WRRCTMR No.71 Disinfection of Bacteria and Viruses by Sludge Heat-Treatment Process at Sand Island WWTP, O'ahu, Hawai'i

dc.contributor.author Fujioka, Roger S. en_US
dc.contributor.author Hirano, Wesley M. en_US
dc.contributor.author Loh, Philip C. en_US
dc.date.accessioned 2008-09-30T23:50:49Z
dc.date.available 2008-09-30T23:50:49Z
dc.date.issued 1983-09 en_US
dc.description.abstract The Zimpro heat-treatment process installed at the Sand Island Wastewater Treatment Plant was evaluated for its reliability in disinfecting fecal bacteria and viruses in the treated sludge. Samples of the untreated sludge and the heat-treated sludge cake were initially analyzed for fecal coliforms, fecal streptococci, and human enteric viruses. The detection of high concentrations of indicator bacteria in the sludge cake suggested that the heat-treatment process was not properly disinfecting the sludge. However, samples of sludge obtained from the plant immediately after the heat-treatment process yielded no fecal coliforms, fecal streptococci, Clostridium perfringens, or human enteric viruses, thus demonstrating that the plant heat-treatment process will disinfect the sludge of all fecal bacteria and viruses. It was subsequently determined that the heat-treated sludge becomes contaminated with fecal bacteria in the sludge storage tank, and that the use of improperly disinfected chlorinated sewage effluent to wash plant equipment or of pipes to transport untreated and heat-treated sludge contributed to the contamination of the heat-treated sludge. Additional evidence showed that the very acidic (pH 4.5-5.0), heat-treated sludge inhibited the multiplication of fecal bacteria. When the pH of the heat-treated sludge was adjusted to pH 5.5 to 6.5, fecal coliforms and fecal streptococci - but not C. perfringens –multiplied. Al though fecal bacteria cannot multiply in the heat-treated sludge at pH 4.5, other bacteria will. The growth of these non-fecal bacteria in the heat-treated sludge is speculated to raise the pH to at least 5.5 and thus allow the fecal bacteria to multiply. en_US
dc.description.sponsorship City and County of Honolulu, Department of Public Works Grant/Contract No. F-710-80 en_US
dc.format.extent ix + 50 pages en_US
dc.identifier.citation Fujioka RS, Hirano WM, Loh PC. 1983. Disinfection of bacteria and viruses by sludge heat-treatment process at Sand Island WWTP, O'ahu, Hawai'i. Honolulu (HI): Water Resources Research Center, University of Hawaii at Manoa. WRRC technical memorandum report, 71. en_US
dc.identifier.uri http://hdl.handle.net/10125/2683
dc.language.iso en-US en_US
dc.publisher Water Resources Research Center, University of Hawaii at Manoa en_US
dc.relation.ispartofseries WRRC Technical Memorandum Report en_US
dc.relation.ispartofseries 71 en_US
dc.subject pathogenic bacteria en_US
dc.subject viruses en_US
dc.subject sludge treatment en_US
dc.subject disinfection en_US
dc.subject sewage bacteria en_US
dc.subject heat treatment en_US
dc.subject fecal coliforms en_US
dc.subject fecal streptococci en_US
dc.subject human enteric viruses en_US
dc.subject Zimpro heat-treatment en_US
dc.subject Sand Island WWTP en_US
dc.subject Oahu en_US
dc.subject Hawaii en_US
dc.subject.lcsh Sand Island (Oahu, Hawaii) en_US
dc.subject.lcsh Sewage -- Purification -- Hawaii -- Oahu. en_US
dc.subject.lcsh Sewage disposal plants -- Hawaii -- Oahu. en_US
dc.subject.lcsh Sewage sludge -- Disinfection -- Hawaii -- Oahu. en_US
dc.subject.lcsh Enterobacteriaceae. en_US
dc.subject.lcsh Streptococcus. en_US
dc.title WRRCTMR No.71 Disinfection of Bacteria and Viruses by Sludge Heat-Treatment Process at Sand Island WWTP, O'ahu, Hawai'i en_US
dc.type Report en_US
dc.type.dcmi Text en_US
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