SOURCES OF WATER:-
1- RAIN AND SNOW
2- SURFACE WATER
- STREAMS
- NATURAL PONDS AND LAKES
- IMPOUNDING RESERVOIRS
3- GROUND WATER
- SPRINGS
- SHALLOW WELLS
- DEEP WELLS (.20M DEEP)
- ARTESIAN WELLS.
CONSIDERATIONS POINTS OF WATER SUPPLY SCHEME:-
- QUALITY OF WATER OF SOURCE.
- QUANTITY OF YIELD.
- LOCATION OF SOURCE.
CLASSIFICATION AND PURITY OF SOURCES:-
1- SAFE AND VERY POTABLE
- SPRING WELL
- DEEP WELL
- LAKE AND MOUNTAIN
- RIVER WATER.
2- SUSPICIOUS AND POLATABLE
- STORED RAIN WATER
- SURFACE WATER FROM CULTIVATED LAND.
3- DANGEROUS AN PALATABLE
- SHALLOW WELL WATER
- DOWN LAND RIVER WATER.
ON THE BASIS OF PHYSICAL, CHEMICAL AND BIOLOGICAL TESTS WATER CAN BE DIVIDED INTO 4 CLASSES.:-
CLASS I:-
STANDARD-BEST
DOES NOT REQUIRED ANY OTHER TREATMENT EXCEPT DISINFECTION
EXAMPLE- DEEP WELLS.
CLASS II:-
STANDARD- SATISFACTORY
REQUIRE TREATMENT LIKE FILTERATION AND DISINFECTIONS.
EXAMPLES- SHALLOW WELL, SPRINGS, LAKES.
CLASS III:-
STANDARD- SPECIOUS WATER SOURCE.
REQUIRES TREATMENT LIKE COAGULATION, FILTERATION, SOMETIMES SPECIAL TREATMENTS LIKE- AERATION, SOFTENING AND FOLLOWED BY FILTERATION.
CLASS IV:-
STANDARD- UNSATISFACTORY
IT MAY CONTAIN TOXIC SUBSTANCES OR HIGHLY POLLUTED WITH SEVAGE AND INDUSTRIAL WASTES. THIS CAN'T BE PURIFIED BY NORMAL TREATMENT AND NEVER TAKEN UP AS A WATER SUPPLY SOURCE.
SOME DEFINITIONS:-
PURE WATER:- IS FREE FROM ANY OBJECTIONABLE MATTER.
SAFE WATER- IS POTABLE AND FREE FROM PATHOGENIC GERMS AND TOXIC IMPURITIES.
CLEAR WATER- HAVING NO SUSPENDED MATERIALS.
CONTAIMINATED WATER- CONTAINS PATHOGENIC BACTERIA.
POLLUTED WATER- CONSISTS UNDESIRABLE SUBSTANCES RENDERING IT UNFIT FOR DRINKING AND DOMESTIC USE.
POTABLE WATER- IS TASTY, SAFE AND SUITABLE FOR DRINKINGAND DOMESTIC USE.
NOTE:- "THE CONTAIMINATED WATER IS ALWAYS POLLUTED BUT ALL THE POLLUTED WATERS MAY NOT BE NECCESARILY CONTAIMINATED".
COMMON IMPURITIES IN WATER :-
SUSPENDED IMPURITIES:-
- BACTERIA, ALGAE, PROTOZOA, SILT.
DISSOLVED IMPURITIES:-
SALT, CALCIUM, MAGNESIUM, SODIUM, IRON, MAGNESE, VEGETABLE DYES.
SOME CAUSE DISEASES ODOUR, TURBIDITY MURKINESS/ TURBIDITY:-
BICARBONATE ALKALINITY, HARDNESS, SOFTENING
CARBONATE ALKALINITY, HARDNESS, SOFTENING
SULPHATE ALKALINITY, HARDNESS, FOAMING IN STEAM BOILERS
CHLORIDE COHESIVENESS, HARDNESS, TASTE.
FLUORIDE MOLTED ENAMEL OF TEETH
GASES:-
- OXYGEN- CORROSIVENESS TO METALS
- CARBONDIOXIDE- ACIDITY, CORROSIVENESS
- HYDROGEN SULPHIDE- ODOUR, ACIDITY, CORROSIVENESS
- NITROGEN
WATER BORNE DISEASES:-THE CONTAIMINATED OR POLLUTED WATER CAUSES DISEASES.
DECAYING ORGANIC MATTER- DYSENTRY AND DIARRHEA.
IRON- DYSPEPSIA (INDIGESTION) AND CONTIPATION.
LEAD- POISIONING, PAIN IN ABDOMEN, LOSS OF APETITE, CONSTIPATION THIRST.
CLASSIFICATION OF TESTS:-
1- TESTS THAT MEASURE OR REFLECT THE SAFETY OR WHOLESOMENESS OF WATER.
A- TESTSFOR CONTAIMINATION AS MEASURED BY THE PRESENCE OF THE COLIFORM GROUP.
B- TESTS FOR TOXIC QUALITIES OF As, Pb, Cr, Bo, Se, Ba, Cu, NITRATES AND FLUORIDES.
C- TESTS FOR PHYSIOLOGICALLY BENEFICIAL QUANTITIES OF IODIDE AND FLUORIDE.
D- TESTS FOR POLLUTION AS INDICATED BY THE ORGANIC, ALBUMINOIDAL, NITRITE AND NITRATE NITROGEN'S
E- TESTS FOR LAXATIVE PROPERTIES OF Mg AND SO4.
