DETECTION OF INFECTIOUS ADENOVIRUS IN TERTIARY TREATED AND UV DISINFECTED WASTEWATER DURING A UV DISINFECTION PILOT STUDY

A pilot study investigating the efficacy of low pressure, high intensity ultraviolet (UV) radiation for disinfection of urban wastewater was conducted. The pilot study utilized a small-scale version of the Ultra Guard UV treatment system provided by UV Systems Technology, Inc. (Burnaby, Canada). The primary objective was to determine whether low pressure, high intensity UV irradiation could potentially be used to meet the California Water Reclamation Criteria (CWRC) for total coliform bacteria in reclaimed water and to determine its potential for a 99.99% reduction of two model enteric viruses(MS2 coliphage and poliovirus). UV pilot unit inactivation of the total and fecal coliform bacteria, sewage indigenous F-specific coliphage, seeded F-specific coliphage (MS2), sewage indigenous enteric viruses, and seeded poliovirus type I in tertiary treated wastewater was investigated. During the course of the pilot study, an infectious adenovirus was isolated from UV disinfected tertiary and secondary treated wastewater. The virus was detected in 15 of 16 experiments involving large volume (352-697 L)sampling and analysis for indigenous enteric viruses and seeded poliovirus. The adenovirus was identified via electron microscopy and enzyme immunoassay after isolation using traditional cell culture based methods. Tertiary treated samples in which the adenovirus was detected received calculated UV doses in the range of 34-71 mW-sec/cm2. Turbidity and total coliform bacteria levels in these samples were within the CWRC standards of