Insight into simultaneously sludge dewatering and antiviral drugs removal by integrated particle electrodes assisted electrochemical oxidation

Abstract

Given the widespread occurrence of pandemic influenza, antiviral drugs (ATVs) as emerging pollutants which are ubiquitously present in wastewater and become concentrated in sewage sludge (SS). Therefore, achieving the simultaneous elimination of ATVs during sludge dewatering holds significant importance. Herein, six representative ATVs including amantadine, rimantadine, memantine hydrochloride, imiquimod, oseltamivir, and morpholidine were detected in sewage sludge. Their partitioning between solid and liquid phases was also examined under simultaneous sludge conditioning by particle electrodes-assisted electrochemical process (3D-SAC). The findings indicated that 3D-SAC significantly enhanced sludge dewaterability, achieving a moisture content reduction to 64.22 %. The total removal rates of the six ATVs ranged from 17.97 % to 66.22 %, closely associated with the degree of sludge cells cracking. Sludge lysis resulted in the destruction of protein-like EPS structures, exposing hydrophobic bonding sites, finally releasing more bonded water and ATVs into filtrate. The ·OH induced hydroxylation, backbone cleavage, and ring-opening of ATVs occurred concurrently as the sludge flocs disrupted and structural transformed. Environmental risk assessment revealed that the ecological risks and potential toxicity associated with the sludge filtrate were significantly diminished following electrochemical conditioning (EC). This process achieved the dual objectives of contaminant degradation and enhanced sludge dewatering.