Water Supply Compilation of Reports

GROUP1 – WATERSUPPLY
Chapter 1-2 INTRODUCTION TO SEWERAGE AND WATER SUPPLY
I. Environmental Engineering
II. Sources Of Environmental Contaminants
III. Water Supply
IV. Sewerage
V. Interrelationship Of Environmental Problems
VI. Quantity of Water and Sewerage
a. Relation of Quantity and Population
 Population Estimation
 Water UseFor Different Purposes
 Factors Affecting Water Use
 Variation in Water Use
b. Fire Demand
VII. Design Periods For Water Supply Components
VIII. Sewage
a. Source
b. Sewage in Relation to Water Supply
c. Design Periods for Sewerage Systems
I. ENVIRONMENTAL ENGINEERING
Definition: Environmental Engineering involves the application of technology to minimize unfavorable
impacts of both humans on the environment and of the environment on humans.
Advantages of Technology:
 Control the spread of many communicable disease
 Expanded the agricultural production
 Greatly improved the quality of our lives
Disadvantages of Technology:
 Produced air and water pollution
 Radioactive and hazardous wastes
 Modified the climate of the world
Responsibility of An Environmental Engineer: To reduce or eliminate the unfavorable impacts of our
activities while enhancing or at least preserving its favorable results.
Environmental Engineering: This course includes the design, construction and operation of systems
for the treatment and supply of potable water and for the collection, treatment and disposal of waste
water.
II. SOURCES OF ENVIRONMENTAL CONTAMINANTS
Contaminants: can be defined as constituents of the air, water, or soil which render them unsuitable for
their intended use.
Natural contaminants of water:
 Viruses
 Bacteria
 Dissolved mineral species
 Organic and inorganic suspended solids
III. WATER SUPPLY
 Inadequate water supplies
 Aqueducts were used to convey water from distant sources.
 Pipes that can withstand significant pressures were not available until 17th century.
 Pipes made of wood, clay or lead was used.
 Development of cast-iron pipes and of improved pumps driven by steam
 Water Treatment
a. 2000 B.C.: Coagulants and Filtration
b. 1906: Slow Sand Filters
c. 1906: Disinfection with Chlorine
d.
IV. SEWERAGE
Definition: Sewers were primarily intended to carry storm water, but, since refuse was deposited in the
streets, these sewers often carried organic materials as well.
 Waste water discharged to the nearest surface water
 Became source of disease to downstream users
 Development and application of Waste Treatment Techniques

Classification of Streams:
 Effluent Limited: Suitable for their highest intended use.
 Quality Limited: Not suitable for their highest intended use.
Waste load allocation: allowable waste load allocated to each discharge point.
National Pollution Discharge Elimination System (NPDES): they regulates the waste discharges.
V. INTERRELATIONSHIP OF ENVIRONMENTAL PROBLEMS
The removal of a contaminant from one region of the environment will result in its being put somewhere
else – where its effects may be undesirable as in the original location.
Disposal of solid and hazardous wastes in the past has become a long-term sources of environmental
contamination which will continue to cause problems for many years.
Incineration of Solid wastes which can cause air pollution.
Environmental Engineers must consider very carefully all the effects of their actions so that pollutants
are not simply hidden or transferred from one place to another.
VI. QUANTITY OF WATER AND SEWERAGE
Population Estimation:
• Arithmetic Method
• Uniform Percentage Method
• Curvilinear Method
• Logistic Method
• Declining Growth Method
• Ratio Method
Water Use For Different Purpose:
• Domestic
• Commercial and Industrial
• Public Use
• Loss and Waste
Factors Affecting Water Use:
• Size of the City
• Industry and Commerce
• Commercial
• Characteristics of the Population
• Metering
• Miscellaneous factors
VII. Design Periods for Water SupplyComponents
 Dam
 Treatment Plant
 Distribution
TheEconomic Design Period Of TheComponents OfA Water Supply System Depends On:
 Their life
 First cost/initial cost
 The ease with which they can be expanded
 Technological advances
Pipelines From The Source: Generally designed for a period of 25 years or more.
Water Treatment Plant: Are commonly designed for a period of 10 to 15 years.
Pumping Plant: Are generally designed for a period of about 10 years.
Storage: Design of such structures are closely linked to design of the pumping plant.
Distribution System: Design period is indefinite and the capacity is based on the development of the
area served.
VIII.SEWAGE
Definition: Sewage is a water-carried waste that is intended to be removed from a community which is
also known as wastewater.
Sources:
A. Sanitary or Domestic Sewage: From residences and institutions, carrying body wastes
(primarily feces and urine), washing water, food preparation wastes, laundry wastes.
B. Industrial waste: Wastes that result from an industrial processes such as the production or
manufacture of goods are classified as industrial wastewater.
C. Infiltration, Inflow, Storm Sewage: Infiltration are drawn from the soil and may occur even
in dry weather.
D. Inflow:is associated with runoff events like rainfall.
E. Storm sewage or storm water: is runoff from precipitation that is collected in a system of
pipes or open channels.
Sewage and its Relation to Water Use: sanitary sewage and industrial wastes are derived principally
from the water supply.
Design Periodsfor Sewerage System:
 Sewers: These are designed for an indefinite period since, like the water distribution system.
 Sewage Pumping: These are designed for the period of not exceeding 10 years.
 Sewage Treatment: These are generally designed to be adequate for a period of 15 to 20
years.
GROUP 2 – WATER SUPPLY
Chapter 6 AQUEDUCTS AND WATER PIPES
I. Introduction
II. Aqueducts
III. Pipes
i. Stresses in Pipes and Pipeline
ii. Standard Pipe Beddings
iii. Types of Pipes
a) Iron Pipes

b) Steel Pipes
c) Concrete Pipes
d) Asbestos-Concrete Pipes
e) Plastic Pipes
iv. Valves
v. Water Distribution Appurtenances
vi. Effects of Pipes and Water Quality
vii. Corrosion and its Prevention
Chapter 7 COLLECTION AND DISTRIBUTION OF WATER
I. Intakes
II. Methods of Distribution
III. Storage
IV. Flow Estimation
V. Pressure Regulation in Distribution Systems
CHAPTER6: AQUEDUCTSANDWATERPIPES
OBJECTIVE:
 To be able to identify the different types of conduits and the materials used in conveying and
distributing water
 To be able to identify and familiarize with the different materials used in water conveyance
II. AQUEDUCTS
Definition: Aqueducts are conduits constructed of masonry and built at a certain hydraulic gradient. In
modern engineering, the term is used for any system of pipes, ditches, canals, tunnels, and other
structures used for this purpose.
Usage: Aqueducts are built only for the conveyance of water. It can also be used as means of
transportation and as source of energy and electricity
Types of Modern Aqueducts:
A. Open Channels: a conduit in which liquid is open to the atmosphere. The simplest
aqueducts are small ditches cut into the earth, like the irrigation canals in farms. A major
factor in the design of all open channels is its gradient. A higher gradient allows a smaller
channel to carry the same amount of water as a larger channel with a lower gradient, but
increases the potential of the water to damage the aqueduct's structure.
Example: Central Arizona Project, 7.3m wide open channels, coveys water from Colorado
River to central Arizona
B. Underground Water Tunnels: are underground tunnels used to transport water to areas
with large population
Example: Smart Tunnel (Storm water Management And Road Tunnel) in Kuala Lumpur
Malaysia, 4KM long, completed in November 2007
C. Pipes: Closed conduits are mostly used to carry treated/clean water. It is also used to
transport sewage water to water treatment plants for sanitation and to avoid the risk of
leaking contaminants from used water. Pipelines are useful for transporting water over long
distances when it needs to move overhills, or where open channels are poor choices due to
considerations of evaporation, freezing, pollution, or environmental impact.
Example: Tinupur Water System, India, completed on 2006 , 55-km pipeline that carries
water form 25 different reservoir, carries 185 million liters of water and delivers 30 million
liters of wastewater to water treatment plants
III. PIPES
Definition: A Pipe is tubular section or a hollow cylinder but not necessarily f circular cross-section used
to convey flowing substances. Technically, pipes only refer to those with circular cross-section, while,
tubes are for those that are non-circular in cross-section
Stresses in Pipes:
A. Static Water Pressure: the pressure exerted by a static fluid depends only upon the depth of
the fluid, the density of the fluid, and the acceleration of gravity.
B. Centrifugal Force Caused by Changes on Direction: The force exerted by flowing water in
pipes when direction changes.
C. External Loads: stresses caused by the environment. While static and centrifugal force
damages pipes from the inside, external loads damages pipes from the outside, like vibration
from nearby establishment like construction sites , vertical load from passing vehicles,
horizontal load which is soil induced (when pipe is situated underground, and other liveloads.
D. Changes in Temperature: change in temperature depending on the current weather which
causes drastic changes in the pipe depending on what material it is made from.
E. Water Hammer: is a pressure surge or wavecaused when a fluid (usually a liquid but
sometimes also a gas) in motion is forced to stop or change direction suddenly (momentum
change).
Weak Point in Pipes: Joints are considered the weakest point in pipes.
Measures against Stress:

