DENR Wastewater Discharge Standards: DAO 2016-08 and DAO 2021-19
What the Philippine effluent standards require
Wastewater discharged to a water body in the Philippines is governed by DENR Administrative Order 2016-08, the Water Quality Guidelines and General Effluent Standards of 2016, signed on 24 May 2016. It was partially amended by DENR Administrative Order 2021-19, issued on 20 June 2021, which updated selected parameters.
The limit that applies to you is decided by the classification of the water body you discharge into, not by your industry alone. The same wastewater discharged to a Class D river and a Class SB coastal water is held to different numbers. Establishing that classification is engineering and regulatory work, and at IWSI we treat it as our scope rather than the client's — we determine it, state it in the quotation, and file for written confirmation where one is needed.
What DAO 2021-19 changed
DAO 2021-19 updated six parameters: ammonia, phosphate, fecal coliform, boron, copper and sulfate. Several nutrient limits became less stringent. Nitrate, BOD and TSS were not changed by it. One change was not a relaxation — copper was redefined from dissolved copper to total copper, which is a stricter basis of measurement.
| Parameter | Class | DAO 2016-08 | DAO 2021-19 |
|---|---|---|---|
| Ammonia as NH3-N (mg/L) | A | 0.5 | 2 |
| B | 0.5 | 3 | |
| C | 0.5 | 4 | |
| D | 7.5 | 9 | |
| SB | 0.5 | 3 | |
| SC | 0.5 | 4 | |
| Phosphate (mg/L) | B | 1 | 1.5 |
| C | 1 | 4 | |
| SB | 1 | 2 | |
| SC | 1 | 4 | |
| Fecal coliform (MPN/100 mL) | A | 4 | 100 |
Class SB is not equivalent to Class C. SB allows 3 mg/L ammonia against C's 4, and 2 mg/L phosphate against C's 4 — SB is the stricter of the two.
Effluent limits by water body class
The tables below set out the limits IWSI designs against for each receiving water classification.
| BOD | ≤ 30 mg/L |
|---|---|
| COD | ≤ 60 mg/L |
| TSS | ≤ 85 mg/L |
| Ammonia | ≤ 3 mg/L |
| Phosphate | ≤ 1.5 mg/L |
| Nitrates | ≤ 14 mg/L |
| pH | 6.0–9.0 |
| Fecal Coliform | ≤ 200 MPN/100mL |
| Total Coliform | ≤ 3,000 MPN/100mL |
| Surfactants (MBAS) | ≤ 3 mg/L |
| Oil & Grease | ≤ 5 mg/L |
| Color | ≤ 100 TCU |
| Sulfate | ≤ 500 mg/L |
| Dissolved Oxygen | ≥ 5 mg/L |
| Temperature | 26–30°C |
| BOD | ≤ 50 mg/L |
|---|---|
| COD | ≤ 100 mg/L |
| TSS | ≤ 100 mg/L |
| Ammonia | ≤ 4 mg/L |
| Phosphate | ≤ 4 mg/L |
| Nitrates | ≤ 14 mg/L |
| pH | 6.0–9.5 |
| Fecal Coliform | ≤ 400 MPN/100mL |
| Total Coliform | ≤ 10,000 MPN/100mL |
| Surfactants (MBAS) | ≤ 15 mg/L |
| Oil & Grease | ≤ 5 mg/L |
| Color | ≤ 150 TCU |
| Sulfate | ≤ 550 mg/L |
| Dissolved Oxygen | ≥ 5 mg/L |
| Temperature | 25–31°C |
| BOD | ≤ 120 mg/L |
|---|---|
| COD | ≤ 200 mg/L |
| TSS | ≤ 150 mg/L |
| Ammonia | ≤ 9 mg/L |
| Phosphate | ≤ 10 mg/L |
| Nitrates | ≤ 30 mg/L |
| pH | 5.5–9.5 |
| Fecal Coliform | ≤ 800 MPN/100mL |
| Total Coliform | ≤ 15,000 MPN/100mL |
| Surfactants (MBAS) | ≤ 30 mg/L |
| Oil & Grease | ≤ 5 mg/L |
| Color | ≤ 300 TCU |
| Sulfate | ≤ 1,000 mg/L |
| Dissolved Oxygen | NA |
| Temperature | 25–32°C |
| BOD | ≤ 30 mg/L |
|---|---|
| COD | ≤ 60 mg/L |
| TSS | ≤ 70 mg/L |
| Ammonia | ≤ 3 mg/L |
| Phosphate | ≤ 2 mg/L |
| Nitrates | ≤ 20 mg/L |
| pH | 6.0–9.0 |
| Fecal Coliform | ≤ 200 MPN/100mL |
| Total Coliform | ≤ 3,000 MPN/100mL |
| Surfactants (MBAS) | ≤ 3 mg/L |
