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Effluent discharge limits in Kenya

Kenya replaced its water quality regulations in December 2024. Most sources online — including several consultancies and equipment suppliers — still quote the 2006 instrument. The table below is taken from the current one.

The Third Schedule

Standards for effluent discharge into the environment. Reproduced from the Third Schedule as published. The regulation notes that standard values are daily, weekly or monthly average discharge values, and that “nd” means below the detection level of the measurement method established by the Authority.

Parameter	Maximum allowable limit	Relevance to a flotation plant
Biochemical oxygen demand, BOD₅ at 20 °C	30 mg/L	Requires biological treatment. DAF removes only the particulate share
Chemical oxygen demand, COD	50 mg/L	Requires biological treatment
Total suspended solids	30 mg/L	Achievable by DAF plus filtration
Oil and grease	Nil	See the note below — this is not the operative FOG limit
n-Hexane extracts, animal and vegetable fats	30 mg/L	The practical FOG limit for food industry effluent. DAF’s core duty
n-Hexane extracts, mineral oil	5 mg/L	Applies to workshop, garage and petroleum streams
pH, non-marine	6.5–8.5	Acidic coagulants consume alkalinity — watch the lower bound
pH, marine	5.0–9.0	—
Temperature	± 3 °C on ambient	Relevant to condensate and CIP discharges
Total nitrogen	2 mg/L	Requires nitrification and denitrification
Total phosphorus	2 mg/L	Achievable with iron dosing at the DAF. See ferric chloride
Total dissolved solids	1,200 mg/L	Coagulant choice affects this
Chloride	250 mg/L	Ferric chloride adds chloride. Consider ferric sulphate
Sulphide	0.1 mg/L	Iron dosing precipitates sulphide as FeS
Detergents	Nil	Significant for laundry, CIP and car wash streams
Colour	15 Hazen units	Overdosed iron leaves a tint that can breach this
Ammonia, ammonium, NO₃ and NO₂ compounds (ammonia-N × 4 plus nitrate-N and nitrite-N)	100 mg/L	Biological
Total coliforms	30 counts/100 mL	Disinfection required
E. coli	Nil per 100 mL	Disinfection required
Arsenic	0.02 mg/L	—
Boron	1.0 mg/L	—
Cadmium	0.01 mg/L	Hydroxide precipitation
Chromium, hexavalent (VI)	0.05 mg/L	Reduce with ferrous sulphate then precipitate
Chromium, total	2 mg/L	Tannery duty
Copper	1.0 mg/L	—
Dissolved iron	10 mg/L	Generous — iron coagulant residual is not a constraint
Dissolved manganese	10 mg/L	—
Fluoride	1.5 mg/L	—
Lead	0.01 mg/L	—
Total mercury	0.005 mg/L	—
Total nickel	0.3 mg/L	—
Selenium	0.01 mg/L	—
Zinc	0.5 mg/L	—
Phenols	0.001 mg/L	Very tight. Relevant to petroleum and resin streams
Total cyanide	Not detectable	—
Alkyl mercury compounds	Not detectable	—
Polychlorinated biphenyls	0.003 mg/L	—

The oil and grease trap

The Schedule lists “oil and grease: Nil” and, separately, “n-Hexane extracts (animal and vegetable fats): 30 mg/L” and “n-Hexane extracts (mineral oil): 5 mg/L”. Read literally, the first line is unachievable — no treatment process produces zero.

In practice the n-hexane extract figures are the measurable, enforceable limits, because they specify a laboratory method. A food processing plant is being measured against 30 mg/L of animal and vegetable fats; a garage or fuel depot against 5 mg/L of mineral oil. Both are comfortably within what a correctly dosed flotation unit achieves — 30 mg/L from a dairy or abattoir influent of 500–2,000 mg/L is a 94–98% removal, which is inside the normal 90–99% band.

Confirm with your NEMA officer which line your licence is written against before designing to either. This is exactly the kind of ambiguity that should be resolved in writing at licensing stage rather than argued at an inspection.

What this means for plant design in Kenya

• Flotation alone will not meet these limits on an industrial organic effluent. COD at 50 mg/L and BOD at 30 mg/L require biological treatment. A DAF ahead of an aerobic or anaerobic stage is the correct configuration; a DAF as the whole plant is not.
• Where the DAF earns its place is FOG, TSS and phosphorus. Taking 500–3,000 mg/L of fats down to under 30 mg/L protects the biological stage from the load that would otherwise destroy it, and iron dosing at the flotation stage handles the 2 mg/L phosphorus limit in the same step.
• Total nitrogen at 2 mg/L is the hardest number in the Schedule. It requires full nitrification and denitrification with careful control. Budget for it explicitly rather than discovering it at commissioning.
• Watch the chloride limit if you use ferric chloride. At 250 mg/L, a high ferric chloride dose on an already-saline stream can contribute meaningfully. Ferric sulphate delivers the same iron without it.
• Watch the lower pH bound. 6.5 is not generous when acidic coagulants are consuming alkalinity. On a soft water, plan the alkalinity balance rather than assuming it.
• Discharge to a licensed sewer is a different regime. These are the standards for discharge into the environment. Where a county sewerage provider accepts trade effluent, its own conditions apply and are usually looser on COD and BOD.

Licensing

The Regulations require an effluent discharge licence from the National Environment Management Authority for any trade or industrial undertaking discharging into the environment. Compliance with the Third Schedule is a licence condition, and the Fourth Schedule sets out the monitoring guide that accompanies it. County governments and sewerage operators are subject to the same Schedule.

Source and verification

Instrument	The Environmental Management and Coordination (Water Quality) Regulations
Citation	Legal Notice No. 177 of 2024
Parent act	Environmental Management and Co-ordination Act, Cap. 387
Regulator	National Environment Management Authority (NEMA)
Schedule used	Third Schedule — Standards for effluent discharge into the environment
Version date	6 December 2024
Read directly on	5 August 2026
Source	Kenya Law — official repository

This page is a working reference, not legal advice. The current text of the law, and your NEMA officer’s reading of it, take precedence over anything published here. If you spot a discrepancy, tell us and we will recheck it.

Frequently asked questions