A. Buttressing: Buttress is installed along where pipes connect to prevent displacement or
separations of pipes.
B. Embedding Underground: The ideal location for pipes are underground in order to protect
them from surface loads and to keep out of the way of sub-surface structures.
C. Bedding: supports the pipe within the trench against the total external load on the pipeline.
The type of bedding, depend on pipe size, type of sub-soil, the load on the surface of the
trench, the cover depth and trench width. Also, youmust use the right bedding or else, the
bedding itself will add more stress to the pipe. It is recommended to uses granular uniformly
sized aggregates as bedding and not backfill because backfill tend sot have irregular shaped
aggregates and is inconsistent that it may not be able to support the weight of the pipe
D. Stress Relievers: Usedto relieve stress inside the pipes to maintain a stable or consistent
internal pressure
 For low points: use pressure relieving devices like blow-off valves
 For high points: use pressure inducing devices to resist vacuum
pressure which tends to prevent water supply form continuously flow
and buckle the pipe
Factors in Selection of Pipes:
A. Capacity – the amount of discharge the pipe is designed to carry
B. Durability – depends upon the material and its compatibility with the physical environment
C. Maintenance Cost – the cost of maintaining the pipes in good condition to avoid further
expenses by replacement
D. Initial Cost – the amount of the purchase of materials, labor, cost of installation and
reinforcements
A. IRON PIPES
Properties: Iron Pipes are manufactured by casting iron alloy in sand molds with solid patterns or core
boxes. It has been used for 300 year in piping systems and construction.
Kinds of Iron Pipes:
A. Ductile Iron:consist of an alloy of iron, carbon, silica, manganese, phosphorus, and graphite
which gives its flexibility and strength.
It can bend without breaking, less corrosive than cast iron, flexible
B. Cast Iron: consists of an alloy of iron, carbon, and silica which gives it strength but tends to
be brittle.
Advantages:
 Flexible
 Strong and Durable
 Cheap and Abundant
 Resistance to external Corrosion - Since iron pipes are manufactured w/ relative thickness,
corrosion from the outside is much likely neglected because it doesn’t affect the hydraulic
capacity of iron pipes unless corrosion has reached inside
Disadvantages:
 Highly Corrosive in the Inside - Iron Pipes tend to corrode easily specially on the inside
because of its exposure to water which is a major cause of corrosion. Internal corrosion in
pipes are called Tuberculation, that causes the pipe to lose 70% of its original hydraulic
capacity
Iron Pipe Connections:
A. Bell and Spigot; Push-On: max. deflection is 5 degrees, cannot resist longitudinal forces
B. Mechanical: max. deflection is 8 degrees
C. Flanged: is done by threading the pipe ends and screwing them with flanges; doesn’t permit
defections
D. Ball: max. deflection is 15 degrees; ideal to use when large deformation is anticipated
E. Threaded: used in large pipes in large-scale pipeline systems because of its durability and
strong hold of connection
F. Victaulic Coupling: can be used as substitute to flanged joints in residential pipes because it
is much cheaper
G. Dresser Coupling: permits rotation and misalignment of the pipe centerlines, also
accommodates longitudinal motions
B. STEEL PIPES
Properties: Steel Pipes is ideal to use where large diameter and high pressure is required. It is also
ideal to use steel rather than iron, aluminum or brass pipes when weight concerned.
Its average lifespan is up to 50 years.
Usage/Application: Steel pipes can be used in water conveyance and distribution systems, in
sewerage, in oil & gas pipelines and in the structural and industrial industry.
You can see steel pipes being used in the Maynilad Water Distribution System, also in Petroleum and
Oil Plants where high pressure and large capacity is concerned.
Advantages:
 Lightweight
 High Strength
 Easy installation and assemblage
 Cheaper than Iron by weight
 Can resist high pressure conditions
Disadvantages
 Buckles easily due to its suppressed flexibility and relative thinness
 Highly Corrosive
 High Treatment/Coating Cost - Steel can be covered in tar or bituminous enamel inside and
out to delay corrosion. Though covering steel pipes with cement mortar is the best remedy to
corrosion, plus it increases the pipe resistance to buckling, thus increasing the lifespan of
steel pipes.
 High Maintenance Cost -Steel Pipe coating loses its elasticity and adhesion over time so it is
required to have regular intervals for recoating, which also cost a lot than of iron pipes. If not
recoated, the coating itself might start contributing to the corrosion of the steel pipe. Also
steel pipes are costly to handle once coated because you must avoid scratching/abrasion in
the coating.
C. CONCRETE PIPES
Properties: Concrete Pipes are frequently used to convey water and wastewater.

Concrete Pipes are manufactured by centrifugally placing cement mortar on a steel cylinder mold then
wrapping it with high-tensile wireor pre-stressing wire(wire is wounded tightly to pre-stress the mortar
core) then covered with another concrete coating.
Concrete Pipes are produced in lengths 3.7-4.9 m. or 12-16 ft. and can resist pressure gauging to 270
kPa.
It can last for up to 75 years.
Kinds of Concrete Pipes:
A. Reinforced Concrete Pipe:has a tensile or pre-stressing wireembedded in it,
B. Unreinforced Concrete Pipe: does not have a reinforcement embedded in it:
Concrete Pipe Connections: Concrete Pipe Fittings consists of concentric rings which are welded to
each other to develop enough thrust resistance from sudden jolts of water pressure during storm or
flooding to avoid pipe misalignment)
Though concrete pipes are very rigid, it can still be deflected along adjoining sections to permit gradual
curvature since pipe line systems are not all straight line, or you can simple order specially made
sections which are curved already for the purpose of deflection can be ordered. Maximum deflection of
concrete pipes is 5 degrees.
Usage/Application: Concrete Pipes can be used in water drainage systems, sewer and storm water
canals
Advantages:
 Low Cost
 Readily Available
 Easy to produce
 Easy to install
 Low Maintenance Cost
Disadvantages:
 Very Rigid, thus, it cannot be readily suspended
 Heavy Weight
 Low resistance to abrasion
 Low resistance to vibration unless reinforced
D. ASBESTOS-CEMENT PIPE
Properties: Asbestos-Cement Pipes is composed of mixture of Portland cement and asbestos fiber
which is manufactured using a rotating steel mandrel then compacted with steel rollers. It has been used
worldwide for over 60 years because of its high hydraulic capacity; high discharge capacity and relatively
low coefficient of friction.
Asbestos-Cement Pipe Connections: Iron Fittings are used to connect asbestos-cement pipes. Joints
consists of cylindrical sleeves that fit over adjoining sections. Both fittings and pipe section ends are
covered with rubber rings that serve as gaskets to avoid leaks.
Maximum deflection of Asbestos-cement pipes are 12 degrees.
Usage/Application: Gas Pipelines, Petroleum Pipelines, Liquid Nitrogen and OxygenPipe Systems in
Industrial Plants
Advantages:
 High Hydraulic Capacity
Disadvantages:
 Costly
 Cannot be used in water conveyance due to health threatening properties - Asbestos-cement
pipes releases carcinogens which can cause intestinal cancer when inhaled/consumed.
Acidic waters tends to corrode concrete thus asbestos leaches out and is exposed to the
environment. Standard Rules and Regulations in using Asbestos-cement pipe have been
established in 1989
E. PLASTIC PIPES
Properties: is made of solid and fiber-reinforced materials.
Kinds of Plastic Pipes:
A. ABS (acrylonitrile butadiene styrene) pipes: ABS is used for the conveyance of potable
water, slurries and chemicals. Most commonly used for DWV (drain-waste-vent) applications
B. UPVC (unplasticized polyvinyl chloride) and CPVC (post chlorinated polyvinyl chloride)
pipes: UPVC has excellent chemical resistance across its operating temperature range, with
a broad band of operating pressures. Due to its long-term strength characteristics, high
stiffness and cost effectiveness, UPVC systems account for a large proportion of plastic
piping installations.
C. PB-1 (polybutylene) pipes: PB-1 is used in pressure piping systems for hot and cold potable
water, pre-insulated district heating networks, and surface heating and cooling systems.
D. PP (polypropylene) pipes: Polypropylene is suitable for use with foodstuffs, potable and
ultra-pure waters, as well as within the pharmaceutical and chemical industries.
E. PE (polyethylene) pipes: Polyethylene has been successfully used for the safe conveyance
of potable and waste water, hazardous waste, and compressed gases.
F. PVDF (polyvinylidene fluoride) pipes: PVDF has excellent chemical resistance which
means that it is widely used in the chemical industry as a piping system for aggressive
liquids.
Plastic Pipe Connections: Small diameter Plastic pipes are connected through solvent welding in
cylindrical sleeves. Large Plastic Pipes are connected thru bell-and-spigot or push-on connections with
cast iron fittings
Usage/Application: It is widely used in domestic plumbing and in water distribution systems.
Advantages:
 Light weight
 Easy to handle and install
 Cheaper than iron and concrete pipes
Disavantages:
 Low resistance to heat and chemicals in comparison to iron/steel/concrete pipes
 Very Flexible
 Health risks
 Low resistance to stress and pressure

