Table 1.

Methane yield of pretreated orange peel waste at different temperature, time, and peel/solvent ratio.

Temperature (°C)	Time (min)	Peel/solvent ratio	Citrus waste size	Methane yield (Nm3/kg VS)
Untreated			Homogenized	0.131 ± 0.008
20	10	1 : 2	Homogenized	0.101 ± 0.011
40	10	1 : 2	Homogenized	0.097 ± 0.009
20	300	1 : 2	Homogenized	0.040 ± 0.004
40	300	1 : 2	Homogenized	0.051 ± 0.010
20	10	1 : 12	Homogenized	0.071 ± 0.006
40	10	1 : 12	Homogenized	0.074 ± 0.006
20	300	1 : 12	Homogenized	0.094 ± 0.016
40	300	1 : 12	Homogenized	0.060 ± 0.014
Untreated			Chopped	0.061 ± 0.004
20	10	1 : 2	Chopped	0.177 ± 0.011
40	10	1 : 2	Chopped	0.162 ± 0.015
20	300	1 : 2	Chopped	0.134 ± 0.016
40	300	1 : 2	Chopped	0.102 ± 0.017
20	10	1 : 12	Chopped	0.217 ± 0.009
40	10	1 : 12	Chopped	0.076 ± 0.011
20	300	1 : 12	Chopped	0.120 ± 0.005
40	300	1 : 12	Chopped	0.121 ± 0.016