WATER TREATMENT – PERFECT WATER STANDARDS
Here below please find a summary of the World Health Organisation – WHO’s Guidelines for Drinking-water Quality, set up in Geneva, 1993. These standards are the international reference point for standard setting for drinking-water. For India these standards are set by the Bureau of Indian Standards – BIS, the erstwhile Indian Standards Institute – ISI.
The relevant BIS standard is BIS: 10500 available from the BIS site www.bis.org.in
For those of you interested in seeing the American Water Standards set by the internationally famous Environmental Protection Agency – EPA of USA, please visit the EPA site or get it from a Copy on our site.
Chlorine is widely to treat drinking water to reduce the risk of infectious disease through water consumption. Chlorination destroys all animal and microbial life in the water. It is a major factor in the reduction in the mortality rates associated with waterborne pathogen. Our reverse osmosis drinking water system removes chlorine from water.
|
Element/substance |
Symbol/formula |
Normally found in fresh water/ surface water/ ground water |
Health based guideline by the WHO |
| Aluminium | Al | 0.2 mg/l | |
| Ammonia | NH4 | < 0.2 mg/l (up to 0.3 mg/l in anaerobic waters) | No guideline |
| Antimony | Sb | < 4 μg/l | 0.005 mg/l |
| Arsenic | As | 0.01 mg/l | |
| Asbestos | No guideline | ||
| Barium | Ba | 0.3 mg/l | |
| Berillium | Be | < 1 μg/l | No guideline |
| Boron | B | < 1 mg/l | 0.3 mg/l |
| Cadmium | Cd | < 1 μg/l | 0.003 mg/l |
| Chloride | Cl | 250 mg/l | |
| Chromium | Cr+3, Cr+6 | < 2 μg/l | 0.05 mg/l |
| Colour | Not mentioned | ||
| Copper | Cu | 2 mg/l | |
| Cyanide | CN- | 0.07 mg/l | |
| Dissolved oxygen | O2 | No guideline | |
| Fluoride | F | < 1.5 mg/l (up to 10) | 1.5 mg/l |
| Hardness | mg/l CaCO3 | No guideline | |
| Hydrogen sulfide | H2S | No guideline | |
| Iron | Fe | 0.5 – 50 mg/l | No guideline |
| Lead | Pb | 0.01 mg/l | |
| Manganese | Mn | 0.5 mg/l | |
| Mercury | Hg | < 0.5 μg/l | 0.001 mg/l |
| Molybd enum | Mb | < 0,01 mg/l | 0.07 mg/l |
| Nickel | Ni | < 0.02 mg/l | 0.02 mg/l |
| Nitrate and nitrite | NO3, NO2 | 50 mg/l total nitrogen | |
| Turbidity | Not mentioned | ||
| pH | No guideline | ||
| Selenium | Se | < < 0.01 mg/l | 0.01 mg/l |
| Silver | Ag | 5 – 50 μg/l | No guideline |
| Sodium | Na | < 20 mg/l | 200 mg/l |
| Sulfate | SO4 | 500 mg/l | |
| Inorganic tin | Sn | No guideline | |
| TDS | No guideline | ||
| Uranium | U | 1.4 mg/l | |
| Zinc | Zn | 3 mg/l |
Organic compounds
|
Group |
Substance |
