Co-digestion of food waste and domestic wastewater – effect of copper supplementation on biogas production

This work aims to study the effect of copper supplementation (as CuCl2), at different concentrations (10, 30, and 50 mg/L Cu2+) to enhance the conversion of organics present in a mixture of food waste and domestic wastewater (0.183, v/v) to biogas. The UASB reactor was operated under mesophilic conditions (35±0.1°C) at hydraulic retention time of 10 days in the intermittent feed mode (48 h feed/48 h feedless). Regardless of the Cu2+ concentration supplemented, a higher cumulative biogas yield (260-329 mL CH4/g CODremoved) was obtained compared to the control without supplementation (175 mL CH4/g CODremoved). The microelement supplementation reduced the amount of short chain fatty acids accumulated in the reactor by 35%, stimulating the methane production.