IV. VALVES
Definition: A Valveis a device for controlling the passage of fluid through a pipe or duct, especially an
automatic device allowing movement in one direction only.
Valves must be designed to resist wear and are often given with hydraulic or electric operator. Large
water distribution systems have their valves electrically operated so breaks can be isolated quickly,
though when electric operation failed to operate, valves must still have their manual switch so they can
be operated even without electricity.
Kinds of Valves:
A. Gate Valve:most commonly used for on-off service since they are relatively inexpensive and
offer a relatively positive shut-off. Gate Valves are the most common valveused in the water
distribution system not only because it is cheap but also because it is easy to operate. They
are located throughout the distribution system so that if any break in the system it can be
isolated quickly by shutting close the valves near the break, thus, avoiding too much water
loss. Valves are usually found in manholes for accessibility, smaller valves may be buried
provided it is within a valvebox made of iron or plastic.
Gate Valves are manufactured with threaded, flanged, bell-&-spigot, or combination ends.
B. By-Pass Valve: valves which reduces pressure from main valveto reduce occurrence of
water hammer; helps decrease pressure within valves when operating, since opening and
closing of valves tends to make water flow produces water hammer or jolts of water pressure
due to sudden changes in the flow. Water Hammer can damage pipes and even the valve
itself)
C. Check Valves or Foot Valves: prevents reversal of flow when pumps are shut off. Prevents
water to go to the reverse direction once the pump sustaining its flow stop operating. It is
usually found at the end of the suction line of pumping line. It is also placed on the side of
discharge pumps to reduce water hammer forces during pumping operations.
D. Globe and Angle Valves: are seldom used in water distribution systems because their
primary use is in household plumbing because of their poor hydraulic capacity.
E. Plug Valves: are valves with cylindrical or conical tapered plugs inside which is rotated to
control water flow flowing through the valve
F. Butterfly Valves: can be used in both high and low pressure applications, although only
purely liquid substances can be accommodated by butterfly valves. They are substantially,
cheaper, more compact and easier to operate but only if the liquid doesn’t not contain any
solid material which can block the valve.
G. Air-Vacuum and Air-Relief valves: attached to long pipeline to permit release of air which
accumulates at high points and also to prevent negative pressure when lines are drained.
These valves automatically operate once installed; It sucks out or pumps in air so as not to
disturb the rate of flow of water in the pipe and ensure it continues to flow whether it is down
below or high up in location
H. Pressure Regulating Valves: Automatically reduce pressure on the downstream side to the
desired level throttle. (Pressure is increased or decreased by tightening or loosening the
opening of the valveuntil desired pressure is reached)
I. Backflow Preventers: Valves designed to automatically prevent reversal of flows with
additional margin of safety against water hammer. It prevents flow reversal by preventing
unfavorable pressure gradients/irregularities of pressure within the pipeline.
V, APPURTENANCES IN WATER DISTRIBUTION SYSTEM
Definition: Appurtenances are all accessories used in the water distribution system that have a direct
affect to the water supply in terms of flow, direction, velocity, pressure and etc.
Examples of Appurtenances in Water Distribution System:
A. Fire Hydrants: consists of a cast iron barrel with bell of flange at the bottom which is
connected to water line branch which is part of the fire protection measures in any structure.
B. Fittings : connect straight pipe or tubing sections, to adapt to different sizes or shapes, and
for other purposes, such as regulating or measuring fluid flow.
C. ValveBoxes: are provided so that valves above ground or below ground are protected from
external damage and for easy access and maintenance of valve.
VI. EFFECTS OF PIPEMATERIALS ON WATER QUALITY
The quality of water can be greatly affected depending on the pipe materials through which it flows.
Water which is acidic and low in dissolved solids is likely to attack cement or any metals that comes in
contact. Dissolve materials in pipes are found to be harmful to health, aside from just having the water it
contaminates undesirable to consume.
Common Substances That Contaminate Water Supply:
A. Iron: when dissolved from iron or steel pipes can produce a red color and also the cause as
to why sometimes water from our faucets may taste or smell metallic. ExcessiveIronintake
can lead to Hemochromatosis or Iron-overload Disease
B. Lead: maybe dissolved from lead pipelines, soldered joints in pipes or from copper pipeline. It
can lead to Lead Poisoning if considerably enough amount of lead spread out in the water
distribution system
C. Organic Matters: concrete or plastic pipes, under some circumstances, may permit organic
materials to pass through its wall and contaminate the water being conveyed. Organic Matter
includes fungi, bacteria, worms, etc.
D. Carcinogens: can come not only from asbestos-cement pipes but other plastic pipes as
well.
VII. CORROSION AND ITS PREVENTION

Definition: Corrosion may be define as the conversion of a metal to a salt or oxide with a loss of
desirable properties such as mechanical strength.
Corrosion Process: In all types of corrosion, an electron transfer must occur either between dissimilar
metals or between different areas on a single material.
 Anodic: a zone which releases electrons (in most cases, this is the metal surface)
 Cathodic: a zone which accepts the electrons from Anodic (this is the oxidizing agent, like air
or water)
Kinds of Corrosion:
(Kinds of Corrosion are based on how the destructive process of Corrosion affects the metal)
 Uniform Corrosion: reaction starts at the surface and proceeds uniformly
 Localized Corrosion: Portions of metal is being eaten away and damage tends to bore a
hole in the metal while the rest of the affected surface is slightly affected or not at all
 Wide Pitting Corrosion: causes localized or uneven scarring
 Intregranular Corrosion: corrosion is unnoticeable from the outside since corrosion starts at
grain boundaries inside the metal
 Transgranular or Intragranular Corrosion: Corrosion occurs within metal material grains
while retaining grain boundaries
 Galvanice Corrosion: Corrosion in crevices or cracks in the metal surface/ contact surface
where two metal come in contact with each other
 Selective Corrosion: corrosion only attacks one element of the metal alloy, example for an
alloy of cooper and silver , only copper elements are subjected to corrosion)
 Exfoliation Corrosion: Corrosion follows fiber orientation
 Interfacial Corrosion: Occurs in water-air interfaces
Processes That Prevents Or Delay Corrosion:
A. Impressed Current/ Cathodic Protection: protects metal from corrosion by applying
DC Voltage to the metal making its molecular behavior act like cathodes instead of
anodes This process makes the metal electrons flow at a rate the same as it does
during the oxidation process of corrosion, thus, forbidding the electrons to transfer when
an anode is present nearby. If voltage used is greater than what is required, it can lead
to a more rapid corrosion. Too much voltage applied may break the polarized film of
every metal surface, making it anodic against the rest of the surface along the process,
thus, it will be the reason for an extremely rapid corrosion
B. Galvanizing:is the process of applying zinc coating to steel or iron pipes. Non-
corrosive zinc will serve as the sacrifice anode during oxidation, in this process the zinc
coating will receive the effects of corrosion, thus protecting the delicate metal within it.
Magnesium and Aluminum can also be used in galvanizing. These coatings can be
applied by hot dipping, metal spraying, cladding, vapor deposition, electroplating,
metalliding and mechanical plating to form a film 0.0002 to 5.0 mm thick. (The coating
may serve as the final coverbut in some instances wherein the environment is too
corrosive, another coating may be applied so the galvanizing coat may only act as the
base coat.)
C. Chemical Coating: include paints, coal tar preparations, asphalt, epoxy materials and
even cement. Once coated, these coating will isolate the materials from the
environment thus providing a protective coating against the elements that may inhibit
corrosion.
D. Inhibition:the removal or binding of molecules or particles in the surface of metals with
the use of chemicals such as include, chromate, nitrate, phosphates, silicates and
benzoates. Such coating is effective to reduce or delay corrosion against neutral or
alkaline solution, metals are treated with these chemical so it will not be reactive to
cathodic substances.
E. Inert Materials: is the substitution of other materials to replace the corrosive metal or
iron pipes.
CHAPTER7: COLLECTIONANDDISTRIBUTIONOF WATER
OBJECTIVES:
 To be familiar with the different methods and facilities used in water collection
 To be able to identify the different methods of distributing water
 To be able to estimate flow rate and pressure required in the design of water conveyance
system
I. INTAKES:
Definition Intakes or Intake Structures are structures wherein water will initially enter from its source
such as different bodies of water to be collected and distributed. Intakes must be able to resist natural
fluctuations such as wide variations of flow, temperature, quality of water, and other natural forces etc.
They are usually built within dams.
Factors to Consider in the Site-Selection for Building Intakes:
 Water Level: When building intake structures, one must consider the water level both
maximum and minimum before designing an intake structure.
 Navigation Requirements: the manner of operation and control over the intake structure.
 Local Currents: the type and magnitude of flow, how often or intervals between flow
variations.
 Sediment Deposition Pattern: engineers should be aware of the processes and outcomes
when disrupting sediment depositions on bodies of water before planning and building
intakes. Disturbing sediment depositions may affect the quality of water to be collected, it may
also pose serious environmental issues and may be a hindrance in building the foundation
and stability of the structure when building over sediment-filled areas.
 Variation of Water Quality: water quality varies with depth and location. Water quality is not
uniform all throughout a body of water so it is necessary to determine at what depth and
location the desired quality of water to intake to locate where to build the intake structure,
avoid depths wherein organic matter is abundant and low in dissolved oxygen.
 Quantity and Type of Floating Debris: natural bodies of water bears different kinds of
debris. It Is necessary to separate it from the water intake.
Kinds of Intake Structures:
A. Lake Intakes: Since saltwater is much tedious to treat, most intakes are built near lakes
where there is freshwater. Lake intakes should be placed as far as possible from sources of

