Table 1 Standards for effluents discharged into foul sewers leading into Government sewage treatment plants

(All units in mg/L unless otherwise stated; all figures are upper limits unless otherwise indicated)

Flow rate
(m2/day)
Determinand
<=10 >10
and
<=100
>100
and
<=200
>200
and
<=400
>400
and
<=600
>600
and
<=800
>800
and
<=1000
>1000
and
<=1500
>1500
and
<=2000
>2000
and
<=3000
>3000
and
<=4000
>4000
and
<=5000
>5000
and
<=6000
pH (pH units) 6-10 6-10 6-10 6-10 6-10 6-10 6-10 6-10 6-10 6-10 6-10 6-10 6-10
Temperature(oC) 43 43 43 43 43 43 43 43 43 43 43 43 43
Suspended solids 1200 1000 900 800 800 800 800 800 800 800 800 800 800
Settleable solids 100 100 100 100 100 100 100 100 100 100 100 100 100
BOD 1200 1000 900 800 800 800 800 800 800 800 800 800 800
COD 3000 2500 2200 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000
Oil & Grease 100 100 50 50 50 40 30 20 20 20 20 20 20
Iron 30 25 25 25 15 12.5 10 7.5 5 3.5 2.5 2 1.5
Boron 8 7 6 5 4 3 2.4 1.6 1.2 0.8 0.6 0.5 0.4
Barium 8 7 6 5 4 3 2.4 1.6 1.2 0.8 0.6 0.5 0.4
Mercury 0.2 0.15 0.1 0.1 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001
Cadmium 0.2 0.15 0.1 0.1 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001
Copper 4 4 4 3 1.5 1.5 1 1 1 1 1 1 1
Nickel 4 3 3 2 1.5 1 1 0.8 0.7 0.7 0.6 0.6 0.6
Chromium 2 2 2 2 1 0.7 0.6 0.4 0.3 0.2 0.1 0.1 0.1
Zinc 5 5 4 3 1.5 1.5 1 0.8 0.7 0.7 0.6 0.6 0.6
Silver 4 3 3 2 1.5 1.5 1 0.8 0.7 0.7 0.6 0.6 0.6
other toxic metals individually 2.5 2.2 2 1.5 1 0.7 0.6 0.4 0.3 0.2 0.15 0.12 0.1
Total toxic metals 10 10 8 7 3 2 2 1.6 1.4 1.2 1.2 1.2 1
Cyanide 2 2 2 1 0.7 0.5 0.4 0.27 0.2 0.13 0.1 0.08 0.06
Phenols 1 1 1 1 0.7 0.5 0.4 0.27 0.2 0.13 0.1 0.1 0.1
Sulphide 10 10 10 10 5 5 4 2 2 2 1 1 1
Sulphate 1000 1000 1000 1000 1000 1000 1000 900 800 600 600 600 600
Total nitrogen 200 200 200 200 200 200 200 100 100 100 100 100 100
Total phosphorus 50 50 50 50 50 50 50 25 25 25 25 25 25
Total surfactants 200 150 50 40 30 25 25 25 25 25 25 25 25