TRADE PROJECT

PROJECT TITLE: WASTE WATER TREATMENT

PRESENTED BY: BEVERLINE MUTIMBA

INDEX NUMBER: 616104095

COURSE CODE:1305

COURSE: CERTIFICATE IN PLUMBING

SUPERVISOR: JOHN NDURURU

CENTER NAME: SIGALAGALA NATIONAL POLYTECHNIC

PRESENTED TO: KENYA NATIONAL EXAMINATIN COUNCIL

FOR THE AWARD OF CERTIFICATE IN PLUMBING
 DECLARTION
I hereby declare that this is my own original work and it has never been presented by
any academic or any other course academic purpose.

NAME:

SIGNATURE:……………………………

DATE:……………………………………

SUPERVISOR:

DATE:……………………………………

SIGN:……………………………………..

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 DEDICATION
I declare my project to my sincere parents for supporting me with financial and other
facilities and even moral lessons to complete my project and also my entire school. I
also give thanks to my friends who helped me with good ideas to come up with the
project. I also thank myself for a good creativity and also thank my Almighty God for
the life.

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 ACKNOWLEDGEMENT
I’m glad to express my great appreciation and thank to our entire institution, fellow
classmates and my Supervisor. I sincerely thank them since they helped me to
complete my project, simulating suggestion and encouragement in helping me during
all the time conducting this project. I’m glad to thank to them for all the knowledge
either in theory part or practical, I also thank members or friends who are helped me
during conducting this project from the beginning until the end. Your contributions
are always appreciated.

Thank you.

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 ABSTRACT

Municipal and industrial waste waters in Kenya are treated before their
release into the environment. New legislation also requires that waste waters
from all households with running water are treated before release, whereas
the methods for treatment may vary. In this project i pooled my resources in
an effort to study and improve waste water treatment.
In the case of household waste waters, minimum removal requirements exist
only for the bulk components, organic matter (BOD, COD), nitrogen, and
phosphorus. While i also monitored the removal of these components the
main focus was on micro pollutants (pollutants that exist in waste water in ng
per litre to µg per litre concentrations,
Two different types of reactors were used for studying the effect of biofilm
activity: Rotating Bed Bioreactors (RBBR), where the biofilm develops on
plastic beads with a large surface area, and Fixed Bed Bioreactors (FBBR),
where wood chips were used as the support

Contents
v
DECLARTION..............................................................................................................................ii
DEDICATION.............................................................................................................................iii
ACKNOWLEDGEMENT..............................................................................................................iv
ABSTRACT..................................................................................................................................v
CHAPTER ONE...........................................................................................................................1
INTRODUCTION.....................................................................................................................1
1.1 Micro pollutants........................................................................................................1
1. Introduction......................................................................................................................2
1.1 Micro pollutants........................................................................................................2
Biofilm processes..................................................................................................................2
1.1 Aims of the project....................................................................................................3
CHAPTER TWO..........................................................................................................................4
2.0 LITERATURE REVIEW.......................................................................................................4
2.1 METHODOLOGY..............................................................................................................4
2.2 TRICKLING FILTERS..........................................................................................................5
2.3 ACTIVATED SLUDGE PROCESS.........................................................................................5
CHAPTER THREE........................................................................................................................7
3.1 BIOLOGICAL WASTE WATER TREATMENT OF CAR WASHES............................................7
CHAPTER FOUR.........................................................................................................................8
4.0 SAMPLING, MEASUREMENTS AND ANALYSIS OF CAR WASH WASTE WATER.................8
CHAPTER FIVE.........................................................................................................................10
5.1 Conclusion challenges...................................................................................................10
5.2 CONCLUSIONS...............................................................................................................11

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 CHAPTER ONE
INTRODUCTION
Waste water treatment plants, both municipal large scale units and smaller
units used for single family homes and cottages in rural areas, do a relatively
good job if the reduction in organic contents of the water and nutrients is
considered. However, a large part of the chemicalization of the environment
that we experience, even in a relatively sparsely populated arrears is a result
of the failure of the waste water treatment plants to remove harmful
recalcitrant substances that enter the plants as dilute suspensions or solutions.
Among the harmful substances that may harm the environment are
pharmaceuticals and hormones that pass through patients, compounds used in
cosmetics, plastics additives, flame retardants and so on. Higher
concentrations of harmful substances may be released from hospitals,
landfills, factories, etc. The main outcome of flushing the substances with the
rest of the waste water to the treatment plants is so that they are diluted.
Much of the substances are removed from the water but end up in sludge,
from where they may be spread in the environment. Their con- centration in
water released from treatment plants is below permissible levels and
therefore overlooked

