ebook water 123

e-Book
DCC5152
Water Supply & Wastewater Engineering

Raja Norazilla Bt Raja Yunus 0177181033
Dr. Zummy Dahria Binti Mohamed Basri 012-8556927

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WATER SUPPLY & WASTE WATER ENGINEERING is a
study of water resources, water characteristics, usage

and demand of water supply, raw water treatment
process and water distribution system. This course also

includes the information on the process in sewage
treatment plant, sludge treatment and disposal. It also

emphasize on the parameter of drinking water and
effluent from sewage treatment plant.

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CHAPTER 1

WATER RESOURCES
AND QUALITY

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Chapter 1 : Water Resources and Quality

Streams Lakes Sources of Water Supply Well
River
Reservoirs Surface water Ground water Precipitation

Aquifers.

Stored rain Wastewater Sea water
water in reclamation
cisterns

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Chapter 1 : Water Resources and Quality

Colour temperature Suspended solid
Turbidity Taste & odour
Physical
pH value Dissolved solid Biological Algae
Dissolved oxygen Water Quality Bacteria
Chemical Characteristics

Virus

Hardness Nutrient Protozoa
(C, N, P)
Mineral content Fecal coliform &
(Pb, Fe, Mn) Organic matter Total coliform

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Industrial Municipal Agricultural Chapter 1 : Water Resources and Quality
Landfill Natural
Sources of Water Pollution Solution

Stormwater 7

Sources Examples Effect

Industrial sources of water pollution washing and
Municipal sources of water pollution rinsing water, solubilizing water, diluting water, sewage and shower or sink
Agricultural sources of water pollution water
Natural sources of water pollution
wastewater are feces, urine, paper, food waste, laundry wastewater and
sink, shower or bath water. These pollutants are all biological and such can be
readily biodegraded.

Agricultural wastewater can
be of animal or vegetable origin or be from a nutrient, fertilizer, pesticide or
herbicide source.

animal, vegetable and soil sources

Landfill sources of water pollution surface and underground leachate

heavy metals including acid mine drainage Lead, a metal found in natural deposits, is commonly used in household
plumbing materials and water service lines.

CHAPTER 2

USAGE AND DEMAND
OF WATER

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Domestic Chapter 2 : Usage and Demand of Water

Commercial / trade
purposes

Public or civic use Water Usage Industrial
Classification

Losses / wastes Agricultural

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Chapter 2 : Usage and Demand of Water
Industries and commerce

Size of city

Miscellaneous factors Factors Affecting
Demand of Water
Characteristics of population
Metering

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Forecasting the Population Chapter 2 : Usage and Demand of Water

Migration rate Birth

Factors Influence the
Population Growth

Decease rate

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Forecasting the Population Chapter 2 : Usage and Demand of Water

Geometric Graphical / Curvilinear

Arithmetic

Methods of Forecasting Population Logistic curve / S-curve

Incremental Zoning Ratio / Correlation

Arithmetic Geometric

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1. Arithmetic Increase Method

Methods of Forecasting✓ This method is based on the assumption that the rate of growth is
constant. An average increment in the population of the past three or
four decades is worked out.

Population✓ For each successive future decade, this average increment is added. This

method gives too low estimate.
✓ This method can be adopted for forecasting populations of large cities

which have achieved saturation conditions.

EXAMPLE

Referring to the given data, estimate the population for

Behrang Bitara for the year 2020 and 2030 by using

Arithmetic Method. (5 marks)

Year 1970 1980 1990 2000 2010
Population 29 000 36 000 38 000 42 000 43 000

SOLUTION

1 decad = 10 years

P2020 = pn-1 + ka.∆t
= P2010 + ka. (2020-2010)
= 430v 00 + (350 x (10))
= 46500 persons

P2030 = pn-1 + ka.∆t
= P2v020 + ka. (2023-2020)
= 46500 + (350 x (10))
= 50000 persons

Problem2.1

Calculate the expected population in 2010, 2020 and 2030
by arithmetic increase method

Year 1960 1970 1980 1990 2000
population 55,000 60,000 66,000 75,000 80,000

Answer:

P2010 = 86,250 person
P2020 = 92,500 person
P2030 = 98,750 person

Methods of Forecasting Population

2. Geometric Increase Method

✓ This method assumes the percentage increase in population
from decade to decade as constant, and it gives high results.