pollution. When designing Lake Intakes, consider the wind and direction of the current to
avoid collecting many contaminants in the water. If Intakes is located on shallow waters or
near the bottom, sediments may stir up from the bottom and be carried along in the intake.
B. Submerged Cribs: Intake structures that consist of an inlet with a screen that is submerged
with its opening facing upward. This kind of intake is often used by small communities.
Multiple pipe inlets maybe used which is connected to a much larger single pipe to reduce
inlet velocities when pumping water in
C. River Intakes: River version of lake intakes. Opening for this kind of intakes should be place
slightly below water surface to avoid floating debris at water surface and sediment
suspension at the bottom of the river. Some river may accommodate traffic, so it is also
recommended to place the opening of the intake or inlet far off the river bank. This may be far
off the bank, or on the shore. Screens must be provide to avoid fish/any aquatic animals from
entering the inlet.
II. METHODS OF WATER DISTRIBUTION
Design Purpose:
 For domestic use – residential areas, households, apartments, condominiums
 For commercial use – establishments like mall, company buildings, museums, hospitals,
school
 For industrial use – factories, power plants, chemical or petroleum plant, construction sites
etc
 For Fire-Fighting purposes – This purpose must be applied on all kinds of design, because
fire is dangerous in most every kind of community and wemust take safety measures for it
Methods of Water Distribution:
A. Gravity Distribution: using gravity to push water to its intended destination by manipulating
conduits into a certain gradient from the source/reservoir to its intended users. This is only
possible only when the water supply is substantially located above city level. This is
considered the most dependable technique of distribution because it doesn’t require pumps
or motors which only run if there is electricity, provided that conduits carrying the water is well
protected and well-sealed from outside contaminants. Motor pumps must be provided when
water from this system will be used in fire-fighting.
B. Pumping without Storage: considered the least desirable of all methods because it has no
reserve flows, varied rate of flows, varyingwater pressure, and consistent amount of water
supply.
C. Pumping with a Storage: is the most common method of distribution by using elevated
storage tanks to store water and to distribute it by gravity or pump to its destination. This kind
of water distribution ensures reliability when power fails. Motor pumps must be provided when
water from this system will be used in fire-fighting.
Patterns of Distribution Systems:
A. Branching Pattern: similar to the branching of the tree. It consists of (1) Main (trunk) line, (2)
Sub-mains and, (3) Branches.
 Main line is the main source of water supply. There is no water distribution to
consumers from trunk line.
 Sub-mains are connected to the main line and they are along the main roads.
 Branches are connected to the sub-mains and they are along the streets
Advantages:
 It is a very simple method of water distribution. Calculations are easy and simple
to do.
 The required dimensions of the pipes are economical.
 This method requires comparatively less number of cut-off valves.
Disadvantages:
 The area receiving water from a pipe under repair is without water until the work is
completed.
 Frequent sedimentation inside pipes and growth of organic matter. Drain Valves
must be provided for every dead ends. In this system, there are large number of
dead ends where water does not circulate but remains static. Sediments
accumulate due to stagnation of the dead end and bacterial growth may occur at
these points. To overcome this problem drain valves are provided at dead ends
and stagnant water is drained out by periodically opening these valves but a large
amount of water is wasted.
 Water available for fire-fighting will be limited since it is being supplied by only one
water main source.
 The pressure at the end of the line may become undesirably low as additional
areas are connected to the water supply system.
B. Grid Pattern: In grid pattern, all the pipes are interconnected with no dead-ends. In such
system, water can reach any point from more than one direction.
Advantages:
 Nowater stagnation and bacteria growth - Since water in the supply system is free
to flow in more than one direction, stagnation does not occur as readily as in the
branching pattern.
 Continuous Water Supply - In case of repair or break down in a pipe, the area
connected to that pipe will continue to receive water, as water will flow to that area
from the other side.
 Water reaches all points with minimum head loss.
 Efficient for fire-fighting purposes -At the time of fires, by manipulating the cut-off
valves, plenty of water supply may be diverted and concentrated for fire-fighting
Disadvantages:
 Cost of pipe laying is more because relatively more length of pipes is required.
 More number of valves are required.
 The calculation of pipe sizes are more complicated.
C. Grid Pattern with Loops: Loops are provided in a grid pattern to improve water pressure in
portions of a city (industrial, business and commercial areas).
Loops should be strategically located so that as the city develops the water pressure should
be sustained. The advantages and disadvantages of this pattern are the same as those of the
grid pattern
III. STORAGE
Water is stored to equalize pumping rates in the short term, to equalize supply and demand in long term
and to prepare water for emergencies. Water is stored so pumps will avoid dealing with unstable water
currents when pumping directly from a body of water, also water is stored to cater demand and to
provide a continuous water supply and lastly for emergencies like fire or loss of pumping capacity.

Storage may be made of metal, earth, concrete and shall be considered as reservoirs. They are usually
located on high ground or simply elevated higher than the outlets
Types of Water Storage:
A. Natural – existing water pockets or reservoirs although some have little man-made structures
in it. (For example, reservoir, ponds, groundwater, example: La Mesa) Natural reservoirs
tends to be bigger than Artificial Ones.
B. Artificial – man-made water storages. (For example, dam , tanks)
IV. FLOWESTIMATION:
Water distributions system requires accurate estimation of flow to each section of community. Thus, an
engineer must predict a pattern of distribution to cater all demands such as industrial, commercial,
public, and residential demands without or little failure.
Industrial Use: 20 L/m-day or 21 gal/acre-day
Commercial use: 330 L/m-day or 350,000 gal/acre-day
Office and Retail Sales Facilities: 90 L/m-day or 100,000 gal/acre-day
Commercially Developed Areas: 40 L/m-day or 45,000 gal/acre-day
Residential Areas: depends upon population densities whichcan be determined by surveying average
water consumption per head.
Designing and estimating water flow systems does not extend to the degree of detail in which individual
connections are considered. When designing and estimating water flows, the design only extend to the
branches in the street. Beyond that, individual distributions systems called system of nodes are series
of pipes branching from the main street line to each individual house having many faucets or outlets.
Also, estimation of water supply should include fire protection water allowance since in reality, you will
be designing to provide water for industrial, commercial and residential area using only one large-scale
water distribution design pattern/system.
Fire Protection: For large communities- Max Flow: 45.4 m/min or 12,000 gal/min
For small communities/residential areas- Minimum Flow: 1.9 m/min or 500
gal/min; Max. Flow: 9.5 m/min or 2500 gal/min
Fire hydrants must be place throughout the city every 3720 m, thus, spacing between hydrants must be
60m to 150 m. and should be place at street intersections so hose can run in different directions. High-
value district must have extra fire-hydrants.
V. Pressure Required
Residential Districts with 4-Storey Structures: 150-300 kPa or 20-40 lbs/sq. inch
Commercial Districts: 400-500 kPa or 60-75 lbs/sq. inch
Areas with 10-Storey Structures: 400-500 kPa or 60-75 lbs/sq. inch or greater
High-Value districts have a separate water supply system, one for domestic use of water and other for
fire-protection. Example is the area of Global City.
Fire Protection (in High-value districts): 2,100 kPa or 300 lbs/sq. inch
This method or system is not applicable to city wide distribution systems because it is very expensive.
As substitute, city government must provide motor pump trucks to boost pressure to the level necessary
specially when dealing fire in high-rise structures.
Very tall and private buildings must provide their own fire protection system by installing internal
pumping systems and standpipes which are connected to external fire hydrants.
Chapter 7 COLLECTON AND DISTRIBUTION OF WATER

I. Pipe System
II. Design of Water Distribution Systems
Chapter 8 QUALITY OF WATER SUPPLIES
I. Definition of Terms
II. Water and its Impurities
i. Common Water Impurities
ii. Waterborne Diseases
iii. Organic and Inorganic Contaminants
III. Quality of Water Supply
I. THE PIPESYSTEM
Primaryor Arterial Mains: form the basic structure of the system and carry flow the pumping station to
and from elevated storage tanks and to the various district of the city.
Secondary lines: form smaller loops within the primary mains and run from primary line to another.
Small Distribution Mains: form a grid over the entire service area-supplying water to every user and to
the fire hydrants.
II. DESIGN OF WATER DISTRIBUTION SYSTEMS
A plumbing system is a long-term investment and should be designed so that it does not become
outdated and need replacement while its major parts are still serviceable. This requires careful
estimation of current and future demand so that the correct capacity can be specified.
-Cleaning -Leak Surveys
-Hydrants -Disinfection
-Valves - Thawing
CHAPTER 8 – QUALITY OF WATER SUPPLY
I. DEFINITION OF TERMS
Water : known as “life” for it has no alternative
: Essential for the sustenance of living organisms (plants, animals, and man)
: Potable Water: safe to drink, pleasant in taste, and suitable for domestic
purposes.
: Contaminated or Polluted Water: contains suspended or dissolved material
which makes it unsuitable for its intended use.
Waterborne Diseases: caused by pathogenic microorganismsthat most commonly are transmitted in
contaminated fresh water.
Inorganic Contaminants: means "material such as sand, salt, iron, calcium salts and other mineral
materials. Inorganic substances are of mineral origin.
Organic Contaminants: substances that come from animal or plant sources. Organic substances
always contain carbon.
Environmental Protection Agency (EPA): is an agency which was created for the purpose of
protecting human health and the environment by writing and enforcing regulations based on laws passed
by Congress.
Maximum Contaminant Level (MCL): are standards that are set by the United States Environmental
Protection Agency (EPA)for drinking water quality
Recommended Contaminant Level (RCL): a secondary standard set by EPA for few contaminants
which do not have chronic or toxic health impacts
II. WATER AND ITS IMPURITIES
Impurity: a thing or constituent that impairs the purity of something.
Water is the universal solvent and in nature, it is never totally pure. Nomatter how isolated it is from
sources of contamination, it will always have some chemicals. Gases or minerals in the air, soil, or rock

