Parameter

CLASS I

CLASS II

CLASS III

CLASS IV

Temperature (˚C)

25

25

30

>30

pH

6.5 - 8.5

6.5 - 8.5

6.0 - 9.0

>6.0 - 9.0

D.O. (mg/L)

8

6

3

<3

COD (mg/L)

25

50

70

>70

Total P (mg/L)

0.02

0.16

0.65

>0.65

NO₃-N (mg/L)

5

10

20

>20

NH₄-N (mg/L)

<0.2

0.2 - 1

1 - 2

>2