The document provides information about a module on water supply, drainage and sewerage technology. The module aims to enable students to determine capacity requirements and supervise operation and maintenance of these systems. It includes topics like water supply design, sources of water, pumps, transmission and distribution systems. For drainage and sewerage, it covers waste water characteristics, sewerage systems design, and storm water drainage. The document also outlines the learning outcomes, lecture hours, assessment methods and topics to be covered in the module.

1. CONSTRUCTION
TECHNOLOGY NVQ LEVEL 5
(CBT Curriculum Code: F45C001)
WATER SUPPLY, DRAINAGE AND
SEWERAGE TECHNOLOGY I
Module code - F45C001M12
Module Type - Compulsory
Eng. Y.A.P.M Yahampath
B Sc. Eng (Hons), Dip Highway & Traffic Eng, AMIESL, AMECSL

2. AIM OF THE MODULE
To enable the students to:
Determine capacity requirements of a water supply, drainage & sewerage.
 Supervise the operation and maintenance of water supply, drainage and
sewerage systems.
Learning Outcomes
The student will be able to:
Identify the requirements for water supply, drainage & sewerage
Supervise the construction of water supply drainage & sewerage systems
Maintain water supply drainage & sewerage systems and related
appurtenances

3. Lecture Hours Allocated
Lecture / Tutorial Practical Demonstrations/
Industrial visits
Self Study Total
60 Hrs 20 Hrs 20 Hrs 100 Hrs
Type Topic / Activity Weighting
Tutorials (04) based on main session
topics
10%
Case studies (02) 20%
Field visits (02) Report & viva 20%
End semester exam 50%
Assessment and Weighting

4. Topics Learning content Time
(Hrs)
Water supply
Design of water supply systems Types of systems and their components,
forecasting of average per capita water consumption and peak domestic
water demand,
forecasting of industrial, commercial and agricultural water demand, other
basic design data required, service level
6
Sources of water supply ground water and surface water, their characteristics, rain water harvesting 4
Intake structures ground water intakes - bored / drilled wells, calculation of yield, surface
water intakes
4
Pumps - types of pumps (displacement, centrifugal, airlift, hydraulic etc.), their
capacities and efficiencies, operational characteristics, advantage and
disadvantages
4
Transmission and distribution of water different types of transmission devices and their effects including strength
considerations
4
Distribution systems Types, layout & design of distribution systems, sizing of pipes, use of Hazen
William formula, pipe material and jointing
4
Distribution reservoirs storage capacity, types of reservoirs 4
Valves and water meters Types of valves and water meters, their uses and maintenance 4
Total 34

5. Topics Learning content Time
(Hrs)
Drainage & sewerage
waste water Types of waste water (domestic and industrial) and their characteristics,
measurement of strength of waste water (BOD and COD tests), hazardous
waste
4
sewage Nature and characteristics of liquid / semi liquid waste, collection in urban
areas, sanitary sewage and storm sewage, conveyance systems of sewage
4
Sewerage systems Sewerage systems (separate and combined etc.), design of sewerage
systems, sewer sections, sewer materials and specific properties, design
dimensions of sewers, quantity of sewage, construction procedure of sewer
systems, testing and back filling, sewer appurtenances
6
storm water Surface and storm water drainage, quantity of storm water, storm water
sewer systems, surface drains for sullage and rain water in urban areas,
runoff coefficients self – cleansing velocity, methods of laying and aligning
sewers
4
Sewer appurtenances man holes, their sizes and spacing, storm water inlets and types, catch basins 4
Waste and its transmission- pumps and types, Need for pumping, types of pumping stations, capacity
maintenance of sewerage systems - problems and hazards, cleaning
equipment and machinery, safety equipment
4
Total 26

6. Water Treatment Plant
In Water Supply Systems

7. Definition of a Water Treatment Plant
• A water treatment plant is a facility designed to purify and clean raw water
from various sources, making it safe for human consumption and industrial
use.
• Water treatment plants are essential for ensuring that water from natural
sources, such as rivers, lakes, or wells, meets quality standards.

