Co-digestion of agricultural and industrial wastes

The efficiency of anaerobic digestion process is dependent on the type and composition of the material to be digested. This work examines the co-digestion of corn silage, beet pulp silage, carrot residues, and cheese whey in different configurations together with a glycerin fraction — the waste product of transestrification of oils (biodiesel production) in a 25 L bioreactor operated mesophically in a quasi-continuous mode. Co-digestion of corn silage with carrot residues appeared to be more effective than that with cheese whey resulting in the gas production rate equal to 5.9 L L⁻¹ d⁻¹ and 1.4 L L⁻¹ d⁻¹, respectively. The performed experiments showed that a combination of three substrates: corn silage, cheese whey, and glycerin fraction resulted in the highest methane content equal to 61 % and the biogas production rate of 1.8 L L⁻¹ d⁻¹.