herewith i am uploading the important points on water supply engineering.

1. General requirements for water
supply:
• To ensure safe wholesome water to the public
adequately.
• To provide assured supply of water easily to the
users.
• To minimize the loss during transmission.
• To eliminate the chances of water contamination.
• To achieve the necessary flushing action in the
sewerage system.
• To provide adequate supply for fire-fighiting.

2. Population forecasting:
The expected population after the design period (25 to50
years) can be forecast using the following formulae.
1. Arithmetical increase method
2. Geometrical increase method
3. Incremental increase method
4. Graphical method
5. Comparative method
6. Zoning method
7. Ratio and correlation method
8. Growth composition analysis method
9. Logistic method

3. Sources of water:
1. River
I. Perennial rivers
II. Non perennial rivers
III. Lakes and streams
IV.Impounded or storage reservoirs
V. Seas
VI.Stored rain water in cisterns
VII.Ponds
VIII.Waste water reclamation
2. Springs
a. Artesian springs
b. Gravity springs
c. Surface springs

4. Sources of water:
3. Infiltration galleries
a. Pores pipe galleries
b. Infiltration wells
c. Wells
4. As per aquifer types
a. Shallow well
b. Deep wells
5. As per the condition of flow
a. Gravity wells
b. Artesian wells
6. As per the types of construction
a. Dug wells
b. Driven wells
c. Tube wells
d. Sunk wells

5. Yield of a well:
• The rate of withdrawal or pumping of water from well
without causing failure or drying of it is called yield of a
well.
• Thus it is the rate at which a well delivers water.
The following factors affect the yield of the wells.
1. Dimensions of wells
2. Location of nearby wells
3. Porosity of aquifer
4. Quantity of water present in the aquifer
5. Rate of pumping water
6. Slope of water table
7. Height of water table above bottom of well.

6. Collection and conveyance of water:
• Intakes are the structures used to collect
water from the surface sources which are
relatively clean, free from pollution, sand
other objectionable floating materials.
Types of intakes.
1. Canal intakes
2. Reservoir intakes
3. Lake intakes
4. River intakes

7. Necessity of pumps:
1. To lift raw water from source of water supply.
2. To lift raw water from wells
3. To increase the pressure in the pipe lines
4. To pump the treated water into the distribution
reservoirs or overhead tanks.
5. To lift raw water from, low level sources to
treatment works
6. To deliver treated water to desired pressure etc.,

8. Types of pumps:
1. Service pumps
2. Mechanical principle of operation
3. Type of power required
Service pumps:
1. Booster pumps
2. Deep well pumps
3. High lift pumps
4. Low lift pumps
5. Stand-by pumps
6. Chemical injection pumps
7. Unchokable pumps
8. Boiler-feed pumps
9. Cooling-water pumps etc.,

9. Conveyance of water:
• Transmission of water indicates the conveyance of water
from the source to purification plants and from treatment
plants to consumers.
Types of pipes:
1. Cast-iron pipes
2. Cement concrete pipes
3. GI pipes
4. Lead pipes
5. Plastic pipes
6. Steel pipes
7. Vitrified clay pipes
8. Wrought iron pipes
9. Copper pipes
10. Cement lined CI pipes
11. Asbestos cement pipes

10. Laying of pipes:
1. Preparation of detailed maps
2. Fixing the alignment.
3. Excavation of trenches
4. Bottoming of trenches
5. Lowering of pipes
6. Laying of pipes
7. Joining of pipes
8. Anchoring of pipes
9. Back-filling

11. Quality of water:
1. It should be free from disease producing
bacteria's.
2. It should be colourless, odourless and tasty less.
3. It should be free from harmful salts and other
objectionable matter.
4. It should be noncorrosive, cheap in cost.
5. Free from iron and manganese.
6. It should have high amount of DO.

12. Physical characteristic:
They impart colour, odours, and taste of the
water.
They are not serious and can be detected and
removed.
They are may be presence of suspended,
dissolved and colloidal forms.

