PREAMBLE
The Quality of drinking water in Chennai is maintained and monitored by Chennai Metropolitan Water Supply and Sewerage Board through the Quality Assurance Wing. The Quality of water is monitored through sampling, testing and reporting through the team of trained personnel in the laboratory and field. This division is headed by Executive Engineer and consists of Engineers and Analysts.
The Engineers of this wing provides the necessary Engineering service for effective functioning of the wing preparation of reports to take preventive actions, and providing necessary assistance to the field staff in water quality surveillance.
The Analysts does the work of collecting water samples, analysis and report to the Engineers concerned in regard to the quality of water supplied to the public confirming to water quality standards. Outsourced sample takers have been engaged for collection of water samples throughout Chennai City.
MONITORING WATER QUALITY
The scientific personnel in the Analytical section have a periodical sampling programme as per the W.H.O. norms, for monitoring water quality at the sources, treatment plants, Water distribution stations and in the distribution net work.
Water samples are being collected, once in a month from the three lakes, which is major source of water supply to the Chennai City daily . The treated water from the water treatment plants are collected from the test tap and samples were examined for conformity to physical, chemical and Bacteriological standards, besides monitoring the treatment process at various units.
About 250 samples are collected from the City distribution system every day for physical, chemical and Bacteriological analysis, Out of this, 60 samples are tested for Bacteriological analysis and 15 samples are tested for Physiochemical analysis to ensure the water is safe for drinking.
Apart from the sampling carried out by Quality Assurance wing, 200 depot. Engineers monitor the minimum level of Residual chlorine available in the water distribution net work.
The water supplied to the public is assured as per norms laid down in BIS: 10500-2012,the Indian Standard. The Physical, Chemical and Bacteriological quality of water should not exceed the limits shown in the table below:
| Sl.No. | Substance or Characteristic | Requirement (Acceptable Limit) | Permissible Limit |
|---|---|---|---|
| (i) | Colour | Colourless & Clear | |
| (ii) | Odour | Agreeable | Agreeable |
| (iii) | Turbidity (N.T.U) | 1 | 5 |
| (iv) | Total Dissolved Solids at 105 0 C (mg/l) | 500 | 2000 |
| (v) | Calcium (As Ca) (mg/l) | 75 | 200 |
| (vi) | Magnesium (As Mg) (mg/l) | 30 | 100 |
| (vii) | Total Hardness (As CaCO3) (mg/l) | 200 | 600 |
| (viii) | Chlorides (As Caco3) (mg/l) | 250 | 1000 |
| (ix) | Ammoniacal Nitrogen (as N)(mg/l) | - | - |
| (x) | Albuminoid Nitrogen (as N)(mg/l) | - | - |
| (xi) | Nitrous Nitrogen (As N)(mg/l) | - | - |
| (xii) | Oxygen absorbed (Tidy's hours test)(mg/l) | - | - |
| (xiii) | Hydrogen Ion Concentration (pH) | 6.5 to 8.5 | 6.5 to 8.5 |
| (xiv) | Alkalinity to Phenolphthalein (AS CaCO3) (mg/l) | Nil | - |
| (xv) | Alkalinity to methyl orange (As CaCO3) (mg/l) | 200 | 600 |
| (xvi) | Sulphates (As SO4)(mg/l) | 200 | 400 |
| (xvii) | Phosphates (as PO4)(mg/l) | - | - |
| (xviii) | Iron (As Fe) (mg/l) | 0.30 | 1.0 |
| (xix) | Florides (as F)(mg/l) | 1.0 | 1.5 |
| (xx) | Specific Conductance(micro Siemens /cm at 25o C) | - | - |
| (xxi) | Ammonia | - | - |
| (xxii) | Disolved Oxygen | - | - |
| (xxiii) | Bacterlological Quality MPN(Total Coliforms in 100 ml) | - | - |
BACTERIOLOGICAL STANDARDS
I. Water entering the Distribution system Coliform count in any sample of 100 ml should be Zero. A sample of the water entering the distribution system that does not conform to this standard calls for an immediate investigation in to both the efficacy of the purification process and the method of sampling.
II. Water in the distribution system
- E.coli count in 100ml of any sample should be zero.
- Coliform organisms not more than 10 per 100 ml in any sample.
- Coliform organisms should not be present in 100ml of any two consecutive samples or more than 5% of the samples collected for the year.
