Biogas Production through Anaerobic Codigestion of Distillery Wastewater Sludge and Disposable Spent Yeast

Table 7

Coefficient in terms of coded factors, fit statistics, and values of the response of methane yield using RSM.

Variable	Methane yield (%)
	Coefficient of estimation	value	Significance
Intercept	60.30	<0.0001 (model)
Volume ratio (A)	2.73	0.0011
pH (B)	2.19	0.0037
Temperature (C)	2.53	0.0017
AB	0.2559	0.7352
AC	−0.1654	0.8265
BC	−0.5812	0.4502
A^2	−3.12	0.0031
B^2	−10.44	<0.0001
C^2	−5.92	<0.0001
	0.9830
Adjusted	0.9611
Predicted	0.7651
Adequate precision	19.4333
Lack of fit		0.0405
F value	44.97

significant terms and insignificant terms.