8. Importance of Water Treatment Plants
• Ensuring the supply of safe and clean drinking water to communities is
critical for public health. Waterborne diseases can be devastating, and
water treatment is the primary defense.
• Water treatment plants protect public health by removing harmful
substances, including bacteria, viruses, chemicals, and heavy metals.
• Preventing waterborne diseases like cholera and dysentery is one of the
most significant contributions of these plants.
• These plants also play a crucial role in providing water for industrial
processes, agriculture, and irrigation, supporting economic activities.
• By removing pollutants from water, water treatment plants help preserve
aquatic ecosystems, safeguarding fish, wildlife, and the environment.

9. Types of Water Treatment Plants
• Surface Water Treatment Plant: These plants treat water from rivers,
lakes, or reservoirs. They are commonly used for municipal water supply
where surface water sources are available.
• Groundwater Treatment Plant: Groundwater is generally cleaner than
surface water and may require less treatment. These plants focus on
removing minerals, iron, and other localized contaminants.
• Desalination Plant: Desalination plants are crucial in arid regions or
areas with limited freshwater sources. They convert seawater or brackish
water into freshwater through processes like reverse osmosis or
distillation.
• Wastewater Treatment Plant: Wastewater treatment plants clean sewage
and industrial wastewater, preventing the release of harmful pollutants into
natural water bodies. They are vital for environmental protection.

11. Steps Involved in Treating Water
•Coagulation and Flocculation: Addition of chemicals to clump together
particles
• Sedimentation: Settling of large particles at the bottom
• Filtration: Passage of water through sand, gravel, or other media to remove finer
particles
• Disinfection: Killing or inactivation of harmful microorganisms, typically with
chlorine or UV light
• pH Adjustment: Balancing the water's acidity/alkalinity
• Taste and Odor Control: Removal of compounds causing unpleasant taste or smell

12. Step 1: Coagulation and Flocculation
• Coagulation: In this step, chemicals such as aluminum sulfate (alum) or
ferric chloride are added to raw water.
• These chemicals create positively charged particles (coagulants) that
attract and neutralize negatively charged particles in the water, like dirt,
bacteria, and other impurities.
• In the coagulation step, a commonly used chemical is aluminum sulfate,
often referred to as alum. The chemical reaction occurs as follows:
Aluminum Sulfate (Alum) Coagulation: Al2(SO4)3 + 6H2O → 2Al(OH)3
+ 3H2SO4
Ferric Chloride Coagulation: FeCl3 + 3H2O → Fe(OH)3 + 3HCl
In both reactions, the coagulant combines with water to form metal
hydroxides (e.g., aluminum hydroxide or ferric hydroxide) and may generate
acids (H2SO4 or HCl). These metal hydroxides are positively charged
and serve as nuclei for the aggregation of negatively charged

13. Flocculation:
• Once coagulation has introduced these positively charged particles into
the water, the next step is flocculation.
• Once the coagulants have neutralized the impurities, slow mixing is used
to encourage the formation of larger particles known as floc.
• The purpose of flocculation is to facilitate the removal of these
impurities in the subsequent sedimentation step.
• No specific chemical reactions occur during flocculation; rather, it is a
physical process that encourages the collision and sticking together of the
coagulated impurities.
• Floc particles are a combination of coagulated impurities, and they are
easier to settle and remove in subsequent steps.

14. • Together, coagulation and flocculation are crucial for reducing the negative
charge on suspended particles and forming larger, settleable floc.
• This prepares the water for the subsequent sedimentation step where the floc
settles out, leaving clearer water above.

15. Step 2: Sedimentation
• After flocculation, the water is allowed to sit undisturbed in a large basin
or settling tank.
• During this period, gravity causes the heavy floc particles to settle at the
bottom of the tank.
• This leaves the clearer water above the settled particles. Sedimentation
helps separate the bulk of impurities from the water.
• During this period, gravity plays a key role in the separation of heavy floc
particles from the water.

16. Settling Process:
• After the water has undergone coagulation and flocculation, it contains floc
particles that are now much larger and heavier due to the aggregation of
impurities. In the settling tank, these larger floc particles begin to settle under
the influence of gravity.
Gravity's Role:
• Gravity causes the heavier floc particles to gradually descend to the bottom of
the settling tank.
• This downward movement occurs because the floc particles are denser than the
surrounding water.

