Microwave-enhanced advanced oxidation process of biogas slurry from cow manure anaerobic digester

Abstract

ABSTRACT In order to improve the sedimentation performance of biogas slurry and reduce the COD, microwave-enhanced advanced oxidation process (MW/H2O2-AOP) was used to pretreat the cow manure biogas slurry. A laboratory-scale microwave reactor was used to strengthen the H2O2 advanced oxidation process to achieve the solid–liquid separation of biogas slurry which was difficult to be settled. The results showed that the maximum COD removal efficiency reached 68.8% when pH, H2O2/total solid, microwave time and microwave power were 3, 0.4, 5 min and 300 W, respectively. COD was reduced from 24,157 mg/L to 7536 mg/L, and the settlings volume was reduced to 38%, while other pollutants such as the total solid and total dissolved solid were significantly reduced. Total solid and total dissolved solid removal efficiency reached 50.0% and 62.0%, respectively. Since no other agents were added, MW/H2O2-AOP can effectively reduce secondary pollution and reduce the cost of treatment.