2- TESTS THAT MEASURE OR REFLECT THE PALATIBILITY OR ESTHETIC ACCEPTABILITY OF WATER-
A- TEMPERATURE, TURBIDITY, COLOUR, AND ODOUR. BY THE MICROSCOPIAL EXAMINATION AND BY TESTS FOR RESIDUES AND METALS, CHLORIDE, ACTIVE CHLORINE, HYDROXIDE, LENIN AND LIGNIN AND HYDROGEN SULPHIDE, ONE OR ANOTHER OF WHICH MAY EXPLAIN THE ORIGIN OF THE OBSERVED TURBIDITY, COLOUR, ODUOR AND TASTE.
3- TESTS ARE RELATED IN PARTICULARTO WATER TREATMENT PROCESSES. Eg- IN ADDITION TO THE PERTINENT TEATS FOR THE SUBSTANCES REMOVED/ DESTROYED, OR TO BE REMOVED/ DESTROYED ARE-
A- TESTS FOR ALKANITY, pH, CO2 AND Al, Fe IN CONNECTION WITH THE USE OF COAGULANTS.
B- TESTS FOR ODOR ANMD Cu AFTER THE DESTRUCTION OF ALGAE BY Cu COMPOUND.
C- TESTS FOR Cl DEMAND, pH AND ACTIVE CHLORINE IN CONNECTION WITH CHLORINATION.
D- TESTS FOR STABILITY, PHOSPHATE, SILICATE, pH AND HYDROXIDE FOLLOWING TREATMENT FOR CORROSIVENESS.
E- TESTS FOR HYDROXIDE, Na, K AND Si IN CONNECTION WITH WATER SOFTENING.
F- TESTS FOR pH, CO2 AND DISSOLVED O2 IN CONNECTING WITH DEFERRIZATION AND DEMANGANIZATION.
SOME SIMPLE TESTS FOR DETECTING DANGROUS MATTERS IN WATER:-
1- SEWAGE:- TAKE A SMALL GLASS OF WATER AND ADD 4 DROPS OF KMNO4. IF THE COLOR OF WATER TURNS PALE OR YELLOW, THE PRESENCE OFDECOMPOSED ORGANIC MATTER MAY BE INFERRED.
2- Pb- THE PRESENCE OF Pb CAN BE DETECTED BY 6 DROPS OF H2SO4 WHICH WILL YIELD A WHITE PPT.
3- Cu:- ADDITION OF 8 DROPS NH3 WILL TURN THE SMALL GLASS OF WATER TO BLUE IF Cu IS PRESENT.
4-Zn:- ADDITION OF 6 DROPS OF POTASSIUM TERROCYANIDE TO A SMALL GLASS OF WATER WILL TURN TO GREEN. IF Zn IS PRESENT.
COMMON GERMICIDES TO PURIFY THE WATER:-
1- KMNO4:-
- STRONG OXIDISING ACTION.
- KILLINH BACTERIS
- USEFUL FOR STERLIZING SMALL QUANTITIES OF WATER
- EXPENSIVE
- DOSE 1/16TH GRAM/ GALLON.
2- CAUSTIC LIME (CaO) :- IT IS USED WHEN KMNO4 IS UNAVAILABLE.
3- CUSO4:-
- USED FOR REMOVAL OF ALGAE AND OTHER VEG GROWTH IN TANKS.
- DOSE 0.1-0.25 PART PER MILLION PARTS OF WATER TO BE TREATED.
4- CHLORINE SUSPENSION:-
- AVAILABLE IN LIQUID FORM.
- USED FOR STERLIZATION OF DRINKING WATER SUPPLY
- DOSE 5-7 LB OF CL2 ACCORDING TO BACTERIAL PURITY AND AMOUNT OF ORGANIC MATTER PRESENT IN WATER.
5- OZONE:-
- MOST POWERFUL GERMICIDE.
- VERY EXPENSIVE AND DIFFICULT IN MASS PRODUCTION.
6- UV-RAYS:-
- HIGHLY EXPENSIVE AND SPECIAL APPRATUS REQUIRED RESTRICTED USE.
TESTS:-
A- PHYSICAL TESTS:-
TEMPERATURE:- WATER SHOULD BE CLEAN, COOL AND SPARKLING IN APPEARENCE.
- WATER BECOMES UNPALATABLE BEYOND 25 DEGREE CELCIUS.
TURBIDITY:- ITS AN INDICATION OF APPARENT CLOR OF WATER ON ACCOUNT OF SUSPENDED INORGANIC MATTER SUCH AS SILICA, CLAY AND MUD PARTICLES.
- EXPRESSED IN PPM BY WEIGHT-
10 PPM HARDLY NOTICEABLE
~ 30 PPM WATER STARTS CLOUDY IN APPEARENCE
> 100 PPM WATER IS DISTINCTLY TURBID.
JACSON TURBIDIMETER MEASURES TURBIDITY ABOVE 100 PPM AND BAYLIS TURBIDIMETER RECORDS LESS THAN 5 PPM.
TASTE AND ODOR:- GENERALLY DUE TO MINERAL, SALTS, OILS AND TARRY SUBSTANCES INDUSTRIAL WATES, DOMESTIC SEWAGE, CHLORINATION, ACID WATES ETC.
- ODOR IS TESTEDAT 22 AND 80 DEGREE CELCIUS.
- QUALITY OF ODOR IS EXPRESSED AS-
A- AROMATIC
B- DISAGRREABLE
C- EARTHY
D- FISHY
E- GREASY
F- MOLDY
G- SWEETISH
- THRESHOLD ODOR NUMBER IS USED TO EXPRESS THE INTENSITY OF ODOR.
- THE NUMBER INDICATES THE MAXIMUM DILUTION TO BE MADE OF A SAMPLE. THUS IF 100CC OF FRESH WATER HAVE TO BE ADDED TO 8 CC OF A SAMPLE OF WATER TO PRODUCE NO EFFECT OF ODOR IN IT, THE THRESHOLD ODOR NUMBER IS 8. IT SHOULD BE NOTED THAT 9CC OF THE SAMR SAMPLE WHEN ADDED TO 100 CC OF FRESH WATER PRODUCE ODOR.
