F-specific RNA bacteriophage strain aerosols cell culture chlorination fecal source tracking fecal-source marker index virus infectivity microbial contamination molecular methods next-generation sequencing oyster pathogenic microorganisms pathogenic virus real-time PCR reuse rotavirus sewage tanker water ultraviolet disinfection viral contamination viral indicator virus wastewater wastewater reclamation wastewater treatment waterborne gastroenteritis viruses