Testing the equivalency of ultraviolet light and chlorine for disinfection of wastewater to reclamation standards
Abstract:Full-scale ultraviolet (UV) light and chlorine disinfection systems were operated in parallel using nitrified and partially denitrified tertiary treated wastewater effluent. A UV dose of 75 mW · s/cm2 reduced the concentration of fecal coliforms, enterococci, fecal streptococci, MS2 bacteriophage, and poliovirus by four logs. A higher dose was needed to reduce the concentration of heterotrophic plate count (HPC) by four logs and to achieve a total coliform value ≤2.2 MPN per 100 mL within a consecutive 7-day period as required by the most restrictive California Wastewater Reclamation Criteria (CWRC). The cleaning frequency needed to maintain a minimum operational UV dose was assessed by constructing a lamp fouling curve describing reduction in UV intensity as a function of elapsed time since lamp cleaning. Substitution of UV light for chlorine disinfection eliminated formation of trihalomethanes, reduced formation of aldehydes, and formed a mid-polarity unidentified peak at a bench-scale dose of 2 800 mW·s/cm2 The unidentified UV peak was not detected at a full-scale dose of 188 mW·s/cm2. No chronic toxicity was observed for the full-scale UV irradiated effluent; a decline in the reproductive rate of Ceriodaphnia dubia was observed for the full-scale chlorinated effluent.
Document Type: Research Article
Publication date: January 1, 1997
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- Water Environment Research® (WER®) publishes peer-reviewed research papers, research notes, state-of-the-art and critical reviews on original, fundamental and applied research in all scientific and technical areas related to water quality, pollution control, and management. An annual Literature Review provides a review of published books and articles on water quality topics from the previous year. Published as: Sewage Works Journal, 1928 - 1949; Sewage and Industrial Wastes, 1950 - 1959; Journal Water Pollution Control Federation, 1959 - Oct 1989; Research Journal Water Pollution Control Federation, Nov 1989 - 1991; Water Environment Research, 1992 - present.
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