Formula |
Health based guideline by the WHO |
||
| Chlorinated alkanes | Carbon tetrachloride | C Cl4 | 2 μg/l | ||
| Dichloromethane | C H2 Cl2 | 20 μg/l | |||
| 1,1-Dichloroethane | C2 H4 Cl2 | No guideline | |||
| 1,2-Dichloroethane | Cl CH2 CH2 Cl | 30 μg/l | |||
| 1,1,1-Trichloroethane | CH3 C Cl3 | 2000 μg/l | |||
| Chlorinated ethenes | 1,1-Dichloroethene | C2 H2 Cl2 | 30 μg/l | ||
| 1,2-Dichloroethene | C2 H2 Cl2 | 50 μg/l | |||
| Trichloroethene | C2 H Cl3 | 70 μg/l | |||
|
Tetrachloroethene |
C2 Cl4 |
40 μg/l |
|||
|
Aromatic hydrocarbons |
Benzene |
C6 H6 |
10 μg/l |
||
|
Toluene |
C7 H8 |
700 μg/l |
|||
|
Xylenes |
C8 H10 |
500 μg/l |
|||
|
Ethylbenzene |
C8 H10 |
300 μg/l |
|||
|
Styrene |
C8 H8 |
20 μg/l |
|||
|
Polynuclear Aromatic Hydrocarbons (PAHs) |
C2 H3 N1 O5 P1 3 |
0.7 μg/l |
|||
|
Chlorinated benzenes |
Monochlorobenzene (MCB) |
C6 H5 Cl |
300 μg/l |
||
|
Dichlorobenzenes (DCBs) |
1,2-Dichlorobenzene |
||||
|
C6 H4 Cl2 |
1000 μg/l |
||||
|
(1,2-DCB) |
|||||
|
1,3-Dichlorobenzene (1,3-DCB) |
C6 H4 Cl2 |
No guideline |
|||
|
1,4-Dichlorobenzene (1,4-DCB) |
C6 H4 Cl2 |
300 μg/l |
|||
| Trichlorobenzenes (TCBs) | C6 H3 Cl3 | 20 μg/l | |||
| Miscellaneous organic constituents | Di(2-ethylhexyl)adipate (DEHA) | C22 H42 O4 | 80 μg/l | ||
| Di(2-ethylhexyl)phthalate (DEHP) | C24 H38 O4 | ||||
| Acrylamide | C3 H5 N O | 0.5 μg/l | |||
| Epichlorohydrin (ECH) | C3 H5 Cl O | 0.4 μg/l | |||
| Hexachlorobutadiene (HCBD) | C4 Cl6 | 0.6 μg/l | |||
| Ethylenediaminetetraacetic acid (EDTA) | C10 H12 N2 O8 |
200 μg/l |
|||
| Nitrilotriacetic acid (NTA) | N(CH2COOH)3 | 200 μg/l | |||
| Organotins | Dialkyltins | R2 Sn X2 | No guideline | ||
| Tributil oxide (TBTO) | C24 H54 O Sn2 | ||||
Pesticides
| Substance | Formula | Health based guideline by the WHO | |
| Alachlor | C14 H20 Cl N O2 | 20 μg/l | |
| Aldicarb | C7 H14 N2 O4 S | 10 μg/l | |
| Aldrin and dieldrin | C12 H8 Cl6/ C12 H8 Cl6 O |
0.03 μg/l | |
| Atrazine | C8 H14 Cl N5 | 2 μg/l | |
| Bentazone | C10 H12 N2 O3 S | 30 μg/l | |
| Carbofuran | C12 H15 N O3 | 5 μg/l | |
| Chlordane | C10 H6 Cl8 | 0.2 μg/l | |
| Chlorotoluron | C10 H13 Cl N2 O | 30 μg/l | |
| DDT | C14 H9 Cl5 | 2 μg/l | |
| 1,2-Dibromo-3-chloropropane | C3 H5 Br2 Cl | 1 μg/l | |
| 2,4-Dichlorophenoxyacetic acid (2,4-D) | C8 H6 Cl2 O3 | 30 μg/l | |
| 1,2-Dichloropropane | C3 H6 Cl2 | No guideline | |
| 1,3-Dichloropropane | C3 H6 Cl2 | 20 μg/l | |
| 1,3-Dichloropropene | CH3 CHClCH2 Cl | No guideline | |
| Ethylene dibromide (EDB) | Br CH2 CH2 Br | No guideline | |
