Source of water

Source of water

Surface source Sub surface or GW source

Rivers and Streams Lakes Ponds

Springs Wells Infiltration galleries Infiltration wells

Impounding reservoir

Artesian wells Dug wells Tube wells

Shallow wells Deep wells

Intake works

Treatment works

Plain sedimentation Sedimentation with coagulation

Filtration Disinfection Miscellaneous treatment

Distribution system

Gravity system Pumping system Dual systemService reservoir

Service main

Branches

Consumer Waste water

Quality of water

Water during precipitation itself it carries some amount of physical, chemical, or biological impurities.

During the runoff also it pick up some dissolved particles of soil, garbage, sewage, pesticides, other human or animal waste or chemical.

During passage through the soil before joining water table though the water gets filtered out the suspended particles, some mineral may dissolve in it.

Note → Lesser amount of iron, calcium, magnesium, fluorine etc. are useful for drinking but larger amount make it unfit for drinking

Presence of toxic or poisonous substances such as arsenic, barium, cadmium, chromium, cyanides, lead, etc. →harmful even in very low quantities

Brackish water → presence of salts

Quality of water - contd

Analysis of water ↕ Physical Chemical Biological Radiological ↕ ↕ ↕ ↕ Turbidity Total solids Bacteria Radium 226Colour pH value Viruses

Radium 228Taste and odour Hardness Plankton RadonTemperature chloride content Algae UraniumSpecific conductivity Nitrogen content Fungi Gross

alpha activityMetals and other chemical substance Dissolved gases

Quality of wter-contd

Physical impurities Turbidity →Dispersion of suspended solid particles such as

clay, algae, fungi, minerals, organic and inorganic matters Depends on concentration and fineness Though not harmful →aesthetic and psychological effects Measurements Equipment → turbidity rod/Turbidimeter Turbidity rod When immersed in sample →Read aluminum rod when the

platinum needle ceases to be seen Unit →1mg finely divided silica dissolved in 1 litre of distilled

water Desirable below 5 units Not objectionable up to 10 units


Jackson’s turbidimeter (JTU scale) →Light path eg: 10.8cm-200JTU, 21.5cm -100JTU, 72.9cm -25 JTU

Lake water →25JTU Turbid water →100 JTU Disadvantage → Read up to 25 JTU Baylis turbidimeter → Comparing sample and

standard turbidity water Commercial form → Nephlometer → NTU

scale/FTU(Formazine)


Colour →Due to presents of colloidal or dissolved organic matter such as coloured soil, micro organism, algae etc.

Though not harmful →aesthetic and psychological effects →not suitable for washing industry

Unit →1mg platinum cobalt dissolved in 1.litre of water (cobalt scale)

Measurements → comparing sample with tubes (Nessler tubes) containing standard solutions

For drinking water → Preferable-less than 10 units and maximum up to 20

units Commercial form → Tintometer


Taste and odour → Due to presents of dissolved organic /inorganic matter (salts) gases such as CH4, H2S, CO2 etc. combined with organic matter, minerals such as NaCl, Iron compound, carbonates and sulphates of other elements, phenols etc. also contribute.

Measurements → By odour intencity Unit → Threshold odour number →Dilution ratio

(The number of times the sample is diluted) Eg: 20ml diluted to 100ml →Threshold odour

number= 5 Max: permissible value →3


Temperature →Desirable value = 10°C and Objectionable →Above 25°C

Specific conductivity →The total amount of dissolved salts can be measured by sp. conductivity

Measurements → sp. conductivity can be measured by equipment called dionic water tester

Unit: Micro-Mho →1 amp. /1volts Total dissolved salts = A constant (0.65 –depends

on type of salt) * sp. Conductivity AT 25°C


Chemical analysis Total solids (suspended as well as dissolved solids) Measurements → Total solids→ evaporating the samples and

weighing the residue Suspended solids → Obtained by filtration Dissolved solids → Total solid-Suspended solids Desirable limits → 500-1000mg/lit


pH value →Negative logarithm of H⁺ concentration pH scale → ` pH =0 pH =7 pH =14 ↑ ↑ ↑ Max:acidity ←neutral water → max: alkalinity H₂O↔H⁺ + OH⁻ HCl ↔ H⁺ +Cl⁻ →Hydrogen ion concentration is more than 10^ - 7→ Acidic NaOH ↔ Na⁺ + OH⁻ → Hydroxyl ion concentration is more than 7→Alkaline


