Integrated Approach to Problem of Viruses in Water

Large numbers of viruses enter water intakes daily. The inability of epidemiologists to detect waterborne transmission may be the result of preoccupation with disease rather than infection in index cases. Efficient procedures are available for recovering viruses from sewage and effluents (aluminum hydroxide-protamine sulfate and phase separation), and from large volumes of clean waters containing salt (cellulose nitrate membrane filtration), but the best technique available for large volumes of raw water (polyelectrolyte PE60-filtration-silt elution) is not efficient. Most treatment procedures remove viruses from sewage and from raw waters, but complete removal depends upon terminal disinfection. The choice of water disinfectant depends in part upon the chemical quality of the water to be treated, and upon the toxicity to aquatic life of the disinfectant and the products it forms in water.