| Heptachlor and heptachlor epoxide | C10 H5 Cl7 | 0.03 μg/l | |
| Hexachlorobenzene (HCB) | C10 H5 Cl7 O | 1 μg/l | |
| Isoproturon | C12 H18 N2 O | 9 μg/l | |
| Lindane | C6 H6 Cl6 | 2 μg/l | |
| MCPA | C9 H9 Cl O3 | 2 μg/l | |
| Methoxychlor | (C6H4OCH3)2CHCCl3 | 20 μg/l | |
| Metolachlor | C15 H22 Cl N O2 | 10 μg/l | |
| Molinate | C9 H17 N O S | 6 μg/l | |
| Pendimethalin | C13 H19 O4 N3 | 20 μg/l | |
| Pentachlorophenol (PCP) | C6 H Cl5 O | 9 μg/l | |
| Permethrin | C21 H20 Cl2 O3 | 20 μg/l | |
| Propanil | C9 H9 Cl2 N O | 20 μg/l | |
| Pyridate | C19H23ClN2O2S | 100 μg/l | |
| Simazine | C7 H12 Cl N5 | 2 μg/l | |
| Trifluralin | C13 H16 F3 N3 O4 | 20 μg/l | |
| Chlorophenoxy herbicides (excluding 2,4-D and MCPA) |
2,4-DB | C10 H10 Cl2 O3 | 90 μg/l |
| Dichlorprop | C9 H8 Cl2 03 | 100 μg/l | |
| Fenoprop | C9H7Cl3O3 | 9 μg/l | |
| MCPB | C11 H13 Cl O3 | No guideline | |
| Mecoprop | C10H11ClO3 | 10 μg/l | |
| 2,4,5-T | C8 H5 Cl3 O3 | 9 μg/l | |
Disinfectants and disinfectant by-products
|
Group |
Substance |
Formula |
Health based guideline by the WHO |
||
| Disinfectants | Chloramines | NHnCl(3-n), where n = 0, 1 or 2 |
3 mg/l | ||
| Chlorine | Cl2 | 5 mg/l | |||
| Chlorine dioxide | ClO2 | No guideline | |||
| Iodine | I2 | No guideline | |||
| Disinfectant by-products | Bromate | Br O3- | 25 μg/l | ||
| Chlorate | Cl O3- | No guideline | |||
| Chlorite | Cl O2- | 200 μg/l | |||
| Chlorophenols | 2-Chlorophenol (2-CP) | C6 H5 Cl O | No guideline | ||
| 2,4-Dichlorophenol (2,4-DCP) | C6 H4 Cl2 O | No guideline | |||
| 2,4,6-Trichlorophenol (2,4,6-TCP) | C6 H3 Cl3 O | 200 μg/l | |||
| Formaldehyde | HCHO | 900 μg/l | |||
| MX (3-Chloro-4-dichloromethyl-5-hydroxy-2(5H)-furanone) | C5 H3 Cl3 O3 | No guideline | |||
| Trihalomethanes | Bromoform | C H Br3 | 100 μg/l | ||
| Dibromochloromethane | CH Br2 Cl | 100 μg/l | |||
| Bromodichloromethane | CH Br Cl2 | 60 μg/l | |||
| Chloroform | CH Cl3 | 200 μg/l | |||
| Chlorinated acetic acids | Monochloroacetic acid | C2 H3 Cl O2 | No guideline | ||
| Dichloroacetic acid | C2 H2 Cl2 O2 | 50 μg/l | |||
| Trichloroacetic acid | C2 H Cl3 O2 | 100 μg/l | |||
| Chloral hydrate (trichloroacetaldehyde) | C Cl3 CH(OH)2 | 10 μg/l | |||
| Chloroacetones | C3 H5 O Cl | No guideline | |||
| Halogenated acetonitriles | Dichloroacetonitrile | C2 H Cl2 N | 90 μg/l | ||
| Dibromoacetonitrile | 100 μg/l | ||||
| Bromochloroacetonitrile | CH Cl2 CN | No guideline | |||
| Trichloroacetonitrile | C2 Cl3 N | 1 μg/l | |||
| Cyanogen chloride | Cl CN | 70 μg/l | |||
| Chloropicrin | C Cl3 NO2 | No guideline | |||
