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

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.