Biogas production via anaerobic codigestion of chemically treated wheat straw with sewage sludge or cow manure

Biogas production from wheat straw (WS), cow manure (CM), and sewage sludge (SS) have positive impacts on the environment and economy. Therefore, this study investigated the optimization of biogas production from WS and pretreated with H 2 SO 4 during codigesting with SS or CM as co-substrate. The total solids (TS), volatile solids (VS), carbon (C), nitrogen (N), and pH of biomass samples were measured. WS was first treated with different concentrations of H 2 SO 4 and then mixed with different ratios of SS and digested under anaerobic digestion (AD). Both daily and cumulative biogas generated by AD were recorded under mesophilic conditions for 21 days. Chemical analysis indicated that WS and SS showed closely similar values of TS and VS, except CM had the lowest TS and VS. Also, WS had the highest C/N ratio, followed by CM, while the least C/N ratio was observed in SS. The pH values of CM and SS were within the ideal pH range for the AD process. The highest volume of biogas production was observed only in 4% H 2 SO 4 treated WS with 50% SS, followed by 4% H 2 SO 4 treated WS with 10% CM inoculum, whereas the lowest rate of biogas production was found with untreated WS with 10% SS. The highest VS consumed was 64.8% for WS treated with 4% H 2 SO 4 and the lowest VS consumed was 12.75% for untreated WS mixed with SS at ratio of 30:70. Overall, it can be concluded that codigestion of H 2 SO 4 treated WS with SS or CM can greatly enhance the efficiency of biogas production under the AD process. Graphical abstract