Measurements → Colorimetric method → Colour comparator Electrolytic method → PH meter Causes of alkalinity → Bicarbonate alkalinity → Bicarbonates of calcium and

magnesium Carbonate alkalinity → Carbonate of sodium, potassium,

calcium and magnesium Hydroxide alkalinity → Hydroxide of sodium, potassium,

calcium and magnesium Causes of acidity→ Presents of mineral acids, free

carbon dioxide, sulphate of Iron and Aluminum


Hardness of water It is the characteristics which prevents leathering

of soap when used with water and usually due to the presence of calcium and magnesium salts.

Causes of hardness → Temporary or carbonate hardness→ Due to the

presents of carbonate and bicarbonate of calcium and magnesium → Removed by boiling

Noncarbonated or permanent hardness → Due to the presents of sulphate, chloride and nitrates of calcium and magnesium → Removed by special method of water softening


Classification of hardness→ Up to 75mg/lit → soft water 75 -200mg/lit → moderately hard water Above 200mg/lit → hard water Desirable limit for drinking water → 75 to 115mg/lit Problems due to hardness → Greater soap consumption Scaling of boiler Corrosion and incrustation of pipes Food tasteless


Chlorides → Chlorides are generally present in water in the form of sodium chloride and may be due to the leaching of marine sedimentary deposits, pollution from sea water, industrial or domestic waste, etc.

Determined by titrating against std. silver nitrate solution with potassium chromate as indicator

Desirable limit →250mg/lit


Nitrogen → It is the indicates the presents of organic matter in

the water and may occur in the following forms → Free ammonia → First stage of decomposition It indicates recent pollution un (decomposed) Max: limit =0.15mg/lit Albuminoid/organic nitrogen → Second stage of decomposition Free nitrogen is first removed by boiling Then adding strong alkaline solution of KMnO4 and

boiled to collect ammonia liberated Max: limit =0.30mg/lit


Nitrites → Partly decomposed stage of organic matter Extremely dangerous Presents not desirable Determined by colour matching method → Sulphonic

acid and naphthamine colour and is matched with std. concentration

Nitrates → Fully decomposed organic matter Presents are harmless Normal limit = 45mg/lit Determined by colour matcing method → Phynol-di-

sulphonic acid and potassium hydroxide develop colour and is matched with std. concentration


Metals and other chemical substances Metals such as iron, manganese, copper, lead,

barium, cadmium, arsenic, selenium, fluorine Desirable limits → Iron = 0.30mg/lit Manganese = 0.05mg/lit Copper → affects human lungs Sulphate greater than 250mg/lit → laxative

effects on human system


Fluoride Greater than 1.5mg/lit, cause Fluorosis and less than 1mg/lit, cause dental carries

Dissolved gases Nitrogen, methane, hydrogen sulphide, carbon

dioxide, and oxygen Methane and hydrogen sulphide, even in small

extent is not permitted Hydrogen sulphide → imparts taste and odour


Biochemical oxygen demand → Oxygen consumed for 100% oxidation-prolonged process and 5 days BOD is determined

Determination → Mix known volume of sample with known volume of

distilled water saturated with known quantity of oxygen 5 days incubation at 20°C Determine the oxygen consumed by deducting the

present quantity of oxygen from known quantity of oxygen

BOD5 → Oxygen consumed * dilution factor

Quality of wter-contd Living organism in water Bacteria Protozoa Algae Plankton Funki Viruses Types of bacteria → Pathogenic –Disease causing-Harmful Eg: Salmonella typhi - Typhoid Salmonella paratyphi – Paratyphoid Vibrio cholera - Cholerae Mycobacterium tuberculosis - Tuberculosis

