DENR Administrative Order No. 35 Series of 1990 (Philippines)
WEPA Water Environment Partnership in Asia
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DENR Administrative Order No. 35 Series of 1990

Year of Enactment and Implementation Enacted in 1990
Purpose To prevent, abate and control industrial pollution
Control Area Nationwide
Overview
  • Effluent standards are limits in terms of concentration and/or volume that any wastewater discharge coming from a point source i.e. industrial plants and municipal sewerage systems shall meet. These consist of a set of water quality parameters and their corresponding numerical limits. Each set is prescribed for each of the water classes i.e. there is one set of effluent standards for Class AA, another for Class A, etc. Effluent standards are usually a certain factor say 10 over the Water Quality Criteria.
Features

Effluent Standards for different water quality parameters are described below:

Heavy Metals and Toxic Substances. - Industrial and other effluents when discharged into bodies of water classified as Class A, B, C, D, SA, SB, SC and SD in accordance with Section 68, as amended, of the 1978 NPCC Rules and Regulations shall not contain toxic substances in levels greater than those indicated in Table 1.

Table 1 - Effluent Standards: Toxic and Other Deleterious Substance
(Maximum Limits for the Protection of Public Health)
(a)
Parameter Unit Protected Waters Protected Waters Inland Waters Marine Waters Marine Waters
Category I Category II Class C Class SC Class SD
(Class AA & SA) (Class A,B & SB)
OEI NPI OEI NPI OEI NPI OEI NPI OEI NPI
Arsenic mg/L (b) (b) 0.2 0.1 0.5 0.2 1.0 0.5 1.0 0.5
Cadmium mg/L (b) (b) 0.05 0.02 0.1 0.05 0.2 0.1 0.5 0.2
Chromium (hexavalent) mg/L (b) (b) 0.1 0.05 0.2 0.1 0.5 0.2 1.0 0.5
Cyanide mg/L (b) (b) 0.2 0.1 0.3 0.2 0.5 0.2 - -
Lead mg/L (b) (b) 0.2 0.1 0.5 0.3 1.0 0.5 - -
Mercury (Tot.) mg/L (b) (b) 0.005 0.005 0.005 0.005 0.005 0.005 0.05 0.01
PCB mg/L (b) (b) 0.003 0.003 0.003 0.003 0.003 0.003 - -
Formaldehyde mg/L (b) (b) 2.0 1.0 2.0 1.0 2.0 1.0 - -
(a) Except as otherwise indicated, all limiting values in Table 1 (Section 4) are maximum and therefore shall not be exceeded.
(b) Discharge of sewage and/or trade effluents are prohibited or not allowed.

Conventional and Other Pollutants Affecting Aesthetics and Oxygen Demand. - Effluents from domestic sewage and industrial wastewater treatment plants not covered under Section 6 of these Regulations, when discharged into receiving waters classified as Class A, B, C, D, SA, SB, SC, and SD in accordance with Section 68, as amended, of the 1978 NPCC Rules and Regulations shall not contain the following pollutants in concentrations greater than those indicated in Tables 2A and 2B.

Table 2A - EFFLUENT STANDARDS: Conventional and Other Pollutants in Protected Waters Category I and II and in Inland Waters Class C (a)
Parameter Unit Protected Waters Inland Waters
Category I Category II
(Class AA & SA) (Class A, B & SB) Class C
OEI NPI OEI NPI OEI NPI
Color PCU (b) (b) 150 100 200c 150c
Temperature
(max rise in deg. Celsius in RBW)
°C rise (b) (b) 3 3 3 3
pH (range) (b) (b) 6.0-9.0 6.0-9.0 6.0-9.0 6.5-9.0
COD mg/L (b) (b) 100 60 150 100
Settleable Solids (1-hour) mg/L (b) (b) 0.3 0.3 0.5 0.5
5-Day 20 oC BOD mg/L (b) (b) 50 30 80 50
Total Suspended Solids mg/L (b) (b) 70 50 90 70
Total Dissolved Solids mg/L (b) (b) 1,200 1,000 - -
Surfactants (MBAS) mg/L (b) (b) 5.0 2.0 7.0 5.0
Oil/Grease (Petroleum Ether Extract) mg/L (b) (b) 5.0 5.0 10.0 5.0
Phenolic Substances as Phenols mg/L (b) (b) 0.1 0.05 0.5 0.1
Total Coliforms MPN/100mL (b) (b) 5,000 3,000 15,000 10,000
(a) Except as otherwise indicated, all limiting values in Tables 2A and 2B are 90th percentile values. This is applicable only when the discharger undertakes daily monitoring of its effluent quality, otherwise, the numerical values in the tables represent maximum values not to be exceeded once a year.
(b) Discharging of sewage and/or trade effluents is prohibited or not allowed

