Nitrogen and Phosphorous Removal in Municipal Wastewater Treatment Plants in China: A Review

Table 3

National discharge criteria of municipal WWTPs in China.

Standards	Levels	CODCr	BOD5	SS	NH3–N	TP	TN	Active time
GB-73		100	60	500				1973
GB8978-88		120	30	30				1989.1.1
GB8978-96	II level	120	30	30	15	1		1998.1.1
	I level	60	20	20	15	0.5
GB18918-2002	II level	100	30	30	25  (30)^a	3		2003.1.1
	I-B level	60	20	20	8  (15)	1	20
	I-A level	50	10	10	5  (8)	0.5	15
Expectation		20^b	3	3	1	0.1^c	5	future

^aCriteria for chilly weather lower than 12 Celsus degree; ^bCOD_Mn in surface water instead of COD_Cr in wastewater; ^cStandards only for lake water and reservoirs.