评价因子

分级标准

I

II

III

IV

V

pH

6~9

${\text{NH}}_4^{-}$ -N (mg/L)

0.15

0.5

1

1.5

2

${\text{NO}}_3^{-}$ -N (ug/L)

0.05

0.1

0.2

0.4

0.6

TN (mg/L)

0.2

0.5

1

1.5

2

TP (mg/L)

0.02

0.05

0.1

0.15

0.2

COD_Cr (mg/L)

15

15

20

30

40

BOD₅

3

3

4

6

10