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

Table 3

Influence of temperature, agitation, sludge concentration, and SRT on PS from WWTP 2 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		7.35	4.46	77%	4863	312	6%	0.09
	1	Static fermenter	Room temperature	7.13	3.92	75%	4863	334	7%	0.11
			30°C	6.57	3.99	75%	4863	508	10%	0.17
		Completely mixed fermenter	Room temperature	7.78	4.76	73%	4863	345	7%	0.10
Sample 4			30°C	7.06	4.23	76%	4863	482	10%	0.15
	3	Static fermenter	Room temperature	6.81	3.75	72%	4863	401	8%	0.15
			30°C	6.98	4.20	70%	4863	462	10%	0.16
		Completely mixed fermenter	Room temperature	7.97	4.13	74%	4863	423	9%	0.14
			30°C	8.18	4.61	73%	4863	543	11%	0.16
		Raw sludge		7.48	2.99	73%	2677	125	5%	0.06
	1	Static fermenter	Room temperature	7.14	3.20	74%	2677	204	8%	0.09
			30°C	6.79	2.33	70%	2677	207	8%	0.13
		Completely mixed fermenter	Room temperature	6.62	2.95	72%	2677	129	5%	0.06
Sample 5			30°C	6.64	2.63	73%	2677	157	6%	0.08
	3	Static fermenter	Room temperature	6.61	3.16	72%	2677	168	6%	0.07
			30°C	6.50	1.94	66%	2677	190	7%	0.15
		Completely mixed fermenter	Room temperature	6.51	2.55	69%	2677	238	9%	0.14
			30°C	6.44	2.67	68%	2677	278	10%	0.15
		Raw sludge		7.41	5.26	73%	5621	247	4%	0.06
	1	Static fermenter	Room temperature	6.88	4.60	75%	5621	383	7%	0.11
			30°C	6.53	4.28	74%	5621	547	10%	0.17
		Completely mixed fermenter	Room temperature	6.74	4.66	75%	5621	526	9%	0.15
Sample 6			30°C	6.79	4.86	74%	5621	630	11%	0.18
	3	Static fermenter	Room temperature	6.55	4.66	75%	5621	575	10%	0.16
			30°C	6.78	4.07	74%	5621	697	12%	0.23
		Completely mixed fermenter	Room temperature	6.37	3.91	75%	5621	679	12%	0.23
			30°C	7.14	4.36	74%	5621	653	12%	0.20