Synergistic effects in anaerobic codigestion of chicken manure with industrial wastes

Abstract

Synergy in anaerobic codigestion is described as positive interactions between a substrate and cosubstrate(s). Synergistic effects increase methane production over the weighted average methane production from monodigestion. Limited current knowledge defines synergy as a parameter in the plant control and design and in solving operational problems. In this study, synergy was determined in the anaerobic codigestion of chicken manure with industrial wastes (sugarcane molasses, cheese whey, and crude glycerol). A simplex lattice mixture design was used to determine mixing ratios. Synergy was assessed in terms of substrate composition and ammonia inhibition. The greatest synergistic effects were achieved with ternary mixtures. Synergy was also noticed when total ammonia nitrogen concentrations decreased and the organic load increased. Nonetheless, it was concluded that synergy could be reliably achieved when cosubstrate supplementation reduces ammonia inhibition and increases methane production as increases in organic load.