Quality of wter-contd Non pathogenic – harmless - useful –decomposition etc. Aerobic – Bacteria which can survive in presents of oxygen Anaerobic - Bacteria which can survive in absents of

oxygen Facultative – Those which can survive with or without

oxygen Eg: Cocus → spherical Diplococus → pairs Streptococus → chain Staphilococus → irregular colonies Bacillius → rod like Spirillum → spiral shaped Vibro → curved


Protozoa → Unicellular animals Eg: Amoeboid – irregular shape, naked or

shelled, single or colonial Fagellate – lash like appendages Ciliat protozoa – hairlike appendages Problems: Form scum, unsightly deposit on

porcelain utensils


Algae → A type of plant, which grows in water and

flourishes in presents of sunlight Eg: Asterionella – Diatomaceae group Volvox – chlorophyceae group Anabaena – Cyanophyceae group Problems: Taste and odour


Plankton → microscopic plants and animal life that either swim or float in water and serve as food for small sea creature

Problems: Taste and odour, colour, problems on filter bed, stain on porcelain fixtures, dye works, photographic cells etc.

Fungi → Plants which grows without sunlight and live on other plants or animals

Eg: Toastools Removal –Chlorine treatment Viruses →small agents compared to bacteria and

some are not visible even under microscope


Analysis of bacteria → Total count test, membrane filter technique and B-

coli test Total count → Mix 1ml of sample in 99ml sterilized water To diluted 1ml of sample, add 10ml of agar gelatin Keep in incubator, 37°C for 24hrsor 20°C for 48 hrs Count the number of colonies Number of colonies * dilution factor – No. of

bacteria per lit. of sample


Membrane filter technique Sample is filtered in specially designed filter

paper (80% porosity, aperture size of 5-10mµ) Culture the filter paper with”M Endo’s medium,

37°C for 24hrs [M. End broth, LES Endo agar, 35°C, 20hrs – coli

form group] and [M-Fc broth, 44.5°C, 22hrs – fecal coli form]

Count colonies which give the presents of bacteria

Quality of water - contd

B-coli test → Presumptive and confirmed test Presumptive test Take diluted sample in standard fermentation tube

with “lactose broth” as culture media Keep in the incubator, 37°C-24-48hrs If gas produced indicates B-coli Confirmed test A sample of presumptive test is taken in to another

std. fermentation tube containing ‘brilliant green lactose brile ‘as medium

Keep in incubator, 37° If colour is formed, confirms-B-coli

QUANTITY OF WATER-MODULE-II

Before designing a water supply project, the

water work Engineer should Study or Survey about the demand of water Study about availability(source) of water

Let,V → Annual vol. of water →

Annual avg. rate of draft → V/365 lit/dayAnnual avg. rate of draft per person /service→ Annual avg. rate of draft ÷ (No. of person/services) in lit /day

QUANTITY OF WATER- CONTD

Water supply project

Survey of availability of water

Analysis of demand of water

Forecasting future population Analysis of percapita demand

Total quantity of water

QUANTITY OF WATER- CONTD Percapita demand→ It is the annual average amount of daily

water required by one person and includes, the domestic use, industrial and commercial use, public use, wastes and theft etc. and is given by→

Total yearly water requirement of the city in litres ÷ (365 * Design population)

To determine percapita demand we have to find out various purposes for which water is to be used

Domestic Industrial Institutional Commercial Public Fire demand Loss & Waste

QUANTITY OF WATER- CONTD Domestic demand →IS: 1172-1993 Cooking →5 lit Drinking →5 lit Bathing →75 lit Washing of clothes →25 lit Washing of utensils→15 lit Gardening →15 lit Washing of room →15lit Flushing →45 lit TOTAL→200 lit/person/ day For low income group→135 lpcd For high income group→250 lpcd


Industrial demand It depends on Nature & magnitude of Industries Economic prosperity of the city Size of city Future expansion of both the city & industries On the average→ 50 lpcd Max → 450 lpcd Note: Some industry may have their own

water supply arrangements


Institutional & Commercial demand Hospital, College, School, Railway station,

Restaurant, Govt. offices etc. On the average→20 lpcd Max →50 lpcd Public demand The consumption for public parks, gardens,

sprinkling & washing of road, Drinking, fountain etc.

