applying aluminium cleaner (WAVER-209,
code IB-00025) at least every 12 months.
o Internal cleaning: every month. The interior of the tanker tank must be cleaned thoroughly with this
time interval, to eliminate any deposits or residues, using bristle brushes impregnated in strong
hypochlorite solution, WVER-405, or using a steam jet that this product has also been added to, rinsing,
filling and emptying the tanker afterwards with clean, drinking water, as indicated in the following
paragraph. After a cleaning a disinfection has to be performed.

o Disinfection of the Bowser: weekly. It will be filled with a recommended dose of 50 mg/litre (50 ppm)
of a free residual chlorine solution (sodium hypochlorite or calcium hypochlorite, not chloramines).
Some bacteria is resistant against chlorine, this can make it necessary to change the cleaning procuct
from time to time. Only use approved cleaning agents. This solution will be left in the tank for 30
minutes or in accordance to manufacturer recomondations. After that time, the tanker must be shaken
energetically, repeatedly moving it from side to side so that the solution impregnates all the inner
surfaces of the tanker. By a local procedure it must be ensured that all pipes, pumps and level indicators
are treated by the disinfection procedure.

Once rinsed in this way, the solution must be left for 10 minutes and then the content will be emptied
through the delivery hose and not down the drain. After this, the drain will also be opened to completely
empty the rest of the solution.

Once the drain and the upper trapdoors have been closed, the container will be rinsed again, filling it
and emptying it with drinking water through the connection valve.

(Note.- The pressure of the supply water will not be greater than 1 Kp/cm², as excess pressure could
damage the tanks when they are completely full.
o A chlorination test must also be carried out in the disinfected tanks, using CTX testers or similar. The
concentration of the total residual chlorine must continuously be between 0.3 to 0.8 mg/l.)

● The tankers must have information about the dates when the last cleaning and disinfection was carried
out.

● These vehicles cannot be parked in the same areas as other waste water service vehicles, and they must
be separated by at least 30 metres.

6th Edition 2020 77

 Training Manual

Supply of Drinking Water to the Aircraft

Personnel who directly supply the drinking water to the aircraft must satisfy the requirements on health
conditions indicated in section 4.5 of the WHO manual.

As a general rule, the personnel performing this task will not be the same as the personnel who clean the
lavatories and waste water.

The execution of both tasks could be permitted but never at the same time, so long as the worker washes
adequately (shower) when changing tasks.

To carry out the service, the personnel must use the appropriate clothing, and will receive the necessary
training about the use and handling of the means used, as well as all other applicable training (risk prevention,
operational safety, etc.). The company must keep a record of the training received by each worker, with the
contents, times employed and certificates obtained.

It is also important to point out that those workers with contagious diseases must be removed from the service.

Finally, the facilities used by the workers to wait for the services, must also meet some specific minimum
cleaning requirements. .

Inspection and Control in the Aircraft

The final step of the supply chain of drinking water to the aircraft corresponds to the controls to be made in the
aircraft. This part is the responsibility of the airline companies. As a general rule:

● The station airline manager must be aware of the treatment received by the drinking water before the
aircraft departure on any of its routes, verifying that the residual chlorine levels in the water do not exceed
standards limits.

● If negative results are obtained in the analyses or deficiencies are observed in the aircraft drinking water
supply installations or vehicles, the Station Manager will adopt the appropriate corrective measures with
respect to the responsible person from the company or organisation involved (Handling Agent, Airport
Management or local authority.

78 6th Edition 2020

 Waste vs. Potable Water

Section 14—Waste vs. Potable Water

General
It is very important to ensure that a safe and reliable supply of drinking water is provided to aircraft passengers
and crew. Although safe drinking water maybe supplied to the airport authorities and then to the ground service
providers, there is a significant risk that this safe water can be contaminated by microbial if proper procedures
and sanitation practices are not continuously followed.

Potable water is vulnerable to contamination by bacteria and other microorganisms. The drinking water made
available to crew and passengers must be free from chemical substances and microorganisms which might
cause illnesses in any form. It is therefore essential that potable water is chlorinated and that handling
companies adhere to sanitary requirements.

Definitions
4.2.1 Water servicing is the process by which safe and reliable water is supplied to the aircraft tanks for
the use of passengers and crew whilst following all proper procedures and sanitation practices.