B- CHEMICAL TESTS:-
TOTAL SOLIDS:-
GENERAL RANGE 600-1500 PPM
PERMISSIBLE RANGE 500-1000 PPM
PREFERABLE RANGE <500 PPM
CHLORIDE:- ACCORDING TO IS:3025-1964, CHLORINE CONTENT MAY BE DETERMINED BY ADDING AGNO3 SOLUTION OF KNOWN CONCENTRATION AND POTASSIUM CHROMATE (INDICATOR) TO THE SAMPLE OF WATER.
HARDNESS:- CAUSED BY HCO3, CO3, SO4, CHLORIDE AND NITRATES OF CALCIUM AND MAGNESIUM.
- EXPRESSED IN TERMS OF CACO3.
HARD WATER 100 PPM
SOFT WATER <50 PPM
VERY HARD WATER 200-250 PPM
ACCORDING TO IS:3025-1964, EDTA (ETHYLENE DIAMIDE TETRA ACETIC ACID) METHOD IS USED FOR DETERMINING THE HARDNESS.
SCALE OF HARDNESS HARDNESS
(DEGREES)
DISSOLVED H2O:- THE AMOUNT OF O2 PRESENT IN H2O ABSORBED BY 10% SOLUTION OF KMNO4 AT 27 DEGREE CELCIUS FOR 4 HOURS SHOWS THE QUANTITY OF CARBONACEOUS MATTER OF ORGANIC ORIGIN
ALKANITY:- BICARBONATE, CARBONATES AND HYDROXIDES OF SODIUM, CALCIUM AND MAGNESIUM.
- EXPRESSED IN PPM IN TERMS OF EQUIVALENT CACO3 PRESENT IN A SAMPLE OF H2O CAUSE IT.
- DETERMINED BY TITRATING THE SAMPLE AGAINST STANDARD ACID USING METHYL ORANGE ALAKNITY.
NITROGENOUS COMPOUNDS:- THESE ARE-
I- FREE AMMONIA
II- ALBUMINOID AMMONIA
III- NITRITES
IV- NITRATES
FOR TESTS, THE KNOWN AMOUNT OF WATER IS BOILED WITH STANDARD SOLUTION OF KMNO4 WHICH RESULTS IN THE BREAKDOWN OF LEAST SOLUBLE NITROGENOUS COMPOUNDS AND ALBUMINOID AMMONIA IS FORMED. NITRITES AND NITRATES ARE FORMES DUE TO OXIDATION OF ORGANIC MATTER.
PH:- THE ACIDITY OR ALKANITY OF H2O IS MEASURED IN TERMS OF PH VALUE OR H POSITIVE IN CONCENTRATION. WATER BECOMES ACIDIC WHEN H POSITIVE IONS ARE EXCESS THAN OH NEGATICE IONS AND IT BECOMES ALKALINE IN REVERSE CASE.
PH:-
ACIDIC WATER 0-7
ALAKLINE WATER 7-14
MEUTRAL WATER 7
IRON AND MAGNESE:- IRON AND MAGNESE MAY BE DETERMINED BY ADDING CERTAIN CLORING REAGENTS TO THE SAMPLE OF H2O AND TO THE SOLUTIONS OF KNOWN AMOUNTS OF IRON AND MAGNESE.
SOLUBLE MINERAL IMPURITIES:-
ALL SALTS IMPORT CERTAIN TASK IF PRESENT IN GREATER AMOUNTS.
NACL GIVES TASTE >200 PPM
UNDESIRABLE >3000 PPM
SULPHATES OF SODIUM, MAGNESIUM NOTICEABLE TASTE >500 PPM
DIFFICULT TO SUGGEST ANY PERMISSIBLE LIMIT BUT GENERAL RECOMMENDATION IS 500-1000 PPM
RESIDUAL CHLORINE:-
IT GIVES AN INDICATION OF THE FACT THAT THE BACTERIA ARE REDUCED TO A SAFE LIMIT. IT MAY BE DETERMINED BY ADDING ORTHOTOLODIN SOLUTION IN A SAMPLE OF WATER. THE YELLOW COLOR OF THE SAMPLE ENSURES THE PRESENCE OF RESIDUAL CHLORINE.
MINIMUM AMOUNT OF FREE CHLORINE- 0.05-0.1 PPM
DURING WATER BORNE DISEASES- 0.2-0.3 PPM
ACIDITY:-
IT IS DETERMINED BY TITRATING THE SAMPLE AGAINST STANDARD ALAKALI USING PHENOLPHTHALEIN INDICATOR.
SULPHATES:-
EDTA, METHOD CAN BE USED IN DETERMINING SULPHATES. IN THE METHOD , A MEASURED EXCESS OF STANDARD BARIUM CHLORIDE SOLUTION IS ADDED TO THE SAMPLE AND THE EXCESS BARIUM CHLORIDE IS ESTIMATED BY TITRATION AGAINST EDTA SOLUTION.
BIOCHEMICAL OXYGEN DEMAND (BOD):-
IT INDICATES BIOCHEMICA OXIDISABLE ORAGANIC MATTERS AND ITS USE COMMONLY RESTRICTED TO SEWAGE ANALYSIS. THE 5-DAY, 20 DEGREE CELCIUS BOD OF DOMESTIC WATER SHOULD BE LESS THAN 2 MG/U
C- MICROBIOLOGICAL TESTS:-
THE MICROBIOLOGICAL EXAMINATION OF WATER INCLUDES BOTH BACTERIOLOGICAL AND BIOLOGICAL EXAMINATIONS. THE WATER MAY BE CONTAIMINATED WITH PATHOGENIC (HARMFUL) AND NON-PATHOGENIC (NON-HARMFUL) BACTERIA. B-COLI GROUP BACTERIA DESIGNATES THE COMBINED GROUP OF THESE BACTERIA. THE BACTRIOLOGICAL EXAMINATION OF A SAMPLE IS CARRIED OUT ACCORDING TO IS:1622-1964 STANDARD.
