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Trade Effluent


Trade effluent refers to any liquid, including particles of matter and other substances suspended in the liquid, that is the outflow from any trade, business, or manufacture or of any works of engineering or building construction.

Managing Trade Effluent Discharge

Used water is a precious resource to Singapore as PUB reclaims used water to produce NEWater. Used water discharged from industries and households is collected and conveyed via an extensive sewerage network system and treated at the water reclamation plants. The treated used water is further purified using advanced membrane technologies to produce high-grade reclaimed water, known as NEWater. You can help preserve this water resource by complying with our Sewerage and Drainage Act and Sewerage and Drainage (Trade Effluent) Regulations.

Discharging trade effluent containing prohibited substances or excessive concentration of regulated substances may pose the following risks:
1)     Endanger the safety and health of workers maintaining the public sewerage system.
2)     Impact the used water treatment operations at Water Reclamation Plants (WRP).

For example, the presence of volatile solvents in certain quantities renders the atmosphere in the public sewer explosive and can result in fire or explosion endangering safety of workers maintaining the public sewerage system.

Trade Effluent

Good Practices

Trade Effluent
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Written Approval

Premises which discharge trade effluent into the public sewerage system are required to obtain a permit (Written Approval) from PUB, Singapore’s National Water Agency.

Written Approval

Application can be done via an online system, GoBusiness at Documents required for submission include type of trade, name and quantum of chemicals used, procedure to manage spent chemicals and design details of wastewater treatment plant.

Written Approvals are valid for 5 years upon issuance. Written Approval holders are encouraged to renew their Written Approval three months before its expiry. To renew your WA, you should submit the completed renewal form by e-mail to You may find the form here:

Businesses are required to inform PUB in the following scenarios:
a)     Change in company's name, address, process or operation.
b)     Change in plant layout or machinery, which affects the amount or nature of trade effluent discharged.
c)     Change in company's status e.g. from sole proprietor to private limited.
d)     Company has ceased operations.

Trade Effluent Fee (TEF) Scheme

Trade effluent to be discharged into the public sewer must at all times meet the standards specified in the Sewerage and Drainage (Trade Effluent) Regulations. If trade effluent discharged into the public sewer contains BOD or TSS greater than 400mg/L or COD greater than 600mg/L, you may consider taking up the Trade Effluent Fee (TEF) scheme and pay TEF in accordance with the scale set out in the Fourth Schedule of the regulations, subject to approval by PUB. The maximum limits for TEF specified under reg 11 of TER are BOD < 6,000mg/L, TSS < 6,000mg/L, and COD < 10,000mg/L O2 and/or COD/BOD ratio < 3. The TEF is computed based on the concentration of BOD, TSS and COD in the trade effluent and the volume of trade effluent discharged into the public sewer. The concentrations will be established based on trade effluent samples taken from your premises. Companies under the TEF scheme should make payment promptly or risk being removed from the scheme.

Proper Management and Disposal of Spent Chemicals

Discharging chemicals such as solvents into the drains or sewers can not only affect our water reclamation process but can also be harmful to the environment and personnel maintaining the sewerage and drain networks.

Adopting proper source-control practices can ensure spent chemicals are properly disposed to prevent accidental discharge into public sewers:
a)    Engage an NEA-licensed toxic industrial waste collector to collect spent chemicals. You should conduct audits or request for documentation proof from your licensed toxic industrial waste collector to ensure the spent chemicals are properly treated.
b)     Empty drums and containers previously used for storing chemicals such as solvents and oil should be disposed of by an NEA-licensed toxic industrial waste collector or the chemical manufacturers. If reusing containers, wash them thoroughly and ensure trade effluent generated is properly treated or disposed of by an NEA-licensed toxic industrial waste collector.
c)     Label chemicals clearly in the appropriate containers.
d)     Ensure spill kits and/or other containment measures are available for use during spills.
e)     Do not wash any chemicals or spent chemicals into the sewers or drains.
f)     Companies carrying out renovation works on their premises should ensure that renovation contractors have put in place measures to properly dispose the discarded emulsion paints, paint strippers, glues and other industrial solvents.
g)     Paintbrushes and other accessories used for painting should be washed in a dedicated washing bay. Trade effluent generated should be properly collected for disposal by an NEA-licensed toxic industrial waste collector.
h)     Conduct regular briefings and in-house training for workers on techniques for proper waste segregation and disposal


Q1. What is trade effluent?


Q2. Does the act apply to me?


Q3. What if I want to discharge my trade effluent into the open drains?


Q4. Is my Written Approval valid for all the operations of my business?


Q5. What kind of trade effluent can be discharged into the public sewers?


Q6. What should I do with trade effluent that does not comply with the requirements for discharge into sewers?


Q7. What do I need to do if my company generates toxic industrial wastes?


Q8. If my trade effluent has BOD and SS exceeding 400 mg/l which I cannot treat, what can I do?


Q9. What should I do if there is an accidental discharge of non-compliant trade effluent into the sewers?


Q10. What precautions can I take to avoid discharging non-compliant trade effluent into sewers?


Q11. How can a maintenance schedule help me?


Q12. How can a process monitoring schedule for the pre-treatment plant help me?


Q13. What are some good practices that can be adopted in maintaining oil interceptors?


Q14. Where should I collect samples?


Q15. What should I test for in the trade effluent samples?


Q16. Whom can I send my sample to for 3rd party analysis?


Q17. How can I find out more about the Acts and regulations?