PRIVATE SAMPLES
Besides monitoring the Quality of water supplied by Metro Water, the C.M.W.S.S.B. facilitates the public to assess the water quality of their own sources(Well / Bore Well water) by testing for Physical and Chemical examination on nominal charges as follows:
| 1. | Public (Individual houses-Drinking) | Rs.75/- | Per Sample |
| 2. | Private Institute(Drinking) | Rs.200/- | Per Sample |
| 3. | Private Institute(Construction) | Rs.200/- | Per Sample |
The following parameters are tested for Physical and Chemical Examination for Drinking Purpose as per BIS 10500:2012.
| Sl.No. | Parameters Name | BIS:10500-2012 ACCEPTABLE LIMIT |
BIS:10500-2012 PERMISSIBLE LIMIT |
|---|---|---|---|
| (1) | Colour | Colourless & Clear | Colourless & Clear |
| (2) | Odour | Agreeable | Agreeable |
| (3) | Turbidity (N.T.U) | 1 | 5 | (4) | Total Dissolved Solids at 105'C(mg/l) | 500 | 2000 |
| (5) | Calcium (As Ca) (mg/l) | 75 | 200 |
| (6) | Magnesium (As Mg) (mg/l) | 30 | 100 | (7) | Total Hardness (As CaCO3)(mg/l) | 200 | 600 |
| (8) | Chlorides (As Cl) (mg/l) | 250 | 1000 |
| (9) | Ammoniacal Nitrogen (as N) (mg/l) | - | - |
| (10) | Albuminoid Nitrogen (as N) (mg/l) | - | - |
| (11) | Nitrous Nitrogen (as N) (mg/l) | - | - |
| (12) | Oxygen absorbed (Tidy's 4 hours test) (mg/l) | - | - |
| (13) | Hydrogen Ion Concentration (pH) | 6.5 to 8.5 | 6.5 to 8.5 |
| (14) | Alkalinity to Phenolphthalein (AS CaCO3)(mg/l) | Nil | - |
| (15) | Alkalinity to methyl orange (As CaCO3)(mg/l) | 200 | 600 |
| (16) | Sulphates (As SO4) (mg/l) | 200 | 400 |
| (17) | Phosphates (as PO4) (mg/l) | - | - |
| (18) | Iron (As Fe) (mg/l) | 1.0 | 1.0 |
| (19) | Fluorides (as F) (mg/l) | 1.00 | 1.5 |
| (20) | Specific Conductance (micro Siemens/cm)at 25'c | - | - |
| (21) | Residual Chlorine (Cl2) | - | - |
In case of water qality for Construction purpose the following parameters are tested for its suitablity
Water used for mixing and curing shall be clean and free from injurious amounts of oils, acids, alkalis, salts, sugar, organic materials or other substances that may be deleterious to concrete or steel.
Permissible Limit for Solids for Construction purposes - IS 456 : 2000
| Sl.No | Name of the parameter | IS:456-2000 Permissible Limit |
|---|---|---|
| 1. | Colour | - |
| 2. | Odour | - |
| 3. | Turbidity (N.TU) | - |
| 4. | Chlorides (As Cl) (mg/l) | 2000 |
| 5. | Hydrogen Ion Concentration (pH) | Not less than 6.0 |
| 6. | Sulphates (As SO4) (mg/l) | 400 |
| 7. | Iron (As Fe) (mg/l) | Nil | 8. | Ignited Residue (mg/l) | 3000 | 9. | Organic Solids (mg/l) | 200 | 10. | Requirement of 0.02 N H2 SO4 to neutralise 100 ml sample (ml) |
25 ml | 11. | Requirement of 0.02 N N2OH to neutralise 100 ml sample (ml) |
5 ml |
3. Quantity of samples required for testing are as follows:
| Drinking Purpose: | 2 litres |
| Construction Purpose: | 5 litres |
The Containers used for collecting water samples should be free from any contamination. It is advised to use new plastic container of required capacity as mentioned above.
Procedure for remittance of Testing Charges:
On request, Junior Administrative officer, Q.A.Wing issues a challan for making necessary payment. The Analytical Report shall be collected from the laboratory after 15 days from the date of receipt of samples.
