1. Different categories used to describe water quality.

Physical Parameters
There are six main physical parameters tested to determine water quality: turbidity,
temperature, colour, taste and odour, solids, and electrical conductivity.
 Turbidity is measuring the amount of light able to pass through water and is
determined by the cloudiness of the water. Cloudy water is visually undesirable, can
be a hiding place for harmful microbes, and has a greater chance of absorbing heavy
metals.
 Water temperature is another important parameter, as temperature impacts
palatability, odours, solubility, and chemical reactions.
 Colour, taste, and odour are parameters that are typically noticeable when at
extremely unsafe levels. Water that is pure is colourless, but water with a slight colour
does not necessarily mean it is harmful to consume. Drinking water taste and odour
can come from a variety of sources, including organic materials, industrial runoff, and
dissolved gases. Solids in water can be identified based on the filter test, where
dissolved solids pass through a testing filter, but suspended solids do not. Suspended
solids are defined as particles larger than two microns, whereas dissolved solids are
particles smaller than two microns.
 The electrical conductivity of water is measured by the ability of the water to carry an
electrical current and is more important to measure when using water for irrigation or
firefighting purposes.
Chemical Parameters
 Chemical parameters are the water quality parameters typically referred to when
discussing water quality, and testing includes measuring the presence of a variety of
chemicals. This parameter also includes testing the hardness of water, which is testing
for the level of dissolved minerals in the water. Typically, Calcium and Magnesium
are naturally occurring minerals that can lead to hard water, and groundwater is
usually harder than surface water. Water with up to 500 mg/L of hardness is viewed
as safe, but water with more than 150 mg/L of hardness is usually noticed by
consumers. Obtaining some Calcium and Magnesium nutrients through water is not
considered harmful, and may indeed be beneficial for people with Calcium and
Magnesium deficiencies.
 Other water quality chemical parameters include testing pH, alkalinity, chloride,
chlorine residual, acidity, sulphates, nitrogen, fluoride, iron, manganese, copper, zinc,
dissolved oxygen, oxygen demand, toxic inorganic, and organic substances, and
radioactive substances. Additional chemical parameters may be included in water
testing depending on the chemical composition of water in specific geographical
locations. Some of the most important chemical parameters to measure are pH, toxic
organic and inorganic substances, and radioactive substances. pH is an indicator of
how acidic or basic drinking water is, and typically the 6.5 to 8.5 pH level range is
considered safe for drinking water. Toxic inorganic substances include metallic and
non-metallic compounds, and even slight exposure to these substances can lead to
negative health impacts. A few of the inorganic metallic compounds tested are lead,
 mercury, and arsenic, and non-metallic compounds include nitrates and cyanides.
There are over 100 toxic organic substances that can be included in water quality
testing. All these substances are man-made pollutants, and this category includes
pesticides, disinfectants, detergents, and insecticides. Radioactive chemical
substances include waste from industrial runoff and nuclear power plants, and
naturally occurring radon gas from groundwater. Common radioactive chemicals
tested include alpha and beta particles, photon emitters, radium, and uranium.
Biological Parameters
 The four main biological parameters involved in water quality testing are bacteria,
viruses, algae, and protozoa. While there are millions of microorganisms in the water
we drink, the majority are harmless. One of the biggest challenges with biological
parameters is when waste from people with infectious diseases enters the drinking
water system, increasing the likelihood of others contracting the disease. Some of the
more well-known bacteria include E. coli and Salmonella, and waterborne diseases
resulting from high concentrations of bacteria are typhoid fever, leptospirosis, and
cholera. Improving sanitary practices, like washing hands more frequently or longer,
when possible may help reduce outbreaks of these diseases. Viruses are much smaller
than bacteria, and viral pathogens found in water can lead to viral infections, such as
hepatitis. Most, if not all, waterborne viruses and pathogens are destroyed by the
disinfection processes at local water treatment plants, therefore transmission is no
longer a major threat in the U.S. Algae is typically more of a nuisance, as it creates an
unappealing taste and odour in drinking water. Certain types of algae do have
associated health risks when consumed, including blue-green algae. Common
pathogenic protozoa include Cryptosporidium and Giardia, both of which have the
ability to survive water treatment plant disinfection processes and have been found in
surface water and filtered drinking water. These protozoa are able to survive in water
for extended periods of time and must be monitored regularly.