On the average→10 lpcdOr

5% of total demand

QUANTITY OF WATER- CONTD Fire demand The damages due to fire may depend upon many things

such as size of city, commercial establishment, Industrial establishment, population density of the city.

A separate service reservoir is required to meet fire demand

Fire hydrants are provided in the distribution system100 to 150m apart

The minimum pressure should be about 10-15m of water (100-150KN/m²)

Minimum 3 water jets are required for a singlefire.→ One for jetting on fired property Other two on either sides each the minimum discharge for one jet is →1100 lit/min


Problem: Estimate the quantity of water required for fire fighting for a city of 50 lakhs, if the number of fire per day is 6, with 3 hr duration

Quantity of water→6[3*1100*3*60] →35,64,000 lit/dayPercapita demand→35,64,000/50,00,000→<1lit/dayThough the percapita demand is negligible, the quantity of water influence the design of distribution systemFor population above 50,000→Water in KL →√P*100Where, P →population in thousands


Thumb rule for determination of fire demand.

Hatchling's formula Q→3,182√P

Where, Q →is in lit/minP →population in thousands

Freeman’s formula Q→1136 [(P/10) + 10]

QUANTITY OF WATER- CONTD National Board of fire underwriter’s formula. When population below 2 lakhs

Q→4637 √P [1-0.01√P] When population more than 2 lakhs a provision of

54600 lit/minute, plus additional for second fire 9100-36400 lit/min

For Residential city (a) Small or low building → 2200 lit/min (b) Large or high building →4500 lit/min (c) High Value apartments → 7650-13500 lit/min Three storied building in densely built section→ up to

2700 lit/min Three storied building in densely build section up to

27000 lit/min.

QUANTITY OF WATER- CONTD Buston’s formula

Q→5663√P Note: →In Indian condition, 2hr storage is considered in

design of standby units All the above formula not consider the type of city

(Zoning) Actual , observed in Jabalpur city of India

Q = 4360 R0.275

(t +12 ) 0.757

Where, Q → in lit/min R →Recurrence internal of fire(depends on Zoning,

min→1 year) t →time duration in minute (min→30 mints)


Problem: The quantity of water required for fighting a fire of duration 2 hr with intervals of 3 years.

t → 2 hr → 2 x 60 → 120 min

R → 3Q → 4360 R0.275

(t +12 ) 0.757

→ 4360 x 30.275

(t +12 ) 0.757

=146.36 lit/min


Demand for loss and waste Normally, this is assumed as 15% of the total

consumption Factors affecting losses Water tight joints Pressure in distribution line. System of supply. Metering Unauthorized connection

Quantity of water - contd

Factors affecting percapita demand Climate condition →In summer season-more

water requirements Size of the city→ Cleaning, sewered city

requires 5 times, Ind.&Comm. Estt., affluent rich family etc.

Industries →more industries more water Habit of the people →Rich and upper class-

more water Cost of water→ High cost-less water


System of supply →continues or intermittent Policy of metering →min. tariff or based on

consumption Distribution pressure →High pressure-more

loss (20-30m pressure→20-30% loss) Quality of water →Best quality-more

consumption Sewerage→ more consumption


Variation in demand Hourly variation Daily variation Monthly variation Seasonal Variation Consider average daily demand → (q) Max. hourly demand, 150% of the ave. value Max. daily demand, 180% of the ave. daily→ Max. monthly demand, 140% of the ave. value Max. Seasonal demand, 130% of the ave. value Total / Absolute max →[1.5*1.8*1.4*1.3] of ave. daily

demand (q)

Quantity of water - variation in demand


Effects of variation in demand on capacity of various components

Source of Supply → Max. daily demand Pumping main → Max. daily demand Filter unit → Max. daily demand Distribution → Max. hourly demand Service reservoir → Max. hourly demand


Problem: A water supply scheme is to be designed for a city having a population of 1 lakh. Estimate the important kinds of draft which may be required to be recorded for an avg. annual consumption of water. Also determine the required capacities of the major components of the proposed water supply projects using river as a source of supply. Assume suitable fig & data required.


