Djb Report

8/12/2019 Djb Report

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DELHI J L BO RD

Delhi Jal Board (DJB), constituted under Delhi Jal Board Act l998, is

responsible for the production and distribution of potable Water As also for

collection, treatment and disposal of Waste/ sewage in the Capital. It provides:

Supply of potable drinking Water. Supply of potable drinking Water through tankers wherever needed. Supply of packaged water 'JAL' in jars through Jal Suvidha Kendra Treatment of Sewage. Supplies of Biogas/ Sludge manure/treated Waste Water. Testing of Water samples.

DJB has 9 Water laboratories at Water treatment plants, which examine and

evaluate suitability of Water to be supplied to public and also control the Water

treatment process round the clock. The Work of quality control (labs) starts

right from examining raw Water characterstics.This helps to determine the


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extent of treatment needed and finally the examination of final Water to

ascertain that it conforms to the prescribed standards.

For Surveillance 6(six) modern zonal laboratories have been set up in NCT of

Delhi. They also check the quality of Water from Ranney wells, tube in regard to

Bacteriological and chemical aspects in all parts of Delhi

Each Zonal laboratory is preparing daily reports (Routines), which are compiled

and sent to various public Health Departments.

In addition, microbiological examination are also carried out in raw, clarified

filtered and final treated Waters on daily basis to ascertain that drinking Water

is free from microbes.

As such, the Water being supplied by the Delhi Jal Board from all available

sources is tested regularly right from the raw Water stage up to the consumer

end for ensuring portability as per BIS drinking water specifications 10500-

1993.0n an average ,every day, about 300 Water samples are lifted from the

distribution systems including individual taps and public stand posts

CHIEVEMENTS

Ensuring average availability of about 50 Gallons of filteredwater per capita per day for 1.675 crore residents of Delhi

Extensive network of more than 10000 kilometres of pipelines


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W TER TRE TMENT C P CITY

S No Plant name Installed capacity source Supply area

1 Wazirabadwater works 120 MGDRiver Yamuna Old, CentralNew Delhi

2 Chandrawalno. 1 2 35+60 MGDRiver Yamuna Old, CentralNew Delhi

3 Haiderpurwater works 100+100 MGD WesternYamunaCanalWest Delhi,Outer Delhi,Rural

4 Bhagirathiwater works 100 MGD Upper GangaCanal East andSouth Delhi

5 Nangloi 40 MGD WesternYamunaCanal

West Delhi

6 Okhla waterworks 12 MGD Ranney well South Delhi

7 Sonia vihar 140 MGD Upper GangaCanal South andEast Delhi


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8 Bawana 20 MGD WesternYamunaCanalNearlysituated area

W TER100% natural, 0% replaceable

3D Structure of Water showing Bond Angle

Water is natures most wonderful, abundant and useful compound. Of the

many essential elements for the essential elements for the existence of

human beings, animal and plants (viz. air, water, food, shelter, etc.), swatter

is rated to be of the greatest importance. Without food, human can survive

for a number of days, but water is such as an essential that without it one

cannot survive.

Water is not only essential for the lives of animal and plants, but it also

occupies a unique position in industries. Probably, its most important use

an engineering material is in the steam generation. Water is also used as a

coolant in power and chemical plants. In addition to it, water is widely used

in other fields such as production of steel, rayon, paper, atomic energy,

textiles, chemicals, ice and for air-conditioning, drinking, bathing, sanitary,

washing, irrigation, fire-fighting, etc.


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Further, it is necessary that the water required for their needs must be

good, and t is should not contain unwanted impurities or harmful chemical

compounds or bacteria in it. Therefore, in order to ensure the availability of

sufficient quantity of good quality water, it becomes almost imperative in a

modern society, to plan and build suitable water supply schemes, whichmay provide potable water to the various sections of community in

accordance with their demands and requirements.

PROPERTIES OF WATER

S. noSystematic

name Measure

1 Alternative names

Aqua, Dihydrogenmonoxide, Hydrogen

hydroxide

2 Molecular FormulaH2O

3 Molar mass 18.0153 g/mol

4 Density1.0 g/cm3liquid

0.917 g/cm3solid

5 Melting point 273.15K

6 Boiling point 373.15K


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7 Specific heat

capacity

4184 J/(kgK)

DISTRIBUTION OF WATER

Water is one of the most abundant resources on the earth, and more

significantly it is renewable resources which may potentially be available for

a long time or even perpetually is used properly. However 97.54 of the 1.4billion cubic km of water on earth is sect water in the oceans of the

approximately 3% of fresh water more than three quarts is locked frozen in

polar ice, and nearly 20% is need in underground water, leaving only about

1%of the total fresh water, as early accessible surfers water of consumption

by plants and animal.

DISTRIBUTIONN OF WATER ON EARTH

DISTRIBUTION OF FRESH WATER ON EARTH

Series1,

OCEAN, 97%,

97%

Series1, FRESHWATER, 3%, 3%

OCEAN

FRESH WATER


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DISTRIBUTION OF SURFACE WATER

TYPES OF IMPURITIES IN NATURAL WATER

The main type of impurities in the natural water may be classified into

following group :-

1) Floating impurities i.e., leaves and twigs of tree, living algae andvarious form of aquatic organism.

2) Suspended impurities i.e., fine particles of clay or silt, decaying

vegetable and organic matters also includes protozoa, fungi, algae etc.

3) Dissolve impuritiesi.e., gases like oxygen, hydrogen sulphide, ammonia,

or chemical like different effluents and mineral substance like salts of

potassium, calcium .

NEED FOR WATER TREATMENT

Series1,

GROUND

WATER,

20%,

20%

Series1, ICE

CAPS AND

GLACIERS,

79%, 79%

Series1,

SURFACE

WATER, 1%,

1%

GROUND WATER

ICE CAPS AND GLACIERS

SURFACE WATER

Series1,

LAKES, 52%,

52%

Series1,

WATER

WITH LIVING

ORGANISMS,

1%, 1%

Series1,

RIVER, 1%,

Series1,

ATMOSPHERIC

WATER, 8%, 8%

Series1, SOIL

MOISTURE,

38%, 38%

LAKES

WATER WITH LIVING

ORGANISMS

RIVER

ATMOSPHERIC WATER

SOIL MOISTURE


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All the types impurities mentioned before or not present in all the surface or

ground waters in appreciable concentration necessitating rigorous

treatment. Sometimes only disinfection by adequate chlorination is

sufficient. Impurities when present in concentration beyond certain limit

may impair the health of the consumers or interfere with the domestic orother uses of water. The purpose for water treatment is to render the

otherwise unsuitable water, suitable for use for the purpose for which water

the may be used. Different qualities of water may be suitable for different

purpose. The quality criteria for drinking water irrigation water, food

processing water, cooling water or boiler feed are not the same. We are

however, concerned here with the drinking water.