4.2.2 Toilet servicing is the process by which toilet waste is removed from an aircraft at the end of the
flight, in a sanitary manner. The toilet waste holding point is flushed, then re-charged with a toilet fluid.
The aircraft system is function tested and declared serviceable.

Sanitary Practices and Procedures

4.3.1 The main fill point connectors shall be at least one meter above the ground level and at more than
thirty (30) meters from waste storage or treatment, water toilet servicing and trucks.

4.3.2 Potable water service units and toilet service units must not be parked in the same area.

4.3.3 Personnel engaged in toilet servicing are not allowed to perform water service at the same time.

4.3.4 Before the fill hose is connected to an aircraft, a few liters of water shall be pumped to ensure thorough
flushing of hose and nozzle. When the hoses are not in use, all nozzles or connectors must be
protected from contamination either by covers or by immersing them in receptacles containing
chlorinated water.

4.3.5 The contents of the potable water service unit must be drained not later than twenty-four (24) hours
after filling.

6th Edition 2020 79

 Training Manual

4.3.6 The cleaning and disinfecting of servicing vehicles must be performed weekly. The interior of the
water tank should be scoured once a month to remove any deposits.

4.3.7 Potable water servicing should be performed before servicing aircraft toilets.

4.3.8 Potable water service units must be parked in a specific clean, shaded and secure area.

4.3.9 Operators shall not touch the filling port and connectors with bare hand.

4.3.10 Toilets, hand washing stands and other hygienic amenities should be provided and maintained clean
and disinfected daily.

4.3.11 Any contagious operator should be removed from servicing operation.

4.3.12 Operators must clean and disinfect their hands or gloves before drinking water servicing.

4.3.13 For hygiene reasons, operators should not conduct both toilet and water servicing functions on the
same shift. But in those extreme cases, operators must perform the service potable water before
servicing aircraft toilets. After servicing aircraft toilets, protective clothing/equipment must be removed
and then hands washed with soap and water. If a significant splash has happened during toilet
servicing, the operators should take a shower and change clothing before servicing water on other
aircraft.

80 6th Edition 2020

 Section 15—Water Servicing
What should you be doing?

▪ Follow global standards from AHM

▪ Review your ground handling agreement
▪ Perform regular hygiene audits
▪ Carry out regular testing
▪ If unsafe, prohibit water uplifts
▪ Use only airline approved purifying chemicals

6th Edition 2020 81

 Training Manual

Section 16—How to Prepare for the

Inspection
Inspection Auditing Guidelines

▪ Purpose
▪ Basic Approaches to Inspecting
▪ Performance versus Compliance / Conformance Inspections
▪ Inspection Process
▪ Inspection Standards
▪ Specifications
▪ Laws and Regulations
▪ Inspection Participants
▪ Inspection Processes
▪ Basic Inspection Steps
▪ Inspection Planning
▪ Code of Conduct / Ethics and Social Responsibility
▪ First Impression (Make it count)
▪ Three Keys an Inspector Requires
▪ Retention of Information
▪ Close-ended Questions
▪ Open-Ended Questions
▪ Interviewing Techniques for Inspectors
▪ General Modes of Communication
▪ Communication Barriers
▪ Barriers to Effective Listening
▪ Time and Place
▪ General Rules for Physical Environment
▪ Elements of Inspection Planning
▪ Inspection Purpose
▪ Prior to arriving Onsite
▪ Opening Meeting
▪ Onsite Inspection
▪ Interviewing Personnel
▪ Closing Meeting with Vendor
▪ Issuing Inspection Report to (Vendor)
▪ Findings and Observations
▪ Accepting Corrective Action Plan (CAP)

82 6th Edition 2020

 Checklist

Section 17—Checklist
Checklist Structure
The checklist is divided into 3 parts;

1. Inspection summary and recommendations

2. Contact details

3. Checklist

All sections are to be completed in full, and if not applicable, annotated as such.

Part 3, Checklist, contains 6 main sections;

A. General and Airport Records

B. Potable Water – Fill Point

C. Potable Water Servicer(s)

D. Potable Water Cabinet(s)

E. Potable Water Servicing

F. Miscellaneous (for information only)

Each section identifies the requirements to be checked during the audit in the check point column. Each item
will be marked in the second column as follows;

Y Yes

N No

X Unsatisfactory (Not Acceptable).

