Culturable enteroviruses were detected by applying concentration techniques and by inoculating the concentrates on the BGM cell line. Samples were obtained from a wide variety of environments, including raw sewage, secondary effluent, coagulated effluent, chlorinated and UV-irradiated effluents, river water, coagulated river water, and lake water. The virus concentrations varied widely between 0.001 and 570/liter. The same cell line also supported growth of reoviruses, which were abundant in winter (up to 95% of the viruses detected) and scarce in summer (less than 15%). The concentrations of three groups of model organisms in relation to virus concentrations were also studied. The concentrations of bacteria (thermotolerant coliforms and fecal streptococci) were significantly correlated with virus concentrations in river water and coagulated secondary effluent, but were relatively low in disinfected effluents and relatively high in surface water open to nonhuman fecal pollution. The concentrations of F-specific RNA bacteriophages (FRNA phages) were highly correlated with virus concentrations in all environments studied except raw and biologically treated sewage. Numerical relationships were consistent over the whole range of environments; the regression equations for FRNA phages on viruses in river water and lake water were statistically equivalent. These relationships support the possibility that enteric virus concentrations can be predicted from FRNA phage data.

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F-specific RNA (FRNA) bacteriophages can be assayed in wastewater by simple and rapid methods. Their inactivation by UV radiation follows first-order kinetics and relatively simple formulas can describe the effect of UV absorbance by wastewater and the wavelength-dependent killing efficiency of polychromatic lamps. Because the organisms can be grown in high concentrations, biological calibration of full-scale reactors requires only relatively small volumes of phage culture. Naturally occurring FRNA-phages were more resistant to UV than somatic coliphages, Escherichiacoli and faecal streptococci. The inactivation rate constant was almost equal to that of reoviruses, which underlines the suitability of FRNA-phages as a process indicator for UV inactivation of viruses. A pure culture of MS2 was inactivated at a rate which was almost twice that of naturally occurring FRNA-phages, indicating the necessity of designing reactors for practical applications on field-data rather than laboratory experiments.

Risk-based evaluations of the hygienic quality of drinking water require accurate data on removal and inactivation of pathogens by different steps of the treatment chain. The continuing trend to reduce chemical disinfection leads to an increased interest in the effect of other processes, based on physical removal or biological inactivation. This study reports data on the removal and inactivation of entero- and reoviruses by three such processes. For comparison, data on a variety of model organisms are also reported. All studies were carried out in the winter period because the concentration of viruses is then at its maximum, and the reducing capacities of the processes are at their minima. Storage in three reservoirs in series (average detention time 7 months) reduced the concentration of enteroviruses by a factor of 400-1,000, river bank filtration was highly effective, reducing enteroviruses by a factor of at least 10,000. The effect of coagulation/flocculation/sedimentation/filtration processes was highly variable, and was better when rapid sand filtration was included. The removal of F-specific RNA bacteriophages most closely followed that of viruses in these three processes.