1.1 Micro pollutants

Efficiency of municipal waste water treatment is evaluated by removal of
nutrients and organic load measured as biological oxygen demand. Municipal
waste water treatment plants remove phosphorous and BOD at a rate of 95%
and nitro- gen at 90%. However, numerous organic compounds have been
detected in mu-

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 1. Introduction
Waste water treatment plants, both municipal large scale units and smaller
units used for single family homes and cottages in rural areas, do a relatively
good job if the reduction in organic contents of the water and nutrients is
considered. However, a large part of the chemicalization of the environment
that we experience, even in a relatively sparsely populated country like
Finland, is a result of the failure of the waste water treatment plants to
remove harmful recalcitrant substances that enter the plants as dilute
suspensions or solutions. Among the harmful substances that may harm the
environment are pharmaceuticals and hormones that pass through patients,
compounds used in cosmetics, plastics additives, flame retardants and so on.
Higher concentrations of harmful substances may be released from hospitals,
landfills, factories, etc. The main outcome of flushing the substances with the
rest of the waste water to the treatment plants is so that they are diluted.
Much of the substances are removed from the water but end up in sludge,
from where they may be spread in the environment. Their con- centration in
water released from treatment plants is below permissible levels and
therefore overlooked

1.1 Micro pollutants

Efficiency of municipal waste water treatment is evaluated by removal of
nutrients and organic load measured as biological oxygen demand. Municipal
waste water treatment plants remove phosphorous and BOD at a rate of 95%
and nitro- gen at 90%. However, numerous organic compounds have been
detected.
Biofilm processes
Bacteria in aquatic environments are predominantly not in a free-floating

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planktonic stage, but have a tendency to attach to surfaces and form multi-
species com-munities called biofilms produce extracellular polymeric
substances which form complexes with the surface materials.

1.1 Aims of the project

The aim of the project is to improve waste water treatment processes

applicable in various environments and situations, for example households,
industrial plants and other sources of waste water such as landfills, laundries,
car washes, hospitals, etc. The aim was also to exploit the tendency of
microbes to live on surfaces and feed on organic compounds and nutrients
that exist in waste water. A model of sequential bioreactors was studied to
enhance the efficiency of waste water treatment. We also aimed to
characterize microbial communities in the bio- films from different stages of
multi-stage waste water treatment processes. In addition, the efficacies of
multi-stage biofilm processes were studied using different sources of waste
water: grey water, municipal waste water and car wash waste water.

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 CHAPTER TWO
2.0 LITERATURE REVIEW
This project examines the environmental release of certain pollutants with
industrial and municipal waste waters, and the spread of these pollutants in
rivers and lakes. Drainage water from landfills was also included. It is
concluded in the project that the concentration of pollutants in both influent
and the effluent is so low that the detection level is often not reached. It is
concluded in the project that due to dilution factors, it is unlikely that the
concentrations in the water of the catchment basin would exceed
environmental norms.
Harmful substances, also called micro pollutants may, however, cause
problems in the ecosystem, and are often a challenge for the waste water
treatment process, even at low concentrations. Furthermore, many of the
micro pollutants are novel contaminants for which monitoring data is
lacking.
The main idea behind this project was, on one hand, to enrich and optimize biofilms
that are able to degrade micro pollutants, and on the other hand.

2.1 METHODOLOGY
The purpose of waste water treatment is to remove the contaminants from
water so that the treated water meet the acceptable quality standards. The
quality standards usually depend upon whether the water will be reused or
discharged into a receiving stream. Available waste water treatment
processes can be broadly classified as physical, chemical or biological. These
processes which consists of series of unit operations, are applied in different
combinations and sequences depending upon the prevailing situations of
influent concentration, composition and condition and specification of the

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effluent.