✓ The percentage increase gradually drops when the growth of
city reaches the saturation point.

✓ The fixation of percentage increase should be done carefully.
✓ This method is useful for expansion and where a constant

rate of growth is anticipated.

EXAMPLE

Referring to the given data, estimate the population
projection for Taman Wangsa Suria for the year 2030 by
using Geometric Increase Method. (CLO1, C2) ((5 marks)

Year 1990 2000 2010
Population 28 000 32 000 42 500

SOLUTION

Year Population Nilai ka ln (32 000/28 000)
2000- 1990
t1 – 1990 p1 – 28 000 Kj1 = ln (p2/p1)
t2 - t1 = 0.0133

t2– 2000 P2 -32 000 Kj2 = ln (p3/p2 ) ln (42 500/32 000)
t3– 2010 P3 -42 500 t3 - t2 2010- 2000

0.0284

Kj average = (0.0133 + 0.0284)/2
= 0.0208

• lnP2020 = ln pn-1 + kj.∆t 1 decad = 10 years

= ln (4v2 500) + 0.0208 (2020 – 2010) Year Population

= shift ln (10.86526)

• P2020 = 52v327 peoples t1 – 1990 p1 – 28 000

• lnP2030 = ln pn-1 + kj.∆t t2– 2000 P2 -32 000
P3 -42 500
= ln (52 327 ) + 0.0208 (2030 – 2020) t3– 2010

= shift ln (11.07326)

• P2030 = 64425 peoples

Problem2.2

Calculate the expected population in 2010, 2020 and 2030 by
geometric increase method

Year 1960 1970 1980 1990 2000
population 55,000 60,000 66,000 75,000 80,000

Answer:
P2010 = 87,858 person
P2020 = 96,488 person
P2030 = 105,966 person

PASS YEAR QUESTION JUN 2019



Chapter 2 : Usage and Demand of Water

Problem

• Calculate the expected population in 1990, 2000 and 2010 by arithmetic increase method and
geometric increase method.

Year 1940 1950 1960 1970 1980
Population 55,000 60,000 66,000 75,000 80,000

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Chapter 2 : Usage and Demand of Water

Water Demand Forecasting

Total population served Population served means the total number of persons served by a public water supply that provides water intended for human consumption. For
Percapita consumption municipalities which serve only the population within their incorporated boundaries, it is the last official U.S. census population (or officially amended
census population).
Service factor
Per Capita Demand (q) in litres per day = Total water demand a year (litre)
365 x total population (capita/day)

A service factor of 0.9 means that the distribution system covers adequately 90% of the area
and the population located in that area can get easy access to public water supply

Design factor The design factor is to equalize the differences from month to-month according to season
factors, weather, society's habit, industrial activities, trade and agriculture.

Additional demand such as industrial, army camp, institution of higher learning.

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Estimation for Water Demand Chapter 2 : Usage and Demand of Water

Useful life based Expected Formula for water demand
on wear and tear population estimation
growth &
developments WDn=Pn x q x F1 x F2 ……… + Dm
WDn = water demand at the end of year “n”
Design period governed by Pn = projected population at the end of year “n”

F1 = service factor at the end of year “n”
F2 = design factor at the end of year “n”

Feasibility for Financial
addition or constraints &
expansion interest rates

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Case 1 : Resident Area Only (Houses)

• From the data given, WDn = (Pn x q x F1 x F2) + Dm
• Pn = population estimation year n
• q = water demand

F1 = service factor

• F2 = design factor

• Dm = additional demand

Water Demand for Resident Additional Demand for resident

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Case 2 : Resident Area with Indusrtrial / institution

• From the data given, WDn = (Pn x q x F1 x F2) + Dm
• Pn = population estimation year n
• q = water demand

• Industrial water needs = 1 / 3 of the population needs
F1 = service factor

• F2 = design factor

• Dm = additional demand

Water Demand Additional Demand Water Demand Additional Demand
for Resident for resident for Industrial for Industrial

WDn = (P x q x f1 x f2) + % Dm (P x q) +1/3 (P x q x f2) + % Dm (1/3 x P x q)

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The following data obtained from Parcel 7 in 2012. Calculate the water demand in 2017.

