ABSTRACT
Several advanced wastewater treatment processes are particularly effective for removing viruses which pass conventional secondary treatment. Proper operation of conventional secondary wastewater treatment facilities, including effective disinfection, provides the most practicable virus removal scheme for the majority of municipalities. Most modern conventional wastewater treatment processes employ some form of activated sludge for secondary treatment. Wastewater conveyed to a treatment facility comes from households and industries. Conventional wastewater treatment facilities are designed to reduce the amount of organic material and suspended material discharged to natural waters. Most conventional wastewater treatment facilities consist of some preliminary processes such as pumping, screening, and grit removal. The activated sludge process is effective for the removal of large numbers of viruses from the liquid portion of wastewater. Viruses are concentrated in the sludges or concentrates of the waste streams of most advanced wastewater treatment processes such as coagulation, filtration, and reverse osmosis or ultrafiltration.
