PERFORMANCE EVALUATION OF COMBINED ELECTRO-FENTON PROCESS AND MEMBRANE BIOREACTOR (MBR) FOR TREATING WASTEWATER CONTAINING GLYPHOASTE HERBICIDE

Abstract

Treatment of a wastewater from a pesticide manufacture has been investigated by electro-Fenton process coupled with a membrane bioreactor (MBR). The electro-fenton pretreatment system used the carbon felt (300 cm²) as cathode and Pt gauze (240 cm²) as anode, pH = 3, [Fe²⁺] = 0,1 mM; pH = 3; [Na₂SO₄] = 0,05M; I = 2,5A. The MBR for secondary treatment used the hollow fiber membranes (Microfiltration) with the 0,3 µm pore size (total surface area= 0,2 m²) , MLSS = 7.900 – 8.900 mg.L^-1, aeration/ non-aeration mode : 60 min/60 min. The result proved that after 40 minutes of pre-treatment by electro- fenton system and  24 hours of secondary treatment by MBR, the concentration of glyphosate herbicide decreased from 29,5 mg.L^-1 to 0.3 mg.L^-1, COD from 1430 mg.L^-1  to 32.6 mg.L^-1, BOD₅ from 317.6 mg.L^-1  to 10.8 mg.L^-1 and ammonium from 16.3 mg.L^-1  to 0.76 mg.L^-1, the quality of treated wastewater reached QCVN 40: 2011 / BTNMT.