Abstract:

In order to control the membrane fouling caused by the half coagulation/ozonation/ceramic membranefiltration of micro- polluted water and investigate the removal capability of this process for pollutants,a bench- scaletest was carried out,and the effects of coagulant dosage and ozone dosage on trans- membrane pressure and effluentquality were explored. The results show that (1) membrane fouling can be alleviated significantly by half coagula-tion and ozonation,for instance,the trans- membrane pressure decreases rapidly from the original －0.074 MPa to－0.021 MPa at a PAC (Polyaluminum Chloride) dosage of 12.5 mg/L and decreases from － 0.068 MPa to－0.049MPa as the O₃ dosage increases from 0mg/L to 2mg/L; (2) the organic matter in water can be removedefficiently by the integrated process; for instance,the molecular mass distribution range of the organic matter chan-ges from less than 5 ku to less than 3 ku,which means a transformation of part of organic matter from large molecu-lar mass to a smaller one; (3) the integrated process helps achieve 60.00% and 68.00% of COD_Mn and UV₂₅₄ re-movals as well as 57.59% and 48.39% of THMFP and HAAFP removals,respectively; (4) after the integratedprocess, the effluent turbidity decreases to less than 0.05NTU,the number of particles larger than 2μm decreasesto less than or equal to 10CNT/mL,and the bacteria and coliform groups in water are entirely removed.Thus,themicrobial safety of the effluent is successfully guaranteed.

Key words: water purification process, half coagulation, ozone, ceramic membrane, trans- membrane pressure, microbial safety