◦ Total household = 6000
◦ Average household member = 6 people
◦ Per capita water consumption = 270 L/day
◦ Population growth = 2.65% per year
◦ Industrial water needs = 1/3 of the population needs
◦ Design factor = 2.4
◦ Percentage of NRW = 15%
◦ Water supply coverage = 97%

Pn = Po(1+r)n ; WDn=Pn x q x F1 x F2 + Dm
Answer : WD = 36.87 x 106 L/day

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Chapter 2 : Usage and Demand of Water

Problem

• The data given are collected from Seksyen 7 Shah Alam in 2015. Estimate the daily water demand if water
supply coverage is 95%.

Total population = 330,200
Water usage per capita = 280 L/day
Industry water demand = 1/3 from requirements of population
Design factor = 1.5
NRW = 15%

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CHAPTER 3

WATER TREATMENT

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Water Quality Standards

• The definition of water quality depends on the intended use of
the water which may be either human consumption or it may be
for industries, irrigation, recreation etc..

• Depending upon the proposed use of water, certain water quality
criteria are established and based on these criteria quality
standards are specified by health and other regulation agencies.

• Different types of water require different level of water purity.

• Drinking water requires highest standard of purity where as water
of lower quality

Chapter 3 : Water Treatment

To provide final water
going into supply with an

acceptable quality

Reasonable cost for Objectives of Ensure the final water
treated water Water Treatment leaving the treatment
plant complied with

regulation

To remove dissolve To provide safe water for
gasses, taste and odor in human

water

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More on appearance of Chapter 3 : Water Treatment
water, colour, turbidity,
Microbiological
taste & odour

Physical

Importance of Water
Characteristics

Chemical

- The reaction in water Very important because its
- Different are not visible relationship to human health

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Chapter 3 : Water Treatment
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Chapter 3 : Water Treatment

General Water Treatment Processes

Raw Water Bar screen Water pump Fine screen

Grit removal

User Storage Tank

Fluoridation Disinfection Aeration

pH
adjustment

Filtration sedimentation Flocculation Pre
coagulation sedimentation

Sludge Rapid mixing

Liquid Sludge Semi-solids
treatment

Clean Water 40

General Water Treatment Processes Chapter 3 : Water Treatment
BAR SCREEN
removal of any coarse floating
objects, weeds, etc.

Bar screen assemblies are normally
installed at 60° to 80° angle from the

horizontal.

Prevent pump,
pipe and equipment from clogging or

damage.

Designated to handle relatively large debris, a bar screen 41
consist of a rack of straight steel bars welded at both end to
horizontal steel member.

General Water Treatment Processes AERATION Chapter 3 : Water Treatment
Coke tray aerator
Spray aerator Waterfall / cascade aerator Diffusion / bubble aerator

Mechanisms Mechanisms Mechanisms

Direct the water upward, vertically This aerator allowing the water Consist of rectangular concrete tanks Consist of a series of trays
or at an inclined angle, in such a to flow downwards over a in which perforated pipes, porous equipped with slatted, perforated,
manner that the water is series of steps or baffles. diffuser tubes or
broken into small drops. various patented impingement or or wire-mesh bottoms over
which water is distributed and
Spurger devices are inserted near the allow to fall to a collection basin at
bottom of the aeration
basin. the base.