EFFECTS OF IMPURITIES ON PROPERTIES OF WATER

Suspended impurities

Organism Some cause disease

Algae Cause taste, colour odour, turbidity

Suspended solid Causes turbidity

Dissolved impurities

Salts

Calcium &magnesium

BicarbonateCarbonateSulphateChloride

Causes alkalinity..Causes hardness..Causes hardness..Corrosive to boiler

Sodium

BicarbonateCarbonate

SulphateFluorideChloride

Causes alkalinity..Causes alkalinity..

Foaming in boiler.Mottling of enamel...Causes salty taste.

Iron ............... Causes taste, red water

Manganese ............... Causes black or brown water


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Vegetable dye Causes colour acidity

Gases

Oxygen.....Carbon dioxideHydrogen..Sulphide

Causes corrosion of metalsCauses acidityCauses odour.No effect..


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YAMUNA RIVER

From ages, river Yamuna has held an important place in our culture and

history. While Ganga symbolizes flowing knowledge, Yamuna represents

flowing love. This flavour is highlighted in lard Krishnas colourful childhood

adventures, to which Yamuna plays a silence witness providing an

enchanting setting.

Yamuna is not merely a source water .It is a sacred river that find dissolved

in its water the very essence of Indias rich cultural heritage. From

Yamunotri glacier in the high Himalaya, to its confluence with the mightyGanga at Allahabad, the 1375 km long river carries along its course a rich,

vibrant and ancient heritage, an engaging mix of mythology, reverence and

substance for the millions of people residing on its numerous banks.

(1) Seasonal Flow in Yamuna

From above pie chart, it can be deduced that majority of flow of volume of

water through the Yamuna river is in monsoon season only.

NON MONSOON

MONSOON


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(2) sharing of Yamuna water by different states

Delhi, nestled on the bank of this river, derives from its water a constant

fuel that has made it one of the great cites of the world. Almost 55% of

Delhis drinking water comes from Yamuna. The most polluted part of the

river is the 22 km length of Yamuna from Wazirabad to Okhla in Delhiregion which contributes about 77% of the total pollution recorded from

the1375 km Long River.

(3) Contribution of pollution load in Delhi

DELHI

HP

RAJASTHAN

UP

HARYANA

CIVIL MILL DR

POWER HOUSE

DR

SEN NURSING

HOME DR

SHAHADARA

NAJAFGARH

DR


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(4) City wise contribution of pollution load in Yamuna


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IMPORTANT LABORATORY RAGENTS

H2So4(SULPHURIC ACID)

Structure of sulphuric acid showing bond length

Sulfuric acid (alternative spelling sulphuric acid) is a highly corrosivestrongmineral acid with themolecular formula H2SO4.It is a pungent, colorless toslightly yellow viscous liquid which is soluble in water at allconcentrations.[4] Sometimes, it is dyed dark brown during production toalert people to its hazards. The historical name of this acid is oil of vitriol.[6]

Sulfuric acid is a diprotic acid and shows different properties dependingupon its concentration. Its corrosiveness on other materials, like metals,living tissues (e.g. skin and flesh)or evenstones,can be mainly ascribed toits strong acidic nature and, if concentrated, strong dehydrating andoxidizing property. Sulfuric acid at a high concentration can cause veryserious damage upon contact, as it not only causes chemical burns viahydrolysis, but also secondary thermal burns via dehydration. It burnscornea and can lead to permanent blindness if splashed onto eyes.Accordingly, safety precautions should be strictly observed when handlingit. Moreover, it ishygroscopic,readily absorbing water vapour from theair.

HNO3(NITRIC ACID)
https://en.wikipedia.org/wiki/Sulfur#Spelling_and_etymologyhttps://en.wikipedia.org/wiki/Corrosivehttps://en.wikipedia.org/wiki/Strong_acidhttps://en.wikipedia.org/wiki/Mineral_acidhttps://en.wikipedia.org/wiki/Molecular_formulahttps://en.wikipedia.org/wiki/Hydrogenhttps://en.wikipedia.org/wiki/Hydrogenhttps://en.wikipedia.org/wiki/Hydrogenhttps://en.wikipedia.org/wiki/Hydrogenhttps://en.wikipedia.org/wiki/Hydrogenhttps://en.wikipedia.org/wiki/Waterhttps://en.wikipedia.org/wiki/Sulfuric_acid#cite_note-ds-4https://en.wikipedia.org/wiki/Sulfuric_acid#cite_note-ds-4https://en.wikipedia.org/wiki/Sulfuric_acid#cite_note-ds-4https://en.wikipedia.org/wiki/Sulfuric_acid#cite_note-6https://en.wikipedia.org/wiki/Sulfuric_acid#cite_note-6https://en.wikipedia.org/wiki/Sulfuric_acid#cite_note-6https://en.wikipedia.org/wiki/Diprotic_acidhttps://en.wikipedia.org/wiki/Metalshttps://en.wikipedia.org/wiki/Tissue_%28biology%29https://en.wikipedia.org/wiki/Skinhttps://en.wikipedia.org/wiki/Fleshhttps://en.wikipedia.org/wiki/Stonehttps://en.wikipedia.org/wiki/Strong_acidhttps://en.wikipedia.org/wiki/Dehydration_reactionhttps://en.wikipedia.org/wiki/Oxidizing_agenthttps://en.wikipedia.org/wiki/Concentrationhttps://en.wikipedia.org/wiki/Chemical_burnhttps://en.wikipedia.org/wiki/Hydrolysishttps://en.wikipedia.org/wiki/Burn#By_depthhttps://en.wikipedia.org/wiki/Dehydration_reactionhttps://en.wikipedia.org/wiki/Corneahttps://en.wikipedia.org/wiki/Blindnesshttps://en.wikipedia.org/wiki/Eyeshttps://en.wikipedia.org/wiki/Hygroscopichttps://en.wikipedia.org/wiki/Water_vapourhttps://en.wikipedia.org/wiki/Airhttps://en.wikipedia.org/wiki/Airhttps://en.wikipedia.org/wiki/Water_vapourhttps://en.wikipedia.org/wiki/Hygroscopichttps://en.wikipedia.org/wiki/Eyeshttps://en.wikipedia.org/wiki/Blindnesshttps://en.wikipedia.org/wiki/Corneahttps://en.wikipedia.org/wiki/Dehydration_reactionhttps://en.wikipedia.org/wiki/Burn#By_depthhttps://en.wikipedia.org/wiki/Hydrolysishttps://en.wikipedia.org/wiki/Chemical_burnhttps://en.wikipedia.org/wiki/Concentrationhttps://en.wikipedia.org/wiki/Oxidizing_agenthttps://en.wikipedia.org/wiki/Dehydration_reactionhttps://en.wikipedia.org/wiki/Strong_acidhttps://en.wikipedia.org/wiki/Stonehttps://en.wikipedia.org/wiki/Fleshhttps://en.wikipedia.org/wiki/Skinhttps://en.wikipedia.org/wiki/Tissue_%28biology%29https://en.wikipedia.org/wiki/Metalshttps://en.wikipedia.org/wiki/Diprotic_acidhttps://en.wikipedia.org/wiki/Sulfuric_acid#cite_note-6https://en.wikipedia.org/wiki/Sulfuric_acid#cite_note-ds-4https://en.wikipedia.org/wiki/Waterhttps://en.wikipedia.org/wiki/Hydrogenhttps://en.wikipedia.org/wiki/Hydrogenhttps://en.wikipedia.org/wiki/Molecular_formulahttps://en.wikipedia.org/wiki/Mineral_acidhttps://en.wikipedia.org/wiki/Strong_acidhttps://en.wikipedia.org/wiki/Corrosivehttps://en.wikipedia.org/wiki/Sulfur#Spelling_and_etymology


