Detection of Enteroviruses in Biosolids

There are high numbers of human pathogenic microorganisms existing in municipal sewage sludge including bacteria، viruses، and protozoan parasites. Therefore، biosolids could be considered as the environmental contaminants and a major carrier of disease causing diseases. As the etiological agents of acute gastroenteritis and hepatitis، enteroviruses are one of the most significant enteric pathogens affecting human health. The aim of this research was to detect the enteroviruses in the sludge of two wastewater treatment plants (WWTP) in Isfahan، Iran.

In this study، 30 biosolid samples were taken from two WWTPs. After measuring the temperature، the samples were transported to the laboratory and analyzed for total solids (TS)، volatile solids (VS) and enteroviruses according to the test methods of Standard Methods (part 9510F) and manual of Control of Pathogens and Vector Attraction in Sewage Sludge from Environmental Protection Agency (EPA) appendix F.

Average temperature of the samples was about 23° C. The average number of enteroviruses was 4. 5 × 106 and 7. 7 × 105 plaque-forming unit (PFU) in 4 grams sludge for two WWTPs، respectively. The statistical analysis revealed a significant association between the enteroviruses and volatile solids. The number of enteroviruses was higher in summer in comparison to autumn.

The results showed that all the biosolid samples could not meet the Class A pathogen requirements for enteroviruses and poses a potential health risk for people exposed to. Therefore، restrictions in land application of biosolids are required in order to protect public health and the environment. Moreover، special biosolid treatment procedures must be used to reduce pathogens and to meet land-application standards.