N/A If not applicable.

C Comment (add comments).

The Seventh column allows for the auditor to record comments/observations during the audit.

Reference to numbers where applicable can be recorded in the comments column, these numbers can be
found in the IATA Drinking Water Quality Pool Safety Standards booklet in section 5 – checklist items, where
a detailed description of each check list item can be found. Numbers identified in RED are health critical items.

Note: Certain other items call for specific values which should be recorded depending on the frequency of
the operation these can be recorded in the comments column. Observation may not always be
possible.

6th Edition 2020 83

 Training Manual

Once the checklist is completed in full, it can be used and referenced to transfer the audit to your on-line audit.

To assess the facility

IDQP has implemented a process where all new inspections are risk rated depending on the level of finding.

Each item on the checklist has been assigned a risk rating, or classification. When inspection results are
entered into IDQP PRIVATE WEB the severity of findings, categorized, is recorded. The original risk is
displayed under classification and this cannot be changed or moved. This will; appear as you publish the
report and will not change. Color coding under “companies” however, can be updated as corrective actions
are entered.

For the purpose of the allocation and frequency, the original risk or classification will be the determining factor.

84 6th Edition 2020

 Checklist

Following are the color codes assigned to an agent at an airport as defined by IDQP SG:

Non-significant findings
Green
No operational restrictions

Amber Level 2 finding

Level 1 finding involved or too many level 2 findings

Red
resulting in operational restriction

Black Not been inspected

The intent of fixing a classification in the checklist is to remove the subjectivity from the colour rating system
currently in place and provide an objective rating methodology. This classification is the one that will be the
base for the next allocation and inspection cycle as it depicts the original level of findings found at time of
inspection.

The colour displayed on the Airport information page should be the colour rating (green, yellow, red) assigned
to the vendor by the Inspector.

Contact numbers and e-mail addresses can be found in IDQP PRIVATE WEB.

In order to have a better transparency for quality and /or service related issues, all IDQP inspectors can assess
the capability or restrictions of each location identified by four attention levels.

Green:
• No findings or non-significant findings
• The inspected party can be used without any restriction
• Inspection interval remains at 36 months intervals

Amber:
• Major findings which are not expected to disturb the safe (Drinking Water) operations of an aircraft but is
considered as a safety concern.
• Inspection interval is 12 months or less (follow-up inspection highly recommended).
• Examples: A number of findings, while each is not necessarily critical on its own, but cumulatively indicate
a lack of system controls which may lead to a critical failure.

Red:
• Level 1 finding(s)

6th Edition 2020 85

 Training Manual

• Major findings affecting the safe (Drinking Water) operations of an aircraft

• The inspected party should not be used. The final decision to use such a vendor remains with each
individual airline.
• Follow-up inspection mandatory with an interval of 12 months or less, extension can be granted which
will be agreed with all parties flying to the affected destination.
• Examples: A high number of findings, while each is not necessarily critical on its own, but cumulatively
indicate a total lack of system controls which may lead to a critical failure.

Black:
• Has not been inspected, should not be used

RC – General & Airport Records

Aircraft Potable Water Transfer & Supply Chain

The operator has to have a system which for IDQP minimum contains:
• Safety Policy, Details could be found e.g. in ICAO Annex 19
• Safety Manager, Details could be found e.g. in ICAO Annex 19
• Quality control shall be done by an approved authority or certified employees. Record organization’s
name.
• Incident / Accident reports

86 6th Edition 2020

 Checklist

Safety Training & Awareness

Specific training should be provided to the operators. Trainings and qualified operators shall be recorded.
List of qualified operators shall be available in the foreman office.
An employee training record must be maintained for every employee; that record indicates which tasks
training has been given and the date of such training, the signature of the trainer, a „yes/no“ assessment
of whether the trainee demonstrated satisfactory understanding of the training, and the signature of the
trainee.
Training should include at least:
• Hygienic principles (personnel sanitary precautions and cleaning equipment procedures),
• Water servicing and water draining procedures
• Safety and security,
• Specific equipment and individual equipment
• Fire extinguishers are needed for mobile powered servicing trucks used for water servicing.
Operators shall be trained to use them and will be aware of the fire extinguishers available on the
tarmac and their locations.