Residual Chlorine Report on 06.01.2020
| R.C. in p.p.m. | I | II | III | IV | V | VI | VII | VIII | IX | X | XI | XII | XIII | XIV | XV | Total |
| More than 2.0 PPM | 20 | - | 25 | 25 | 22 | - | 17 | 6 | 25 | 25 | 25 | - | - | - | 30 | 220 |
| 1.0 to 2.0 PPM | - | - | - | - | 8 | - | - | - | - | - | - | - | - | - | - | 8 |
| 0.6 to 0.9 PPM | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | 0 |
| 0.2 to 0.5 PPM | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | 0 |
| Less than 0.2 PPM | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | 0 |
| Total | 20 | 0 | 25 | 25 | 30 | 0 | 17 | 6 | 25 | 25 | 25 | 0 | 0 | 0 | 30 | 228 |
ANALYTICAL REPORT OF SEWAGE AT KODUNGAIYUR SEWAGE TREATMENT PLANT
| S. No. | Parameters | Raw Sewage | Treated Sewage | |
| 1 | Color | Greyish | Sl.Yellowish | |
| 2 | Odour | Objectionable | Unobjectionable | |
| 3 | Temperature | oC | 30 | 30 |
| 4 | B.O.D (5 days at 20oC) | mg/lit. | 360 | 20 |
| 5 | C.O.D | mg/lit. | 696 | 95 |
| 6 | Total Suspended Solids | mg/lit. | 420 | 30 |
| 7 | Total Solids | mg/lit. | 2170 | 1680 |
| 8 | Total Dissolved Solids | mg/lit. | 1750 | 1650 |
| 9 | Settelable Solids | mg/lit. | 25 | 2 |
| 10 | pH | 7.3 | 7.6 |
ANALYTICAL REPORT OF SEWAGE AT NESAPAKKAM SEWAGE TREATMENT PLANT
| S. No. | Parameters | Raw Sewage | Treated Sewage | |
| 1 | Color | Blackish Grey | Colourless | |
| 2 | Odour | Sulphide | Odourless | |
| 3 | Temperature | oC | 27 | 26 |
| 4 | B.O.D (5 days at 20oC) | mg/lit. | 330 | 12 |
| 5 | C.O.D | mg/lit. | 620 | 70 |
| 6 | Total Suspended Solids | mg/lit. | 440 | 15 |
| 7 | Total Solids | mg/lit. | 940 | 820 |
| 8 | Total Dissolved Solids | mg/lit. | 1380 | 835 |
| 9 | Settelable Solids | mg/lit. | 6 | Nil |
| 10 | pH | 7.3 | 7.8 |
ANALYTICAL REPORT OF SEWAGE AT KOYAMBEDU SEWAGE TREATMENT PLANT
| S. No. | Parameters | Raw Sewage | Treated Sewage | |
| 1 | Color | Blackish | Colourless | |
| 2 | Odour | Offensive | Sl.Fishy | |
| 3 | Temperature | oC | 29 | 28 |
| 4 | B.O.D (5 days at 20oC) | mg/lit. | 350 | 21 |
| 5 | C.O.D | mg/lit. | 910 | 79 |
| 6 | Total Suspended Solids | mg/lit. | 563 | 29 |
| 7 | Total Solids | mg/lit. | 1580 | 1510 |
| 8 | Total Dissolved Solids | mg/lit. | 2143 | 1539 |
| 9 | Settelable Solids | mg/lit. | 23 | 1 |
| 10 | pH | 7.3 | 7.8 |
STANDARD FOR TREATED SEWAGE EFFLUENT LET INTO INLAND WATER WAYS
| 1 | B.O.D ( 5 days at 20o c) mg/l: 20 |
| 2 | SUSPENDED SOLIDS mg/l: 30 |
| Sl. No. | WATER QUALITY | |||
| RAW WATER KPS+300 MLD + Veeranam | TEST TAP KPS+300 MLD + Veeranam | CITY DISTRIBUTION | ||
| 1 | PERCENTAGE OF BACTERIOLOGICALLY GOOD SAMPLES | 22 | 40 | 1276 |
| 2 | NUMBER OF SAMPLES | 0% | 100% | 98% |
| 3 | Colour | Sl.Yellowish | Colourless | Colourless |
| 4 | Odour | Sl.Earthy | Chlorinous | Chlorinous |
| 5 | Turbidity (NTU) | 13 | 4 | 5 |
| 6 | Total solids at 105 "C (mg/i) | 303 | 295 | 305 |
| 7 | Total Hardness (As CaCO3) | 123 | 133 | 125 |
| 8 | Calcium (As Ca) | 24 | 22 | 23 |
| 9 | Magenesium (As Mg) | 14 | 18 | 18 |
| 9 | Magenesium (As Mg) | 14 | 18 | 18 |
| 10 | Chlorides (AsCI) | 64 | 71 | 78 |
| 11 | Sulphates (As SO4) | 33 | 32 | 39 |
| 12 | Ammoniacal Nitrogen (As N) | 0.07 | 0.04 | 0.03 |
| 13 | Albuminoid Nitrogen (As N) | 0.53 | 0.15 | 0.23 |
| 14 | Nitrous Nitrogen (As N) | Nil | Nil | Nil |
| 15 | Nitric Nitrogen (As N) | 3.5 | 2.08 | 2.67 |
| 16 | Oxygen absorbed (Tidy's test) | 2.49 | 1.01 | 0.92 |
| 17 | Alkalinity to Phenolphthaleint (As CaCO3) | 108 | Nil | Nil |
| 18 | Alkalinity to Methyl Orange (As CaCO3) | 0.01 | 107 | 101 |
| 19 | Phosphates (As PO4) | 0.15 | 0.01 | 0.01 |
| 20 | Iron (As Fe) | 8.1 | 0.06 | 0.12 |
| 21 | Hydrogen Ion Concentration (pH) | 8.1 | 7.9 | 7.6 |
| 22 | Silicate (As SiO2) | 10 | 10 | 10 |
| 23 | Fluoride (As F) | 0.1 | 0.1 | 0.1 |
| 24 | Specific Conductance (Micromhos/cm) | 472 | 450 | 475 |
LOCATION OF THE LABORATORY:
WATER ANALYSIS LABORATORY
C.M.W.S.S.Board, New Avadi Road, Kilpauk,
(Near Kilpauk Water Works) Chennai - 600 010.
Phone Number: 2644 9851