are dissolved by the water. Some dissolved materials give water its characteristic taste, and “pure water”
is generally considered to be flat and tasteless.
Classification of Water Impurities:
- Living organisms and solid
- Dissolved organics and inorganics
i. Common Water Impurities
Table: Impurities in Fresh Water
Constituent
Chemical
Formula
Difficulties Caused Means of Treatment
Oxygen O2 corrosion ofwater lines,heatexchange
equipment, boilers, return lines,etc.
De-aeration; sodium sulfite;
corrosion inhibitors
Ammonia NH3 corrosion ofcopper and zinc alloys by
formation of complex solubleion
Cation exchange with hydrogen
zeolite; chlorination; de-aeration
Sodium Na+ adds to solids contentofwater: when
combined with OH-, causescorrosion in
boilers under certain conditions
demineralization, reverse
osmosis, electro-dialysis,
evaporation
Carbon
Dioxide
CO2 corrosion in water lines, particularly steam
and condensate lines
aeration, de-aeration,
neutralization with alkalies
Turbidity non-
expressed
in analysis
as units
imparts unsightly appearance to
water; deposits in water lines,
process equipment, etc.; interferes
with most process uses
coagulation, settling, and
filtration
Hardness calcium
and
magnesium
salts,
expressed
as CaCO3
chief source of scale in heat
exchange equipment, boilers, pipe
lines, etc.; forms curds with soap,
interferes with dyeing, etc.
softening; demineralization;
internal boiler water
treatment; surface active
agents
Alkalinity bicarbonate
(HCO3-),
carbonate
(CO32-),
and
hydroxide(
OH-),
expressed
as CaCO3
foam and carryover of solids with
steam; embrittlement of boiler steel;
bicarbonate and carbonate produce
CO2 in steam, a source of corrosion
in condensate lines
lime and lime-soda softening;
acid treatment; hydrogen
zeolite softening;
demineralization
dealkalization by anion
exchange
Free Mineral
Acid
H2SO4 ,
HCI. etc.,
expressed
as CaCO3
corrosion neutralization with alkalies
ii. Waterborne Diseases
Table: Protozoal Diseases
Disease and
Transmission
Microbial Agent
Sources of Agent in Water
Supply
General Symptoms
Amoebiasis (hand-
to-mouth)
Protozoan
(Entamoeba
histolytica) (Cyst-like
appearance)
Sewage, non-treated
drinking water, flies in water
supply
Abdominal
discomfort, fatigue,
weight loss, diarrhea,
bloating, fever
Cryptosporidiosis
(oral)
Protozoan
(Cryptosporidium
parvum)
Collects on water filters and
membranes that cannot be
disinfected, animal manure,
seasonal runoff of water.
Flu-like symptoms,
watery diarrhea, loss
of appetite,
substantial loss of
weight, bloating,
increased gas,
nausea
Cyclosporiasis Protozoan parasite
(Cyclospora
cayetanensis)
Sewage, non-treated
drinking water
cramps, nausea,
vomiting, muscle
aches, fever, and
fatigue
Giardiasis (fecal-
oral) (hand-to-
mouth)
Protozoan (Giardia
lamblia) Most
common intestinal
parasite
Untreated water, poor
disinfection, pipe breaks,
leaks, groundwater
contamination,
campgrounds where
humans and wildlife use
same source of water.
Diarrhea, abdominal
discomfort, bloating,
and flatulence
iii.a. Inorganic Contaminants
A. Suspended Materials: alters color, taste and odor of water
B. Dissolved Substances: Aluminum, Arsenic, Barium, Cadmium, Chromium, Fluoride
iii.b. OrganicContaminants: Taste and Odors in water may be produce by either organic or inorganic
materials.
- Humic and fulvic acids encompass a group of acidic randomly polymerized
macromolecules which constitute the major organic constituent of natural waters.
- Pesticides which enter water supplies from either agricultural or domestic use are, in
general, quite resistant to removal by ordinary water techniques.

III. WATER QUALITY
Environmental Protection Agency: (EPA)sets the international standards for the quality of water for
commercial and domestic use.
Regulation of Water Quality:
1. Liabilities for Unsafe Water: liability for health or other problems of the users
2. Characterization of Waterborne Epidemics: outbreaks of waterborne disease in the past have been
associated with use of untreated water.
3. Watershed and Reservoir Protection: impounding reservoirs and their watershed are should be
protected to the degree necessary to ensure that the water supply is not contaminated
4. Groundwater and Well Protection: ground water supplies and individual wells may be contaminated
by surface water during floods and by percolation of waste material through the soil
5. Protection within the Treatment and Distribution Systems: careful design, regulation and
maintenance of water treatment system and facilities
GROUP 4 and 5 – WATER SUPPLY
Chapter 9 SEWAGE AND WATER TREATMENT
I. Water Clarification
II. Water Filtration
i. Types of Filtration Methods
ii. Types of Filters and Media Usedin Filtration
iii. The Underdrain System
iv. The BackwashProcess
v. Operating Difficulties
vi. Clear Well and Plant Capacity
vii. Other Filtration Processes
III. Treatment of Brackish and Saline Water
i. Stabilization
ii. Reverse Osmosis
iii. Freezing
iv. Ion Exchange
v. Electro-dialysis
IV. Water Treatment Wastes
V. Miscellaneous Water Treatment Techniques
V. General Considerations in Sewerage
CHAPTER 9 - WATER TREATMENT
I. WATER CLARIFICATION
Purpose:
 Water is essential in life.
 Water is treated for a variety of purposes.
Water Clarification Process:
1. Screening: are used at surface water intakes to prevent the entrance of materials
2. Coagulation: is the destabilization of colloids by addition of chemicals that neutralize the
negative charges. Coagulation is essentially a chemical process.

Water is added with a chemical called alum. Alum produces positive charges to neutralize the
negative charges on the particles. Then the particles can stick together, forming larger
particles which are more easily removed.
3. Flocculation: is a physical and chemical process which is used for the removal of the visible
sediments and material from water which makes it a colloidal solution
.
4. Settling or Sedimentation: is a physical water treatment process using gravity to
remove suspended solids from water.
• Settling- a unit operation in which solids are drawn toward a source of attraction. The
particular type of settling that will be discussed in this section is gravitational settling. It
should be noted that settling is different from sedimentation.
Types of Settling:
- Type I:Discrete particle settling - Particles settle individually without
interaction with neighboring particles.
- Type II: Flocculent Particles – Flocculation causes the particles to increase
in mass and settle at a faster rate
- Type III: Hindered or Zone settling –The mass of particles tends to settle
as a unit with individual particles remaining in fixed positions with respect to
each other.
- Type IV: Compression – The concentration of particles is so high that
sedimentation can only occur through compaction of the structure.
Types of Settling Basin:
- Rectangular Basin: are commonly found in large-scale water treatment
plants; are basins that are rectangular in plans and cross sections. In plan,
the length may vary from two to four times the width.
The length may also vary from ten to 20 times the depth. The depth of the
basin may vary from 2 to 6 m. The influent is introduced at one end and
allowed to flow through the length of the clarifier toward the other end
Rectangular tanks are popular as they tend to have:
• High tolerance to shock overload
• Predictable performance
• Cost effectiveness due to lower construction cost
• Lower maintenance
• Minimal short circuiting
- Circular Basin: are frequently referred to as clarifiers.These basins share
some of the performance advantages of the rectangular basins, but are
generally more prone to short circuiting and particle removal problems.
- Square Basin: For square tanks the design engineer must be certain that
some type of sludge removal equipment for the corners is installed.
• Sedimentation- The condition whereby the solids are already at the bottom and in the
process of sedimenting. Settling is not yet sedimenting, but the particles are falling
down the water column in response to gravity. Of course, as soon as the solids reach
the bottom, they begin sedimenting. In the physical treatment of water and wastewater,
settling is normally carried out in settling or sedimentation basins.
Advantages of Clarification Process:
• Simplest technologies
• Little energy input
• Relatively inexpensive to install and operate
• Nospecialized operational skills
• Easily incorporated into new or existing facilities
Disadvantages of Clarification Process:
• Low hydraulic loading rates
• Poor removal of small suspended solids
• Large floor space requirements
• Re-suspension of solids and leeching
II. WATER FILTRATION
Definition:
- Water Filtration: is required because settling does not eradicate all flocs in the
contaminated water. Filtration provides the additional opportunity for separation of small
flocs or particles
Filtration is used to separate non-settle able solids from water and wastewater by passing it
through a porous medium.
The most common system is filtration through a layered bed of granular media, usually a
coarse anthracite coal underlain by finer sand.
- Filter Controls: The original rapid filter designs incorporated rate of flow controllers to
maintain constant filtration rates despite variations in head loss within the filter during a run.
The designer must recognize that filter systems are not likely to be operated at a constant
rate from the beginning to the end of a filter run.
Classification of Filter Control Systems:
• Constant head loss: constant head systems employ weirs at the fiber entrances which
provide equal flow to each unit.

• Variable head loss
- Uniform flow systems split the incoming flow uniformly among the filters in
operation.
- Declining flow systems provide a common head on all filters and in their
common supply structure.
- TurbiditySensors: commonly connected to an alarm system which is triggered
by increase beyond 1 ntu.
- Flow Meter: Should be provided for the total influent and effluent flow.
i. TYPES OF FILTRATION
A. Mechanical Straining
B. Physical Adsorption
C. Slow Sand Filtration: The early filtration units developed in Great Britain used a process in
which the hydraulic loading rate is relatively low. Gravity is the driving force. Water filters
through a layer of sand with gravel base.
Figure: Slow Sand Filter Schematic Diagram
***Water Filter Systems consists of a layer called Schmutzdecke. The schmutzdecke
consumes and adsorbs/absorbs organic contaminants.
***Layers of sand strain out particulate contaminants due to the small pores created by fine
sand particles.
D. Rapid Filtration: Water from the settling basins enters the filter and seeps through the sand
and gravel bed, through a false floor, and out into a clear well that stores the finished water.
Rapid sand filtration is the flow of water through a bed of granular media, normally following
settling basins in conventional water treatment trains.
Theory of Filtration in Rapid Filters: the overall removal of impurities from the water in
rapid filtration is brought about by a combination of several different processes. The most
important are straining, sedimentation, adsorption, and bacterial and biochemical processes.
In rapid filtration, however, the filter bed material is much coarser and the filtration rate much
higher (up to 50 times higher than in slow sand filtration). These factors completely alter the
relative importance of the various purification processes
Solid Removal Mechanism in Filtration:
a. Straining: the most important mechanism which takes place in the first few centimeters of the
filter medium. Only large enough particles are removed through the pores
b. Sedimentation: Particles do streamline and settle on the sand grain. It does not follow the
fluid flow direction.
c. Interception: occurs when there are too large particles that follow the streamline but get
caught by the sand grains in the process
d. Diffusion: occurs when the random movement of particles collide with the sand grains by
chance
ii. FILTER MEDIA
An Ideal Medium Filter:
- Such a size that it will provide a satisfactory effluent