2. Main differences between groundwater and surface water.

Definition: Groundwater is the water that occurs below the surface of Earth while surface
water is the water that is above the surface of Earth.
Location: While groundwater is beneath the surface of Earth, surface water is on the surface
of Earth
Pollution: Moreover, groundwater is less prone to pollution while surface water is highly
prone to pollution.
Occurrence: Groundwater is found at groundwater table, aquifers, soil pore spaces, and rock
fracture points while surface water is found at permanent sources such as oceans, semi-
permanent sources such as some lakes, and man-made sources such as reservoirs.
Uses: Groundwater is used for household needs, agricultural needs, and industrial purposes
while surface water is used for drinking, cleaning, irrigation purposes, agricultural needs,
wastewater treatment, livestock, hydropower production, etc.
Conclusion: In conclusion, water is an essential liquid for all living things. Water can occur
on two forms on Earth as groundwater and surface water. The main difference between
groundwater and surface water is that groundwater is beneath the Earth’s surface, whereas
surface water is on the top of Earth’s crust.
3. Challenges in water treatment
The five most common problems in water treatment are:
Training issues: Most water treatment plants are small sectors in larger working systems,
such as a reverse osmosis system supplying water to a 16-stage facility. Teams are large, and
the process is highly technological. Managing the systems involved requires extensive,
ongoing personnel training at every level within the team. Without the right training, teams
are at risk of misunderstanding the complex aspects of their sector. With quality, ongoing
training you can avoid this and help employees across your entire facility to flourish as
industry experts with up-to-date knowledge. Regardless of job role or position, every member
of a team in a water treatment facility should have a basic knowledge on the appropriate
subject matter. This includes identifying each piece of the water treatment equipment, how it
works and the operating parameters, Understanding the preventative maintenance procedures
to minimise the risk of difficulties and Knowing which parameters to monitor and how to
identify problems.
More advanced knowledge is defined as being able to troubleshoot problems before they
occur. The most common problems in water treatment that employees are likely to encounter
are:
 Scaling
 Membrane fouling
 Bacteria
 Mechanical failure
 Instrument failure

Bacteria control: Bacteria growth is most extensive under the following conditions:
 The presence of food for the bacteria
 Warm temperature
 A low flow rate
 The absence bacterial control solutions
Most microorganisms feed on organic carbon-containing compounds. The ideal breeding
temperature range for most water-born microorganisms is 30°- 40° (86-105°F); where the
fastest growth occurs. The concentration of the dissolved organic compounds in the feed
water is measured as Total Organic Carbon or Total Oxidisable Carbon (TOC).Micro-
organisms grow best when a constant supply of food is bought in at a low flow rate, giving
the bacteria time to breed. Increasing flow rates minimises this due to the sheer force of
water.Chemicals that kill micro-organisms are called biocides.
A common practice used to be using oxidising agents, such as chlorine, as biocidal agents.
However, following the introduction of stricter health and safety, environmental and
chemical laws, such as COSHH, ultraviolet (UV) bacterial disinfectants are now the most
common bacterial control methods utilised today. However, there are micro-organisms that
can withstand UV, making the use of UV bacterial disinfection is better for membrane
filtration. Most nanofiltration and reverse osmosis membranes have a very limited tolerance
to oxidising agents. It’s best practice to remove these oxidising agents from the feed-water
upstream from the membrane unit. This is done by passing the feed-water through an
activated carbon bed or water softener. Failure to remove these oxidising agents results in
bacterial growth which causes membrane fouling. This reduces the flow and makes the issue
progressively worse.
Poor monitoring and record keeping: Many water treatment systems don’t have enough
instrumentation to check all the parameters to catch problems at their most preventable or
reversible stages. Even where the instrumentation is adequate, many facilities do not record
the data correctly to allow them to see patterns in the data or plan preventative procedures. It
may seem like if you have excellent feed water combined with an excellent membrane unit
and pre-treatment design, the system operates on its own and looks after itself.
Equipment design and specification: Industrial Water Treatment is booming. With more
OEM’s (Original Equipment Manufacturer) entering the market, many of them with little
experience, it is important to understand what an ideal design specification should look like
to minimise problems.
Maintenance problems: Poor maintenance of the water treatment facility can have serious
implications for the performance. Poor maintenance can result in increased costs, serious
damage to systems and financial losses to the clients.It is important to have continual
maintenance processes in the water purification systems because:
 Preventative maintenance schedule for changing the pre-filtration cartridges and bags
helps prolong the life of the membranes within the system
 It reduces the scaling and fouling of membranes
 Money is saved because of reduction in down time of units because leaks are found
and repaired faster
 Clients can predict trends in flow and pressure and pure water quality to enable the
best results through keeping detailed maintenance records
 Unit stay in good condition giving the best results for the longest period of time