2 STANDARD BACTERIOLOGICAL TESTS FOR BACTERIOLOGICAL EXAMINATION-
1- TOTAL COUNT/ AGAR PLATE ACOUNT TEST:-
IN THIS TEST, BACTERIA ARE CULTIVATED ON SPECIALLY PREPARED MEDIUM OF AGAR FOR DIFFERENT DILUTION OF SAMPLE OF WATER WITH STERILIZED WATER. THE DILUTED SAMPLE IS PLACED IN AN INCUBATOR FOR 24 HOURS AT 35 DEGREE CELCIUS OR FOR 48 HOURS @ 20 DEGREE CELCIUS. THESE REPRESENTS THE SO CALLED 'HOT COUNTS' AND 'COLD COUNTS' WHICH ARE FORMES, ARE THEN COUNTED AND THE RESULTS ARE COMPUTED FOR 1 CC
2- COLI TEST:- DIVIDED INTO 3 PARTS-
A- PRESUMPTIVE TEST:- BASED ON THE ABILITY OF COLIFORM GROUP TO FERMENT THE LACTOSE BROTH AND PRODUCING GAS.
B- CONFIRMED TEST:- CONSISTS OF GROWING CULTURES OF COLIFORM BACTERIAN ON MEDIA WHICH SUPPRESS THE GROWTH OF THE OTHER MICRO-ORGANISMS.
C- COMPLETED TEST:- BASED ON THE ABILITY OF CULTURE GROWTH IN THE CONFIRMED TEST TO AGAIN FERMENT THE LACTOSE BROTH.
THE MICROSCOPIC ORGANISMS (OTHER THAN BACTERIA) IN WATER INCLUDE A LARGE VARIETY OF ALGAE, FUNGI, YEASTS, PROTOZOA, ROTIFIERS, CRUSTACEAN, ANIMALULA ETC. MANY OF THESE AFFECT THE QUANTITY OF WATER FOR DRINKING AND INDUSTRIAL USE.
THE EXAMINATION OF NATURE AND NUMBER OF ORGANISMS PRESENT IN WATER IS NECESSARY TO UNDERSTAND THE NATURE OF POLLUTION, CAUSE OF BAD TASTE AND ODORS, SLIME GROWTH ADHERE TO STRUCTURES ETC.
MAINTENANCE OF PURITY OF WATER:-
1- THE CONTENT OF DISSOLVED OXYGEN PRESENT IN WATER SHOULD BE HIGH.
2- THE ENTRY OF UNDESIRABLE ELEMENTS SUCH AS ACIDIC AND ALKALINE DISCHARGE FROM THERMAL POWER STATIONS ETC INTO SOURCE OF WATER SUPPLY SHOULD BE PREVENTED BY SUITABLE MEANS.
3- THE PRESENCE OF ALGAE SUPPLYING O2 TO H2O IS DESIRABLE.
4- THE QUANTITY OF TOTAL DISSOLVED SOLIDS ESPECIALLY THE CHLORIDE CONTENTS, SHOULD BE VERY LOW.
5- THERE SHOULD BE ABSENCE OF ORAGANIC WASTES EXERTING O2 DEMAND ON WATER.
6- THERE SHOULD BE ENOUGH RE-AERATION FOR THE PURPOSE OF DE OXYGENATING OF WATER.
7- THE TEMPERATURE OF WATER SHOULD BE MAINTAINED LOW.
8- THE TURBULENCE OF WATER SHOULD BE ENCOURAGED TO MAKE AVAILABLE MORE O2 FROM AIR.
STANDARDS FOR PURIFIED WATER:-
1- TASTE AND ODOR SHOULD NOT BE OBJECTIONABLE.
2- COLOR SHOULD BE LIMITED TO 20 UNITS OF COBALT SCALE.
3- TURBIDITY SHOULD BE LIMITED TO 10 UNITS(PPM) ON SILICA SCALE.
4- PHENOLIC COMPOUNDS SHOULD NOT BE GREATER THAN 0.01 PPM.
5- CHLORIDES SHOULD NOT BE GREATER THAN 250 PPM.
6- SULPHATES SHOULD NOT BE GREATER THAN 250 PPM.
7- NITRITES- NIL.
8- NITRATES SHOULD NOT BE GREATER THAN 20 PPM.
9- FREE AMMONIA SHOULD NOT BE GREATER THAN 0.15 PPM.
10- ALBUMINOID AMMONIA SHOULD NOT BE GREATER THAN 0.3 PPM.
11- pH- 8-10
12- DISSOLVED O2 SHOULD NOT BE GREATER THAN 10 PPM.
13- POISONOUS METALS- NIL.
14- FLUORIDES SHOULD NOT BE GREATER THAN 1.5 PPM.
15- LEAD SHOULD NOT BE GREATER THAN 0.1 PPM.
16- ARSENIC SHOULD NOT BE GREATER THAN 0.05 PPM
17- COPPER SHOULD NOT BE GREATER THAN 3 PPM.
18- MAGNESIUM SHOULD NOT BE GREATER THAN 125 PPM.
19- IRON AND MAGNESE SHOULD NOT BE GREATER THAN 0.3 PPM.
20- RESIDUAL CHLORINE SHOULD NOT BE -
A- AT LEAST 0.05-0.1 PPM AT ALL POINTS IN THE DISTRIBUTION SYSTEM.
B- 0.2-0.3 PPM DURING WATER BORNE .
21- IODINE SHOULD BE PRESENT IN SMALL QUANTITIES.
22- B-COLI INDEX SHOULD NOT BE GREATER THAN 10.
