Occurrence of coliphages in urban stormwater and their fate in stormwater management systems

AIMS: To investigate the occurrence of coliphages in, and their removal from, urban stormwater. METHODS AND RESULTS: Inflow and outflow concentrations of somatic and f-specific RNA coliphages to two stormwater treatment systems were determined on 21 occasions over a period of 5 months. Somatic coliphages were detected in 19 (90%) of the constructed wetland inlet samples, 13 (62%) of the pond inlet samples, and less frequently at the outlets of the two systems. F-specific RNA coliphages were detected at the inlets but only occasionally at the pond outlet. Somatic coliphages were found to attach preferentially to particles <5 microm in size and persisted in the sediments of the two systems. CONCLUSIONS: Treatment systems providing conditions that are conducive to the settlement of fine particles may effectively remove sediment-bound coliphages and, therefore, possibly enteric viruses from stormwater. SIGNIFICANCE AND IMPACT OF THE STUDY: The results will aid the design of systems for effective removal of viral contaminants from urban stormwater.