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Nitric acid (HNO3), also known as aqua fortis and spirit of niter, is a highlycorrosive strong mineral acid. The pure compound is colorless, but oldersamples tend to acquire a yellow cast due to decomposition into oxides ofnitrogen and water. Most commercially available nitric acid has aconcentration of 68%. When the solution contains more than 86% HNO3, it

is referred to as fuming nitric acid. Depending on the amount of nitrogendioxide present, fuming nitric acid is further characterized as white fumingnitric acid orred fuming nitric acid,at concentrations above 95%.

Nitric acid is the primary reagent used for nitration - the addition of anitrogroup, typically to an organic molecule. While some resulting nitrocompounds are shock- and thermally-sensitive explosives,a few are stableenough to be used in munitions and demolition, while others are still morestable and used as pigments in inks and dyes. Nitric acid is also commonlyused as astrong oxidizing agent.

HCl (HYDROCHLORIC ACID)

Hydrochloric acid is a clear, colourlesssolution ofhydrogen chloride (HCl)inwater. It is a highly corrosive, strong mineral acid with many industrialuses. Hydrochloric acid is found naturally ingastric acid.

Historically called muriatic acid, and spirits of salt, hydrochloric acid was

produced from vitriol (sulfuric acid) and common salt. It first appearedduring the Renaissance and then it was used by chemists such asGlauber,Priestley andDavy in their scientific research.

With major production starting in the Industrial Revolution, hydrochloricacid is used in the chemical industry as a chemical reagent in the large-scale production of vinyl chloride for PVC plastic, and MDI/TDI forpolyurethane. It has numerous smaller-scale applications, includinghousehold cleaning, production of gelatin and other food additives,descaling,and leather processing. About 20 million tonnes of hydrochloric