1- RAIN AND SNOW
2- SURFACE WATER
- STREAMS
- NATURAL PONDS AND LAKES
- IMPOUNDING RESERVOIRS
3- GROUND WATER
- SPRINGS
- SHALLOW WELLS
- DEEP WELLS (.20M DEEP)
- ARTESIAN WELLS.
CONSIDERATIONS POINTS OF WATER SUPPLY SCHEME:-
- QUALITY OF WATER OF SOURCE.
- QUANTITY OF YIELD.
- LOCATION OF SOURCE.
CLASSIFICATION AND PURITY OF SOURCES:-
1- SAFE AND VERY POTABLE
- SPRING WELL
- DEEP WELL
- LAKE AND MOUNTAIN
- RIVER WATER.
2- SUSPICIOUS AND POLATABLE
- STORED RAIN WATER
- SURFACE WATER FROM CULTIVATED LAND.
3- DANGEROUS AN PALATABLE
- SHALLOW WELL WATER
- DOWN LAND RIVER WATER.
ON THE BASIS OF PHYSICAL, CHEMICAL AND BIOLOGICAL TESTS WATER CAN BE DIVIDED INTO 4 CLASSES.:-
CLASS I:-
STANDARD-BEST
DOES NOT REQUIRED ANY OTHER TREATMENT EXCEPT DISINFECTION
EXAMPLE- DEEP WELLS.
CLASS II:-
STANDARD- SATISFACTORY
REQUIRE TREATMENT LIKE FILTERATION AND DISINFECTIONS.
EXAMPLES- SHALLOW WELL, SPRINGS, LAKES.
CLASS III:-
STANDARD- SPECIOUS WATER SOURCE.
REQUIRES TREATMENT LIKE COAGULATION, FILTERATION, SOMETIMES SPECIAL TREATMENTS LIKE- AERATION, SOFTENING AND FOLLOWED BY FILTERATION.
CLASS IV:-
STANDARD- UNSATISFACTORY
IT MAY CONTAIN TOXIC SUBSTANCES OR HIGHLY POLLUTED WITH SEVAGE AND INDUSTRIAL WASTES. THIS CAN'T BE PURIFIED BY NORMAL TREATMENT AND NEVER TAKEN UP AS A WATER SUPPLY SOURCE.
SOME DEFINITIONS:-
PURE WATER:- IS FREE FROM ANY OBJECTIONABLE MATTER.
SAFE WATER- IS POTABLE AND FREE FROM PATHOGENIC GERMS AND TOXIC IMPURITIES.
CLEAR WATER- HAVING NO SUSPENDED MATERIALS.
CONTAIMINATED WATER- CONTAINS PATHOGENIC BACTERIA.
POLLUTED WATER- CONSISTS UNDESIRABLE SUBSTANCES RENDERING IT UNFIT FOR DRINKING AND DOMESTIC USE.
POTABLE WATER- IS TASTY, SAFE AND SUITABLE FOR DRINKINGAND DOMESTIC USE.
NOTE:- "THE CONTAIMINATED WATER IS ALWAYS POLLUTED BUT ALL THE POLLUTED WATERS MAY NOT BE NECCESARILY CONTAIMINATED".
COMMON IMPURITIES IN WATER :-
SUSPENDED IMPURITIES:-
- BACTERIA, ALGAE, PROTOZOA, SILT.
DISSOLVED IMPURITIES:-
SALT, CALCIUM, MAGNESIUM, SODIUM, IRON, MAGNESE, VEGETABLE DYES.
SOME CAUSE DISEASES ODOUR, TURBIDITY MURKINESS/ TURBIDITY:-
BICARBONATE ALKALINITY, HARDNESS, SOFTENING
CARBONATE ALKALINITY, HARDNESS, SOFTENING
SULPHATE ALKALINITY, HARDNESS, FOAMING IN STEAM BOILERS
CHLORIDE COHESIVENESS, HARDNESS, TASTE.
FLUORIDE MOLTED ENAMEL OF TEETH
GASES:-
- OXYGEN- CORROSIVENESS TO METALS
- CARBONDIOXIDE- ACIDITY, CORROSIVENESS
- HYDROGEN SULPHIDE- ODOUR, ACIDITY, CORROSIVENESS
- NITROGEN
WATER BORNE DISEASES:-THE CONTAIMINATED OR POLLUTED WATER CAUSES DISEASES.
DECAYING ORGANIC MATTER- DYSENTRY AND DIARRHEA.
IRON- DYSPEPSIA (INDIGESTION) AND CONTIPATION.
LEAD- POISIONING, PAIN IN ABDOMEN, LOSS OF APETITE, CONSTIPATION THIRST.
CLASSIFICATION OF TESTS:-
1- TESTS THAT MEASURE OR REFLECT THE SAFETY OR WHOLESOMENESS OF WATER.
A- TESTSFOR CONTAIMINATION AS MEASURED BY THE PRESENCE OF THE COLIFORM GROUP.
B- TESTS FOR TOXIC QUALITIES OF As, Pb, Cr, Bo, Se, Ba, Cu, NITRATES AND FLUORIDES.
C- TESTS FOR PHYSIOLOGICALLY BENEFICIAL QUANTITIES OF IODIDE AND FLUORIDE.
D- TESTS FOR POLLUTION AS INDICATED BY THE ORGANIC, ALBUMINOIDAL, NITRITE AND NITRATE NITROGEN'S
E- TESTS FOR LAXATIVE PROPERTIES OF Mg AND SO4.
2- TESTS THAT MEASURE OR REFLECT THE PALATIBILITY OR ESTHETIC ACCEPTABILITY OF WATER-
A- TEMPERATURE, TURBIDITY, COLOUR, AND ODOUR. BY THE MICROSCOPIAL EXAMINATION AND BY TESTS FOR RESIDUES AND METALS, CHLORIDE, ACTIVE CHLORINE, HYDROXIDE, LENIN AND LIGNIN AND HYDROGEN SULPHIDE, ONE OR ANOTHER OF WHICH MAY EXPLAIN THE ORIGIN OF THE OBSERVED TURBIDITY, COLOUR, ODUOR AND TASTE.