13. Chemical characteristic:
• Organic impurities: suspended impurities,
dissolved impurities
• Inorganic or mineral impurities: suspended
impurities, dissolved impurities

14. Biological characteristic:
pathogens: or disease producing
microorganisms
Non pathogens or non dangerous
microorganisms
Viruses, microscopic organisms, algae, protozoa,
fungi, actinomycetes, worms, bacteria etc.,

15. Water borne diseases:
The diseases are cholera, dysentery, typhoid,
paratyphoid, jaundice, tuberculosis, hepatitis
etc.,

16. WHO Standards of water:

18. BIS standard:

19. Water treatment process:

20. Water distribution system:
Safe and wholesome water to all parts of the area served
at adequate pressure and quantity.
The distribution system consists of :
1. Pipes line of different sizes to convey water.
2. Valves for controlling the flow in the pipe line
3. Meters for measuring the consumption.
4. Hydrants for providing connections with water mains
for releasing water during fires.
5. Service connections to the individual houses.
6. Pumps for lifting and facing the water into the
distribution pipes.
7. Service reservoirs: for storing the treated water and
feeding to the distribution pipes.

21. Different types of water suppling:
1. System of conveyance:
a) Gravity system
b) Pumping system
c) Combined pumping and gravity
2. System of water supply:
a) Continuous system
b) Intermittent system
3. System of distribution:
a) Tree branch or dead end system
b) Grid system
c) Circular or ring system
d) Radial system

22. Types of reservoirs:
1. Surface reservoirs
2. Elevated reservoirs

23. DO and BOD in streams:
• The rate of biological activity increases with increase in
temperature and decreases with decrease in
temperature, hence the rate of oxygen demand also
increases with increase in temperature and decrease in
temperature
• The dissolved oxygen content of water, which is very
essential for maintaining aquatic life and aerobic
conditions, is also influence by the temperature. The
solubility of oxygen decreases with increase in
temperature. The solubility of oxygen decreases with
increase in temperature. So at higher temperature the
rate of biological activities is high and the DO
concentration is low, causing rapid depletion of DO.
This can results in a development of anaerobic
conditions and subsequent nuisance.

24. Waste water engineering:

25. Chemical characteristics of sewage
• These indicate the state of sewage
decomposition, its strength and type of
treatment required.
• Fresh sewage is alkaline and good for bacterial
action.
• Stale or septic sewage is acidic and difficult to
be efficiently treated.
• The chemical characteristics are dependent
upon the substances contained in sewage.

26. Composition:
• An average sewage contains around 1000 mg/l in
solution and suspension and this is about 99.9
percent pure water.
Forms of solids present:
I. Suspended solids – either suspended or in
floating in the liquids.
II. Dissolved solids – dissolved in sewage
III. Colloidal solids – finely divided solids either
solution or suspension.
IV. Settleable solids – portion of solid matter which
settle out if sewage allowed to remain
undisturbed for a period of 2 hours.

27. The solids in sewage comprise of both the organic and
inorganic matter.
Organic matter:
• For about 70 percent of the total solids and consists of
animal and vegetable wastes and proteins,
carbohydrates from vegetable matter, etc.,
Inorganic matter:
• For remaining 30 percent of solids and consists of
minerals and salts, sand, gravel, debris, dissolved salts,
chlorides, sulphates etc.,
• Sewage also contains gases obtained from atmosphere
and reaction of bacteria on compounds in solution and
suspension. These gases are mostly H2S, CO2, CH4.

28. Biological characteristic of sewage:
• The presence in microorganisms which include
bacteria, fungi, algae, protozoa, rotifers,
crustaceans and viruses.
• The role played by them in stabilizing organic
matter as in sewage treatment and in
influencing human environment.

29. Bacteria:
• These are single cell organisms which use soluble and
are capable of reproduction.
• The fundamental organisms in the stabilization of
organic wastes and are much important in biological
treatment.
• 1 liter of sewage may contain 22-55 million bacteria.
• Most of the bacteria are harmless to man and largely
engaged the process of complex to simple form of
organic matter of sewage.
• Some of the bacteria may be harmful, particularly the
disease – producing or pathogenic type, may real
danger to the health of the public.

