Fungal fermentation on anaerobic digestate for lipid-based biofuel production

Table 1 Characteristics of the feed and performance of the MSU CSTR digester

Characteristics of animal wastes (AD feedstock)	Value
Total solids (%, TS)^a	8.5 ± 2.2
Volatile solids (%, VS)^a	7.2 ± 1.9
COD (mg/L)^b	133,250.0 ± 21,173.0
TP (mg/L)^c	670.0 ± 6.0
TN (mg/L)^d	4487.0 ± 788.0

Digester performance	Value
Operating temperature (°C)	40
HRT (days)	25
Biogas production (m³/day)	2919.9
Methane composition (% v/v)	60
Mixed wastes feeding the AD (wet tons/day)	76.1
Solid digestate generated (wet tons/day)	11.0
Liquid digestate generated (tons/day)	64.5
Electricity demand for the AD operation (MJ/day)^e	4593.6
Thermal energy demand for the AD operations (MJ/day)^f	8161.7

^aData is the average of 45 samples with standard deviation
^bData is the average of 8 samples with standard deviation
^cData is the average of 3 samples with standard deviation
^dData is the average of 9 samples with standard deviation
^eIt is for pumps and agitators used in the AD operation
^fThe thermal energy required by the AD unit was calculated by: mass of the wet mixed feed × specific heat of the wet mixed feed × (the digester temperature—the average temperature of the mixed feed) × (1 + 10%), where the average temperature of the mixed feed is 15 °C, the digester temperature is 40 °C, the amount of wet feed is 76,100 kg, the specific heat of the wet mixed feed is 3.9 kJ/kg °C, and 10% was the extra energy that needs to maintain the digester temperature besides heading the feed

ISSN: 2731-3654