Biogas production from food waste hydrolysate using a subcritical water pretreated process and pulp wastewater seed sludge

This study was investigated the biogas production performance from subcritical water hydrolysate (SCWH) using a pretreated food waste (FW) process, and pulp wastewater (PW) as seed sludge according to different volatile solid (VS) ratio of PW to SCWH, and different substrate concentration. The subcritical water hydrolysis was acted for 30 mins in a 70 ml Teflon reactor under different temperatures varied from 119, 129, 139, 159, and 195 degrees C, respectively. A batch system for optimal biogas and methane production yields examination were fermented in a 60 ml flask under 37 degrees C and 120 rpm. A maximum biogas yield of 807.0 ml/g VSre and methane yield of 329.5 ml/g VSre were achieved at a VS ratio of PW to SCWH 1:3 and substrate concentration of 25 g/L with a hydrolysate under 159 degrees C and the volatile solids (VS) removal efficiency of 80%. These results indicated that the food waste pretreated by subcritical water hydrolysis can efficiently increase the biogas production under optimal conditions.