Table 1.

Sludge and water quality indicators.

Indicators	A1	A2	A3	A4
Cumulative residual sludge discharge (mg)	2,668	1,373	2067	1840
Final SVI (ml/g)	98	72	270	87
COD of effluent (mg/L)	14.97	41.52	27.12	27.12
TP of effluent (mg/L)	5.38	5.86	9.13	9.34
TN of effluent (mg/L)	14.92	45.69	14.75	7.40
NH4+-N of effluent (mg/L)	0.60	1.15	0.56	0.73
NO2−-N of effluent (mg/L)	0.47	0.48	0.53	0.47
NO3−-N of effluent (mg/L)	14.04	41.95	14.93	9.07