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Ultraviolet Disinfection of Fecal Coliform in Municipal Wastewater: Effects of Particle Size
Author(s) -
Madge Bethany A.,
Jensen James N.
Publication year - 2006
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143005x94385
Subject(s) - turbidity , fraction (chemistry) , particle size , wastewater , suspended solids , chemistry , fractionation , ultraviolet , fecal coliform , particle (ecology) , particle size distribution , pulp and paper industry , environmental chemistry , environmental science , environmental engineering , chromatography , materials science , water quality , biology , ecology , optoelectronics , engineering
Suspended solids interfere with the efficiency of disinfection using UV radiation by decreasing the rate of disinfection and inducing tailing. However, conventional measures of solids (total suspended solids, turbidity, and UV transmittance) do not adequately predict the presence or degree of these effects. Bacteria and viruses can become associated with particles in wastewater. A fractionation technique was developed to separate particle‐associated bacteria into three fractions, based on particle size. The results show that the degree to which particles interfere with UV disinfection efficiency is dependent on particle size. The small size fraction (<5 μm) consistently produced a statistically significant faster disinfection rate than the large fraction (>20 μm), with the unfiltered sample and the medium fraction (particles >5 μm, but <20 μm) between the two extremes. Tailing also was observed only in the large fraction. Correlations between the disinfection rate constant and the percentage of large fraction bacteria of a sample were good.