acid are produced worldwide annually.
https://en.wikipedia.org/wiki/Hydrogenhttps://en.wikipedia.org/wiki/Hydrogenhttps://en.wikipedia.org/wiki/Hydrogenhttps://en.wikipedia.org/wiki/Aqua_fortishttps://en.wikipedia.org/wiki/Corrosivehttps://en.wikipedia.org/wiki/Strong_acidhttps://en.wikipedia.org/wiki/Mineral_acidhttps://en.wikipedia.org/wiki/Nitrogen_oxidehttps://en.wikipedia.org/wiki/Nitrogen_oxidehttps://en.wikipedia.org/wiki/Nitrogen_dioxidehttps://en.wikipedia.org/wiki/Nitrogen_dioxidehttps://en.wikipedia.org/wiki/White_fuming_nitric_acidhttps://en.wikipedia.org/wiki/White_fuming_nitric_acidhttps://en.wikipedia.org/wiki/Red_fuming_nitric_acidhttps://en.wikipedia.org/wiki/Nitrationhttps://en.wikipedia.org/wiki/Nitro_grouphttps://en.wikipedia.org/wiki/Nitro_grouphttps://en.wikipedia.org/wiki/Organic_moleculehttps://en.wikipedia.org/wiki/Nitro_compoundshttps://en.wikipedia.org/wiki/Nitro_compoundshttps://en.wikipedia.org/wiki/Explosivehttps://en.wikipedia.org/wiki/Oxidizing_agenthttps://en.wikipedia.org/wiki/Solutionhttps://en.wikipedia.org/wiki/Hydrogen_chloridehttps://en.wikipedia.org/wiki/Hydrogenhttps://en.wikipedia.org/wiki/Corrosivehttps://en.wikipedia.org/wiki/Strong_acidhttps://en.wikipedia.org/wiki/Mineral_acidhttps://en.wikipedia.org/wiki/Gastric_acidhttps://en.wikipedia.org/wiki/Sulfuric_acidhttps://en.wikipedia.org/wiki/Sodium_chloridehttps://en.wikipedia.org/wiki/Renaissancehttps://en.wikipedia.org/wiki/Johann_Rudolf_Glauberhttps://en.wikipedia.org/wiki/Joseph_Priestleyhttps://en.wikipedia.org/wiki/Humphry_Davyhttps://en.wikipedia.org/wiki/Industrial_Revolutionhttps://en.wikipedia.org/wiki/Chemical_industryhttps://en.wikipedia.org/wiki/Chemical_reagenthttps://en.wikipedia.org/wiki/Vinyl_chloridehttps://en.wikipedia.org/wiki/Polyvinyl_chloridehttps://en.wikipedia.org/wiki/Methylene_diphenyl_diisocyanatehttps://en.wikipedia.org/wiki/Toluene_diisocyanatehttps://en.wikipedia.org/wiki/Polyurethanehttps://en.wikipedia.org/wiki/Housekeepinghttps://en.wikipedia.org/wiki/Gelatinhttps://en.wikipedia.org/wiki/Food_additivehttps://en.wikipedia.org/wiki/Descalinghttps://en.wikipedia.org/wiki/Leatherhttps://en.wikipedia.org/wiki/Tonnehttps://en.wikipedia.org/wiki/Tonnehttps://en.wikipedia.org/wiki/Leatherhttps://en.wikipedia.org/wiki/Descalinghttps://en.wikipedia.org/wiki/Food_additivehttps://en.wikipedia.org/wiki/Gelatinhttps://en.wikipedia.org/wiki/Housekeepinghttps://en.wikipedia.org/wiki/Polyurethanehttps://en.wikipedia.org/wiki/Toluene_diisocyanatehttps://en.wikipedia.org/wiki/Methylene_diphenyl_diisocyanatehttps://en.wikipedia.org/wiki/Polyvinyl_chloridehttps://en.wikipedia.org/wiki/Vinyl_chloridehttps://en.wikipedia.org/wiki/Chemical_reagenthttps://en.wikipedia.org/wiki/Chemical_industryhttps://en.wikipedia.org/wiki/Industrial_Revolutionhttps://en.wikipedia.org/wiki/Humphry_Davyhttps://en.wikipedia.org/wiki/Joseph_Priestleyhttps://en.wikipedia.org/wiki/Johann_Rudolf_Glauberhttps://en.wikipedia.org/wiki/Renaissancehttps://en.wikipedia.org/wiki/Sodium_chloridehttps://en.wikipedia.org/wiki/Sulfuric_acidhttps://en.wikipedia.org/wiki/Gastric_acidhttps://en.wikipedia.org/wiki/Mineral_acidhttps://en.wikipedia.org/wiki/Strong_acidhttps://en.wikipedia.org/wiki/Corrosivehttps://en.wikipedia.org/wiki/Hydrogenhttps://en.wikipedia.org/wiki/Hydrogenhttps://en.wikipedia.org/wiki/Hydrogen_chloridehttps://en.wikipedia.org/wiki/Solutionhttps://en.wikipedia.org/wiki/Oxidizing_agenthttps://en.wikipedia.org/wiki/Explosivehttps://en.wikipedia.org/wiki/Nitro_compoundshttps://en.wikipedia.org/wiki/Nitro_compoundshttps://en.wikipedia.org/wiki/Organic_moleculehttps://en.wikipedia.org/wiki/Nitro_grouphttps://en.wikipedia.org/wiki/Nitro_grouphttps://en.wikipedia.org/wiki/Nitrationhttps://en.wikipedia.org/wiki/Red_fuming_nitric_acidhttps://en.wikipedia.org/wiki/White_fuming_nitric_acidhttps://en.wikipedia.org/wiki/White_fuming_nitric_acidhttps://en.wikipedia.org/wiki/Nitrogen_dioxidehttps://en.wikipedia.org/wiki/Nitrogen_dioxidehttps://en.wikipedia.org/wiki/Nitrogen_oxidehttps://en.wikipedia.org/wiki/Nitrogen_oxidehttps://en.wikipedia.org/wiki/Mineral_acidhttps://en.wikipedia.org/wiki/Strong_acidhttps://en.wikipedia.org/wiki/Corrosivehttps://en.wikipedia.org/wiki/Aqua_fortishttps://en.wikipedia.org/wiki/Hydrogenhttps://en.wikipedia.org/wiki/Hydrogen


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NaCl (Sodium Chloride)

Crystal Structure of sodium Chloride

Sodium chloride, also known as salt, common salt, table salt orhalite,is an

ionic compound with the formula NaCl, representing equal proportions ofsodium and chloride. Sodium chloride is the salt most responsible for the

salinity of the ocean and of the extracellular fluid of many multicellular

organisms.As the major ingredient in edible salt,it is commonly used as a

condiment and foodpreservative.

In solid sodium chloride, each ion is surrounded by six ions of the oppositecharge as expected on electrostatic grounds. The surrounding ions arelocated at the vertices of a regular octahedron. In the language of close-packing,the larger chlorideions are arranged in a cubic array whereas the

smallersodium ions fill all the cubic gaps (octahedral voids) between them.This same basic structure is found in many other compounds and iscommonly known as the halite or rock-salt crystal structure. It can berepresented as a face-centered cubic (FCC) lattice with a two-atom basis oras two interpenetrating face centered cubic lattices. The first atom is locatedat each lattice point, and the second atom is located half way between latticepoints along the FCC unit cell edge.

Thermal conductivity of NaCl as a function of temperature has a maximumof 2.03 W/ (cm K) at 8 K and decreases to 0.069 at 314 K (41 C). It also

decreases with doping.
https://en.wikipedia.org/wiki/Halitehttps://en.wikipedia.org/wiki/Ionic_compoundhttps://en.wikipedia.org/wiki/Chemical_formulahttps://en.wikipedia.org/wiki/Sodiumhttps://en.wikipedia.org/wiki/Chloridehttps://en.wikipedia.org/wiki/Salt_%28chemistry%29https://en.wikipedia.org/wiki/Oceanhttps://en.wikipedia.org/wiki/Extracellular_fluidhttps://en.wikipedia.org/wiki/Organismhttps://en.wikipedia.org/wiki/Edible_salthttps://en.wikipedia.org/wiki/Condimenthttps://en.wikipedia.org/wiki/Preservativehttps://en.wikipedia.org/wiki/Octahedronhttps://en.wikipedia.org/wiki/Close-packinghttps://en.wikipedia.org/wiki/Close-packinghttps://en.wikipedia.org/wiki/Chlorinehttps://en.wikipedia.org/wiki/Ionhttps://en.wikipedia.org/wiki/Sodiumhttps://en.wikipedia.org/wiki/Chemical_compoundhttps://en.wikipedia.org/wiki/Halitehttps://en.wikipedia.org/wiki/Thermal_conductivityhttps://en.wikipedia.org/wiki/Thermal_conductivityhttps://en.wikipedia.org/wiki/Halitehttps://en.wikipedia.org/wiki/Chemical_compoundhttps://en.wikipedia.org/wiki/Sodiumhttps://en.wikipedia.org/wiki/Ionhttps://en.wikipedia.org/wiki/Chlorinehttps://en.wikipedia.org/wiki/Close-packinghttps://en.wikipedia.org/wiki/Close-packinghttps://en.wikipedia.org/wiki/Octahedronhttps://en.wikipedia.org/wiki/Preservativehttps://en.wikipedia.org/wiki/Condimenthttps://en.wikipedia.org/wiki/Edible_salthttps://en.wikipedia.org/wiki/Organismhttps://en.wikipedia.org/wiki/Extracellular_fluidhttps://en.wikipedia.org/wiki/Oceanhttps://en.wikipedia.org/wiki/Salt_%28chemistry%29https://en.wikipedia.org/wiki/Chloridehttps://en.wikipedia.org/wiki/Sodiumhttps://en.wikipedia.org/wiki/Chemical_formulahttps://en.wikipedia.org/wiki/Ionic_compoundhttps://en.wikipedia.org/wiki/Halite


