Feasibility of Micropollutants Treatment by Coupling Nanofiltration and Electrochemical Oxidation: Case of Hospital Wastewater
Résumé
In spite of good performances of the membrane
bioreactor (MBR) process, permeate from it can still con-
tain refractory pollutants that have to be removed before
water reuse or discharge. The present study is an attempt
to combine the advantages of two well-known technolo-
gies, which are nanofiltration (NF) and electrochemical
oxidation (EO) to treat MBR effluent from hospital waste-
water. The concept is based on a preconcentration of
micropollutants with a reduction of the wastewater
volume by NF and treatment of the NF retentate by
oxidation. During filtration process the rejection of cipro-
floxacin, as a target molecule, reached beyond 97%.
Then the NF retentate was treated by EO using a boron-
doped diamond anode (BDD). Galvanostatic electrolyses
showed that this anode is efficient to mineralize not
only ciprofloxacin but also all the micropollutants and
organics contained in MBR effluent. The results demon-
strated that rapid mineralization occurred: the removal
of total organic carbon and chemical oxygen demand
(COD) reached 97% and 100%, respectively, in our
conditions in 300 min maximum. The specific energy
consumption for the total removal of COD was calculated
to be 50 kW h kg ˗1 COD.
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