Pursuant to the provisions of Section 6 (i) of Presidential Decree No. 984, otherwise known as the "Pollution Control Decree of 1976", and by virtue of Executive Order No. 192, Series of 1987, the Department of Environment and Natural Resources hereby adopts and promulgates the following rules and regulations:

Section 1. Title. - These rules and regulations shall be known as the "Revised Effluent Regulations of 1990".

Section 2. Scope. - These rules and regulations shall apply to all industrial and municipal wastewater effluents.

Section 3. Definitions. - The following words and phrases, as used in these rules and regulations, shall have the following meaning unless the context clearly indicates otherwise:

1. "BOD" means a measure of the approximate quantity of dissolved oxygen that will be required by bacteria to stabilize organic matter in wastewater or surface water. It is a semi-quantitative measure of the wastewater organics that are oxidizable by bacteria. It is also a standard test in assessing wastewater strength.
2. "Coastal Water" means an open body of water along the country’s coastline starting from the shoreline (MLLW) and extending outward up to the 200-meter isobath or three-kilometer distance, whichever is farther.
3. "Department" refers to the Department of Environment and Natural Resources.
4. "Effluent" is a general term denoting any wastewater, partially or completely treated, or in its natural state, flowing out of a manufacturing plant, industrial plant or treatment plant.
5. "Inland Water" means an interior body of water or watercourse such as lakes, reservoirs, rivers, streams, creeks, etc., that has beneficial usage other than public water supply or primary contact recreation. Tidal affected rivers or streams are considered inland waters for purposes of these regulations.
6. "Mixing Zone" is the place where the effluent discharge from a point source mixes with a receiving body of water. The area or extent of the zone shall be determined by the discharger and approved by the Department on a case-to-case basis.
7. "NPI" means New/Proposed Industry or wastewater treatment plants to be constructed.
8. "OEI" means Old or Existing Industry.
9. "Primary Contact Recreation" means any form of recreation, where there is intimate contact of the human body with the water, such as swimming, water skiing, or skin diving.
10. "Protected Water" means a watercourse or a body of water, or any segment thereof, that is classified as a source of public water supply, propagation and harvesting of shellfish for commercial purposes, or spawning areas for Chanoschanos and similar species, or primary contact recreation, or that which is designated by competent government authority or by legislation as tourist zone, national marine park and reserve, including coral reef park and reserve.
11. "Strong Water" refers to wastewater whose initial BOD value before treatment is equal to or greater than 3,000 mg/L.

Section 4.  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

Section 5. 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

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)

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.

Section 6.    Effluent Standards for BOD for Strong Industrial Wastes. -

TABLE 3A - Interim Effluent Standards for BOD Applicable to Old or Existing Industries Producing
Strong Industrial Wastes, (1990-1994)

  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.

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.

Section 7. Mixing Zone Requirements. The following general conditions shall govern the location and extent of the mixing zone:

1. No mixing zone or combination of mixing zones shall be allowed to significantly impair any of the designated uses of the receiving body of water.
2. A mixing zone shall not include an existing drinking water supply intake if such mixing zone would significantly impair the purposes for which the supply is utilized.
3. A mixing zone for rivers, streams, etc., shall not create a barrier to the free migration of fish and aquatic life.
4. A mixing zone shall not include a nursery area of indigenous aquatic life nor include any area designated by the Department of Environment and Natural Resources for shellfish harvesting, tourist zones and national marine parks and reserves, coral reef parks and reserves and declared as such by the appropriate government agency.
5. In general, the length of the mixing zone or plume in rivers or similar waterways shall be as short as possible and its width shall be preferably not more than one-half of the width of the waterway.
6. In discharging hot effluents from power plants, mineral ore milling and similar generators of large volume of liquid wastes the permissible size of the mixing zone shall be determined through modeling taking into consideration the size, hydraulic and hydrological data of the receiving body of water and the design and siting of the wastewater outfall.
7. For the protection of aquatic life resources, the mixing zone must not be used for, or be considered as a substitute for wastewater treatment facility.