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AgNO3(Silver Nitrate)

Silver nitrate is an inorganic compound with chemical formula AgNO3. This compound is a versatile precursor to many other silver compounds,such as those used in photography.It is far less sensitive to light than thehalides. It was once called lunar caustic because silver was called lunaby

the ancient alchemists, who believed that silver was associated with themoon.[1]

In solid silver nitrate, the silver ions are three-coordinated in a trigonalplanar arrangement

Albertus Magnus,in the 13th century, documented the ability ofnitric acidto separate gold andsilver by dissolving the silver.[3]Magnus noted that theresulting solution of silver nitrate could blacken skin. Its common name atthe time was nitric acid silver.
https://en.wikipedia.org/wiki/Inorganic_compoundhttps://en.wikipedia.org/wiki/Chemical_formulahttps://en.wikipedia.org/wiki/Silverhttps://en.wikipedia.org/wiki/Photographyhttps://en.wikipedia.org/wiki/Silver_halidehttps://en.wikipedia.org/wiki/Silver_nitrate#cite_note-1https://en.wikipedia.org/wiki/Silver_nitrate#cite_note-1https://en.wikipedia.org/wiki/Silver_nitrate#cite_note-1https://en.wikipedia.org/wiki/Nitratehttps://en.wikipedia.org/wiki/Albertus_Magnushttps://en.wikipedia.org/wiki/Nitric_acidhttps://en.wikipedia.org/wiki/Goldhttps://en.wikipedia.org/wiki/Silverhttps://en.wikipedia.org/wiki/Silver_nitrate#cite_note-3https://en.wikipedia.org/wiki/Silver_nitrate#cite_note-3https://en.wikipedia.org/wiki/Silver_nitrate#cite_note-3https://en.wikipedia.org/wiki/Silver_nitrate#cite_note-3https://en.wikipedia.org/wiki/Silverhttps://en.wikipedia.org/wiki/Goldhttps://en.wikipedia.org/wiki/Nitric_acidhttps://en.wikipedia.org/wiki/Albertus_Magnushttps://en.wikipedia.org/wiki/Nitratehttps://en.wikipedia.org/wiki/Silver_nitrate#cite_note-1https://en.wikipedia.org/wiki/Silver_halidehttps://en.wikipedia.org/wiki/Photographyhttps://en.wikipedia.org/wiki/Silverhttps://en.wikipedia.org/wiki/Chemical_formulahttps://en.wikipedia.org/wiki/Inorganic_compound


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each level, depending on the pumping rate. The lower layer of ports permits

the direct entry of water at the low flow stage of the river while the upper

layer of ports meet the requirement of the high flood stage.

A typical river intake structure consists of:

1) An inlet well

2) An inlet pipe

3) A jack Well

Inlet well:

Inlet Well or collector well is a circular or more preferably an oblong well,

located in river bed, somewhat away from the river bank, amidst water, so

that it always remains surrounded with Water even during low flow stage

the well is built in masonry or concrete, and is raised above the river HFL

and covered at the top by Wooden sleepers.

Inlet pipe:

It connects inlet well with the jack well is usually of non-pressure type, and

laid with a gentle slope of 1 in 200 or so, towards jack well. Pipe size should

be such that the flow velocity does not exceed about 1.2 m/s. The diameter

of this pipe should, be not less than 45cm.

Jack Well:

Water entering the jack well from the intake pipe is lifted by pumps and isfed into the rising main through the delivery pipe of the pipe. The jack well

should be founded on hard strata with a bearing capacity of not less than

450KN/m2.

The intake well is connected to jack well which is constructed on river bank

by a R.C.C intake pipe and towards jack well. Pipe size should be such that

the flow velocity does not exceed about 1.2 m/s. The diameter of this pipe

should, be not less than 45cm.

Water entering the jack well should be founded on hard strata with aconsiderable bearing capacity


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PLANT DESCRIPTION-RAW WATER INTAKE

(YAMUNA)

Motor No. Horsepower Attached Pumpcapacity

1. 90HP 7MGD

2. 90HP 7 MGD

3. 90HP 7 MGD

4. 200HP 12 MGD

5. 280HP 15.85 MGD

6. ------- -------

7. 228HP 15.85 MGD

8. 200HP 12 MGD

9. 200HP 12 MGD

10. 200HP 12 MGD

11. 250HP 18 MGD

12. 250HP 18 MGD

13. 250HP 18 MGD

14. 110HP 7 MGD

15. 90HP 7 MGD

16. 250HP 18 MGD

17. 250HP 18 MGD


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Pre Chlorination or primary Oxidation

Significant Turbo circular suspended Solid Recirculation Scrapper Bridge

Coagulation. The purpose of providing the pre-chlorination or primary of

the raw water is to:

- Protect the clarifiers and filter from many biological /algae formation.

- Destroy ammonia

- Improve the coagulation of the organics.

PAC Mixing:

Here PAC is mixed according to demand by doing alum dose test. Forexample: we put different doses of alum and PAC in beaker. We consider

that dose where flocks are forms dominant as well as and PAC.if the dose is

25+8; that means 25 mg of alum and 8ml of PAC is mixed in 1L of raw water

at least conc. of Alum

Presettlers/Clarifiers:

The function of the clarifier is to settle out particles. This can be done by

properly recognizing that small turbulence levels can bring particles together

to help them settle more easily and that the effect of shear and strongturbulence levels will break particles an increase in turbidity. Modeling of

the shear velocities in related to the flow.

The results is to create too swirl much radial and axial momentum which

increases turbidity. This is compounded by the fact that most bustle pipes

do not pose problem and pull flow equally in all holes

Filter House

Sand filter or rapid gravity filter is type of filter used in water purificationand is commonly used in municipal drinking water facilities as part of a

multiple-stage treatment system first modern rapid sand filtration plant was

designed and built by George W. Fuller in Little Falls, New Jersey. Fuller's

filtration plant went into operation in 1902 and its success was responsible

for the change to this technology in the U.S. Rapid sand filters were widely

used in large municipal water systems by the l920s, because they required

smaller land areas compared to slow sand filters.