- Retain a maximum quantity of solids with minimum head loss
- Be readily cleaned with a minimum quality of water.
***The size and uniformity of filter media are specified by the effective size and the uniformity coefficient.
Important Considerations in Selecting Media:
 Too fine - surface straining which results in high head loss and short filter runs.
 Too coarse - poor filtrate quality, high backwash flow required.
Types of Filter:
 Single–media filters: (mono-media) these have one type of media, usually sand or crushed
anthracite coal.
 Dual–media filters: These have two types of media, usually crushed anthracite coal and
sand.
 Multi–media filters: These have three types of media, usually crushed anthracite coal, sand,
and garnet.
Types of Filter Media
 Sand - normally the cheapest filter medium.
 Anthracite – used as a substitute for sand in mono medium filters.
 Garnet sand and Ilmenite –used as a component of multimedia filters.
iii. THEUNDERDRAIN SYSTEM
The filter medium in rapid filters is underdrain by a system which serves as a support, as a collector of
filtered water, and as a distributor of backwash flow.
Gravel, when used as a part of the collection and backwash distribution system, it is normally placed in
five or six layers, with the finest material on top.
iv. THEBACKWASH PROCESS
This refers to pumping water backwards through the filter media, sometimes including intermittent use
of compressed air during the process. Backwashing is a form of preventive maintenance so that the filter
media can be reused.
v. OPERATINGDIFFICULTIES
- The turbidity of the effluent from rapid filters at the beginning of a run, like that from slow
sand filters, is usually higher than that obtained after the filter has before some time.
- The most common method of handling the initial poor quality is to filter to waste, that is,
discharge the filtrate to a sewer for the first period operation.
- Slow start – as an alternative to wasting the initial flow, one may operate the filter at a lower
rate.
- Air binding – can best be controlled by adjustment of pretreatment to permit deeper
penetration of floc into the filter.
vi. CLEAR WELL AND PLANT CAPACITY
- The maximum capacity of a filter plant depends on the water consumption rate and the
storage available for treated water.
- Selecting the number and the size of individual filter units also involves balancing cost and
ease of operation.
- It is generally not desirable to build much excess capacity, since expansion is comparatively
easy.
vii. OTHER FILTRATION PROCESSES
• Activated Carbon – effective filtration medium insofar as removal of turbidity is concerned.
• Coal and Metallic Aluminum – used as a filter medium without a previous coagulation step
or the addition of any coagulant aids.
• In-line Filtration– which employ either single or two stage filtration without prior treatment
other than addition of a coagulant in the influent line have been used successfully on waters
of low turbidity.
• Pressure Filters – are rapid filters contained in a pressure vessel.
• Diatomaceous Earth Filters (DE) - were developed by the army for water treatment under
combat conditions. It contains fossil-like skeletons of microscopic water plants called diatoms,
which are a type of algae.
• Upflow Filters – the direction of flow is the same as that of the backwash, hence the water is
filtered by progressively finer layers as it passes through the bed.
• Biflow Filter - The larger proportion of flow is upwards from the base of the filter bed, while
the smaller proportion is downwards from the top of the filter bed. The two flows meet a short
way down the bed where there is an outlet grid across the bed.
III. TREATMENT OF BRACKISH AND SALINE WATER
Increasing water consumption and depletion of existing water resources has led to considerable interest
in conversion of saline and brackish waters.
Desalination systems can be separated into those which employ a phase change, like distillation or
freezing, and those which separate water and dissolved minerals within the aqueous phase, like ion
exchange, electro dialysis, and reverse osmosis.
i.. Stabilization
Stabilization it is the adjustment of the ionic condition of water so that it will neither corrode
the pipes through which it passes nor deposit encrusting films (generally of calcium
carbonate). Some waters are naturally corrosive, while other becomes corrosive through pH
reduction occasioned by addition of metallic coagulants or chlorine.
The marble test for measuring stability is a practical method which clearly indicates the
condition of water. A water of known alkalinity is placed in contact with powdered calcium
carbonate for 24 hours and the alkalinity is measured.

ii. Reverse Osmosis
The principle of osmosis can be readily understood by considering a semi permeable
membrane separating two bodies of water which contain differing salt concentrations.
Reverse osmosis is the best-demonstrated technology for saline water conversion. This
process is particularly useful in coastal communities.
Reverse osmosis systems consist of the membrane, a support structure, a pressure vessel,
and a pump. The optimum membrane configuration is a hollow fiber which has an area to
volume ratio of up to 30,000 (compared to 300 to 3,000 for other designs), requires no
support structure, and has reasonable water flux rates.
iii. Freezing
Freezing for desalination is effected by application of vacuum processes in which evaporation
of a portion of the water or of a miscible secondary refrigerant freezes the flow.
Freezing for desalination is effected by application of vacuum processes in which evaporation
of a portion of the water or of a miscible secondary refrigerant freezes the flow.
iv. Ion Exchange
Ion exchange has been applied to desalting by using the hydrogen- and hydroxyl-base
resins. Ion – exchange systems are simple to operate and have moderate capital costs and
few operating problems, but they require costly regenerants and produce troublesome waste
streams.
v. Electro Dialysis
Electro-dialysis employs electrical energy to drive dissolved ionized solids across
semipermeable membranes. The system consists of cathodic and anionic semipermeable
membranes and two electrodes.
vi. Fluoridation and Defluoridation
It has been established that fluoride is helpful in reducing the incidence of dental caries and
that modest amounts of this ion in drinking water will provide the degree of protection which is
desirable.
Fluoride is added in the form of sodium fluoride, sodium silicofluoride, or hydrofluosilicic acid.
Sodium silicofluoride (Na2SiF6)is the least expensive of the chemicals used in fluoridation but
is somewhat difficult to dissolve.
Waters which naturally contain fluoride in excess of the recommended concentration may be
treated for its removal.
Fluoride is removed by adsorption on or coprecipitation with magnesium hydroxide.
IV. WATER TREATMENT WASTES
• Filter Backwash: similarly, contains all those materials retained by or produced with the bed.
Filter backwash water is the largest single waste flow in water treatment plants. It is typically
managed by directing it to a surge tank and then returning it at a low constant rate to the
head of the plant for recycle.
• Brines: produced in desalting processes, in addition to specific contaminants, are very high
in dissolved solids content. Brines have been managed by discharge to deep wells or saline
surface waters or by lagooning to obtain evaporation.
• Coagulation sludges contain microbial, organic, and inorganic contaminants derived form
the water, the metallic or polymeric coagulants, and any contaminants which the latter may
contain.
• Alum sludges have been concentrated by lagooning, drying on sand beds, gravity
thickening, vacuum or pressure filtration, centrifugation, solvent extraction, and freezing.
Alum sludge concentration in centrifuges or pressure filters may produce solids contents as
high as 40 percent, permitting or causing the sludge to freeze will separate the water. On
thawing, the resulting slurry will settle to about 20 percent solids within 5h and may be further
dewatered on sand beds or by mechanical processes.
Aliphatic amine solvents: are miscible with water at low temperature (18 0C ), but separate
when warmed (550C).
Alum may be recovered from coagulation sludges by addition of sulfuric acid. The resulting
liquid alum solution can be reused as a coagulant in either water or wastewater treatment
plants.
V. MISCELLENEOUS WATER TREATMENT TECHNIQUES
Disinfection: is the killing of disease-causing microorganism.
- Chlorination: Chlorine has been the disinfectant most commonly used in the United States
and other country. Chlorine will combine with water to form hypochlorous and hydrochloric
acids.
- Ozonation: Ozone is an unstable gas that can destroy bacteria and viruses. It is formed
when oxygen molecules collide with oxygenatoms to produce ozone.
- Ultraviolet irradiation: is effective in killing all types of bacteria and viruses through the
probable mechanism of destruction of nucleic acids.
- Algae Control: Algae are microscopic photosynthetic plants which, under certain
circumstances, may produce very heavy growths called “blooms” in lakes and reservoirs used
for water supply. Both copper sulfate and chlorine have been used to control algae.
- Iron and Manganese Removal: Although iron and manganese are most commonly found in
groundwater, surface waters may also contain significant amounts at times.
Iron and manganese contribute to hardness and are removed by water softening.
Iron alone in ground waters which contain little or no organic materials can be removed by
simple aeration followed by sedimentation and filtration.
Both iron and manganese are present or if the water contains organic material such as humic
or fulmic acid, aeration is sufficiently rapid only if it is catalyzed by pyrolusite or by
accumulation of oxidation products on a porous bed such as a coke.

- Aeration: Aeration is used in water treatment to alter the concentration of dissolved gases, to
strip volatile organics, and to reduce tastes and odors.
• Spray nozzle: provide a large air-water surface area but exposure time is short.
• Cascade: consists of a stairlike assembly over which the water flows in a thin film,
falling one level to the next.
• Diffused-air aerators: consists of concrete tanks with depth ranging from 3-5m, width
ranging from 3-10m, and length adequate to provide a detention time of 5 to 30 min. Air
is applied along one side of the basin through the same sort of diffusers used in sewage
treatment.
- Water Softening: If the water is softened by addition of lime, additional benefits include
removal of iron and manganese, coprecipitation of humic and fulvic acid, and reduction in
suspended solids – including bacteria and viruses.
Benefits of softening to domestic users include reduction in soap use, longer life for water
heaters, and less incrustation of pipes.
VI. GENERAL CONSIDERATIONS IN SEWERAGE
Definition of Terms:
• Sewerage – refers to the collection, treatment, and disposal of liquid waste.
• Sewerage works – include all the physical structures required for that collection, treatment
and disposal.
• Sewage – is the liquid waste conveyed by a sewer and may include domestic and industrial
discharges as well as storm sewage, infiltration, and inflow.
• Domestic sewage – originates in the sanitary conveniences of dwellings, commercial or
industrial facilities, and institutions.
• Industrial waste – includes the liquid discharges from industrial processes such as
manufacturing and food processing.
• Storm sewage – is flow derived from rainfall events and deliberately introduced into sewers
intended for its conveyance.
• Infiltration – is water which enters the sewers from the ground through leaks.
• Inflow – is water which enters the sewers from the surface, during rainfall events, through
flaws in the system, or through connections to roof or basement drains.
• Sewer – is a pipe or conduit, generally closed, but normally not flowing full, which carries
sewage.
• Common sewer – serves all abutting properties.
• Sanitary sewer – carries sanitary sewage and is designed to exclude storm sewage,
infiltration, and inflow.
• Storm sewer – carries storm sewage and any other wastes which may be discharged into
the streets or onto the surface of the ground.
• Combined sewer – carries both domestic and storm sewage.
• House sewer – a pipe conveying wastewater from an individual structure to a common sewer
or to other point of disposal.
• Lateral sewer – is a common sewer with no tributary flow except from house sewers.
• Sub-main sewer – collects flow from one or more laterals as well as house sewers.
• Main sewer – collects flow from several sub mains as well as laterals and house sewers.
• Force main – pressurized sewer lines which convey sewage from a pumping station to
another main or to a point of treatment or disposal.
• Sewage treatment – process which may be used to favorably modify the characteristics of
the wastewater.
• Sewage disposal – refers to the discharge of liquid wastes to the environment.
General Considerations
Provision of sewerage for an urban areas requires careful design. The sewers must be adequate in size
and slope so that they will contain the maximum flow without being sub charged and maintain velocities
which will prevent deposition of solids.
Liability for Damages Caused By Sewage
Deficiencies in design or construction may permit the city to involvethe engineer or contractor in any
legal difficulties whichresult. The city, however, as owner of the facilities, may bear the ultimate
responsibility if the other parties are unable to pay for the damages. Damages resulting from poor
operation or maintenance are always the responsibility of the city. Failure to respond quickly to known
deficiencies is normally sufficient to establish legal liability.
Chapter 10 STORM WATER FLOW
I. Presentation of Data
II. Determination of Peak Discharge of Storm Run-off
III. SewerAppurtenances for Storm Drainage
IV. Alternative Sewer Systems
V. Pipe Networks
VI. Components of a Pipe Network

