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PRELIMINARY COMPARATIVE STUDY OF METHODS TO EXTRACT VIRUS FROM RAW AND PROCESSED SEWAGE SLUDGES
Citation:
RHODES, E., B. MCMINN, N. BRINKMAN, J. CASHDOLLAR, AND G. FOUT. PRELIMINARY COMPARATIVE STUDY OF METHODS TO EXTRACT VIRUS FROM RAW AND PROCESSED SEWAGE SLUDGES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-07/118, 2007.
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Description:
Two simple virus extraction techniques were compared to an EPA standard method for detection of human enteric viruses in raw sewage sludge and class A biosolids. The techniques were used to detect both indigenous and seeded virus from a plant that distributes class A material produced by a heat drying process. Virus titers were measured using a plaque assay, a quantal assay and an integrated cell culture-reverse transcription-polymerase chain reaction (ICC-PCR) assay. The best extraction technique overall for detection of indigenous and seeded virus by plaque, quantal, and ICC-PCR assays was a simple chloroform-based technique. The detection of indigenous virus in raw sludge was similar for all three methods by the plaque assay, giving an average of 50±21 PFU/4 grams of sludge. Recovery of seeded virus from raw sludge averaged 0.7% for the EPA versus 22±17% for the other two techniques. Recovery of seeded virus from class A biosolids was similar for all techniques, averaging 95±24%. Both the quantal and the ICC-PCR assays outperformed the plaque assay for virus detection. Virus titers were generally 2->10 fold higher by these assays than by the plaque assay.