3- TESTS ARE RELATED IN PARTICULARTO WATER TREATMENT PROCESSES. Eg- IN ADDITION TO THE PERTINENT TEATS FOR THE SUBSTANCES REMOVED/ DESTROYED, OR TO BE REMOVED/ DESTROYED ARE-
A- TESTS FOR ALKANITY, pH, CO2 AND Al, Fe IN CONNECTION WITH THE USE OF COAGULANTS.
B- TESTS FOR ODOR ANMD Cu AFTER THE DESTRUCTION OF ALGAE BY Cu COMPOUND.
C- TESTS FOR Cl DEMAND, pH AND ACTIVE CHLORINE IN CONNECTION WITH CHLORINATION.
D- TESTS FOR STABILITY, PHOSPHATE, SILICATE, pH AND HYDROXIDE FOLLOWING TREATMENT FOR CORROSIVENESS.
E- TESTS FOR HYDROXIDE, Na, K AND Si IN CONNECTION WITH WATER SOFTENING.
F- TESTS FOR pH, CO2 AND DISSOLVED O2 IN CONNECTING WITH DEFERRIZATION AND DEMANGANIZATION.
SOME SIMPLE TESTS FOR DETECTING DANGROUS MATTERS IN WATER:-
1- SEWAGE:- TAKE A SMALL GLASS OF WATER AND ADD 4 DROPS OF KMNO4. IF THE COLOR OF WATER TURNS PALE OR YELLOW, THE PRESENCE OFDECOMPOSED ORGANIC MATTER MAY BE INFERRED.
2- Pb- THE PRESENCE OF Pb CAN BE DETECTED BY 6 DROPS OF H2SO4 WHICH WILL YIELD A WHITE PPT.
3- Cu:- ADDITION OF 8 DROPS NH3 WILL TURN THE SMALL GLASS OF WATER TO BLUE IF Cu IS PRESENT.
4-Zn:- ADDITION OF 6 DROPS OF POTASSIUM TERROCYANIDE TO A SMALL GLASS OF WATER WILL TURN TO GREEN. IF Zn IS PRESENT.
COMMON GERMICIDES TO PURIFY THE WATER:-
1- KMNO4:-
- STRONG OXIDISING ACTION.
- KILLINH BACTERIS
- USEFUL FOR STERLIZING SMALL QUANTITIES OF WATER
- EXPENSIVE
- DOSE 1/16TH GRAM/ GALLON.
2- CAUSTIC LIME (CaO) :- IT IS USED WHEN KMNO4 IS UNAVAILABLE.
3- CUSO4:-
- USED FOR REMOVAL OF ALGAE AND OTHER VEG GROWTH IN TANKS.
- DOSE 0.1-0.25 PART PER MILLION PARTS OF WATER TO BE TREATED.
4- CHLORINE SUSPENSION:-
- AVAILABLE IN LIQUID FORM.
- USED FOR STERLIZATION OF DRINKING WATER SUPPLY
- DOSE 5-7 LB OF CL2 ACCORDING TO BACTERIAL PURITY AND AMOUNT OF ORGANIC MATTER PRESENT IN WATER.
5- OZONE:-
- MOST POWERFUL GERMICIDE.
- VERY EXPENSIVE AND DIFFICULT IN MASS PRODUCTION.
6- UV-RAYS:-
- HIGHLY EXPENSIVE AND SPECIAL APPRATUS REQUIRED RESTRICTED USE.
TESTS:-
A- PHYSICAL TESTS:-
TEMPERATURE:- WATER SHOULD BE CLEAN, COOL AND SPARKLING IN APPEARENCE.
- WATER BECOMES UNPALATABLE BEYOND 25 DEGREE CELCIUS.
TURBIDITY:- ITS AN INDICATION OF APPARENT CLOR OF WATER ON ACCOUNT OF SUSPENDED INORGANIC MATTER SUCH AS SILICA, CLAY AND MUD PARTICLES.
- EXPRESSED IN PPM BY WEIGHT-
10 PPM HARDLY NOTICEABLE
~ 30 PPM WATER STARTS CLOUDY IN APPEARENCE
> 100 PPM WATER IS DISTINCTLY TURBID.
JACSON TURBIDIMETER MEASURES TURBIDITY ABOVE 100 PPM AND BAYLIS TURBIDIMETER RECORDS LESS THAN 5 PPM.
TASTE AND ODOR:- GENERALLY DUE TO MINERAL, SALTS, OILS AND TARRY SUBSTANCES INDUSTRIAL WATES, DOMESTIC SEWAGE, CHLORINATION, ACID WATES ETC.
- ODOR IS TESTEDAT 22 AND 80 DEGREE CELCIUS.
- QUALITY OF ODOR IS EXPRESSED AS-
A- AROMATIC
B- DISAGRREABLE
C- EARTHY
D- FISHY
E- GREASY
F- MOLDY
G- SWEETISH
- THRESHOLD ODOR NUMBER IS USED TO EXPRESS THE INTENSITY OF ODOR.
- THE NUMBER INDICATES THE MAXIMUM DILUTION TO BE MADE OF A SAMPLE. THUS IF 100CC OF FRESH WATER HAVE TO BE ADDED TO 8 CC OF A SAMPLE OF WATER TO PRODUCE NO EFFECT OF ODOR IN IT, THE THRESHOLD ODOR NUMBER IS 8. IT SHOULD BE NOTED THAT 9CC OF THE SAMR SAMPLE WHEN ADDED TO 100 CC OF FRESH WATER PRODUCE ODOR.
