Biogas production from co-digestion of corn stover and chicken manure under anaerobic wet, hemi-solid, and solid state conditions

Abstract

Corn stover (CS) and chicken manure (CM) are ubiquitous agricultural wastes at low cost and have the potential to achieve a nutrient-balance when mixed together to produce biomethane via anaerobic digestion (AD). The main objective of this work was to investigate methane production at different CS to CM ratios and to evaluate the process stability under wet (W-AD), hemi-solid state (HSS-AD) and solid state (SS-AD) conditions. Results showed that synergistic effects were found when mixing two substrates at CS:CM ratios of 3:1 and 1:1 (on volatile solid basis). The highest methane yield of 218.8 mL/g VS added was achieved in W-AD at CS:CM ratio of 3:1. In SS-AD, the highest volumetric methane productivity of 14.2L methane/L reactor volume was found at CS:CM of 1:1. The results of this work provide useful information to improve the efficiency and stability of co-digestion of CS and CM under different AD conditions.

Keywords: AD; B(d); BMP; Biochemical methane potential; CM; CS; Chicken manure; Corn stover; EMY; FA; HSS-AD; NH(3)-N; Process stability; S/I ratio; SD; SS-AD; Solid state digestion; TA; TMY; TS; VFA; VS; W-AD; Weighted EMY; ammonia-nitrogen; anaerobic digestion; biochemical methane potential; biodegradability; chicken manure; corn stover; experimental methane yield; free ammonia; hemi-solid state anaerobic digestion; solid state anaerobic digestion; standard deviation; substrate/inoculum ratio; theoretical methane yield; total alkalinity; total solid; volatile fatty acid; volatile solid; weighted experimental methane yield; wet anaerobic digestion.