17. Clarification:
• As the floc particles settle, they accumulate at the bottom of the tank,
leaving the water above much clearer.
• The water at the top of the tank is now separated from the bulk of
impurities, and it is referred to as clarified water.
Sludge Removal:
• Over time, the settled floc forms a layer of sludge at the bottom of the tank.
• This sludge contains the impurities that were removed from the water.
• Periodically, the accumulated sludge is removed from the tank for further
treatment or disposal.

18. Benefits of Sedimentation:
• Sedimentation effectively separates a significant portion of impurities,
suspended solids, and large particles from the water.
• It plays a key role in reducing the turbidity (cloudiness) of the water, improving
its clarity.
• The clarified water, which is now substantially cleaner, is ready to proceed to the
next stages of the treatment process, such as filtration and disinfection.
• In summary, sedimentation is a fundamental process that relies on the force of
gravity to allow heavy floc particles to settle at the bottom of a tank,
separating them from the clearer water above.
• This step is crucial for achieving water clarity and quality in the treatment
process.

19. Step 3: Filtration
• The clarified water from the sedimentation tank moves on to the filtration
stage.
• Here, the water passes through layers of different filter media, which
typically include sand, gravel, and sometimes activated carbon.
• These filter materials trap remaining fine particles, suspended solids,
and some microorganisms.
• Filtration further improves water clarity and quality.
• The filtration stage in water treatment is a crucial step that enhances the
clarity and quality of water by removing remaining fine particles,
suspended solids, and some microorganisms.

20. Filtration Media:
• Sand: Sand is often used as the primary filter medium in water treatment plants.
It has fine grains that can effectively trap smaller particles. As water passes
through the sand bed, suspended particles are physically trapped within the
pore spaces between the sand particles.
• Gravel: Gravel, which is coarser than sand, is commonly used as a supporting
layer beneath the sand. It provides structural support for the sand layer and
helps distribute the flow of water evenly.
• Activated Carbon: In some water treatment plants, activated carbon may be
added as an additional layer or used as a separate filtration unit. Activated
carbon has a high surface area and is effective at adsorbing organic compounds,
taste and odor-causing substances, and some chemical contaminants. It helps
improve the taste and odor of the treated water.

21. Filtration Process:
Passage through Media:
• The clarified water from the sedimentation tank is evenly distributed over the top of
the filter bed, typically composed of layers of gravel and sand.
• Water percolates downward through these layers, and as it does, suspended particles in
the water become trapped within the filter media.
Straining and Adsorption:
• Filtration operates based on physical mechanisms such as straining and adsorption.
Larger particles are physically trapped in the gaps between filter media particles, while
activated carbon can adsorb certain dissolved substances.
• Cleaning and Backwashing: Over time, the filter media can become clogged with
accumulated particles. To maintain filtration efficiency, the filters need to be cleaned
periodically through a process called backwashing. In backwashing, water flow is
reversed through the filter, dislodging and flushing out trapped particles. This water,
known as backwash water, is typically treated separately before being discharged.

22. Benefits of Filtration:
• Filtration enhances the quality of treated water by removing fine
particles, sediments, and some microorganisms.
• It contributes to the reduction of turbidity (cloudiness) and improves
water clarity.
• Filtration is a critical step for meeting regulatory standards for safe
drinking water.
• In the case of activated carbon, it can effectively remove organic
contaminants, improve taste, and reduce odors, making the water more
appealing to consumers.
• Overall, the filtration process is a fundamental part of water treatment
that ensures the water supplied to communities is clear, safe, and
aesthetically pleasing.

23. Step 4: Disinfection
• Disinfection is a crucial step to ensure that the treated water is free from
harmful microorganisms such as bacteria, viruses, and other pathogens.
There are two common methods used:
• Chlorination:
• Ultraviolet (UV) Disinfection:

24. Chlorination:
• Chlorine or chloramine is added to the water to kill or inactivate bacteria,
viruses, and other pathogens. It also helps prevent regrowth of
microorganisms in the distribution system.
• Chlorine gas (Cl2) or sodium hypochlorite (NaOCl) is commonly used for
disinfection. The chemical reactions with water result in the formation of
hypochlorous acid (HOCl) and hypochlorite ions (OCl-), which are effective
disinfectants:
• Chlorine Gas (Cl2):
• Cl2 + H2O → HOCl (Hypochlorous Acid) + HCl (Hydrochloric Acid)
• Sodium Hypochlorite (NaOCl):
• NaOCl + H2O → HOCl (Hypochlorous Acid) + NaOH(Sodium Hydroxide)
• Chloramines (NH2Cl):
• Chloramines are formed when chlorine reacts with ammonia in the water. There are
multiple forms of chloramines, such as monochloramine, dichloramine, and
trichloramine, each with different disinfection properties.