Installation commonly consists The simplest cascade aerator is a On rising through the water, these In many tray aerators, coarse
of fixed nozzle on a pipe grid concrete step structure which causes cause turbulence and provide media such as coke, stone, or
opportunity for the ceramic balls ranging from 2 to 6
Spray the water to fall in fairly exchange of volatile materials in size are placed in the trays to
aerators are usually quite efficient thin layers from one level to another. between the bubbles and the improve the efficiency of gas
with respect to gas transfer (CO2 water and between the air and
Exposure time can be increased exchange.
removal or O2 addition) by increasing the the water at the latter’s surface. It
and have esthetic value. provides a longer aeration time This aerators are frequently housed.
number of steps, and the area- than one of the waterfall Stainless steel, aluminum, root-
require a large area, cannot be volume ratio can be improved type. resistant wood and concrete are
housed readily, an pose by adding baffles to produce examples of durable-corrosion-
resistant materials
an operating problem during turbulence.
freezing weather.
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Chapter 3 : Water Treatment

GENERAL WATER TREATMENT PROCESSES
PRE-CHLORINATION / PRE-SEDIMENTATION / RAPID MIXING

Pre-chlorination

to oxidized iron and to prevent alga growth that
manganese can clog up treatment plant

component

to reduce heavy sediment Pre-sedimentation removal of color and taste and
loads in surface supplies prior odor-causing compounds prior

to chemical coagulation to lime softening

the process whereby the Rapid Mixing can be accomplished within
chemicals are quickly and a tank utilizing a vertical
uniformly dispersed in the water shaft mixer

the most important physical
operation affecting coagulant dose

efficiency

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General Water Treatment Processes
COAGULATION AND FLOCCULATION

Alum (aluminum Polymers Chapter 3 : Water Treatment
sulfate
Coagulation and flocculation processes
Sodium Coagulants Ferric Chloride
aluminate(Al3+) 1 Alum added to raw water reacts with the alkalinity naturally

Ferric sulfate(Fe3+ ) Ferrous Sulfate present to form jellylike floc particles of aluminum hydroxide,
Al(OH)3.
Key properties of coagulant Trivalent cation: Colloids mostly found in natural
waters are negatively charged; hence a cation is 2 The positively charged trivalent aluminum ion neutralizes the

required to neutralize the charged. negatively charged particles of color or turbidity. This occurs within l or
2 seconds after the chemical is added to the water.
Non-toxic: This requirement is obvious
for the production of a safe water 3

Insoluble in the neutral pH range: The coagulant that Within a few seconds, the particles begin to attach to
is added must precipitate out of the solution so that each other to form larger particles.
high concentrations of ion are not left in the water.
4
The floc that is first formed consists of micro floc that
still has a positive charge from the coagulant

5

Finally, the micro floc particles begin to collide and stick together
(agglomerate) to form larger, settleable floc particles

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General Water Treatment Processes Chapter 3 : Water Treatment
SEDIMENTATION AND FLOTATION
The float is removed from
electrolytic floatation, the surface, and clarified
dispersed-air water is taken from the
floatation and bottom of the floatation

dissolved air flotation tank.

the treatment of Flotation
nutrient-rich reservoir
water that may contain
heavy algae blooms and

for low-turbidity

Sedimentation removes settleable Water moves slowly though the . Sludge accumulates
solids by gravity. Water moves sedimentation tank or basin at bottom of tank or
slowly though the sedimentation with a minimum of turbulence
tank or basin with a minimum of at entry and exit points with basin
minimum short-circuiting.
turbulence at entry and exit points
with minimum short-circuiting Sedimentation

After sedimentation

So the clarified water, with most of the Particles removed, moves
on to the filtration step where the finer particles are removed

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General Water Treatment Processes Rapid sand filter Chapter 3 : Water Treatment
FILTRATION
Rapid sand filters are the most Pressure filter
Slow sand filter commonly used systems for water
supply treatment because of their pressure filters, as in rapid sand
While slow sand filtration systems are reliable and filters, water flows through
use proven technology, modern plants generally reliability. granular media in a filter bed.