Solution Percaptia demand →

Domestic =200 lit /dayIndustrial =50 lit/dayInstitutional =20 lit/dayPublic purpose =10 lit/day

Total =280 lit/dayLoss and waste → 5% of 280 → 14 lit/dayGrand total → 294 lit/day

Quantity of water - contdAve. daily demand → 294*1,00,000 → 29.4 MldMax. daily demand → 1.8*29.4 →52.92 MldMax. hourly demand → 1.8*1.5*29.4 → 79.38 Mld

Fire Demand Q = 4637√ P (1-0.01 √ P)

= 4637 √100 (1-0.01 √100)= 41733 . lit/min= 41733 x 24 x 60= 60095520 lit/day= 60 Mld


The coincident demand may be taken as the highest of the following →

Max. daily demand + Fire demand or Max. hourly demand

Quantity → 52.92 Mld + 60Mld → 122. 92 MldOr max. hourly demand → 79.38 Mld < 122.92 Mld

Coincident demand → 122.92 Mld


The capacities of various components are → Intake structures → designed for max. daily →

52.92 Mld The pipe- mains → designed for max. daily →

52.92 Mld The filter bed → designed for max. daily or 2

times the ave. daily → That is →2*29.4 Mld →58.80 Mld


The lift pumps → designed for max. daily or 2 times the ave. daily →

That is →2*29.4 Mld →58.80 Mld If the pumps are operated for 8 hrs Quantity of water → 24 x 58.80

8 → 176.40 Mld The distribution pipes are designed for the

coincident demand → 122.92 Mld


Population forecasting Design period →The period for which the

various components of the water supply schemes are designed is called the design period.

The following factors normally, governs the design period

Useful life of the component structures and the chances of their becoming old and obsolete.

Ease and difficult with the expansion if undertaken in future – difficult for expansion long design period is considered.


Availability of funds – less fund, design period less Rate of population growth → less rate →design

period long. Note: Normally various components of the system

are designed for 20 to 30 years. Dam and reservoir are designed for max. up to 50 years.

Quantity of water – population fore casting

Various methods of forecasting population Arithmetical increase Method Geometrical increase Method Incremental increase Method Decreasing rate method Simple graphical method Comparative graphical Master plan method. The apportioned Method Logistic Method


Arithmetical increase methoddp → C, a constantdtP → populationt → time in decades

p₁ → population for next decade

p₀ → present population

n → no. of decadesPn → p₀ + nC

Population fore casting – Arithmetical increase method

Problem:The following are the senses details for the last few years. Determine the population for 1980, 1990 and 2000.Years Population

1930 250001940 280001950 340001960 420001970 47000


Year population increase in population1930 250001950 28000 30001950 34000 60001960 42000 80001970 47000 5000

→ 22000Average increase → 22000/4

C → 5500


Pn → p₀ + nC Population for 1980,

→ 47000 + (1x5500)→ 52500

Population for 1990 → 47000 + (2x5500)→ 58000

Population for 2000 → 47000 + (3x5500)→ 63500


Geometrical increase methodP₁ → p₀ + p₀ (r/100)

→ p₀ (1+r/100)P₂ → p₁ + p₁ (r/100)

→ p₁ (1+r/100)P₂ → P₀ (1+r/100)²

Therefore, Pn → p₀ (1+r/100) n

Population fore casting – Geometrical increase method

Year population Increase in % increase

Population or rate 1930 250001940 28000 3000 12%1950 34000 6000 21.43%1960 42000 8000 23.53%1970 47000 5000 11.91%

∑ 68.86%


Arithmetical growth rate Rate of increase → r₁ = 3000 x 100

25000Average rate of increase → [r₁+r₂+r₃+r₄]/4 = 68.86/4

r → 17.22 Geometrical growth rate = 4√r₁*r₂*r₃*r₄

Therefore r → 4√12x21.43x23.53x11.91 → 16.38 when successive population of year by year is not

given


Assumed growth rate r → t [ p2/p1 ] - 1

Where r→ Growth ratep₁→ Initial populationp₂ →Final populationt → number of decades

The rate of growth can be determined by arithmetically or geometrically. If we are using rate of growth by arithmetical method, the forecasted population will be more, but always better to use, rate of growth by geometrical method by a conservative value.