25. • Hypochlorous acid (HOCl) and other chlorine species are highly effective at
damaging the cellular structures and genetic material of microorganisms,
preventing them from reproducing and causing disease. Chlorine also offers
residual protection by inhibiting the regrowth of microorganisms in the
distribution system.

26. Ultraviolet (UV) Disinfection:
• UV disinfection is a non-chemical method that uses ultraviolet light to
damage the genetic material (DNA) of microorganisms.
• This damage prevents the microorganisms from reproducing, rendering
them harmless.
• UV disinfection does not introduce chemicals to the water, making it an
attractive option for those concerned about chemical additives.
• UV disinfection is especially effective against bacteria, viruses, and
protozoa.
• The process does not involve chemical reactions but relies on the physical
effects of UV light on the genetic material of microorganisms.

27. Benefits of Disinfection:
• Disinfection is a critical barrier against waterborne diseases, ensuring that treated
water is safe for human consumption.
• It provides residual protection in the distribution system, preventing microbial
regrowth and maintaining water quality.
• UV disinfection is a chemical-free method that does not alter the taste or odor of
the water.
• In summary, disinfection is a vital step in water treatment that safeguards public
health by destroying or inactivating harmful microorganisms in the water.
Chlorination and UV disinfection are common methods employed to achieve this
goal.

28. Step 5: pH Adjustment
• pH adjustment is a crucial step in the water treatment process that
focuses on balancing the water's acidity (pH) or alkalinity to achieve a
desired and stable pH range.
• The pH of water has a significant impact on various aspects of water
quality, including its corrosivity and the effectiveness of disinfection.
• Two common methods are used for pH adjustment:
• to raise the pH (make water less acidic), sodium hydroxide (NaOH) may
be added:
• NaOH + H2O → Na+ + OH- + H2O
• To lower the pH (make water more acidic), carbon dioxide (CO2) can be
introduced:
• CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3
-

29. Raising the pH (making water less acidic):
• One common chemical used to raise the pH of water is sodium hydroxide
(NaOH). Sodium hydroxide is an alkaline compound that, when added to
water, increases the concentration of hydroxide ions (OH-) and decreases
the concentration of hydrogen ions (H+). Here's the chemical reaction
involved:
• NaOH + H2O → Na+ + OH- + H2O
• The addition of sodium hydroxide helps increase the pH and makes the
water less acidic. This is particularly important because water that is too
acidic can be corrosive to pipes and infrastructure.

30. Lowering the pH (making water more acidic):
• To lower the pH and make water more acidic, carbon dioxide (CO2) can be
introduced. Carbon dioxide dissolves in water and reacts to form carbonic
acid (H2CO3). Carbonic acid can further dissociate into hydrogen ions (H+)
and bicarbonate ions (HCO3-). This results in increased acidity. The
reactions are as follows:
• CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-
• Lowering the pH can be necessary in cases where water is too alkaline, and
adjusting the pH ensures that disinfection processes, such as chlorination,
remain effective.

31. Benefits of pH Adjustment:
• Proper pH adjustment helps prevent the corrosion of pipes and infrastructure,
ensuring the integrity of the distribution system.
• pH adjustment can enhance the effectiveness of disinfection methods, such as
chlorination, by optimizing the pH for their operation.
• It helps ensure that the treated water is within an acceptable pH range, which is
typically between 6.5 and 8.5 for safe and palatable drinking water.
• In summary, pH adjustment is a critical step in water treatment that involves
adding chemicals like sodium hydroxide or carbon dioxide to bring the pH of
water into a desired and safe range, balancing its acidity or alkalinity for various
important purposes in the treatment process.