don't employ them, because of the variety of Rapid filters contain a layer of pressure systems enclose the bed in a
problems associated with the systems. carefully sieved silica sand over cylindrical steel tank and pump the
water through the media under
These problems are mostly a bed of graded gravel. pressure.
related to small pore spaces in
The pore openings are often This can cause problems with
fine sand. larger than the floc particles to reliability; occasionally solids are
forced through the filter along with the
the small pores filter effectively, be removed, so rapid filter
they also slow down the systems use a combination of effluent
passage of water.
techniques to remove
This also means increased land suspended solids and particulate
usage to house the units. The matter from influent, including
fine pore spaces clog easily as
well, requiring manual scraping simple straining, adsorption,
continued flocculation, and
to clean the filter sedimentation. Filter cleaning is

accomplished by daily
backwashing

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General Water Treatment Processes Characteristics Chapter 3 : Water Treatment
DISINFECTION
They must meet possible fluctuation in composition,
They must destroy the kinds and numbers of pathogens that may be concentration, and condition of the waters or
introduced into water within a practicable period of time over an wastewaters to be treated.
expected range in water temperature

They must be neither toxic to humans and domestic Their strength or concentration in the treated water
animals nor unpalatable or otherwise objectionable must be determined easily, quickly and automatically
in required concentration.

They must be dispensable at reasonable cost,
safe and easy store, transport, handle and apply.

Disinfectant Advantages Disadvantages Application Point
Chlorine
• Effective for viruses, bacteria and Giardia • May result in potentially harmful by-products (THMs) • Variety of application points
Ozone
cysts • Significant safety concerns especially for gas system • To minimize THM formation, generally added to the
Ultraviolet Light
• Can be used either a primary or • May result in precipitation of iron and manganese end of the treatment process

secondary disinfectant

• Chlorine residual can be easily monitored

• Available as a gas, liquid, or solid

• Effective for viruses, bacteria and Giardia • Must be generated on site • Prior to rapid mixing step

cysts • Does not produce a stable, long lasting residual • Should provide adequate time for biodegradation of

• Enhances removal of biodegradable • May result in harmful by-products oxidation products prior to chlorination

organics in slow sand filter • Low solubility in water

• Exhaust gas must be treated to remove ozone

• Difficult to measure residual

• Effective against viruses and bacteria • Not effective against Giardia cysts • Downstream of sedimentation of filtration process

• Limited to groundwater systems not directly influenced

by surface water supply

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produce detectable taste found in to remove Chapter 3 : Water Treatment
and odor, red-colored water groundwater, some of the
surface waters softening
which may stain clothes, hardness reactions are
cooking utensils, and Iron and regulated by
plumbing fixtures. Manganese controlling the pH

removed by Removal Water Softening First, any free
water softening acids are
neutralized

removal can be enhancing by Miscellaneous Water Then pH is raised to precipitate the
Treatment Techniques CaCO3; if necessary, CO32- is added
oxidizing - oxidizing agent to precipitate the noncarbonated
can be atmospheric oxygen,
chlorine, chlorine dioxide, hardness.

ozone, permanganate, or pH adjustment Blowing air into the
any other oxidant water, or spraying water
into the air (to drive off
Adjustment of the pH level during treatment may
be needed to: carbon dioxide).

- make coagulation more effective the addition of alkaline
- make the oxidation of iron and manganese more solutions to the water
placing solid alkaline
effective materials (eg, marble or
- make disinfection by chlorine more effective dolomitic material) in contact
- Reduce its corrosiveness [aggressiveness] before
with the water
distribution.-

the addition of acidic 48
solutions or carbon
dioxide to the water

the application of chlorine to water in order to Chapter 3 : Water Treatment
produce, with natural or added ammonia, a combined Breakpoint Chlorination

available chlorine residual, and to maintain that
residual through part of all of a water-treatment

plant or distribution system.

Combined available chlorine forms have Combined Residual
lower oxidation potential than free Chlorination
available chlorine forms and therefore, are
less effective as oxidant.

Chlorine Residual Free-residual Chlorination
Test
Importance

1 To ensure disinfection occurred completely
2 Chlorine are easily found in various form such as gases, liquid and

powder
3 Easy to use because chlorine has high solubility rate
4 Chlorine can kill most of the microorganism that presence in water

bodies.

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Chapter 3 : Water Treatment

The multiple-tube Presence-absence
fermentation technique
technique

Bacteria Test

Fecal coliform Membrane filter
procedure technique

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