Drinking water samples examples

6th Edition 2020 87

 Training Manual

Water appearance and smell

a) Sample check
b) Visual check

c) Liquid pollution

d) Particulates
e) Micro-organisms

f) Chemical Checks for disinfectant content

Water Installation constructed from appropriate Material:

Potable Water Installation shall be constructed of appropriate materials (e.g. corrosion-resistant materials)
certified for this application, properly designed, operated, labeled, maintained and used for no other purpose
that might adversely affect the quality of the water.
No lead, cadmium alloys, cadmium plating or galvanized steel shall be in contact with water, nor should zinc
material coatings or non-food quality plastic material be used.

o All vehicles should be filled up using a supply connection (closed system)

o The filling station should be situated inside a clean hall
o The filling station (hall) should be secured against unauthorised access to the water supply.
o No direct sunlight on extraction point
o Hose lines should always be filled with chlorinated water
o Hose connection has to be dust and dirt protected,
o Only potable water vehicles can use the facility to uplift water.
o Toilet servicing vehicles must not be parked near the watering point (The minimum 30m rule
apply).
o The extraction point chlorine levels (free chlorine) must be min 0.3ml or 0,1 ml Hydrogen
Peroxide
o Quarterly microbiological testing and recorded.
o Chemical testing every 3 months.
o In case of positive findings the source of contamination has to be determined and
neutralised before the water point can return back to operation.
o In case of repeated “positive findings” extraction point and process have to be checked
o Which procedure is used for water treatment?
o Is this process suited for disinfecting water in order to achieve a depot effect?
o No use of zincked pipes, more suitable: high-grade steel / plastics preferred.
o Is there a suitable water measuring systems in place ?
o Are there procedures in case of an emergency exist (e.g. system failure)?

88 6th Edition 2020

 Checklist

Inspection Check-list

FP – Potable Water Fill Point

Aircraft Potable Water Transfer & Supply Chain

Location of fill point

Fills points shall be clearly identified and can be referenced on a map at the handling company operation
room. Fill point connectors shall be at least one meter above the ground level and at more than 30 m from
waste storage or treatment, water toilet servicing and trucks, etc.
A wall up to the roof which prevents the air exchange between the 2 areas is also acceptable

30 meters minimum

6th Edition 2020 89

 Training Manual

Fill Point
Examples
Fill point labeled and used 'For Aircraft Drinking Water Only'

The drinking water fill point should be labelled "'For Aircraft Drinking Water Only" or equivalent
wording. (e.g. local language) to remind staff not to use it to fill the toilet servicing trucks.

Filling points (loading points) of potable water bowsers shall be clearly identified and can be referenced on a
map at the handling company operation room.

Check that panel it is marked as “Drinking Water Only”.

Potable water bowsers must not be filled up from unknown taps or from the one used for toilet service
carts.
Fixed filling points of potable water shall be equipped with pressure regulator and adequate pressure gage.

Also rinsing (purge) capability of filling hose should be available.

90 6th Edition 2020

 Checklist

Protection and cleanliness of area

Check protection and cleanliness of the area. Advising panels such as “Keep clean” and / or “Do not litter“ are
recommended.

Check the area drainage. Precautions should be taken in the construction of the fill point to ensure drainage
from the area to prevent flooding during heavy rain. The fill point should not be located in a low point.

Adequate drainage

The area around the fill point needs to have adequate drainage to prevent flooding. If flooding occurs,
bacteria can grow in the stagnant water and this could contaminate the hose.

Look to see that there is a clear drain in the area where the hose is stored.

6th Edition 2020 91

 Training Manual

Protection & Cleanliness of the Fill Point Area

Examples

Fill point hose in metal/ pestproof enclosure.

The fill hose must be stored in a secure and clean place free from:
• Contamination
• Pests
• Unauthorised access

Fill point hose end capped or secure in a disinfectant solution

Fill hoses should be capped when not in use. Bacteria will grow if hoses are left open
Handling agents need to ensure that pests and dirt cannot get into the hose when it’s not in use.
The most common way of doing this is by having a screw cap on the end of the hose.
If, however, a screw cap is not available, the same can be achieved by putting the end of the hose into a
bucket of sanitizer solution when not in use. If this method is used you need to make sure the sanitizer is
changed daily.
Alternative you can hang up the end of the hose in a housing (cabinet) with a lockable door (flap) without a
screw cap.