| Oil & Grease | ≤ 5 mg/L |
| Color | ≤ 100 TCU |
| Sulfate | ≤ 500 mg/L |
| Dissolved Oxygen | ≥ 5 mg/L |
| Temperature | 26–30°C |
| BOD | ≤ 100 mg/L |
|---|---|
| COD | ≤ 200 mg/L |
| TSS | ≤ 100 mg/L |
| Ammonia | ≤ 4 mg/L |
| Phosphate | ≤ 4 mg/L |
| Nitrates | ≤ 20 mg/L |
| pH | 6.0–9.5 |
| Fecal Coliform | ≤ 400 MPN/100mL |
| Total Coliform | ≤ 10,000 MPN/100mL |
| Surfactants (MBAS) | ≤ 15 mg/L |
| Oil & Grease | ≤ 5 mg/L |
| Color | ≤ 150 TCU |
| Sulfate | ≤ 550 mg/L |
| Dissolved Oxygen | ≥ 5 mg/L |
| Temperature | 25–31°C |
| BOD | ≤ 150 mg/L |
|---|---|
| COD | ≤ 300 mg/L |
| TSS | ≤ 150 mg/L |
| Ammonia | ≤ 9 mg/L |
| Phosphate | ≤ 10 mg/L |
| Nitrates | ≤ 30 mg/L |
| pH | 5.5–9.5 |
| Fecal Coliform | ≤ 800 MPN/100mL |
| Total Coliform | ≤ 15,000 MPN/100mL |
| Surfactants (MBAS) | ≤ 30 mg/L |
| Oil & Grease | ≤ 5 mg/L |
| Color | ≤ 300 TCU |
| Sulfate | ≤ 1,000 mg/L |
| Dissolved Oxygen | NA |
| Temperature | 25–31°C |
NA = not specified. Sources: DENR Administrative Order 2016-08 and DENR Administrative Order 2021-19. Some industries carry additional parameters — check which apply to your establishment.
Common questions
Which DENR standard applies to my facility?
The one attached to the classification of the water body you discharge into. If you discharge to a sewer line instead, the terms of your connection agreement with the utility may apply instead. Determining this is part of our scope on any project.
Which parameters fail most often?
In the failed laboratory results sent to us, ammonia and phosphate are the two that fail. BOD and COD usually pass, and with reasonable filtration so does TSS. Nitrate rarely fails on its own, because its limit of 14 mg/L for Classes B and C did not change in 2021 while ammonia sits at 3 or 4 — ammonia goes first. Why ammonia fails while everything else passes.
Did DAO 2021-19 make compliance easier?
For nutrients, in most classes, yes. Plants that were failing ammonia by a small margin under the 0.5 mg/L limit began passing at 2, 3 or 4 mg/L without any physical change. It did not make design easier: a plant built to produce exactly the legal limit passes only on days when nothing goes wrong.
What happens if my receiving water is reclassified?
Your limits change without you doing anything. A move from Class D to Class C takes ammonia from 9 mg/L to 4, which can turn an adequate aeration system into an undersized one overnight.
Do I need a Pollution Control Officer?
DAO 2014-02 requires a certified PCO for dischargers at or above 30 kg BOD per day. We support PCOs with sampling, reporting and training as part of operation and maintenance.
How we design for compliance
Right-sized aeration and anoxic zones. Sludge age set for what nitrification actually needs rather than for the cheapest tank. Alkalinity checked at design stage rather than after the plant fails. Probiotics for start-up and recovery, without building a dependency on a proprietary culture only we can supply. Routine laboratory sampling support and document preparation for permit submission.
We design past the discharge minimum rather than to it, because a plant with no margin fails on an ordinary bad day — and because water treated only to a discharge limit is water you can only discharge. See our design and build service, get an indicative price, or send us a lab report and we will read it.