Improved Design of Anaerobic Digesters for Household Biogas Production in Indonesia: One Cow, One Digester, and One Hour of Cooking per Day

Table 1

Performance and chemical characteristics of the dairy manure feedstock and digester influents and effluents.

	Dairy manure	𝑅control-1		𝑅control-2		𝑅mixer		𝑅recycle
		Influent	Effluent	Influent	Effluent	Influent	Effluent	Influent	Effluent
Total solids (TS)	134.3±20.1	48.9±7.5	33.8±5.4	49.0±6.7	34.5±3.6	47.3±6.9	36.2±4.2	49.1±6.9	36.9±4.9
g·L^−1	𝑛=7	𝑛=90	𝑛=25	𝑛=81	𝑛=24	𝑛=84	𝑛=26	𝑛=100	𝑛=29
Volatile solids (VS)	117.1±19.1	42.4±7.2	27.0±5.3	42.5±6.7	27.7±3.5	40.8±6.8	29.4±4.1	42.5±6.8	29.9±4.7
g·L^−1	𝑛=7	𝑛=90	𝑛=25	𝑛=81	𝑛=24	𝑛=84	𝑛=26	𝑛=100	𝑛=29
Fixed solids (FS)	17.2±12.3	6.4±0.9	6.8±0.5	6.7±0.8	6.9±0.5	6.5±0.8	6.8±0.4	6.6±1.0	6.5±0.9
g·L^−1	𝑛=7	𝑛=90	𝑛=25	𝑛=81	𝑛=24	𝑛=84	𝑛=26	𝑛=100	𝑛=29
Total COD	n.d.	60.9±11.0	41.1±11.9	56.6±10.2	33.6±9.5	64.1±14.5	35.0±10.5	56.6±10.8	38.2±14.9
g O2·L^−1		𝑛=8	𝑛=9	𝑛=8	𝑛=9	𝑛=8	𝑛=9	𝑛=8	𝑛=9
Soluble COD	n.d.	9.3±2.7	3.3±1.4	8.6±2.5	3.5±1.4	9.1±3.3	3.2±1.5	9.1±3.9	3.1±1.3
g O2·L^−1		𝑛=29	𝑛=20	𝑛=29	𝑛=20	𝑛=29	𝑛=20	𝑛=29	𝑛=20
Volatile fatty acids	2.00±0.50	n.d.	0.67±0.54	n.d.	0.51±0.32	n.d.	0.41±0.30	n.d.	0.30±0.22
g CH3COOH·L^−1	𝑛=3		𝑛=19		𝑛=19		𝑛=19		𝑛=19
pH	n.d.	7.65±0.48	7.36±0.20	7.57±0.46	7.36±0.20	7.59±0.45	7.33±0.21	7.54±0.45	7.33±0.20
		𝑛=112	𝑛=99	𝑛=114	𝑛=88	𝑛=112	𝑛=86	𝑛=114	𝑛=88
Retained solids	n.d.	84.1±1.0		81.1±1.0		71.4±2.8		74.3±0.6
g TS·LReactor^−1		𝑛=3		𝑛=3		𝑛=3		𝑛=3
Methane content	n.d.	58.0±3.0		58.1±2.1		59.0±2.1		59.4±2.1
%		𝑛=32		𝑛=32		𝑛=32		𝑛=32
Biogas production	n.d.	0.600±0.070		0.630±0.100		0.550±0.090		0.590±0.080
LBiogas⋅LReactor^−1·day^−1		𝑛=96		𝑛=98		𝑛=98		𝑛=98
Methane yield	n.d.	0.150±0.030		0.150±0.020		0.140±0.020		0.150±0.030
LCH4 ·g VS^−1·day^−1		𝑛=82		𝑛=76		𝑛=79		𝑛=94

n.d.: not determined.