No abstract

Bench-scale experiments determined the inactivation rates of adenovirus serotype 2 with low-pressure, high-output ultraviolet (UV) light, chlorine (Cl 2 ), and preformed chloramines.Studies with sequential chloramines were also done to mimic water treatment practices. Sequential experiments with adenovirus serotype 2 suspended in laboratory-grade water and natural waters containing ammonia were exposed to either UV light followed by Cl 2 /chloramines or the reverse sequence. Adenovirus log reductions were quantified through cell culture techniques. A free Cl 2 C × T (concentration × time) of 1.22 mg-min/L resulted in a 3.72-log reduction, a preformed chloramine C × T of 264.5 mg-min/L resulted in a 1.2-log reduction, a sequential chloramine C × T of 40.5 mg-min/L resulted in a 1-log reduction, and a UV dose of 40 mJ/cm 2 resulted in a 1-log reduction. Up to 4-log reductions were achieved with a UV dose of 40 mJ/cm 2 followed by a sequential chloramine C × T of 27.2 mg-min/L. This suggests that sequential disinfection may be the best option for dealing with UV-resistant organisms such as adenoviruses.

We evaluated a two-step enrichment procedure to detect coliphages and an integrated cell culture-nested polymerase chain reaction (ICC-nPCR) to detect human astrovirus, enteroviruses, rotavirus and adenovirus type 40 and 41 in marine water samples collected by the Massachusetts Water Resource Authority (MWRA). MWRA has been monitoring its receiving waters for coliphages, anthropogenic viruses and indicator bacteria in order to evaluate the impact of Boston's Deer Island Sewage Treatment Plant discharge. Coliphages and enteric viruses were originally assayed using single agar overlay and most probable number cell culture (MPN) methods, respectively. Reanalysis of these samples for enteric viruses by ICC-nPCR demonstrated that 46% were positive for at least one virus compared with 23% with the MPN method. Use of the enrichment method showed a 47% increase in the detection of male specific and somatic coliphages compared with the single agar overlay method. Correlations between the presence of coliphages, enteric viruses and indicator bacteria were based on proximity to the treatment plant discharge, seasonal variations and site levels. The presence of enteric viruses was significantly correlated to coliphages but not to indicator bacteria. Preliminary comparative results demonstrate that effective and efficient monitoring of anthropogenic contamination can be achieved using these more sensitive and specific techniques.

The work presented here demonstrates the utility of the integrated cell culture‐reverse transcriptase ‐polymerase chain reaction (ICC‐RT‐PCR) coupled with nested PCR to detect human astroviruses and enteroviruses in sludge biosolids. Viruses were concentrated by beef extract elution and organic flocculation prior to analysis by a plaque assay and ICC‐RT‐PCR. Astroviruses were detected in all but one sample and all of the samples were positive for enteroviruses. We have demonstrated the prevalence and frequency of astrovirus in sludge and validated the ICC‐RT‐PCR/nested PCR technique as a useful tool to detect viruses in sludge.