B- CHEMICAL TESTS:-
TOTAL SOLIDS:-
GENERAL RANGE 600-1500 PPM
PERMISSIBLE RANGE 500-1000 PPM
PREFERABLE RANGE <500 PPM
CHLORIDE:- ACCORDING TO IS:3025-1964, CHLORINE CONTENT MAY BE DETERMINED BY ADDING AGNO3 SOLUTION OF KNOWN CONCENTRATION AND POTASSIUM CHROMATE (INDICATOR) TO THE SAMPLE OF WATER.
HARDNESS:- CAUSED BY HCO3, CO3, SO4, CHLORIDE AND NITRATES OF CALCIUM AND MAGNESIUM.
- EXPRESSED IN TERMS OF CACO3.
HARD WATER 100 PPM
SOFT WATER <50 PPM
VERY HARD WATER 200-250 PPM
ACCORDING TO IS:3025-1964, EDTA (ETHYLENE DIAMIDE TETRA ACETIC ACID) METHOD IS USED FOR DETERMINING THE HARDNESS.
SCALE OF HARDNESS HARDNESS
(DEGREES)
EXTREMELY SOFT 1
VERY SOFT 2
SOFT 3
MADERATELY SOFT 6
MADERATELY HARD 7
HARD 9
VERY HARD 11
EXCESSIVELY HARD 15
TOO HARD TO USE 17
DISSOLVED H2O:- THE AMOUNT OF O2 PRESENT IN H2O ABSORBED BY 10% SOLUTION OF KMNO4 AT 27 DEGREE CELCIUS FOR 4 HOURS SHOWS THE QUANTITY OF CARBONACEOUS MATTER OF ORGANIC ORIGIN
ALKANITY:- BICARBONATE, CARBONATES AND HYDROXIDES OF SODIUM, CALCIUM AND MAGNESIUM.
- EXPRESSED IN PPM IN TERMS OF EQUIVALENT CACO3 PRESENT IN A SAMPLE OF H2O CAUSE IT.
- DETERMINED BY TITRATING THE SAMPLE AGAINST STANDARD ACID USING METHYL ORANGE ALAKNITY.
NITROGENOUS COMPOUNDS:- THESE ARE-
I- FREE AMMONIA
II- ALBUMINOID AMMONIA
III- NITRITES
IV- NITRATES
FOR TESTS, THE KNOWN AMOUNT OF WATER IS BOILED WITH STANDARD SOLUTION OF KMNO4 WHICH RESULTS IN THE BREAKDOWN OF LEAST SOLUBLE NITROGENOUS COMPOUNDS AND ALBUMINOID AMMONIA IS FORMED. NITRITES AND NITRATES ARE FORMES DUE TO OXIDATION OF ORGANIC MATTER.
PH:- THE ACIDITY OR ALKANITY OF H2O IS MEASURED IN TERMS OF PH VALUE OR H POSITIVE IN CONCENTRATION. WATER BECOMES ACIDIC WHEN H POSITIVE IONS ARE EXCESS THAN OH NEGATICE IONS AND IT BECOMES ALKALINE IN REVERSE CASE.
PH:-
ACIDIC WATER 0-7
ALAKLINE WATER 7-14
MEUTRAL WATER 7
IRON AND MAGNESE:- IRON AND MAGNESE MAY BE DETERMINED BY ADDING CERTAIN CLORING REAGENTS TO THE SAMPLE OF H2O AND TO THE SOLUTIONS OF KNOWN AMOUNTS OF IRON AND MAGNESE.
SOLUBLE MINERAL IMPURITIES:-
ALL SALTS IMPORT CERTAIN TASK IF PRESENT IN GREATER AMOUNTS.
NACL GIVES TASTE >200 PPM
UNDESIRABLE >3000 PPM
SULPHATES OF SODIUM, MAGNESIUM NOTICEABLE TASTE >500 PPM
DIFFICULT TO SUGGEST ANY PERMISSIBLE LIMIT BUT GENERAL RECOMMENDATION IS 500-1000 PPM
RESIDUAL CHLORINE:-
IT GIVES AN INDICATION OF THE FACT THAT THE BACTERIA ARE REDUCED TO A SAFE LIMIT. IT MAY BE DETERMINED BY ADDING ORTHOTOLODIN SOLUTION IN A SAMPLE OF WATER. THE YELLOW COLOR OF THE SAMPLE ENSURES THE PRESENCE OF RESIDUAL CHLORINE.
MINIMUM AMOUNT OF FREE CHLORINE- 0.05-0.1 PPM
DURING WATER BORNE DISEASES- 0.2-0.3 PPM
ACIDITY:-
IT IS DETERMINED BY TITRATING THE SAMPLE AGAINST STANDARD ALAKALI USING PHENOLPHTHALEIN INDICATOR.
SULPHATES:-
EDTA, METHOD CAN BE USED IN DETERMINING SULPHATES. IN THE METHOD , A MEASURED EXCESS OF STANDARD BARIUM CHLORIDE SOLUTION IS ADDED TO THE SAMPLE AND THE EXCESS BARIUM CHLORIDE IS ESTIMATED BY TITRATION AGAINST EDTA SOLUTION.
BIOCHEMICAL OXYGEN DEMAND (BOD):-
IT INDICATES BIOCHEMICA OXIDISABLE ORAGANIC MATTERS AND ITS USE COMMONLY RESTRICTED TO SEWAGE ANALYSIS. THE 5-DAY, 20 DEGREE CELCIUS BOD OF DOMESTIC WATER SHOULD BE LESS THAN 2 MG/U
C- MICROBIOLOGICAL TESTS:-
THE MICROBIOLOGICAL EXAMINATION OF WATER INCLUDES BOTH BACTERIOLOGICAL AND BIOLOGICAL EXAMINATIONS. THE WATER MAY BE CONTAIMINATED WITH PATHOGENIC (HARMFUL) AND NON-PATHOGENIC (NON-HARMFUL) BACTERIA. B-COLI GROUP BACTERIA DESIGNATES THE COMBINED GROUP OF THESE BACTERIA. THE BACTRIOLOGICAL EXAMINATION OF A SAMPLE IS CARRIED OUT ACCORDING TO IS:1622-1964 STANDARD.