CHAPTER 10 – STORM WATER FLOW
Definition of Terms:
- Storm Water: is the water that originates from precipitation evens and snow/ice melt. Storm
water can soak into the soil, be held on the surface and evaporate or runoff and end up in
nearby streams, rivers or other bodies of water.
- Urban Hydrology: study of the effects of urban conditions on rainfall-runoff relationship.
Functions of the Actual flow in Sewers:
• Statistical frequency of the Design
• Distribution of the Storm in Time
• Antecedent Condition
• Season of the Year
• Physical Design of the Collection System
I. PRESENTATION OF RELATIONSHIP BETWEEN INTENSITY, DURATION AND FREQUENCY:
The relationship among rainfall intensity, duration and frequency is obtainable from compilation of data
to produce both synthetic hyetographs and intensity-duration curves.
• Hyetographs
• Intensity Duration Curve
II. DETERMINATION OF PEAK DISCHARGE OF STORM RUN-OFF
• Rational Methods: Simplest method used to determine peak discharge from drainage basin
runoff.
Q= iA
Q= CiA
C=0.175t^1/3
C=t/8+t
C=0.3t/20+t

Where: Q=peak discharge A=drainage area
C=runoff coefficient i=rainfall intensity
t=duration of storm
• SCS Technique: originally developed by Soil Conservation Service of the U.S. Dep’t. of
Agriculture for use in rural areas; developed from empirical analysis of runoff from small
catchments and hills slope plot monitored by USDA
• Hydrograph Technique: developed from empirical analysis of runoff from small catchments
and hill slope plot monitored by USDA .
(UH)defined as a hydrograph of direct runoff resulting from one unit of effective rainfall which
is uniformly distributed over the basin at a uniform rate during the specified period of time.
• Computer Simulation Technique: these models require more or less complete definition of
the hydraulic and hydrologic factors which affect the discharge andare capable of producing a
great deal of information concerning the response of a drainage system to any selected
rainfall pattern.
Saint Venant Equation:
- Continuity equation -Momentum equation
III. SEWER APPURTENANCES
A. Manhole: A manhole (maintenance hole) is the top opening to an underground utility vault used to
house an access point for making connections or performing maintenance on underground and
buried public utility and other services.
Types of Manhole:
1. Brick Manhole - Brick manholes tend to be more conical in shape from the manhole rim
to invert and more slender than precast concrete manholes.
2. Precast Concrete Manhole- offers a cost saving, time effective solution. The
interlocking joint profile makes the installation quick and effective, and using a sealing
material between the sections makes the chamber watertight.
B. Inlets: Inlets are drainage structures utilized to collect surface water through grate or curb openings
and convey it to storm drains or direct outlet to culverts.
Applicable Settings for Various Inlet Types:
Inlet Type Applicable Setting Advantages Disadvantages
Grate Sumps and continuous grades
(should be made bicycle safe)
Perform well over wide
range of grades
Can become clogged
Lose some capacity
with increasing grade
Curb-
Opening
Sumps and continuous grades
(but not steep grades)
Do not clog easily
Bicyclesafe
Lose capacity with
increasing grade
Combina-
tion
Sumps and continuous grades
(should be made bicycle safe)
High capacity
Do not clog easily
More expensive than
grate or curb-opening
acting alone
Slotted Locations where sheet flow
must
be intercepted.
Intercept flow over
wide
section
Susceptible to
clogging
Types of Inlet:
1. Grate Inlets: These inlets include grate inlets consisting of an opening in the gutter covered
by one or more grates, and slotted inlets consisting of a pipe cut along the longitudinal axis
with a grate of spacer bars to form slot openings.
2. Combination Inlets: These inlets usually consists of both a curb-opening inlet and a grate
inlet placed in a side by side configuration, but the curb opening may be located in part
upstream of the grate.
3. Inverted Siphons: (also called depressed sewers) allow storm water or wastewater sewers
to pass under obstructions such as rivers.
C. Sewer Outlets: Most drains have a single large exit at their point of discharge (often covered by
a grating) into a canal, river, lake, reservoir, sea or ocean.
IV. ALTERNATIVESEWER SYSTEMS
1. Vacuum Sewer System: Plastic pipe which is buried deep enough to prevent freezing and a
vacuum is maintained.
2. Pressurized Sewer System: pressure sewers differ from conventional gravity collection
systems, because they use pumps instead of gravity to transport wastewater.
A prefabricated pressure sewer unit made out of plastic for outside placement.
V. PIPENETWORKS
Water distribution systems for municipalities
Multiple sources and multiple sinks connected with an interconnected network of pipes.
Computer solutions:
 KYpipes
 WaterCAD
 CyberNET
 EPANET

Water Distribution System Assumption:
Each point in the system can only have one pressure
The pressure change from 1 to 2 by path a must equal the pressure change from 1 to 2 by path b
(1) Lhz
g
Vp
z
g
Vp
 2
2
22
1
2
11
22 
(2)
a
aa
Lhz
g
V
z
g
Vpp
 2
2
2
1
2
112
22
***Applicable for path a and b
Pressure change in path a:
Thus,
ba LL hh  Orsum of head loss around loop is zero.
Pipe diameters are constant or K.E. is small
Model withdrawals as occurring at nodes so V is constant between nodes
1. Find discharge given pressure at A and B
- Energy & Swamee-Jain equation
- Add flows
2. Find head loss given the total flow
- Assume a discharge Q1’ through pipe 1
- Solvefor head loss using the assumed discharge
- Using the calculated head loss to find Q2’
- Assume that the actual flow is divided in the same proportion as the
assumed flow
3. Mass conservation at all nodes
4. The relationship between head loss and discharge must be maintained for each pipe
a. Darcy-Weisbach equation
i. Swamee-Jain
Network Analysis
Sample Problem:
Find the flows in the loop given the inflows and outflows.
The pipes are all 25 cm cast iron (e=0.26 mm).
1. Assign a flow to each pipe link Note: Flow into each junction must equal flow out of the
junction
2. Calculate head loss in each pipe
2
25
8
Q
gD
fL
hf 







where f=0.02 for Re>200000

Thus,
mh
mh
mh
mh
mh
i
f
f
f
f
f
i
53.31
00.0
39.3
222.0
7.34
4
1
4
3
2
1






3. Compute for k (coefficient)
Sign Convention: +counter clockwise
Thus;
k1,k3=339
k2,k4=169
 The head loss around the loop isn’t zero
 Need to change the flow around the loop
- the clockwise flow is too great (head loss is positive)
- reduce the clockwise flow to reduce the head loss
 Solution techniques
- Hardy Cross loop-balancing optimizes correction
- Usea numeric solver (Solver in Excel)to find a change in flow that will givezero
head loss around the loop
- UseNetwork Analysis software (EPANET)
Using Numeric Solver:
1. Set up a spreadsheet as shown below.
2. The numbers in bold(red) were entered, the other cells are calculations initially Q is 0
3. Use“solver” to set the sum of the head loss to 0 by changing Q the column Q0+ Q
contains the correct flows
∆Q 0.000
pipe f L D k Q0 Q0+∆Q hf
P1 0.02 200 0.25 339 0.32 0.320 34.69
P2 0.02 100 0.25 169 0.04 0.040 0.27
P3 0.02 200 0.25 339 -0.1 -0.100 -3.39
P4 0.02 100 0.25 169 0 0.000 0.00
31.575Sum Head Loss
*** Better solution is software with a GUI showing the pipe network.
VI. COMPONENTS OF A PIPENETWORK
1. Controls:
 Check valve (CV): Valve only allows flow in one direction. The valveautomatically closes
when flow begins to reverse
 Pressure relief valve: Valvewill begin to open when pressure in the pipeline exceeds a set
pressure (determined by force on the spring). It is used Where high pressure could cause an
explosion (boilers, water heaters, …)
 Pressure regulating valve (PRV):Valve will begin to open when the pressure downstream
is less than the set point pressure (determined by the force of the spring). Similar function to
pressure break tank
 Pressure sustaining valve(PSV):Valve will begin to open when the pressure upstream is
greater than the set point pressure (determined by the force of the spring).
 Flow control valve (FCV): Limits the flow rate through the valveto a specified value, in a
specified direction. Commonly used to limit the maximum flow to a value that will not
adversely affect the provider’s system
2. Pumps: need a relationship between flow and head
3. Reservoirs: infinite source, elevation is not affected by demand
4. Tanks: specific geometry, mass conservation applies
GROUP 7 & 8 – WATER SUPPLY
Chapter 11 WASTEWATER AND WASTEWATER TREATMENT
I. Characteristic of Wastewater
II. Sewage Disposal