92 6th Edition 2020

 Checklist

Flat connectors are preferred, preventing the introduction of air or pollutants into the circuit and spillage into
the work area

Fill point inspection

The inspection shall ensure, that the fill point area is adequately maintained.
Dates of last / next inspections of the filling point shall be labeled on the outside panel of the enclosure door.

The inspection shall at least include as a minimum but not limited to:
Daily:
• Cleanliness
• Coupling damaged / available / correct connected
• Treatment devices shall be functional
• Hoses, if any, should be completely flushed
• Appearance / smell of the potable water shall be checked

Weekly:
• Disinfection (if applicable)

Monthly:
• Cleaning & Disinfection

6th Edition 2020 93

 Training Manual

Filters

Check for filters or other devices.

If present :
• type and name should be recorded
• inspections and change of elements should be recorded

Fill point hose in good condition and are potable water grade quality and labeled accordingly

If the fill hoses are not in good condition, dirt can get into the water and bacteria could grow on
temporary seals such as tape. If the hoses are damaged they need to be replaced.

Check hoses condition. Hose should be generally in good condition. Check hose for leaks, abrasion blister
and kink. Hose should be replaced if any damages are observed such as heavy connector worn, hose wall
are cuts, and hose is badly kinked.
Hoses should be approved by one of the several standards available for drinking water materials
(examples: BS EN 13618; EU VO 10/2011; NSF/ANSI standard 51/61; KTW DVGW; FDA or equivalent)

Hoses are food quality and labeled accordingly

Check hoses comply food or drinking water grade, check for marking.

94 6th Edition 2020

 Checklist

Check hoses condition. Hose should be generally in good condition. Check hose loop is pulled during servicing
for leaks, abrasion blister and kink. Hose should be replaced if any damages are observed such as heavy
connector worn, hose wall are cuts, and hose is badly kinked.
All metallic parts shall be made stainless steel material only, galvanize or copper-zinc alloys materials are not
allowed to use.
In hose intermediate connector adaptor is prohibited. Only intermediate part used to add chlorine may be used

Does the water from the fill point show a satisfactory level of disinfectant?
(If applicable)

A water sample should be taken to perform a disinfectant test. Free chlorine content at the point of filling into
the aircraft must be in the range of 0,3 to 0,8 mg/l.
(Hydrogen Peroxide 0,1 to 0,3 ml/l)

Do not confuse “Free Chlorine” with “Total Chlorine or Chloride” sometimes there is a confusion with the
wording and the values.

Free Chlorine or active chlorine is a warranty against any microbial pollution.

The recommended concentration is 0.5 mg/l. Some airports may use 1.0 mg/l due to the local conditions.
Airlines must be advised.
Some airports do not add chlorine and provide only pure water. IATA Airlines must be advised of this.

Each airline will take the decision to accept the water servicing or to add chlorine.

Some other airports add hydrogen peroxide. If this method allows a good safety and prevent any risk of
contamination during servicing, it has no remnant effect as free chloride does. IATA Airlines must be advised
of this.

Laboratory examination of water samples

Water samples should be taken on a regular basis from the fill point and from each bowser and sent
to a certified (or by the pool accepted) laboratory for examination.

Samples should be taken every 3 months for microbiological and chemical examination

6th Edition 2020 95

 Training Manual

Samples are used to verify the adequacy and effectiveness of the disinfection and water treatment procedures.
If your first set of samples pass, this does not mean that the water will always be good quality. Micro-samples
are only useful if they are taken on a regular basis.
• Taking a sample from the fill point / bowser immediately before a regular disinfection, will tell you
whether or not the needs to be disinfected more regularly. If the sample fails, then the bowser needs
to be disinfected more often.
• Taking a sample from the fill point / bowser immediately after a disinfection, will tell you whether the
disinfection is being done properly. If the sample fails, the disinfection has not been done properly.
Laboratory analysis and microbial & chemical examination shall fulfil the IATA recommendation.
No water service is recommended in case no sampling is performed

Inspection records must be kept to ensure the fill point is maintained in good condition for safe and
reliable service.
All maintenance work should be scheduled in accordance with the equipment manufacturer’s instructions.
a. This list of daily checks should be carried out on the fill point each day and recorded.
• Disinfectant detector kit – Check that it is available and that reagents are up to date
• Dust caps should be replaced on all points
• Daily checks will include technical and mechanical aspect of the fill point.

b. Methods of cleaning, scaling and disinfecting, frequency and chemicals (trade name and
concentrations) shall be recorded and filed. A procedure should be available.