32. Taste and Odor Control
• Taste and odor control is a significant aspect of water treatment that
focuses on improving the aesthetic quality of water by addressing
compounds that cause unpleasant tastes or odors.
• In some cases, even after undergoing various treatment processes, water
may still contain substances responsible for these undesirable
characteristics.
• Two common methods used for taste and odor control are
• Activated carbon filtration
• Chemical oxidation

33. Activated Carbon Filtration:
• Activated carbon, a highly porous and adsorbent material, is used as a filtration
medium to remove compounds responsible for taste and odor issues.
• The process involves adsorption, where the unwanted substances are attracted
to and retained on the surface of the activated carbon particles.
• These substances can include organic compounds, certain chemicals, and
naturally occurring compounds like geosmin and 2-methylisoborneol (MIB),
which are responsible for earthy and musty odors in water.

34. 2. Chemical Oxidation:
• In some cases, chemical oxidation methods may be employed to neutralize taste
and odor compounds.
• One common chemical used for this purpose is potassium permanganate
(KMnO4).
• The reaction involves the oxidation of the compounds causing the taste and odor
issues.
• While this method is effective, it's essential to carefully control the dosing of the
chemical to avoid introducing excessive residuals or potentially harmful
byproducts into the water.

35. Benefits of Taste and Odor Control:
• Taste and odor control methods improve the overall palatability of the treated
water, making it more appealing to consumers.
• These methods enhance the aesthetic quality of the water and provide a more
enjoyable drinking experience.
• Effective taste and odor control ensures that the water meets regulatory
standards and is safe for consumption while addressing issues that are not
health-related but affect the drinking experience.
• In summary, taste and odor control is a vital component of water treatment that
addresses compounds responsible for unpleasant tastes and odors in water.
Methods like activated carbon filtration and chemical oxidation are used to
enhance the aesthetic quality of the water, providing clean and healthy water to
communities that meet regulatory standards for safe drinking and other uses.

36. Testing and Monitoring
• Testing and monitoring are essential components of the water treatment process.
They serve to verify the effectiveness of treatment, ensure water quality, and
meet regulatory standards. There are various methods employed for this
purpose:
• Laboratory Testing:
• Online Monitoring:

37. • Laboratory Testing:
• Laboratory testing involves the regular collection and analysis of water
samples for various critical parameters.
• These parameters help assess the quality of the treated water. Key
parameters commonly analyzed in the laboratory include:
• pH: The measurement of water's acidity or alkalinity.
• Turbidity: The clarity or cloudiness of the water.
• Microbiological Contaminants: Detection of harmful microorganisms
like coliform bacteria.
• Chemical Contaminants: Analysis for chemicals such as heavy
metals, organic compounds, and disinfection byproducts.
• Nutrients: Monitoring of nutrients like nitrates and phosphates that
may promote the growth of algae and affect water quality.

38. 2. Online Monitoring:
• Online monitoring employs sensors and instruments placed throughout the
treatment process. These devices provide real-time data on various water quality
parameters. Some common parameters monitored online include:
• Turbidity: Continuously measuring water clarity to detect changes or deviations.
• pH: Continuous monitoring to ensure the pH remains within the desired range.
• Chlorine Residual: Monitoring the presence of chlorine to maintain disinfection
effectiveness.
• Flow Rate: Tracking water flow throughout the treatment process.
• Temperature: Measuring water temperature, which can influence various
treatment processes.

39. Compliance with Regulations:
• Water treatment plants are required to adhere to local, state, and national
standards and regulations for water quality.
• These standards define limits for various parameters and establish guidelines to
ensure safe drinking water.
• Compliance with these regulations is crucial to safeguard public health and
environmental protection.

40. Benefits of Testing and Monitoring:
• Testing and monitoring ensure that treated water consistently meets safety and
quality standards.
• They provide early detection of deviations or issues in the treatment process,
allowing for timely corrective actions.
• Compliance with regulations is vital for legal and public health reasons, ensuring
that the water supplied to communities is safe and within established quality
limits.
• In summary, testing and monitoring are integral to the water treatment process,
providing ongoing assessment of water quality and ensuring that the treated
water meets safety standards. Continuous monitoring and compliance with
regulations are key aspects of maintaining a safe and reliable water supply.

41. QUESTIONS ?