Enhancing Solubilization and Methane Yield of Cow Manure via Microwave Pretreatment Using Food Waste Leachate as an Ionic Additive.

This study evaluated microwave pretreatment using food waste leachate (FWL) as an ionic additive to enhance the solubilization and methane yield of cow manure. The effects of operational parameters, heating methods, and Cl- concentrations were investigated, followed by biochemical methane potential assays and net energy gain assessments. Microwave heating outperformed conventional heating, showing 24%-55% higher solubilization despite significantly lower energy inputs. At a target temperature of 40°C, adding FWL to adjust the Cl- concentration to 2500 mg/L enhanced ionic conduction, achieving an sCOD concentration of 17,422 mg/L, which exceeded that of the 60°C microwave-only condition. Consequently, the FWL-mixed condition achieved the highest methane yield (226 mL CH4/g VSadded), a 16% increase compared to the control. Although the net energy gain remained negative, FWL reduced the net energy deficit by 8.11%, suggesting its potential to alleviate the energy burden of microwave pretreatment from a resource circulation perspective.