Trade Effluent to meet the standards prior to discharge to public sewer, water course and controlled water course

ALLOWABLE LIMITS FOR TRADE EFFLUENT DISCHARGE TO SEWER/WATERCOURSE/CONTROLLED WATERCOURSE Rules and Regulations   Items Of Analysis Sewer Watercourse Controlled Watercourse     (Units in milligram per litre or otherwise stated) 1 Temperature of discharge Please refer to PUB's web page 45 °C 45 °C 2 Colour 7 Lovibond Units 7 Lovibond Units 3 pH Value 6 - 9 6 - 9 4 BOD (5 days at 20°C) 50 20 5 COD 100 60 6 Total Suspended Solids 50 30 7 Total Dissolved Solids - **(2000) 1000 8 Chloride (as chloride ion) - **(600) 250 **(400) 9 Sulphate (as SO4) - **(500) 200 10 Sulphide (as sulphur) 0.2 0.2 11 Cyanide (as CN) 0.1 0.1 12 Detergents (linear alkylate sulphonate as methylene blue active substances) 15 5 13 Grease and Oil 10 (Total) 10(Hydrocarbons) 1 (Total) 14 Arsenic 0.1 **(1) 0.01 **(0.05) 15 Barium 2 **(5) 1 **(5) 16 Tin - **(10) 5 17 Iron (as Fe) 10 **(20) 1 18 Beryllium - **(0.5) 0.5 19 Boron 5 0.5 20 Manganese 5 0.5 21 Phenolic Compounds (expressed as phenol) 0.2 Nil 22 *Cadmium 0.1 0.003 **(0.01) 23 *Chromium (trivalent and hexavalent) 1 0.05 24 *Copper 0.1 0.1 25 *Lead 0.1 0.1 26 *Mercury 0.05 0.001 27 *Nickel 1 0.1 28 *Selenium 0.5 0.01 29 *Silver 0.1 0.1 30 *Zinc 1 0.5 31 *Metals in Total 1 0.5 32 Chlorine (Free) 1 1 33 Phosphate (as PO4) 5 2 34 Calcium (as Ca) - **(200) 150 35 Magnesium (as Mg) - **(200) 150 36 Nitrate (as NO3) - 20 NOTE: * Where 2 or more of the metals listed in the table are present in the trade effluent, the total concentration of the metals shall not exceed 10 milligrams per litre. **( ) Old limits before 1 May 2005. Existing industries have a grace period of 2 years to comply with new limits. Controlled Watercourse means a watercourse from which potable water supplied by PUB under the Public Utilities Act is obtained but does not include a watercourse from which water is pumped into a main of the PUB. The trade effluent discharged must not include:- (1) Calcium carbide. (2) Petroleum spirit or other inflammable solvents. (3) Materials that may give rise to fire or explosion hazards. (4) Materials that may be a hazard to human life, a public nuisance, injurious to health or otherwise objectionable. (5) Refuse, garbage, sawdust, timber, or any solid matter. (6) Pesticides, fungicides, insecticides, herbicide, rodenticide or fumigants. (7) Radioactive material. The trade effluent shall be analysed in accordance with the latest edition of Standard Methods for the Examination of Water and Wastewater published jointly by the American Water Works Association and the Water Pollution Control Federation of the United States.