Comparison of bacteriophage and enteric virus removal in pilot scale activated sludge plants

Abstract

Aims:The aim of this experimental study was to determine comparatively the removal of two types of bacteriophages, a somatic coliphage and an F-specific RNA phage and of three types of enteric viruses, hepatitis A virus (HAV), poliovirus and rotavirus during sewage treatment by activated sludge using laboratory pilot plants. Methods and Results:The cultivable simian rotavirus SA11, the HAV HM 175/18f cytopathic strain and poliovirus were quantified by cell culture. The bacteriophages were quantified by plaque formation on the host bacterium in agar medium. In each experiment, two pilots simulating full-scale activated sludge plants were inoculated with viruses at known concentrations, and mixed liquor and effluent samples were analysed regularly. In the mixed liquor, liquid and solid fractions were analysed separately. The viral behaviour in both the liquid and solid phases was similar between pilots of each experiment. Viral concentrations decreased rapidly following viral injection in the pilots. Ten minutes after the injections, viral concentrations in the liquid phase had decreased from 1AE0 ± 0AE4 log to 2AE2 ± 0AE3 log. Poliovirus and HAV were predominantly adsorbed on the solid matters of the mixed liquor while rotavirus was not detectable in the solid phase. In our model, the estimated mean log viral reductions after 3-day experiment were 9AE2 ± 0AE4 for rotavirus, 6AE6 ± 2AE4 for poliovirus, 5AE9 ± 3AE5 for HAV, 3AE2 ± 1AE2 for MS2 and 2AE3 ± 0AE5 for UX174. Significance and Impact of the Study: This study demonstrates that the pilots are useful models to assess the removal of infectious enteric viruses and bacteriophages by activated sludge treatment. Our results show the efficacy of the activated sludge treatment on the five viruses and suggest that coliphages could be an acceptable indicator of viral removal in this treatment system.

Seasonal Detection of Human Viruses and Coliphage in Newport Bay, California

“…Coliphage was suggested as a better indicator for human virus because it shares decay characteristics that are similar to those of human viruses (1,2,11,22). Several studies, including our own study of the southern California coast, showed a correlation between coliphage and PCR-detectable human viral genome (16).…”

“…1). The principle tributary of Newport Bay is San Diego Creek, which accounts for 122 square miles (316 km 2 ), or about 80%, of the Newport Bay watershed. Other drainage areas include the Santa Ana-Delhi Channel, the Big Canyon Wash, and some additional small tributaries.…”

“…Therefore, viral contamination of recreational coastal water is of particular importance and is a rising public health concern. Fϩ coliphage was recently proposed by the U.S. EPA as a surrogate for human viral contamination in groundwater because some groups of Fϩ coliphage resemble human polioviruses and other enteric viruses in terms of survival and morphology (1)(2)(3)22). Fϩ coliphage are most prevalent in human sewage but may not be present in individual human feces.…”

An epidemiological study of enteric viruses in sewage with molecular characterization by RT-PCR and sequence analysis

“…The titre of poliovirus was determined by plaque assay in BGM cells as previously described (Arraj et al 2005).…”

Bacteriophage removal in a full-scale membrane bioreactor (MBR) – Implications for wastewater reuse

“…A range of studies, performed at both pilot-scale and within full-scale municipal wastewater plants, have demonstrated that microbial removal in MBR systems is more effective than in conventional activated sludge treatment systems (Arraj et al, 2005;Ottoson et al, 2006;Francy et al, 2012;Marti et al, 2011). Further, MBR systems have been shown to remove microorganisms that are greater in size than the membrane filter pores.…”