Investigation of the Presence of Adenoviruses and Enteroviruses in Effluent of Municipal Wastewater Treatment Plants

Municipal wastewater contains a variety of pollutants and pathogenic microorganisms. Although a high fraction of photogenic microorganisms is removed during wastewater treatment processes, viruses are not efficiently removed by the processes and wastewater effluents may be a potential source for dissemination of viruses in the environment. This study was conducted to investigate the presence of two important enteric viruses, adenoviruses and enteroviruses, in the effluent of wastewater treatment plants. In this study, 30 wastewater effluent samples were taken from two activated sludge municipal wastewater treatment plants. Investigation of the presence of adenoviruses was performed using a molecular method (PCR) and the concentration of enteroviruses was measured with the standard cell culture method. The concentration of bacterial indicators (total and fecal coliforms) was also determined by the multiple tube fermentation technique. Adenoviruses and enteroviruses were detected in 87% and 40% of effluent samples, respectively. The mean concentration of enteroviruses was 12 and 16 pfu/ml for wastewater treatment plant 1 and 2, respectively. Statistical analysis showed no significant relationship between the concentration of bacterial indicators and viruses. The results of the study showed high viral contamination of effluent samples. The findings also showed that fecal coliforms are not the suitable indicator for viral contamination of wastewater effluent. Regarding to the viral contamination of effluent, discharge of wastewater effluents to the environment or agricultural reuse of wastewater may be a potential route for dissemination of viral infections in the community.