Design and operation:


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RECYCLING PLANT:-

In recycling Water plant, Water enters in the raw Water pump house where

Water pumped to the clarifier (flocculation tank) where sedimentation andflocculation process is done. Further Water is proceed to thickener where

clear water is comes from the sides of the thickener. After thickener water

goes to pulsar tube where mixture of alum and chlorine is added in water

after pulsar tube .Water goes to filter house Where it get purified through

media and finally We get potable Water. There is another pipeline after

thickener which sends the sand water in sludge pump house _ sludge pump

house pump the Water to devoting (centrifuge) building. Centrifuge building

separates sand and water and that Water again pumped to raw Water pump

house for treatment.


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Role of Treatment and Quality Control

Division

SUITABILITY OF RAW WATER AND SUPPLIED TO THE CONSUMER ENDTHE UNDERTAKE TREATMENT OF SEWAGE. TO IDENTIFY THE

CONTAMINATION IN WATER AT THE CONSUMER END, SIX ZONAL LABS

ARE FUNCTIONING FOR SURVEILLANCE WORK.

Quality control staff:

Quality control division of DJB is headed by Director (Treatment & Quality

Control) and who is assisted by a number of skilled and qualified scientific

staff mentioned as below:

Designation Sanctioned post

C.W.A 3 NO.

A.C.W.A 12 NO.

CHEMIST 20 NO.

BACTERIOLOGIST 9 NO.

ASSISTANT CHEMIST 67NO.

ASSISTANT BACTERILOGI 12 NO.

LAB. TECHNICIANS 39 NO.

LAB ASSISTANT 16 NO.

ROLE OF QUALITY CONTROL DIVISION OF DJB IN THE FIELD OF WATERTREATMENT AND QUALITY CONTROL:

Delhi Jal Board is responsible for providing high quality water to 1.7 crore

(approx.) citizens of Delhi and ensuring average availability of about 50

gallons of drinking Water per capita per day .The drinking Water refers to

aesthetically appearing water i.e. free from pathogens and chemical

contaminants that causes undesirable health hazards.

At present Delhi Jal Board is providing about 850 MGD from its 7 treatment

Plants, Ranney and Tubewells.The Water treatment capacity is mentioned infollowing statement:


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INSTRUMENTS USED IN PLANT

LABORATORY

TURBIDITY METER

Turbidity is an optical characteristic or property of a liquid, which in general

terms describes the clarity, or haziness of the liquid. Turbidity has always

been based on human observation and while this phenomenon is

quantifiable by many different means, much discussion still exits around

the various techniques used to measure turbidities of fluids. Turbidity is not

colour related, but relates rather to the loss of transparency due to the effect

of suspended particulate, colloidal particles

HACH PORTABLE TURBIDITMETER

The portable turbid meter offers unsurpassed ease of use and accuracy inturbidity measurement. Only Hach offers this unique combination ofadvanced features and measurement innovation, giving you accurate resultsevery time. Compliant with USEPA Method 180.1 design criteria.

Easy on-screen assisted calibration and verification

Save time and get accurate results with an easy-to-follow interface thateliminates the need for complicated manuals to perform routinecalibrations. Single-standard RapidCal calibration offers a simplifiedsolution for low level measurements, while ensuring you meet reportingrequirements.

Simple data transfer

Data transfer with the optional USB+Power Module is simple, flexible, anddoesn't require additional software. All data can be transferred to themodule in XML format and easily downloaded to your computer with a USBconnection, providing superior data integrity and availability.


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Accurate for rapidly settling samples

The innovative Rapidly Settling Turbidity mode provides accuratemeasurements for difficult to measure, rapidly settling samples. Anexclusive algorithm that calculates turbidity based on a series of automatic

readings eliminates redundant measurements and estimating.

Convenient data logging

Up to 500 measurements are automatically stored in the instrument foreasy access and backup. Stored information includes: date and time,operator ID, reading mode, sample ID, sample number, units, calibrationtime, calibration status, error messages, and the result.

Optical system for precision in the field

The two-detector optical system compensates for colour in the sample, lightfluctuation, and stray light, enabling analysts to achieve laboratory-gradeperformance on a wide range of samples, even under difficult site conditions.

PORATBLE CONDUCTIVITY METER

Designed for your water applications, the Hach portable meter is anadvanced meter that takes the guesswork out of measurements. HQ metersconnect with smart probes that automatically recognize the testingparameter, calibration history, and method settings to minimize errors andsetup time. -


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UV SPECTROPHOTOMETER

Maximum analysis flexibility with high speed wavelength scanningacross the UV and visible spectrum

The Hach DR 5000 UV-Vis Laboratory Spectrophotometer can test for all ofthe parameters listed on page 3. All of the chemistries and supplies neededfor these tests are available from Hach.

Easily Add New Analytical Methods

As Hach releases new test methods and chemistries, the DR 5000spectrophotometer can easily be updated via a USB memory stick.

Stability and Accuracy

The design of the DR 5000 spectrophotometer ensures measurements areaccurate, precise, and stable over time, resulting in repeatable results.

Multiple Cell Sizes and Delivery Methods

A single multi-cell adapter for the DR 5000 spectrophotometer holds the fivemost common sample cell types, including 5 cm path length cells. Moreover,the optional Pour-Thru Cell Module is ideal for Rapid Liquid methods.

Large Touch Screen Display and Interface

The touch screen display of the DR 5000 spectrophotometer is intuitive touse and ergonomic in design.


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Weigh 0.05 g powered methyl orange and transfer to a 100 ml volumetric

flask. Dissolve in 1: 1 ethanol and make up with DDW.

5. Phenolphthalein Indicator

Weigh 0.5 g phenolphthalein disodium salt in 100 ml volumetric flask.Dissolve in 1:1 ethanol and DDW solution. Dilute to the mark with DDW.

Standardization of 0.02N H2SO4solution,1. Take 10 ml of 0.05N

Na2CO3 into a 250-ml conical flask and add 90-ml DDW.

2. Add 0.1 ml methyl orange indicator.

3. Titrate with 0.02N H2SO4and record the volume of titrant used.

4. Prepare a blank using 100-ml DDW instead of standard solution and

repeat the same procedure of titration as done for the standard.

Record the volume of the titrant.