2.2 TRICKLING FILTERS

Conventional trickling filters normally consist of a rock bed, 1 to 3 meters in depth,
with enough opening between the rocks to allow air to circulate easily The
influent is sprinkled over a bed of packing which is coated

2.3 ACTIVATED SLUDGE PROCESS

The most versatile and effective of all the waste treatment processes

is the activated sludge process. A typical activated sludge plant is shown

in fig 3

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The essential features of the process are: an aeration tank where the organic
matter is brought into intimate contact with the sludge from the secondary clarifier.
This sludge is heavily laden with microorganisms which are in an active state of
growth. Air is introduced into the tank, either in the form of bubbles through diffusers
or by surface aerators. The microorganisms utilize oxygen in the air and convert the
organic matter containing N and P into stabilized, low energy compound such as
NO3- , SO42- , NH4+, H2PO4- , HPO42-,CO2, H2O and synthesize new bacterial
cells. The effluent from the aeration tank containing the flocculent biomass, known as
the sludge, is separated in a settling tank, sometimes called a secondary settler or
clarifier.

Oxidation pond

Oxidation ponds are large, shallow typically 1-2m deep, where raw or partially treated
sewage is decomposed by microorganisms. The conditions are similar to those that
prevail in an eutrophic lake. The ponds can be designed to maintain aerobic conditions
throughout, but more often the decomposition taking place near the surface is aerobic,
while that near the bottom is anaerobic. Such ponds having a mixture of aerobic and
anaerobic conditions are called facultative ponds. The oxygen required for aerobic
decomposition is derived from surface aeration and algal photosynthesis; deeper
ponds called lagoons, are mechanically aerated.

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 CHAPTER THREE
3.1 BIOLOGICAL WASTE WATER TREATMENT OF CAR WASHES
Biological waste water treatment is not usual in car washes and most common waste
water treatment technologies are sand and oil separators. Waste water from car washes
consist of dirt from cars, such as sand and dust, chemicals used for the washing,
materials from washing equipment, and lubricants and other chemicals for maintaining
the equipment.
Biological treatment systems are sensitive to chemicals, so non-solvent type detergents
are used for washing. Surface active agents (also called surfactants or tensides) are
generally the active agents in car shampoos, rinses and waxes. They lower the surface
tension of a liquid, the interfacial tension between two liquids, or that between a liquid
and a solid.
The aim of the car wash study was to examine how efficiently rotating bed bio- film
reactors purify car wash waste waters. Sampling, measurement and analysis plans
were first prepared based on literature, Internet sources.

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 CHAPTER FOUR
4.0 SAMPLING, MEASUREMENTS AND ANALYSIS OF CAR
WASH WASTE WATER
Five automatic car washes were involved in this study. An overview of
automatic car washes is presented in Figure 19, and a schematic diagram of
the waste water treatment process and reuse of water is presented in Figure
20.

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Name Car wash type Sampling period 1 Sampling period 2

CW1 Two bioreactors (15 m3 each, Sand filter, bioreactor Purified water
consisting of two and purified water
compartments of similar size)
connected in parallel and
placed underground

CW2 Single door automatic Sand filter and sewer -

CW3 Two-door automatic Sand filter and sewer -

CW4 Bioreactor, in parallel Sand filter and -

purified water

CW5 Four bioreactors (5 m3 each, Sand filter and Purified water

consisting of two compartment purified water
of similar size) connected in
series and placed in a
container

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 CHAPTER FIVE
5.1 Conclusion challenges
We can conclude that biological waste water treatment efficiently purifies COD and
surfactants from car wash waste water. The closed water system saves water and does
not load the municipal sewage system. On the other hand, nutrient sup- ply is needed
and the manual input should be replaced or developed further to avoid an overload of
nutrients. Rainwater could be also used as a water source to save valuable tap water
even further.
The first sampling period was very challenging because of a number of technical
problems. However, many important issues were recognized during the period, which
were performed better and studied further in the next sampling period. This study was
conducted in uncontrolled situations outside the laboratory, and that is why many
questions are still open. On the other hand, it provides an opportunity for the
development of an important application of waste water treatment in a real situation.

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5.2 CONCLUSIONS

The aim of the project was to improve the waste water treatment process performance in
different applications. Several kinds of waste waters were included: municipal waste
water, grey water, landfill leachate and car wash waste water. Depending on the source
of the waste water, it can contain a complex mixture of different kinds of harmful
organic pollutants and one aim was to evaluate the removal of these pollutants during
treatment processes. Both FBBR and RBBR were studied in laboratory conditions and
in the field. In addition, several methods were developed and utilized in order to study
the diversity and function of microbes, because these aspects greatly influence the
process efficiency of bio- film reactors.
The following conclusions can be drawn from the results obtained in the project.
Project showed that before the addition of the micro pollutants, the same bacterial
groups were dominant in all reactors, but different bacterial dominance was observed at
the genus taxonomic level.

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