Effect of ozonation and UV irradiation with direct filtration on disinfection and disinfection by-product precursors in drinking water treatment.
Pilot plant studies were conducted to evaluate the effect of pre-ozonation and ultraviolet irradiation on disinfection, disinfection by-product precursors and water quality in a direct filtration water treatment system. Disinfection parameters including total coliforms, faecal coliforms and heterotrophic plate count were investigated. Total organic carbon (TOC), trihalomethanes (THMs), total organic halides (TOX), filtered water turbidity and colour were also evaluated. It was found that advanced pre-oxidation processes (ozonation and UV irradiation) significantly increase the level of disinfection of raw water. Removal of total trihalomethanes and total organic halides precursors improved with ozonation and UV irradiation, compared to no oxidation treatment in direct filtration and/or in conventional water treatment. All coliforms (total and faecal) were completely destroyed by ozonation alone, and also with ozonation in conjunction with UV irradiation. However, the heterotrophic plate count was not significantly reduced at an ozone residual concentration of 0.1 mg l(-1). This suggests that disinfection efficiency is strongly influenced by competition reactions of organic and inorganic compounds with ozone. Precursors of total trihalomethanes and total organic halides were reduced by 90% and 98%, respectively, with advanced pre-oxidation processes. Water quality parameters were improved by the pre-ozonation and UV irradiation treatment system.
Amirsardari
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Y
School of Environmental Engineering, Griffith University, Brisbane, Queensland, Australia.
Yu
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Q
Willams
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P
D004202:Disinfectants / Q000737:chemistry*; D004755:Enterobacteriaceae; D005374:Filtration; D009930:Organic Chemicals; D010083:Oxidants, Photochemical / Q000737:chemistry*; D010126:Ozone / Q000737:chemistry*; D010316:Particle Size; D022882:Trihalomethanes / Q000032:analysis; D014466:Ultraviolet Rays; D018508:Water Purification / Q000379:methods*; D014881:Water Supply
D004202:Disinfectants; D009930:Organic Chemicals; D010083:Oxidants, Photochemical; D022882:Trihalomethanes; D010126:Ozone