5. Calculate the normality of titrant as follows:

Normality of 0.02N H2SO4 = A 10 = 0.02

53 (CB)

Where A = weight of Na2CO3in gm used to prepare 1 L of 0.05N solution

B = volume of acid used for the blank, ml

C = volume of acid used for the standard, ml

Procedure

1. Take50 ml of unfiltered sample into a 250- ml; conical flask.

2. Record initial pH and temperature.

3. If initial pH is more than 8.3, titrate with 0.02N H2SO4 using

phenolphthalein indicator, till the pink color disappears. This is

phenolphthalein end point. However, if the pH of sample is less than

8.3 and no change in color is observed after the addition of

phenolphthalein indicator, proceed for next steps.

4. Add the 2-3 drops methyl orange and titrate with 0.02N H2SO4till

pink color is obtained, record the reading, this is total alkalinity (T).

Calculations


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Total alkalinity as mg/CaCO3= T N 50000

Sample (ml)

Where T = Total alkalinity

N = Normality of standard acid solution.

CHLORIDES

Principle

In a neutral or slightly alkaline solution, potassium chromate can be used to

indicate the end point of the silver nitrate titration of chloride. Silver

chloride is quantitatively precipitated before red silver chromate is formed.

NaCl + AgNO3= AgCl + NaNO3

2 AgNO3+ K2CrO4 = Ag2CrO4+ 2KNO3

Reagents

1. Potassium Chromate Indicator Solution: Dissolve 50 mg K2CrO4in a

little DDW. Add AgNO3solution until a definite red precipitate isformed. Let stand 12 hr, filters, and dilute to 1 L with DDW.

2. Standard Silver Nitrate Titrant, 0.028N: Dissolve 4.8 g AgNO3 in

distilled water and dilute to 1 L. standardize against 0.028N NaCl.

Store in brown bottle.

3. Standard Sodium chloride, 0.028N: Dissolve 1628 mg NaCl (dried at

140 0C) in DDW and dilute to 1 L.

Procedure

1. Sample Preparation: Use a 100-ml sample or a suitable portion

diluted to 100 ml. If the sample is highly color, add 3 ml Al (OH) 3

suspension, mix, let settle, and filter.

If sulphide, sulphite, or thiosulfate is present, add 1 ml H2O2and stir

for 1 min.

2.Titration: Directly titrate samples in the pH range 7 to 10. Adjustsample pH to 7 to 10 with H2SO4or NaOH if it is not in this range.

Add 1.0 ml K2CrO4 indicator solution. Titrate with standard AgNO3titrant to a pinkish yellow end point. Be consistent in end-point


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recognition.

3. Standardize AgNO3titrant and establish reagent blank value by thetitration method outlined above. A blank of 0.2 to 0.3 ml is usual.

Calculation

Chloride(mg/l) = (A-B) N 35450

Sample(ml)

Where:

A = ml titration for sample,

B = ml titration for blank,

N = normality of AgNO3.

NaCl (mg/l) = Chloride(mg/l) 1.65

HARDNESS

Principle

In alkaline condition EDTA reacts with Ca and Mg to form a soluble

chelated complex. Ca and Mg ions develop wine red Color with

Erichrome black T under alkaline condition. When EDTA is added as

a titrant the Ca and Mg divalent ions get complexed resulting in sharp

change from wine read to blue which indicates end point of the

filtration. The pH for this titration has to be maintained at 10.0 0.1.

At a higher pH, i.e., about 12.0 Mg ion precipitates and only Ca ion

remains in solution. At this pH Murex indicator form a pink Color

with Ca++

When EDTA is added Ca++

gets complexed resulting in a

change from pink to purple which indicates end point of the reaction.


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Reagents

1. Buffer solution: Dissolve 16.9 g NH4Cl in 143 NH

4OH. Add 1.25 g

EDTA Mg salt to obtain sharp change in indicator and dilute to 250

ml.

2. Inhibitor: Dissolve 4.5 g hydroxyl amine hydrochloride in 100 ml

95% ethyl alcohol.

3. Erichrome black T Indicator: Mix 0.5 dye with 100g NaCl to prepare

dry powder.

4. Murex indicator: Dry powder.

5. Sodium hydroxide 2N: dissolve 80 g NaOH and dilute to 1000 ml.

6. Standard EDTA solution 0.01 M: Dissolve 3.723 g EDTA sodium

salt and dilute to 1000 ml. Standardize against standard Ca

solution, 1 ml = 1 mg CaCO3.

7. Standard calcium solution: Weigh accurately 1.0 g AR grade CaCO3

and transfer to 250 ml conical flask. Place a funnel in the neck of

a flask and add 1+1 HCL till CaCO3dissolves completely. Add 200

ml distilled water and boil for 20-3- min. to expel CO2Cool and

methyl red indicator. Ad NH4OH 3N drop wise till intermediate

orange Color develops. Dilute to 1000 ml to obtain 1 ml1 mg

CaCO3.

Procedure

A. Total Hardness

1. Take 25 or 50 ml well mixed sample in porcelain dish or

conical flask.

2. Add 1-2 ml buffer solution followed by 1 ml inhibitor.


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Magnesium hardness = Total hardnessCa hardness

DISSOLVED OXYGEN (DO)

Principle

The basic Winkler procedure entails the oxidation of manganese hydroxide

in highly alkaline solution. Upon acidification in the presence of an Iodide,

the manganese hydroxide dissolve and free Iodine is librated in amount

equivalent to the oxygen originally dissolve in the sample the free Iodine is

titrated with a Sodium thiosluphate standard solution, using starch as

internal indicator, after most of the iodine has been reduced. The normality

of sodium thiosulphate is adjusted so that 1 ml is equivalent to 1 mg/l

dissolved oxygen when 200 ml of the original sample is titrated.

Reagents

1. Manganese Sulphate solution, MnSO4H2O: Weigh 364 g , MnSO4H2O

and dissolved in DDW and make up to the 1 L. Filter the reagents if

any sediment settles at the bottom of the flask.

2. Alkaline Iodide-azide reagent:

Sodium hydroxide, NaOH 500 g

Potassium Iodide, KI 135 g

Sodium Azide, NaN3 10 g

Weigh the above mentioned quantities of solution and transfer to a 1 L

volumetric flask. Dissolved NaN3, in 100 ml separately and add to

alkaline KI solution. Make up the final volume to 1 L.

