According to Singapore's Environmental Law, CODE OF PRACTICE ON POLLUTION
CONTROL, APPENDIX 9, the Singapore ALLOWABLE LIMITS FOR TRADE EFFLUENT DISCHARGED
INTO A PUBLIC SEWER/WATERCOURSE/CONTROLLED WATERCOURSE are as follows:
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 |
|
45·ăC | 45·ăC |
| 2 | Colour |
7 Lovibond Units |
7 Lovibond Units | |
| 3 | pH Value | 6 - 9 | 6 - 9 | |
| 4 | BOD (5 days at 20·ăC) | 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.
Download the Singapore Environmental Laws related to Effluent Discharge Standards documents in pdf format:
1. 
Code
of Practice on Pollution Control (File size: 1.46 Mb)
2. ALLOWABLE
LIMITS FOR TRADE EFFLUENT DISCHARGE TO SEWER/WATERCOURSE/CONTROLLED WATERCOURSE
- Appendix 9 (File size: 16 Kb)
Related links:
1. CODE OF PRACTICE ON POLLUTION CONTROL http://www.nea.gov.sg/cms/pcd/coppc_2002.pdf
2. Singapore statues online: http://statutes.agc.gov.sg/
3. http://app.nea.gov.sg/cms/htdocs/article.asp?pid=1644