III. Primary Treatment
I. CHARACTERISTICS OF WASTEWATER
Type Of Wastewater Source
Gray water Washing waster form kitchen, bathroom, &laundry
Black water Water from flush toilet
Yellow water Urine from separated toilets and urinals
Brown water Black water without urine
Physical Characteristics of Water
 Odor: is produced by gas production due to the decomposition of organic matter or by
substances added to the wastewater. Odor is measured by special instruments such as the
Portable H₂S meter which is used for measuring the concentration of hydrogen sulphide.
 Temperature: Temperature of wastewater is commonly higher than that of water supply.
Depending on the geographic location the mean annual temperature varies in the range of 10
to 21ᵒC with an average of 16ᵒC
 Density: Almost the same density of water when the wastewater doesn't include significant
amount of industrial waste.
 Color:
Fresh waste water------- light brownish gray.
With time -------------------------dark gray
More time-------------------------- black (septic).
Sometimes pink due to algae or due to industrial colors.
Types of Solids in a Sewage:
 Total Solids (TS): All the matter that remains as residue upon evaporation at 103ᵒC to
105ᵒC.
 Settleable Solids: Settleable solids are measured as ml/L, which is an approximate measure
of the sludge that can be removed by primary sedimentation.
 Volatile Solids-solids ignitable at 550ᵒC
 Non Volatile Solidsor Ash- residue following ignition
Chemical Characteristics of Water:
 Inorganic chemicals
1. Nitrogen- can deplete dissolved oxygenin receiving waters, stimulate aquatic
plant growth, exhibit toxicity toward aquatic life, present a public health hazard,
and affect the suitability of wastewater for reuse purposes
2. Phosphorus- Its presence causes many water quality problems including
increased purification costs, decreased recreational and conservation value of an
impoundments, loss of livestock and the possible lethal effect of algal toxins on
drinking water.
3. Toxicinorganic compunds (copper, lead, silver, chromium, arsenic, boron)
4. Heavy metals (Nickels, Mn, Lead, chromium, cadmium, zinc, copper, iron
mercury)
 Organic matter- is derived from animals & plants and man activities.
1. Proteins
2. Carbohydrates
3. Fats, Oils, and Grease
Measurement of Organic Matter in Wastewater:
1. Biochemical Oxygen Demand (BOD): BOD₅ is the oxygenequivalent of organic matter. It is
determined by measuring the dissolved oxygen used by microorganisms during the
biochemical oxidation of organic matter in 5 days at 20ᵒC
2. Chemical Oxygen Demand (COD): It is the oxygenequivalent of organic matter. It is
determined by measuring the dissolved oxygen used during the chemical oxidation of organic
matter in 3hours.
The Chemical Oxygen Demand (COD) test is commonly used to indirectly measure the
amount of organic compounds in water. Most applications of COD determine the amount of

organic pollutants found in surface water (e.g. lakes and rivers) or wastewater, making COD
a useful measure of water quality.
It is expressed in milligrams per liter (mg/L) also referred to as ppm (parts per million), which
indicates the mass of oxygen consumed per liter of solution.
3. Total organic carbon (TOC) is the amount of carbon bound in an organic compound and is
often used as a non-specific indicator of water quality or cleanliness of pharmaceutical
manufacturing equipment.
 Total Carbon (TC) – all the carbon in the sample, including both inorganic and
organic carbon
 Total Inorganic Carbon (TIC) – often referred to as inorganic carbon (IC),
carbonate, bicarbonate, and dissolved carbon dioxide (CO2).
 Total Organic Carbon (TOC)– material derived from decaying vegetation,
bacterial growth, and metabolic activities of living organisms or chemicals.
 Non-Purgeable Organic Carbon (NPOC) – commonly referred to as TOC;
organic carbon remaining in an acidified sample after purging the sample with gas.
 Purgeable (volatile) Organic Carbon (VOC) – organic carbon that has been
removed from a neutral, or acidified sample by purging with an inert gas. These
are the same compounds referred to as Volatile Organic Compounds (VOC)and
usually determined by Purge and Trap Gas Chromatography.
 Dissolved Organic Carbon (DOC) – organic carbon remaining in a sample after
filtering the sample, typically using a 0.45 micrometer filter.
 Suspended Organic Carbon – also called particulate organic carbon (POC); the
carbon in particulate form that is too large to pass through a filter.
Microbiology of Wastewater:
By its nature, domestic wastewater contains quantities of micro organisms. Depending on its
age and the quantity of dilution water, bacterial counts in raw sewage may expected to range from
500,000 to 5,000,000 per ml.
1. Bacteria – are single-celled plants which metabolize soluble food and reproduce by binary
fission.
2. Anaerobic Organism - Ananaerobic organism or anaerobe is any organism that does not
require oxygen for growth. It may react negatively or even die if oxygen is present. An
anaerobic organism may be unicellular or multicellular
 Obligate anaerobes, which are harmed by the presence of oxygen.
 Aerotolerant organisms, which cannot use oxygenfor growth, but tolerate its
presence.
 Facultative anaerobes, which can grow without oxygen but use oxygenif it is
present.
3. Aerobic or aerobe organism - is an organism that can surviveand grow in an oxygenated
environment.
 Obligate aerobes need oxygen to grow.
 Facultative aerobes use oxygen if it is available, but also
have anaerobic methods of energy production.
 Microaerophiles require oxygenfor energy production, but are harmed by
atmospheric concentrations of oxygen (21% O2).
 Aerotolerant anaerobes do not use oxygenbut are not harmed by it.
Sampling for Microorganisms in Wastewater/Water:
1. Grab Sample: Is simply a portion of the flow removed in a manner which will enhance the
probability that it is representative of the flow at instant it is taken. It can be taken from
discharge pump, be manually dipped from the flow or automatically dipped.
2. Composite Sample: Is a mixture of grab samples taken over a period of time, with the
volume of individual samples usually being proportional to the flow at the time the sample is
taken. It can be obtained by manually or automatically
3. Continuous Sample: Represents diversion of a small fraction of the total flow over some
period of time. Continuous samplers are most suitable for instrumental measurements which
can be performed virtually, such as temperature, dissolved oxygen, pH, etc.
Typical Sewage Characteristics
PARAMETER WEAK MEDIUM STRONG
Total suspended solids 100 200 350
Volatile suspended solids 75 135 210
BOD 100 200 400
COD 175 300 600
TOC 100 200 400
Ammonia-N 5 10 20
Organic 8 20 40
PO4-P 7 10 20
II. SEWAGE DISPOSAL
Kinds of Disposal of Sewage:
1. Reuse
2. Discharge to surface waters
3. By injection or percolation to groundwater
4. By evaporation to the atmosphere
Reducing the Negative Effects of Discharging Sewage in Bodies of Water:
1. Self-Purification: results from a variety of physical, chemical and biological phenomena.
2. Dilution: greatly reduces the impact of all contaminants and is the only mechanism by which
the concentration of some chemical species is naturally reduced.
3. Currents: assist in dispersion of the waste in the receiving water, thus reducing the likelihood
of locally high concentrations of pollutants.
4. Sedimentation: results from differences in density between solid pollutants and the water
which carriers them.
5. Bottom Deposits and Non-point-source runoff: provide diffuse sources of contaminants
which can cause water quality degradation.
6. Sunlight: acts as disinfectant and stimulates the growth of algae.
7. Temperature: affects the solubility of oxygenin water, the rate of bacterial activity, the rate
at which gases are transferred to and from the water.
III. PRIMARY WASTEWATER TREATMENT
PrimaryTreatment: is removal of floating and settleable solids through sedimentation
Typical materials that are remove during PrimaryTreatment include:
• Fats, oil and grease ( FOG )
• Sand , Gravel and Rocks ( GRIT )
• Larger settleable Solids including human waste

• Floating materials
Sedimentation: is the separation from water, by gravitational settling, of suspended particles that are
heavier than water
Objective of Sedimentation:
 To Remove coarse dispersed phase
 It reduce heavy sediment load before treating water for other purposes.
 To settle the sludge
PrimaryClarifiers: reduce the content of suspended solids and pollutants embedded in those
suspended solids.
Zones in the Clarifier:
 Inlet zone: is a region where the incoming suspension is distributed uniformly over the cross-
section of the tank.
 Settling zone: the particles settle at the same rate as they would in a quiescent.
 Outlet zone: the clarified liquid is collected uniformly overthe cross-section of the basin. The
solids collect in a sludge zone at the bottom of the tank.
Types of Clarifiers:
A. Rectangular Clarifier: has high tolerance to shock overload ; has a predictable
performance; Cost effectiveness due to lower construction cost; Lower
maintenance; 35 to 200 ft. ( width ) and 6 to 19 ft. ( depth )
B. Circular Clarifier: 15 to 300 ft. ( diameter ) and 6 to 16 ft. ( depth )
Chemical Coagulation: is the process in which certain chemical agent is mixed with water then colloidal
and suspended particles are agglomerated and form insoluble metal hydroxide known as flocks.
Sedimentation alone is not sufficient o remove all the suspended matter. The process of
coagulation is used to remove colloidal particles from water.
Colloidal particles which are fine particles of size finer than 0.0001 mm carry electric charges
on them.
Jar Tests: is a laboratory procedure to determine the optimum pH and the optimum coagulant dose. A
jar test simulates the coagulation and flocculation processes

Water Supply Compilation of Reports

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (10)

Similar to Water Supply Compilation of Reports

Similar to Water Supply Compilation of Reports (20)

More from Jahh Lavz

More from Jahh Lavz (7)

Recently uploaded

Recently uploaded (20)

Water Supply Compilation of Reports