What Is the Difference Between Standard A and Standard B?

Malaysia's Environmental Quality (Industrial Effluent) Regulations 2009 classify industrial wastewater discharge into Standard A and Standard B. Standard A has more stringent discharge limits and generally applies to environmentally sensitive receiving waters, while Standard B applies to other designated receiving waters with comparatively less stringent limits. The applicable standard depends on the discharge location and conditions specified by the Department of Environment (DOE) Malaysia.

Standard A vs Standard B at a Glance

Important: Standard B should not be viewed as an "easy" standard. Both standards require a properly designed and well-operated Industrial Effluent Treatment System (IETS).

Why Are There Two Standards?

Environmental protection. Risk management. Sustainable development.



Different receiving water bodies have different environmental sensitivities.

For this reason, Malaysia uses two discharge standards to ensure wastewater treatment requirements are appropriate for the receiving environment while protecting public water resources.

Does Standard A Require Different Technology?

Not necessarily.

There is no technology that is exclusively "Standard A" or "Standard B."

Instead, compliance depends on:

• Wastewater characteristics
• Influent variability
• Process design
• Hydraulic loading
• Biological treatment performance
• Operation and maintenance
• Process optimisation

Technologies commonly used for both standards include:

• Activated Sludge
• MBBR
• MBR
• DAF
• UASB
• EGSB
• Sand Filtration
• Activated Carbon Filtration
• Reverse Osmosis (where required)

The treatment process should be selected based on engineering evaluation rather than the discharge standard alone.

Which Standard Applies to My Factory?

Common Misconceptions

Engineering Perspective

One observation across many industrial wastewater treatment projects is that plants designed with operational flexibility often achieve better long-term compliance than systems designed only to meet minimum discharge limits.



Features such as adequate equalisation capacity, process redundancy, accessible maintenance layouts, and reliable monitoring instrumentation frequently have a greater impact on long-term performance than simply selecting more advanced treatment equipment.

Final Thoughts

The difference between Standard A and Standard B is not simply a matter of numerical discharge limits and it reflects the level of environmental protection required for the receiving water body.

Regardless of the applicable standard, successful compliance depends on a treatment system that is properly designed, professionally operated, and continuously monitored.

Factories that focus on long-term process stability rather than short-term compliance are generally better positioned to achieve consistent discharge quality and reduce operational risks.

Need Help Designing or Upgrading Your IETS?

Frequently Asked Questions

Is Standard A harder to achieve?

Generally, yes. Standard A requires stricter discharge quality and therefore demands tighter process control and consistent plant operation.

Does Standard B require wastewater treatment?

Yes. Standard B is still a legally enforceable discharge standard and requires an effective Industrial Effluent Treatment System.

Can an existing Standard B plant be upgraded to achieve Standard A?

In many cases, yes. Depending on the existing plant design, upgrades may include process optimisation, additional treatment stages, equipment replacement, or operational improvements.

Is MBR always required for Standard A?

No. MBR is one possible treatment technology, but it is not mandatory. The most appropriate solution depends on wastewater characteristics, required effluent quality, available space, operating costs, and project objectives.

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