Efficient treatment of nanofiltration concentrate of landfill leachate through the coupling process of flocculation-O3/MNBs
Aiming at the problem that nanofiltration concentrate of landfill leachate has the limited bioavailability for biological disposal.In this study,the flocculation-ozone/micro-nanobubbles(O3/MNBs)coupling process was employed to treat nanofiltration concentrate of landfill leachate and improve its bioavailability.The optimal process parameters for the flocculation-O3/MNBs coupling process were explored by adjusting the flocculation time,PFS dosage and flocculation rotation speed in the flocculation process,and O3 inlet volume,initial pH and temperature in the O3/MNBs process.The result showed that at the optimal flocculation process parameters:flocculation time of 40 min,PFS dosage of 10 g·L-1 and flocculation rotation speed of 300 rmin-1,the colorimetry,humus and COD removal rate of nanofiltration concentrate of landfill leachate were 79.8％,59.2％and 73.3％,respectively,the B/C increased from 0.09 to 0.22,and the biotoxicity decreased from 92.4％(high toxicity)to 50.6％(heavy toxicity).The effluent of flocculation process treating nanofiltration concentrate of landfill leachate was further treated by O3/MNBs process.At the optimal process parameters:O3 inlet volume of 400 mL·min-1,initial pH=11 and reaction temperature of 30℃,the removal rates of chromaticity,humus,and COD of flocculation effluent reached 100.0％,80.8％,and 38.9％,respectively,and the B/C increased from 0.22 to 0.62,and the biotoxicity was reduced from 50.6％(heavy toxicity)to 20.3％(low toxicity).The results indicated that the flocculation-O3/MNBs coupling process is an effective method to enhance the bioavailability of nanofiltration concentrate of landfill leachate.
nanofiltration concentrate of landfill leachateflocculationozone micro-nanobubblesbioavailability
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