3. Sulphuric Acid, H2SO4: concentrated.

4. Sodium Thiosulfate Stock Solution, Na2S2O3.5H2O, and [N/10]: Weigh

24.82 g Na2S2O3.5H2O, and transfer to 1 L volumetric flask. Dissolvein DDW, and make up to the mark.

5. Sodium Thiosulfate Titrant, Na2S2O3.5H2O, [N/40]: Take 250 ml

sodium thiosulfate stock solution to 1 L volumetric flask. Dilute up

to the mark with DDW.

6. Standard Potassium Dichromate, K2Cr2O7, [N/40]: Keep K2Cr2O7in an

oven at 103 C for 2 hr. Cool to room temperature in desiccators .

Weigh 1.226 g dry, cool dichromate and transfer to a 1 L volumetric

flask. Dissolve in DDW and dilute up to mark.


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3. Allow the sample to stand until the flock has settled and left the top

half of the solution clear. Again invert it several times and let stand

until the upper half of the bottle is clear. This is to ensure the

complete reaction of chemicals with available DO.

4. Remove the stopper and immediately add 2-ml conc. , H2SO4. Replace

the stopper carefully to avoid the trapping any air bubbles. Invert

several times to mix. The flock will dissolve and leave a yellowish-

orange Iodide color if DO is present.

5. Measure 204 ml of sample, which corresponds to 200-ml of the

original sample(correction for the sample loss by displacement with

reagent) into a 250-ml conical flask.

6. Titrate this solution with standard Na2S2O3.5H2O, [N/40] solution to

faint yellow color. Add 1-2 drop of starch indicator and swirl to mix. A

dark blue color is developed.

7. Continue the titration until the solution change from blue to colorless.

Calculation

1.0 ml of Na2S2O3.5H2O, [N/40] = 1 mg DO

So, the ml solution of Na2S2O3.5H2O, [N/40] used is equal to the mg/l of

DO available in the sample.

OXYGEN ABSORPTION-3 hr. at 37 0C

Principle

When potassium permanganate reacts with sulphuric acid it gives the

dipotassium sulphate and MnSO4, water and oxygen radicals.

2 KMnO4+ H2SO4 K2SO4+ 2 MnSO4+ 3 H2O + 5 O

The free oxygen oxidized the organic matter present in the sample.

Organic matter + 5 O CO2+ H2O

The remaining oxygen present in the sample can be measured by adding the

KI solution, which liberate the equal amount of the Iodine, which is titrated

with the sodium thiosulfate solution in the presence of starch.

KI + O I2(form blue color with starch)

2 Na2S2O3+ I2 Na2S4O6+ 2 NaI


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Reagents

1. Potassium Permanganate Stock Solution, KMnO4[0.1 N]: Weigh 3.2 g

KMnO4and transfer in 1 L volumetric flask and swirl the flask to

dissolve and make up the mark with DDW.

2. Standard Potassium Permanganate Solution, KMnO4[0.025N]: Take

250 ml stock KMnO4in 1 L volumetric flask and make up to the mark

with DDW.

3. Sulphuric Acid, H2SO4[1:3]: Take 500 ml DDW in volumetric flask

and slowly add 250 ml conc. H2SO4and cool to room temperature.

4. Sodium Thiosulfate Stock Solution, Na2S2O3.5H2O, and [N/10]: Weigh

24.82 g Na2S2O3.5H2O, and transfer to 1 L volumetric flask. Dissolve

in DDW, and make up to the mark.

5. Sodium Thiosulfate titrant, Na2S2O3.5H2O, [N/40]: Take 250 ml

sodium thiosulfate stock solution to 1 L volumetric flask. Dilute up

to the mark with DDW.

6. Standard Potassium Dichromate, K2Cr2O7, [N/40]: Keep K2Cr2O7in an

oven at 103 C for 2 hr. Cool Ao room temperature in a desiccators .

Weigh 1.226 g dry, cool dichromate and transfer to a 1 L volumetric

flask. Dissolve in DDW and dilute up to mark.

7. Potassium Iodide, KI: Take 2 g in a 500 ml Erlenmeyer flask and

dissolve in 100 ml DDW.

8. Starch Solution:

I. Take 100 ml DDW in 250-ml beaker and keep on a heater

equipped with magnetic stirrer.

II. Bring to boil.

III. Weigh 2-g laboratory grade starch and suspend in a smallvolume of DDW.

IV. Add starch suspension in small increments to boiling DDW with

constant stirring. Cool the solution. Add 0.2-g salicylic acid as

preservative.

Standardization

a. Sodium Thiosulfate Solution


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I. Take 20 ml standard 0.025N K2Cr2O7. Solution and add 1

ml of 6N H2SO4. Place flask in dark.

II. Dilute to 400 ml with DDW and titrate liberated iodine with

thiosulfate.

III. When pale straw color is reached, add few drops of starch

indicator. A blue color will develop. Titrate till the blue color

disappears. Record the reading.

Normality of Na2S2O3 = 0.025N 20

Volume of Na2S2O3 used, ml

b. Standard Potassium permanganate, KMnO4 [0.025N]

I. Take 20 ml KMnO4[0.025N] in 100 ml flask and titrate

with 0.025N Na2S2O3with starch as indicator.

Normality of KMnO4 = 0.025N Volume of Na2S2O3 used,

ml 20

Procedure

1. Take 50 ml sample in bottle, shake sample well before measuring.

2. Add 5 ml of 1:3 Sulphuric acid in each sample and shake it.

3. Add 10 ml Standard Potassium permanganate, KMnO4[0.025N] in

blank bottle with DDW. and 20 to 50 ml as per the turbidity of

the sample, and note the quantity of KMnO4[0.025N] added in each

labeled bottle.

4. Put the stopper on the bottle and keep the sample bottle in incubator

for 3 hr. set at 37 C.

5. Take the sample bottle after 3 hr. and remove the stopper and

immediately add 2 ml KI solution in each bottle and titrate with

0.025N Na2S2O3, using starch as indicator.

Calculation

N1V1 = N2V2

(sample) (Solution)

N1 50 ml = 0.025 N (ml of Na2S2O3, used)

N1 = 0.025 N (ml of Na2S2O3, used)


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50 ml

Strength = Normality Eq. Wt.

= 0.025 N (ml of Na2S2O3, used) 8 1000

50 ml

= 0.025 N (ml of Na2S2O3, used) 4 mg/l

50 ml

Thus volume of sodium thiosulfate multiplied by 4 gives the oxygen

absorption of the sample for 3 hr. at 37 C.

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