Inspection Check-list

WS/WC – Potable Water Servicers / Cabinets

Aircraft Potable Water Transfer & Supply Chain

96 6th Edition 2020

 Checklist

Vehicles
Check ownership, operating company and quality control of the vehicles

Water bowser / trailer with pump Compressed-air trailer

Flexible hose line linked with passenger bridge Hose line linked with under floor hydrant
system

6th Edition 2020 97

 Training Manual

Water bowser

▪ Preferably with no sharp edges inside the tank

▪ Stainless pump (preferred)
▪ Fill and delivery connectors must be protected from dust and bacteria.
▪ Top covers must be locked
▪ All ports should be plumbed . (Breather !!)
▪ Contents must be drained completely just after the last service of the day, and before every
top-up.
▪ The drain valve must be at the lowest point of the tank.
▪ In case of “positive findings” the source of contamination has to be determined and
neutralised before

Water bowser / trailer with pump

Advantages:
▪ Enclosed hopper
▪ Short hose lines
▪ Easily to disinfect
▪ Temporarily direct sunlight

Disadvantages:
▪ Mobile, sometimes parked at unclean areas
▪ High investment costs

Compressed – air trailer

Advantages:
▪ Enclosed hopper
▪ Short hose lines
▪ Easily to disinfect
▪ Temporarily direct sunlight

Disadvantages:
▪ Mobile, can be parked at unclean areas
▪ Using compressed-air risk of contamination the tank with germs and bacteria

98 6th Edition 2020

 Checklist

Flexible hose line linked with passenger bridge

Advantages:
▪ Low investment costs
▪ Space-saving during the ground handling process.

Disadvantages:
▪ Permanently exposed to heat, coldness and contamination.
▪ Long hose lines, thus high degree of microbial contamination
▪ Water remains in hose lines
▪ Difficult to disinfect

Hose line linked with under floor hydrant system

Advantages:
▪ Space-saving during the ground handling process

Disadvantages:
▪ Permanently be exposed to heat, cold and
contamination
▪ Water remains in hose lines.
▪ Difficult to disinfect
▪ Long hose lines, thus high degree of microbial contamination

Hose line linked with passenger bridge & under floor hydrant system

1. Hose must not be permanently exposed to direct sunlight

2. Supply connection has to be dirt-protected
3. Does suitable procedures to disinfect hoses exist?
4. Documentary proof of all disinfections
5. Chlorine content must be at least 0,3 milligram per litre of free chlorine
6. Water may not remain in hose lines after using, possibly circulation in case of disuse
7. No sewage disposal in same area
8. Chemical testing every six months.
9. Quarterly microbiological testing
10. If Micro testing is found positive that equipment will need to be immediately quarantine and not used
until the problem is found and corrected, and new micro checks are found negative.
11. In the case of repeated “positive findings” filling station and process have to be checked.

6th Edition 2020 99

 Training Manual

Vehicles condition

Check vehicle condition. Vehicles should be identifiable by a fleet number and Company name. Vehicles
should be maintained to a generally accepted standard of mechanical reliability, safety and be leak free.

This will cover all daily and weekly serviceability checks through to periodic preventative maintenance of
engine, chassis and pumping/servicing equipment.
• Record the registration number of the inspected vehicle.
• The vehicles have the proper labels “Drinking Water Only” or “A/C drain Water” Only, do not
reuse as drinking water”. Or equivalent in local languages.
• Check that tank roof area water drains (if any) are clear.
• Check tank lids/dome cover gaskets and proper operation of tank vents.
• Vehicles should be in a roadworthy condition.

