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WQIS

dated

08.2005

WATER QUALITY INFORMATION SYSTEM 

WATER QUALITY STANDARDSThere are two (2) criteria to be met by any treatment process discharging effluent toinland waterway; one concerns the receiving water and the other the discharge wate

s  Receiving Water Quality Standard Under the Interim W ater Quality Standard (INWQS), Malaysian rivers are classiaccording to the six Classes and as described in Table 1.

 

q  Note: 

The Department of Environment (DOE) initiatedthe development of Receiving Water Qualitycriteria for Malaysia in 1985 which aimed atdeveloping a water quality management approachfor the long term water quality of the nation'swater resources. The Water Quality Consultancy

Group of the Institute of Advanced Studies,University of Malaya was commissioned in 1985to undertake Phase I Study for the developmentof water quality criteria and standards forMalysia. The study recommended that Malaysianrivers be classified according to the six classes 

and described in Table 1.

 

s  Discharge Quality Standard 

The effluent quality of any discharge from a sew age treatment process to an inlwater (that is, other than one having an ocean outlet) shall meet the minimumrequirements of the Environmental Quality Act 1974 and the limits set down by Environmental Quality (Sewage Industrial Effluent Regulations, 1979 which arepresented in Table 2.

 

q  Note: 

Standard A criteria applies only to catchments areaslocated upstream of drinking water supply off-takes.

 

Table 1 - Receiving Water Quality (from INWQS)

 

Parameters  (Units)  Classes 

l  llA  llB lll  lV V

DO mg/l 7  5 - 7  5 - 7 3 - 5  < 3 <

COD mg/l 10  25  25 50  100 > 1

BOD mg/l 1  3 3  6  12  > 1

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WQIS

Total Dissolved Solids  mg/l 500  1000  -  -  4000 -

Total Suspended Solids mg/l 25  50 50  150  300 > 3

Faecal Caliform counts/100ml  10  100 400  5000  5000  -

Total Coliform  counts/100ml  100  5000 5000 5000  5000  >500

Table 2 - Environmental Quality (Sewage and Industrial Effluents) Regulations, 1979.

Maximum Effluent Parameter Limits Standards A and B.

 

Parameters  (Units)  Standard 

A (1)  B (2)

1 Temperature oC 40  40 

2 pH - 6.0 - 9.0  5.5 - 9.0 

3 BOD5 @ 20oC mg/l 20  50 

4 COD mg/l 50  100 5 Suspended Solids mg/l 50 100

6 Mercury mg/l  0.005  0.05

7 Cadmium mg/l  0.01  0.02 

8 Chromium, Hexalent mg/l  0.05  0.05

9 Arsenic mg/l 0.05  0.10 

10 Cyanide mg/l 0.05 0.10 

11 Lead mg/l 0.10  0.5 

12 Chromium, Trivalent mg/l 0.20  1.0 

13 Copper mg/l 0.20 1.0 

14 Manganese mg/l 0.20 1.0 

15 Nickel mg/l 0.20 1.0 

16 Tin mg/l 0.20 1.0 

17 Zinc mg/l 1.0 1.0

18 Boron mg/l 1.0 4.0

19 Iron (Fe) mg/l 1.0 5.0

20 Phenol mg/l 0.001 1.0

21 Free Chlorine mg/l 1.0 2.022 Sulphide mg/l 0.50 0.50

23 Oil and Grease mg/l  Not detectable  10.0 

1.Standard A for discharge upstream of drinking w atertake-off 

2. Standard B for inland waters

 

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Class  Uses 

l r epresents water bodies of excellent quality. Standards set for theconservation of natural environment in its undisturbed state.Water bodies such as those in the national park areas, fountainheads, and in land and in undisturbed areas come under thiscategory where strictly no discharges of any kind is permitted.Water bodies in this category meets the most stringentrequirements for human health and aquatic life protection.

 ll   represents water bodies of good quality. Most existing raw water

supply sources come under this category. In practise, no bodycontact activity is allowed in this water for the prevention of probable human pathogens . There is a need to introduce anotherclass for water bodies not used for water supply but similarquality wh ich may be referred to as Class IIB. The determinationof Class IIB standards is based on criteria for recreational use andprotection of sensitive aquatic species.

 

ll l  is defined w ith the primary objective of protecting common and

moderately tolerant aquatic species of economic value. Water

under this classification may be used for water supply w ithextensive/ advanced treatment. This class of water is also definedto suit livestoick drinking needs.

 

lV   defines water required for major agricultural activities which maynot cover minor applications to sensitive crops.

 

V   represents other water which do not meet any of the above uses.

 

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