15. ENTEROVIRUS REMOVAL BY A FULL - SCALE TERTIARY TREATMENT PLANT

A four-year study in which enteroviruses were monitored at a 56-ML/d (15-mgd) advanced wastewater treatment plant is summarized. The process train included high pH-lime treatment, air stripping, recarbonation, prechlorination, multimedia filtration, granular activated carbon adsorption, reverse osmosis demineralization, and final chlorination. The influent and effluent were sampled on the average of once per week. During this study, viruses were detected twice in chlorinated effluent at very low levels and were associated with operational problems of the final disinfection process. Subsequent dilution by blending and injection of the final effluent into a groundwater aquifer, which resulted in additional dilution and treatment, has produced a water that is essentially free of enteroviruses.