Water servicers are referenced and labeled accordingly

They are parked in a specific clean, shaded and secure area and segregated

Vehicles shall have the proper labels “Drinking Water Only” or “A/C drain Water only, do not reuse as drinking
water”.
Potable water servicing vehicles must NOT be parked in the same area of other water servicing vehicles.
Potable servicing vehicles must be parked in a specific clean, shaded and secured area. Toilet trucks and
Water trucks/carts shall never be at less than 30 m each other in distance in any way.

Water bowser parked next to toilet servicing

100 6th Edition 2020

 Checklist

Biofilm in a Hose

How to remove it ?

Biofilm or “parts” in a Potable water tank level indicator!!

6th Edition 2020 101

 Training Manual

Vehicles disinfection / cleaning

Disinfection and cleaning is necessary to guarantee hygienically condition of the water vehicles.
The vehicles should be drained and disinfected at least once a week in accordance with a written procedure.
Inspectors should check the procedure and methods of disinfection.
Usually disinfection is performed with one of the following methods:
• Disinfectant based on chlorine
• Disinfectant based on hydrogen peroxide (with silver)
• Others

Vehicles disinfection / cleaning

Water tank interiors must be scoured at least once a month to remove any scale or deposit.
Rust and lime scale inside of water bowsers can contaminate the water.
Inspect visually through the upper opening that the internal surfaces are well maintained and clean.
Water tanks shall be designed to allow easy cleaning, scaling and sanitizing. Material shall be of smooth
stainless steel or approved plastic.
Best methods for removing scale build up are:
• Manual scraping
• Steam
• Chemical usage ( Citric acid based chemicals)

102 6th Edition 2020

 Checklist

Filters

If filters are installed at water tanks, check when the filters have been changed last time and if the next filter
change due date is labeled.

Hose connectors

Hose connectors have flat connecting valve and are not worn
Hose connector to fill point is capped and stored in a clean protected stowage compartment
Bacteria will grow if hoses are left unprotected.
In accordance with AHM 440 when the hoses are not in use, all nozzles or connectors must be protected
from contamination either by covers or by immersing them in receptacles containing desinfection solution.

6th Edition 2020 103

 Training Manual

Water treatment chemical

Record the test commercial reference used to check the chlorine content or equivalent additive used to
disinfect water.

If an alternative chemical is being used the handling agent needs to use an appropriate kit to test the chemical
levels.
If no chemicals are being added and the background level of chlorine is not satisfactory, you need to check if
water analysis reports show a good water quality.

Chemicals such as chlorine gradually get used up as the water sits in the bowser / hoses during the day. The
speed at which this happens depends on the sunlight, water temperature and the cleanliness of the water.

It is therefore important that the Ground Handling Staff check the chemical levels
immediately prior to an uplift to make sure there is still enough left to give a satisfactory result.
A test for free chlorine can be performed with one of the following methods:
• Free chlorine reagent strip (test strip)
• Indicator reagent tablet for photometer, color comparator (Palintest, DPD No.1)
• Electric measurement of oxidation-reduction potential
LIMITS: 0,3 – 0,8 mg/l

Test Kits for Hydrogen Peroxide

Remember: Limits 0,1 – 0,3 ml/l

104 6th Edition 2020

 Checklist

Vehicle Drain Port

▪ Check that the draining port has no leakage, is at the lowest point and will allow a full drainage.
▪ Tanks should be designed so that they can be disinfected and flushed and should be provided with
a drain that permits complete drainage of the tank.

Water Truck drainage

Make sure that the used potable water truck is fully drained and refilled within 24hours.

Finding on Vehicle Analysis

• In case of “positive findings” the source of contamination has to be determined and neutralized
before the vehicle can return back to operation.
• In case of repeated “positive findings” vehicle and process has to be checked

Scheduled and unscheduled maintenance records available:

Log books and inspection records must be kept to ensure vehicles are maintained in good condition scheduled
in accordance with the equipment manufacturer’s for safe and reliable service.
The logbook should record details of work carried out, including servicing, repairs and replacement parts.
a) This list of daily checks should be carried out on the vehicle each day and recorded.
• Maintenance checks – ensure that the vehicle is serviceable and that past faults have been
rectified.
• Disinfectant detector kit – Check that it is available and that reagents are up to date
• Check ALL points – water servicing carts equipment shall be drained of sediment from all
low points daily. After loading, the vehicle should be allowed to stand for about 10 minutes
for the water to settle. A cargo tank sump sample should then be drawn and checked for
sediment (also trailers Ensure all low points are drained and samples C&B).
• Dust caps should be replaced on all points
• Daily checks will include technical and mechanical aspect of the vehicle and of the water
tank and water delivery system.
b) Methods of cleaning, scaling and disinfecting, frequency and chemicals (trade name and
concentrations) shall be recorded and filed. A procedure should be available.

