Influence of Temperature, Agitation, Sludge Concentration and Solids Retention Time on Primary Sludge Fermentation

Table 2

Influence of temperature, agitation, sludge concentration, and SRT on PS from WWTP 1 fermentation: SCOD yield and specific SCOD production.

Sample	SRT (days)	Fermenter typology	Temperature	pH	TSS (g/L)	VSS/TSS	COD (mg/L)	SCOD (mg/L)	SCOD (mg/L)/COD (mg/L)	SCOD (g)/VSS (g)
		Raw sludge		6.26	28.70	69%	30856	658	2%	0.03
	1	Static fermenter	Room temperature	5.87	24.68	66%	30856	1242	4%	0.08
			30°C	5.47	32.65	66%	30856	1602	5%	0.07
		Completely mixed fermenter	Room temperature	6.16	28.07	67%	30856	1889	6%	0.10
Sample 1			30°C	6.42	30.81	66%	30856	3099	10%	0.15
	3	Static fermenter	Room temperature	5.48	26.84	65%	30856	2676	9%	0.15
			30°C	5.20	29.06	64%	30856	3444	11%	0.18
		Completely mixed fermenter	Room temperature	5.60	28.26	65%	30856	2340	8%	0.13
			30°C	7.16	37.16	65%	30856	4311	14%	0.18
		Raw sludge		5.84	33.88	65%	36298	1139	3%	0.05
	1	Static fermenter	Room temperature	5.11	32.85	65%	36298	1806	5%	0.08
			30°C	4.97	32.78	65%	36298	2336	6%	0.11
		Completely mixed fermenter	Room temperature	5.25	31.76	68%	36298	2492	7%	0.11
Sample 2			30°C	5.60	34.34	64%	36298	3602	10%	0.16
	3	Static fermenter	Room temperature	5.13	36.91	65%	36298	2403	7%	0.10
			30°C	4.83	32.74	64%	36298	3276	9%	0.16
		Completely mixed fermenter	Room temperature	5.10	33.96	64%	36298	3588	10%	0.17
			30°C	5.75	33.02	62%	36298	5043	14%	0.25
		Raw sludge		6.03	29.60	66%	32758	1052	3%	0.05
	1	Static fermenter	Room temperature	5.30	27.68	66%	32758	1545	5%	0.09
			30°C	5.18	28.25	65%	32758	2379	7%	0.13
		Completely mixed fermenter	Room temperature	5.35	28.23	67%	32758	1863	6%	0.10
Sample 3			30°C	6.43	29.39	66%	32758	2871	9%	0.15
	3	Static fermenter	Room temperature	5.14	31.77	66%	32758	2421	7%	0.12
			30°C	5.02	28.36	65%	32758	2955	9%	0.16
		Completely mixed fermenter	Room temperature	5.56	31.38	65%	32758	3330	10%	0.16
			30°C	6.08	34.29	63%	32758	4030	12%	0.19