Feasibility of Micropollutants Treatment by Coupling Nanofiltration and Electrochemical Oxidation: Case of Hospital Wastewater

摘要

In spite of good performances of the membraneudbioreactor (MBR) process, permeate from it can still con-udtain refractory pollutants that have to be removed beforeudwater reuse or discharge. The present study is an attemptudto combine the advantages of two well-known technolo-udgies, which are nanofiltration (NF) and electrochemicaludoxidation (EO) to treat MBR effluent from hospital waste-udwater. The concept is based on a preconcentration ofudmicropollutants with a reduction of the wastewaterudvolume by NF and treatment of the NF retentate byudoxidation. During filtration process the rejection of cipro-udfloxacin, as a target molecule, reached beyond 97%.udThen the NF retentate was treated by EO using a boron-uddoped diamond anode (BDD). Galvanostatic electrolysesudshowed that this anode is efficient to mineralize notudonly ciprofloxacin but also all the micropollutants andudorganics contained in MBR effluent. The results demon-udstrated that rapid mineralization occurred: the removaludof total organic carbon and chemical oxygen demandud(COD) reached 97% and 100%, respectively, in ourudconditions in 300 min maximum. The specific energyudconsumption for the total removal of COD was calculatedudto be 50 kW h kg ˗1 COD.