6th Edition 2020 105

 Training Manual

Inspection Check-list

WU – Potable Water Uplift

Aircraft Potable Water Transfer & Supply Chain

Before servicing begins check the following:

▪ Check vehicle markings and water servicing ports designation as necessary, to ensure potable
water will be delivered.
▪ Check that private mobile phones have not been taken out to the aircraft.
▪ The use of mobile phone whilst driving a servicing vehicle is strictly prohibited.
▪ Also check that the vehicle delivery meter (if any) has been set to zero.
▪ Vehicle(s) should be stopped prior to engagement to an aircraft, to test the brakes and then be
positioned safely and correctly with an unobstructed exit maintained at all times except if agreed by
the Airport Authority. Vehicles should not be reversed onto or from the aircraft unless marshaled.

Separate staff used for water and toilet servicing

Toilet servicing shall be done always after water servicing, this will minimise the risk of cross contamination.

106 6th Edition 2020

 Checklist

There needs to be complete segregation of everything, including the staff.

A person can do both water and toilet servicing but not on the same shift.
They must wash and shower in between the two jobs and must wear different uniforms for each task.

Servicing staff should be dressed with clean working cloths.

• Check work shift plan if the same staff do both the water and the toilet servicing.
• Check that social facilities are segregated of water service staff and toilet service staff. If the same
staffs do both the water and the toilet servicing the staff have to use different uniforms for each task.
• Check also that working clothes are stored in separately if same persons can do both water and
toilet servicing.
• Check the staff changing rooms and shower facilities, there should be segregated changing rooms
and showers for staff of water services and other facilities staff of toilet services.

Refilling and Flushing before AC Water Service

Make sure the water servicing bowser was filled less than 24 hours (check date and filling time). The content
of the treated or untreated potable water servicing vehicle must be delivered to an aircraft or drained not later
than 24 hours after filling.

Cleaning before connection

Aircraft filling port should be cleaned /wiped dry with septic wipes before the hose is connected to the aircraft
adaptor.

Note : Cleaning may be done either by wiping with a clean cotton rag or equivalent soaked with a disinfecting
solution or by wiping with a disinfectant pre-soaked “towelette”. The spray-and-wipe procedure is not
recommended

The hose should be flushed before connecting the hose to the aircraft filling port, to eliminate any trace of
stagnant water existing between bowser and connector.

Note: If the water bowser comes straight from another water uplift no flushing is required.

Hose connectors shall be checked for cleanliness before hose connecting to the aircraft fillport.

Disconnection Procedure

• Hoses should be capped or secured on a dummy connector. Hose end dust caps should be clean,
in good condition and replaced when hoses are not in use.
• If a dummy connector is been used, it shall be in a receptor filled with a disinfecting solution
(permanganate or equivalent).
• Hose filling line shall be drained before stowing only after the last a/c servicing of the day.
• After the stowing of hoses and connector, check that the a/c filling port is wiped dry and plugged.
• The A/C water filling port access door is closed and locked correctly.

6th Edition 2020 107

 Training Manual

Water servicing staff training

The ground handling staff must be properly trained, not just on how to service aircraft but how to
service them hygienically and safely.

Each operator of potable water servicing must have an individual training record.

Each training record should indicate:

1. Dates of training and recorrent trainings
2. Signature of the trainer
3. Compliance or not with the training programme
4. Signature of the trainee

Training should include at least:

1. Hygienic principles (personnel sanitary precautions and cleaning equipment procedures),
2. Water servicing and water draining procedures
3. Safety and security,
4. Specific equipment and individual equipment
5. Fire extinguishers are needed for mobile powered servicing trucks used for water servicing.
Operators shall be trained to use them and will be aware of the fire extinguishers available on the
tarmac and their locations.

All training records should be maintained in good conditions and available for consultation

108 6th Edition 2020