30. Classification of bacteria:
I. Heterotrophic bacteria:
• Use organic compounds and carbon source for
synthesis.
• They can be broken up into three groups based
upon the manner of satisfying their oxygen
requirements.
These are:
1. Aerobic bacteria
2. An aerobic bacteria
3. Facultative bacteria

31. Aerobic bacteria: require free dissolved oxygen
and their multiply.
An aerobic bacteria: live and develop in the
absence of free dissolved oxygen and their
oxygen requirement come from the oxygen
radicals of organic compounds and mineral
substances as nitrates and sulphates.
Facultative bacteria: these types of bacteria live
with or without oxygen.
Eg: E.Coli

32. II. Autotrophic bacteria:
• Use CO2 as a carbon source and oxidize
inorganic compounds for energy.
• their importance is principally in the corrosion
of pipe sewer as well as in pipes conveying
water containing dissolved iron.
They can be classified as aerobic, anaerobic and
facultative depending on their need for oxygen.

33. fungi:
• Are multi cellular, non- photosynthetic plants
and include yeasts, molds and bacteria.
• Most fungi are strict aerobes.
• They have the ability to grow under low
moisture condition and low pH environment
in the range 2 to 9.

34. Algae:
• Are uni-cellular or multi-cellular autotrophic
plants.
• The presence of sunlight algae convert the
inorganic materials in the form of protoplasm
through the process of photosynthesis.
• The ability of produce oxygen is extremely
important to the ecology of the water
environment.
• Algae are autotrophic using CO2, grow in
abundance in oxidation ponds rich in inorganic
nutrients.

35. Protozoa:
• Single cellular animals which reproduce by
binary fission and live mainly eating bacteria.
• The protozoa are of important in biological
treatment are strictly aerobic, non-
photosynthetic, found in oxidation ponds,
trickling filter and activated sludge.

36. Rotifers:
• These are the simplest multi – cellular
animals.
• They are strictly aerobic and metabolize solid
food from bacteria.
• They can ingest only small organic particles.
• They are generally found low polluted water
like stable stream, lakes and ponds.

37. Crustaceans:
• They are multi-cellular animals having rigid
shell structure.
• The crustaceans are strict aerobes which feed
on bacteria and algae.
• They are important as a source of food for
fish.
• They are generally found in stable stream,
lakes and ponds

38. Viruses:
• They are smallest plant cells known at present.
• These are intercellular parasites which their
nutrient from the host organisms in which they
also reproduce.
• Many viruses are pathogenic disease – producing
in humans.
• in waste treatment, viruses need to be effectively
controlled which is usually done by chlorination.

39. Growth pattern of biological
microorganisms:
• Bacteria producing by binary fission. The
original cell begins two new organisms.
• The time required for fission can vary from
days to less than 20 minutes.
• The general growth pattern of bacteria in
three phases.
1. Logarithmic growth phase
2. Declining growth phase
3. Endogenous growth phase

40. Biological growth pattern

41. Logarithmic growth phase:
• The microorganisms come in contract with
substrate I.e., food which is organic matter.
• The microorganisms start to reproduce by
binary fission.
• The number and the mass of microorganisms
rapidly increase but the increase in the rate of
metabolism is limited by the microorganisms
ability to process the substrate.

42. Declining growth phase:
• Occurs due to the limitation of the available
food.
• The micro organisms lower the food
concentration, the rate of growth becomes
less.
• The food gets exhausted, the growth of new
cells is offset by the death of old cells, so the
population remains stationary.

43. Endogenous phase:
• When growth ceases, the food concentration
is at a minimum.
• The microorganisms still compete for the
remaining small quantity of organic matter
solution.

44. Biological oxidation:
• The sewage treatment processes principally
involve the oxidation of organic matter in
association with the heterotrophic group of
bacteria generally under aerobic or anaerobic
conditions.
• Aerobic : organic matter + bacteria+O2 CO2 +
H2O + NH3 + energy
• Anaerobic :organic matter + bacteria
Intermediates + CO2 + H2O + NH3 + energy
Organic acid intermediates CH4 + CO2 + energy