Table 2B - EFFLUENTS STANDARDS: Conventional and Other Pollutants in Inland Waters Class D, Coastal Waters Class SC and SD and other Coastal Waters not yet Classified)
Parameter Unit Inland Waters Coastal Waters Class SD & Other
Coastal Waters
(Class D) (Class SC) Not Classified
OEI NPI OEI NPI OEI NPI
Color PCU --- --- (c) (c) (c) (c)
Temperature
(max. rise in deg. Celsius in RBW)
°C rise 3 3 3 3 3 3
pH (range) 5.0-9.0 6.0-9.0 6.0-9.0 6.0-9.0 5.0-9.0 5.0-9.0
COD mg/L 250 200 250 200 300 200
5-Day 20 oC BOD mg/L 150 (d) 120 120 (d) 100 150 (d) 120
Total Suspended Solids mg/L 200 150 200 150 (g) (f)
Total Dissolved Solids mg/L 2,000(h) 1,500(h) - - - -
Surfactants (MBAS) mg/L - - 15 10 - -
Oil/Grease (Petroleum
Ether Extract)
mg/L - - 15 10 15 15
Phenolic Substances
as Phenols
mg/L - - 1.0(i) 0.5(i) 5.0 1.0
Total Coliforms MPN/100mL (j) (j) - - - -
(c) Discharge shall not cause abnormal discoloration in the receiving waters outside of the mixing zone
(d) For wastewaters with initial BOD concentration over 1,000 mg/L but less than 3,000 mg/L, the limit may be exceeded up to a maximum of 200 mg/L or a treatment reduction of ninety (90) percent, whichever is more strict. Applicable to both old and new industries.
(f) Not more than 30 mg/L increase (dry season)
(g) Not more than 60 mg/L increase (dry season)
(h) If effluent is the sole source of supply for irrigation, the maximum limits are 1,500 mg/L and 1,000 mg/L, respectively, for old industries and new industries.
(i) Not present in concentration to affect fish flavor or taste or tainting.
(j) If effluent is used to irrigate vegetable and fruit crops which may be eaten raw, Fecal Coliforms should be less than 500 MPN/100 mL.
NOTES for Table 2A and Table 2B:
  1. In cases where the background level of Total Dissolved Solids (TDS) in freshwater rivers, lakes, reservoirs and similar bodies of water is higher than the Water Quality Criteria, the discharge should not increase the level of TDS in the receiving body of water by more than ten percent of the background level.
  2. The COD limits in Tables 2A and 2B generally apply to domestic wastewater treatment plant effluent. For industrial discharges, the effluent standards for COD should be on a case to case basis considering the COD – BOD ratio after treatment. In the interim period that this ratio is not yet established by each discharger, the BOD requirements shall be enforced.
  3. There are no effluent standards for chloride except for industries using brine and discharging into inland waters, in which case the chloride content should not exceed 500 mg/L.
  4. The effluent standards apply to industrial manufacturing plants and municipal treatment plants discharging more than thirty (30) cubic meters per day.

Table 3A - Interim Effluent Standards for BOD Applicable to Old or Existing Industries Producing Strong Industrial Wastes, (1990-1994)
Industry Classification Based on BOD of Raw Wastewaters Produced Maximum Allowable Limits in mg/L, according to
Time Period and Receiving Body of Water
Effectivity date - Dec. 31, 1991 Jan. 1, 1992-Dec. 31, 1994
Inland Waters Coastal Waters Inland Waters Coastal Waters
(Class C & D) (Class SC & SD) (Class C & D) (Class SC & SD)
1. Industries producing BOD within 3,000 to 10,000 mg/L 320
or
95% removal
650
or
90% removal
200
or
97% removal
320
or
95% removal
2. Industries producing BOD within 10,000 to 30,000 mg/L 1,000
or
95% removal
2,000
or
90% removal
600
or
97% removal
1,000
or
95% removal
3. Industries producing more than or 30,000 mg/L 1,500
or
95% removal
3,000
or
90% removal
900
or
97% removal
1,500
or
95% removal
Note: *
  1. Use either the numerical limit or percentage removal whichever is lower (or whichever is more strict).
  2. Starting January 1, 1995, the applicable effluent requirements for old or existing industries are indicated in Table 3B.
  3. For parameters other than BOD, Table 2A and Table 2B both under Section 5 shall apply.

