A new approach for concurrently improving performance of South Korean food waste valorization and renewable energy recovery via dry anaerobic digestion under mesophilic and thermophilic conditions

Abstract

Dry semicontinuous anaerobic digestion (AD) of South Korean food waste (FW) under four solid loading rates (SLRs) (2.30-9.21 kg total solids (TS)/m(3) day) and at a fixed TS content was compared between two digesters, one each under mesophilic and thermophilic conditions. Biogas production and organic matter reduction in both digesters followed similar trends, increasing with rising SLR. Inhibitor (intermediate products of the anaerobic fermentation process) effects on the digesters' performance were not observed under the studied conditions. In all cases tested, the digesters' best performance was achieved at the SLR of 9.21 kg TS/m(3) day, with 74.02% and 80.98% reduction of volatile solids (VS), 0.87 and 0.90 m(3) biogas/kg VSremoved, and 0.65 (65% CH4) and 0.73 (60.02% CH4) m(3) biogas/kg VSfed, under mesophilic and thermophilic conditions, respectively. Thermophilic dry AD is recommended for FW treatment in South Korea because it is more efficient and has higher energy recovery potential when compared to mesophilic dry AD.