PHYSICAL AND CHEMICAL CONDITIONS REQUIRED BEFORE EFFLUENT ACCEPTANCE |
SUBSTANCES ACCEPTABLE IN LIMITED CONCENTRATIONS ONLY |
No person shall discharge effluent into the sewerage system which has— |
Parameter |
Allowed Specifications |
Units |
a temperature at the point of entry in excess of; |
43° |
C |
a pH greater than 10,0 or less than 6,0; |
6,0-10,0 |
|
Chemical oxygen demand (COD) greater than |
4 000 |
mg/ℓ |
Electrical conductivity— not greater than |
250 |
m S/m at 25 °C |
Caustic alkalinity (expressed as CaCO₃) |
2 000 |
mg/ℓ |
Substance not in solution (including fat, oil, grease waxes and like substances) |
2 000 |
mg/ℓ |
Substances soluble in petroleum ether |
500 |
mg/ℓ |
Sulphides, hydro-sulphides and polysulphides (expressed as S) |
50 |
mg/ℓ |
Substances from which hydrogen cyanide can be liberated in the drainage installation, sewer or sewage treatment works (expressed as HCN) |
20 |
mg/ℓ |
Formaldehyde (expressed as HCHO) |
50 |
mg/ℓ |
Non-organic solids in suspension |
100 |
mg/ℓ |
All sugars and/or starch (expressed as glucose) |
1 500 |
mg/ℓ |
Available chlorine (expressed as Cl) |
100 |
mg/ℓ |
Sulphates (expressed as SO4) |
1 800 |
mg/ℓ |
Fluorine-containing compounds (expressed as F) |
5 |
mg/ℓ |
Anionic surface active agents |
500 |
mg/ℓ |
No person shall discharge effluent into the sewerage system which contains a substance, either alone or in combination with other substances, having a concentration in excess of those listed below. |
(a) Chemical Substances other than metals |
Parameter |
Allowed specifications |
Units |
Fats, vegetable oil and like substances |
400 |
mg/ℓ |
Sulphides, or substances from which hydrogen sulphide can be liberated (expressed as S) |
5 |
mg/ℓ |
Cyanides or substances from which hydrogen cyanide can be liberated (expressed as HCN) |
20 |
mg/ℓ |
Sulphates (expressed as SO4) |
500 |
mg/ℓ |
Suspended solids |
1 000 |
mg/ℓ |
Tar products and distillates |
50 |
mg/ℓ |
Chloride (expressed as C) |
1 000 |
mg/ℓ |
(b) Metals |
Group 1 |
Chromium (hexavalent) |
0 |
mg/ℓ |
Chromium (trivalent) (expressed as CrO₃) |
10 |
mg/ℓ |
Copper (expressed as Cu) |
10 |
mg/ℓ |
Manganese |
20 |
mg/ℓ |
Nickel (expressed as Ni) |
5 |
mg/ℓ |
Zinc (expressed as Zn) |
20 |
mg/ℓ |
Iron (expressed as Fe) |
20 |
mg/ℓ |
Silver |
5 |
mg/ℓ |
Cobalt |
5 |
mg/ℓ |
Tungsten |
5 |
mg/ℓ |
Titanium |
5 |
mg/ℓ |
Cadmium |
5 |
mg/ℓ |
Total collective concentration of all metals in Group 1 |
50 |
mg/ℓ |
Parameter |
Allowed specifications |
Units |
Group 2 |
Arsenic (expressed as As) |
5 |
mg/ℓ |
Boron (expressed as B) |
5 |
mg/ℓ |
Lead (expressed as Pb) |
5 |
mg/ℓ |
Selenium (expressed as Se) |
5 |
mg/ℓ |
Mercury (expressed as Hg) |
5 |
mg/ℓ |
Cadmium (expressed as Cd) |
5 |
mg/ℓ |
Total collective concentration of all metals in Group 2 |
10 |
mg/ℓ |
(c) Radio-active wastes |
Any radio-active waste or isotopes: such concentration as may be laid down by the Atomic Energy Corporation or any State Department. |