P1980 →p0 * [1+r/100]= 47000x [1+ 16.38/100]= 54700 ======

P1990 = p0 (1+ r/100)2

= 47000 (1+ 0.1638)2

= 63658 ======

P2000 = p0 (1+r/100)3

= 47000 (1+0.1638)3

= 74085 =======


The population for 1930 & 1970 are available from the survey records as 25000, 47000 respectively. Determine the population 2000 and 2006.

Assumed growth rate, r → t√[ p₂/p₁]-1 =4 √[ 47000] -1 25000 = 0.1709 → 17.09%P2000 = 47000 (1+ 0.17)3

= 75449.65 → 75450 P2006 = 47000 (1+ 0.17)3.6 → 82940

Population fore casting

Incremental Increase MethodP1 → p₀ + (¯x+¯y)

P2 → p₁+ (¯x+2¯y)

¯x → arithematical increase¯y → incremental increaseP2 → p₁ + (¯x+2*¯y)

→ p0 (¯x+¯y) + (¯x+2*¯y)

→ p0 + (2*¯x + 3*¯y)

→ p0 + 2*¯x + 2/2 (2+1) ¯y

Therefore, Pn → p0 + n¯x + n/2 (n+1) ¯y

Population fore casting – Incremental increase method

Determine the population 1980,1990,2000

Year Population Increase Incremental Increase

1930 250001940 28000 30001950 34000 6000 30001960 42000 8000 20001970 47000 5000 3000

¯x→ 5500 ¯y → 666.67

Population fore casting – Incremental increase method

P1980 → p₀+¯x+¯y → 47000+5500+666.67 → 53166.67 → 53167

P1990 → P₀ + 2*¯x + 2/2(2+1) ¯y → 47000+ (2*5500) + (3*666.67) → 60000

P2000 →P₀ + 3*¯x + 3*[(3+1)/2]*y → 47000+ (3*5500) +3/2*4*666.67 → 67,500

Population fore casting

Decreasing rate method Since, the rate of increase reduce as the

population reaches saturation, a method which makes use of this decrease in rate of increase, gives rational results. The average decrease in percentage increase is worked out. This percentage decrease is deducted from the last percentage increase for the successive decades.

Population fore casting - Decreasing rate method

Year Population %increase% Decrease in % increase

1930 250001940 28000 121950 34000 21.43 -9.43 (12-21.43)1960 42000 23.53 -2.1 (21.43-23.53)1970 47000 11.91 11.62 (23.53-11.91)

→0.09 Average decrease→ 0.09/3 → 0.03

Population fore casting - Decreasing rate method

P1980 → 47000 + (11.91-0.03)47000→ 52579

P1990 → 52579+ [(11.91-(2x0.03)]52579→ 58809

P2000 → 58809+[11.91-(3x0.03)]58809→ 65756

Simple Graphical Method Comparative Graph method

Population fore casting - Simple Graphical method

Population

47000 Appr. extention

1930 1970 Year

Comparative Graphical method

Population fore casting - Zoning method

Zoning Method

The development of the city in a particular zone is a planned one.

The growth is planned one, and the future growth can be determined easily.

Master plan will give us when and where the development of residential, industrial, commercial etc would develop.

Population fore casting - Apportioned method

Apportioned Method

The ratio of local population to national population is worked out for last 3 or 4 decades

A graph is drawn with these ratios and the corresponding decades

The ratio for the designed decade is taken from the extrapolation of the graph

Knowing this ratio and the national population, the population for the city can be determined.

Date post:	19-Mar-2016
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