Batch anaerobic digestion of synthetic military base food waste and cardboard mixtures

Austere US military bases typically dispose of solid wastes, including large fractions of food waste (FW) and corrugated cardboard (CCB), by open dumping, landfilling, or burning. Anaerobic digestion (AD) offers an opportunity to reduce pollution and recover useful energy. This study aimed to evaluate the rates and yields of AD for FW-CCB mixtures. Batch AD was analyzed at substrate concentrations of 1-50 g total chemical oxygen demand (COD) L−1 using response surface methodology. At low concentrations, higher proportions of FW were correlated with faster specific methanogenic activities and greater final methane yields; however, concentrations of FW ⩾18.75 g COD L−1 caused inhibition. Digestion of mixtures with ⩾75% CCB occurred slowly but achieved methane yields >70%. Greater shifts in microbial communities were observed at higher substrate concentrations. Statistical models of methane yield and specific methanogenic activity indicated that FW and CCB exhibited no considerable interactions as substrates for AD.