2 STANDARD BACTERIOLOGICAL TESTS FOR BACTERIOLOGICAL EXAMINATION-
1- TOTAL COUNT/ AGAR PLATE ACOUNT TEST:-
IN THIS TEST, BACTERIA ARE CULTIVATED ON SPECIALLY PREPARED MEDIUM OF AGAR FOR DIFFERENT DILUTION OF SAMPLE OF WATER WITH STERILIZED WATER. THE DILUTED SAMPLE IS PLACED IN AN INCUBATOR FOR 24 HOURS AT 35 DEGREE CELCIUS OR FOR 48 HOURS @ 20 DEGREE CELCIUS. THESE REPRESENTS THE SO CALLED 'HOT COUNTS' AND 'COLD COUNTS' WHICH ARE FORMES, ARE THEN COUNTED AND THE RESULTS ARE COMPUTED FOR 1 CC
2- COLI TEST:- DIVIDED INTO 3 PARTS-
A- PRESUMPTIVE TEST:- BASED ON THE ABILITY OF COLIFORM GROUP TO FERMENT THE LACTOSE BROTH AND PRODUCING GAS.
B- CONFIRMED TEST:- CONSISTS OF GROWING CULTURES OF COLIFORM BACTERIAN ON MEDIA WHICH SUPPRESS THE GROWTH OF THE OTHER MICRO-ORGANISMS.
C- COMPLETED TEST:- BASED ON THE ABILITY OF CULTURE GROWTH IN THE CONFIRMED TEST TO AGAIN FERMENT THE LACTOSE BROTH.
THE MICROSCOPIC ORGANISMS (OTHER THAN BACTERIA) IN WATER INCLUDE A LARGE VARIETY OF ALGAE, FUNGI, YEASTS, PROTOZOA, ROTIFIERS, CRUSTACEAN, ANIMALULA ETC. MANY OF THESE AFFECT THE QUANTITY OF WATER FOR DRINKING AND INDUSTRIAL USE.
THE EXAMINATION OF NATURE AND NUMBER OF ORGANISMS PRESENT IN WATER IS NECESSARY TO UNDERSTAND THE NATURE OF POLLUTION, CAUSE OF BAD TASTE AND ODORS, SLIME GROWTH ADHERE TO STRUCTURES ETC.
MAINTENANCE OF PURITY OF WATER:-
1- THE CONTENT OF DISSOLVED OXYGEN PRESENT IN WATER SHOULD BE HIGH.
2- THE ENTRY OF UNDESIRABLE ELEMENTS SUCH AS ACIDIC AND ALKALINE DISCHARGE FROM THERMAL POWER STATIONS ETC INTO SOURCE OF WATER SUPPLY SHOULD BE PREVENTED BY SUITABLE MEANS.
3- THE PRESENCE OF ALGAE SUPPLYING O2 TO H2O IS DESIRABLE.
4- THE QUANTITY OF TOTAL DISSOLVED SOLIDS ESPECIALLY THE CHLORIDE CONTENTS, SHOULD BE VERY LOW.
5- THERE SHOULD BE ABSENCE OF ORAGANIC WASTES EXERTING O2 DEMAND ON WATER.
6- THERE SHOULD BE ENOUGH RE-AERATION FOR THE PURPOSE OF DE OXYGENATING OF WATER.
7- THE TEMPERATURE OF WATER SHOULD BE MAINTAINED LOW.
8- THE TURBULENCE OF WATER SHOULD BE ENCOURAGED TO MAKE AVAILABLE MORE O2 FROM AIR.
STANDARDS FOR PURIFIED WATER:-
1- TASTE AND ODOR SHOULD NOT BE OBJECTIONABLE.
2- COLOR SHOULD BE LIMITED TO 20 UNITS OF COBALT SCALE.
3- TURBIDITY SHOULD BE LIMITED TO 10 UNITS(PPM) ON SILICA SCALE.
4- PHENOLIC COMPOUNDS SHOULD NOT BE GREATER THAN 0.01 PPM.
5- CHLORIDES SHOULD NOT BE GREATER THAN 250 PPM.
6- SULPHATES SHOULD NOT BE GREATER THAN 250 PPM.
7- NITRITES- NIL.
8- NITRATES SHOULD NOT BE GREATER THAN 20 PPM.
9- FREE AMMONIA SHOULD NOT BE GREATER THAN 0.15 PPM.
10- ALBUMINOID AMMONIA SHOULD NOT BE GREATER THAN 0.3 PPM.
11- pH- 8-10
12- DISSOLVED O2 SHOULD NOT BE GREATER THAN 10 PPM.
13- POISONOUS METALS- NIL.
14- FLUORIDES SHOULD NOT BE GREATER THAN 1.5 PPM.
15- LEAD SHOULD NOT BE GREATER THAN 0.1 PPM.
16- ARSENIC SHOULD NOT BE GREATER THAN 0.05 PPM
17- COPPER SHOULD NOT BE GREATER THAN 3 PPM.
18- MAGNESIUM SHOULD NOT BE GREATER THAN 125 PPM.
19- IRON AND MAGNESE SHOULD NOT BE GREATER THAN 0.3 PPM.
20- RESIDUAL CHLORINE SHOULD NOT BE -
A- AT LEAST 0.05-0.1 PPM AT ALL POINTS IN THE DISTRIBUTION SYSTEM.
B- 0.2-0.3 PPM DURING WATER BORNE .
21- IODINE SHOULD BE PRESENT IN SMALL QUANTITIES.
22- B-COLI INDEX SHOULD NOT BE GREATER THAN 10.
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