Table 3B - Effluent Standards for New* Industries Producing Strong Wastes upon Effectivity of these Regulations, and for All Industries Producing Strong Wastes starting January 1, 1995.
Industry Classification
Based on BOD of Raw
Wastewater
Maximum Allowable Limits in mg/L
Based on Receiving Body of Water
Inland Waters Coastal Waters
(Class C & D) (Class SC & SD)
1. Industries producing within 3,000 to 10,000 mg BOD/L 130 or 98% removal 200 or 97% removal
2. Industries producing within 10,000 to 30,000 mg BOD/L 200 or 99% removal 600 or 97% removal
3. Industries producing more than 30,000 mg BOD/L 300 or 99% removal 900 or 97% removal

Note:*Including old or existing industries producing strong waste whose wastewater treatment plants are still to be constructed.

  1. Use either numerical limits or percentage removal whichever is lower (or whichever is more strict).
  2. For parameters other than BOD, Tables 2A and 2B shall apply.

Table 4 - Approved Methods of Analysis
PARAMETER METHOD OF ANALYSIS
Arsenic Silver Diethyldithiocarbamate Method (Colorimetric)
BOD Azide Modification (Dilution Technique)
Boron Carmine Method (Colorimetric Method)
Cadmium Atomic Absorption Spectrophotometry(Wet ashing with concentration HNO3 + HCl)
Chlorinated Hydrocarbons Gas Chromatography (ECD)
Chromium (Hexavalent) Diphenyl Carbazine Colorimetric Method
Color Visual Comparison Method Platinum Cobalt Scale
Cyanide Specific Ion Electrode Method
Dissolved Oxygen Azide Modification (Winkler Method), Membrane Electrode (DO meter)
Fecal Coliforms Multiple-Tube Fermentation Technique or Membrane Filter
Lead Atomic Absorption Spectrophotometry
Nitrate As Nitrogen Bruccine Method for Saline Waters, specific Ion Electrode Meter for Fresh Water
Oil And Grease Gravimetric Method (Petroleum Ether Extraction)
Organo Phosphorus Compounds Gas Chromatography (FPD)
PCB Gas Chromatography (ECD)
PH Glass Electrode Method
Phenolic Substances Chloroform Extraction Method
Phosphate As Phosphorus Stannous Chloride Method
Settleable Solids Imhoff Cone Method
Surfactant (MBAS) Methylene Blue Method (Colorimetric)
Temperature Use of Mercury-Filled Thermometer
Total Coliforms Multiple-Tube Fermentation Technique or Membrane Filter
Total Mercury Cold Vapor Technique, (Mercury Analyzer, AAS)
Total Suspended Solids Gravimetric Method
Note: Other methods found in the Philippine Standard Methods for Air and Water Analysis, the "Standard Methods for the Examination of Water and Waste Waters", published jointly by American Public Health Association, the American Waterworks Association and the Water Pollution Control Federation of the U.S. or in accordance with such other method of analyses as the DENR may prescribe.

Maximum Quantity to be Discharged. - For the protection of public health and the aquatic resources of the country and in cases where the volume, strength and nature of one or more pollutants, enumerated in, or not otherwise covered in the preceeding Sections, are expected to cause a serious deterioration of a receiving body of water or cause harm or injury to aquatic life and resources, the Department Secretary shall promulgate guidelines for the use of the concerned line agencies, providing for the maximum quantity of any pollutant or contaminant that maybe allowed to be discharged into the said body of water or watercourse, including the maximum rate at which the contaminant may be so discharged.

This Section particularly applies, but is not limited to industrial effluents covered under Section 6 of these regulations, specifying in kilograms per day the BOD that may be discharged considering the classification and dry weather flow of the receiving body of water.

Penalties. - Any person or group of persons found violating or failing to comply with any Order or Decision of the Department and/or the Pollution Adjudication Board or any provision of these Regulations, shall be liable under Section 9 of the Pollution Control Law (PD No. 984) and/or Section 106 of the 1978 NPCC Rules and Regulations, as amended.

Separability Clause. - Any Section or provision of these regulations declared to be unconstitutional or invalid by a competent court, the other sections or provisions hereof shall remain to be in force.

Repealing Clause. - Any provision of the 1978 Rules and Regulations, as amended, the Effluent Regulations of 1982, and other existing rules and regulations of the Department which are inconsistent herewith are hereby repealed.

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