Advanced treatment of Membrane Bioreactor (MBR) effluents for effective wastewater reclamation

摘要

One of the two main objectives of this work is to oxidize MBR effluents with ozone/peroxide innhigh pH conditions in order to improve oxidation of pharmaceuticals, which could efficiently benrejected by the nanofiltration (NF) stage. The other main objective is to effectively oxidize ofndissolved organic carbon (DOC) in MBR effluents in order to decrease fouling in the filtration stage.nIn this work, ozone/peroxide oxidation was applied to the MBR effluents in high pH conditions innorder to improve the formation of OH radicals, and oxidized effluents were filtered by the NFnmembrane (NE90) in order to investigate fouling potentials and the removal of pharmaceuticals.nNatural and synthetic wastewater samples were used as feed solutions for the MBR system,nwhich was equipped with a U-shaped hollow fiber membrane module. The flux decline wasndecreased from 29% to 15% when 9 mg/L of ozone was used, the same decline was alsonobserved when 6 mg/L ozone and hydrogen peroxide (1/1 ozone/peroxide mol ratio) were used.nA further decrease in flux decline was observed when pH was adjusted to 9.00 (29% to 9%) priornto the ozone/peroxide oxidation. In most cases, the increase in the ozone dose, the addition ofnhydrogen peroxide and the adjustment of the pH level led to an increase in the removal ofnpharmaceuticals. Iopromide, TCEP and Naproxen were found to be more resistant to the oxidationnwhen pH was increased.