  Section 8. Additional Requirements

1. In addition to fulfilling the above-stated requirements in Sections 4 to 6, no effluent shall cause the quality of the receiving body of water to fall below the prescribed quality in accordance with its classification or best usage.
2. Where the combined effect of a number of individual effluent discharges causes one or more water quality parameters to exceed the prescribed limits, the maximum permissible concentrations of such parameters shall be reduced proportionately so as to maintain the desired quality.
3. When discharging effluents into coastal waters, the location and design of the submarine outfall shall be based on prevailing oceanographic and wind conditions so that discharged materials shall not find their way back to the shore and that there shall be minimum deposition of sediments near and around the outfall.
4. Effluents discharged into protected inland and coastal waters Category II, such as Class A, B, and SB, shall meet the requirements of Section 4 and 5 above.
5. Starting January 1, 1995, old or existing industries shall comply with the standards set for new industries in these regulations.
6. For a period to be determined by the Department Secretary and provided that the resulting effect on receiving waters does not pose an immediate threat to life, public health, safety or welfare or to animal or plant life or property, any existing industry that produces strong wastes which cannot meet the limits for BOD in Tables 3A and 3B, maybe allowed to operate and be issued a temporary permit to operate on condition that it pays first a penalty fee for polluting a receiving body of water in the amount equivalent to five pesos (PhP 5.00) per kilogram of BOD discharged per day in exceedance of the allowable effluent limit provided further that the calculated fine shall not exceed PhP5,000 per day in accordance with PD 984 and its implementing rules and regulations. (Conversion Factor: 1 mg/L = 1 g/cu.m.)
7. Each discharger covered under these regulations shall monitor its effluent and its effect on the receiving body of water regularly in order to ensure compliance with Sections 4, 5 and 6 hereof and Section 69, as amended, of the 1978 NPCC Rules and Regulations.

Section 9. Prohibitions. –

1. No industrial or domestic sewage effluent shall be discharged into Class AA and SA waters.
2. In order to avoid deterioration of the quality of the receiving body of water, no new industrial plant with high waste load potential shall discharge into a body of water where the dilution or assimilative capacity of said water body during dry weather condition is insufficient to maintain its prescribed water quality according to its usage or classification.
3. No person shall discharge, wholly or partially, untreated or inadequately treated industrial effluents directly into bodies of water or through the use of bypass canals and/or pumps and other unauthorized means except upon prior approval of the Department Secretary.
4. Other Restrictions:

1. All water pollution control facilities/installations shall be properly and consistently maintained and correctly and continuously operated in order to maintain an effluent quality that complies with Sections 4 to 6 of these regulations.
2. No industrial or manufacturing plant shall be operated without the control facilities or wastewater treatment system in good order or in proper operation except with the permission of the Department Secretary when special circumstance arise.
3. No industrial or manufacturing plant or source of pollution shall be operated at capacities beyond the limits of operation or capability of the wastewater treatment facility in order to maintain the effluent quality within the standards or pertinent conditions required by law and/or stipulated in the permit to operate.
4. No person shall build, erect, install or use any equipment, contrievance or any means the use of which will conceal and/or dilute an effluent discharge and which otherwise constitute a violation of any provisions of these regulations or the 1978 NPCC Rules and Regulations, as amended.

Section 10. Methods of Analysis for Effluents. - For purposes of these Regulations, any domestic or industrial effluent discharged into any body of water or watercourse shall be analyzed in accordance with the latest edition of the "Philippine Standard Methods for Air and Water Analyses", the "Standard Method for the Examination of Water and Wastewater" published jointly by the American Public Health Association, the American Waterworks Association and the Water Pollution Control Federation of the United States, or in accordance with such other methods of analysis as the Department may prescribe. The approved methods of analysis are given in Table 4.

Table 4 - Approved Methods of Analysis

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.

Section 11. 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 preceding 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.

Section 12. 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.

Section 13. 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.

Section 14. 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.

Section 15. Amendments. - This Regulation may be amended and/or modified from time to time by the Department.

Section 16. Effectivity. - This Regulation shall take effect thirty (30) days after publication in the official gazette or any newspaper of general circulation.

APPROVED.

(Sgd.) FULGENCIO S. FACTORAN, JR.
Secretary, Department of Environment and Natural Resources