Performance of leach-bed reactor with immobilization of microorganisms in terms of methane production kinetics

Abstract

In this study, the performance of leach-bed with immobilization device reactor during dry anaerobic fermentation of solid cattle manure was investigated. Laboratory experiments using 50 L bioreactor were performed in batch operated mode at the temperature of 40±0.2°C (mesophilic condition). Immobilization device was positioned at the bottom of the bioreactor as a layer of polyethylene packing rings. Each 2nd run was initiated by inoculating with anaerobically digested liquor from previous run. The performance of the reactor was analyzed in terms of the kinetic constants of methane production. To describe methane production rate kinetics was used Gaussian equation (time to produce maximal methane production (t0) and a (Nm3 (kg oDM)-1 day-1) and b (day) constants) and was calculated Gompertz kinetic parameters of methane production (methane production potential (P), maximum methane production rate (Rm and minimum time to produce methane (λ). Time to produce peak of methane yield (t0) were 7.49±1.15 days and4.82±0.11 days in the 1 st and 2nd run. Kinetic constants P, and A, were indicated in values 0.159; 0.015 and 1.61 for 1 st run and 0.154; 0.021 and 0.7 for 2nd run, respectively. Overall P,Rm and λ to show reactor performance were 0.156Nm3 (kg oDM)-1, 0.018 Nm3 (kgoDM)-1 day-1; 1.16 days, respectively. Time to produce 95% methane production potential was 14.31 days, calculated effective anaerobic digestion time was 13.15 days. Recirculation of the fermentation medium and immobilization of microorganisms in polymeric carriers in the reactor makes it possible to initiate methanogenesis in 1-2 days and reduce the hydrolytic retention time due to biofilm formation. ©2014 Asian Network for Scientific Information.