Detection of Infectious Adenovirus in Tertiary Treated and Uv Disinfected Wastewater During a Uv Disinfection Pilot Study

Abstract

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 WEFTEC 2000 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 mWsec/cm 2 . Turbidity and total coliform bacteria levels in these samples were within the CWRC standards of <2 NTU and no greater than 23 MPN/100 mL for a single sample (30 d sampling period), respectively. Overall, total coliform bacteria were effectively removed from UV disinfected tertiary effluent indicating that low pressure, high intensity UV irradiation could potentially be used to meet the stringent CWRC. Seven-day total coliform median values were not determined from the pilot unit data, however, a conservative estimate suggests that a dose of approximately 60 mW-sec/cm 2 would be sufficient to meet the 7-d median concentration of no more than 2.2 MPN/100 mL for the last 7 samples taken. A 4-log 10 removal of seeded MS2 and indigenous F-specific coliphage in the pilot unit experiments (tertiary effluent) was achieved at doses of 70 and 50 mW-sec/cm 2 , respectively. The seeded poliovirus was not detected in UV treated secondary or tertiary effluents, however, problems with the concentration protocol prevented documentation of a specific 4-log 10 removal of the virus. Comparative collimated UV irradiation studies indicated that the isolated adenovirus was more UV resistant than MS2 coliphage and poliovirus type I. Doses of approximately 33, 112, and 183 mW-sec/cm 2 were required to achieve a 4-log 10 removal of poliovirus, MS2, and the isolated adenovirus, respectively. These findings indicate that UV doses found to be effective at meeting the stringent CWRC total coliform standards may not provide suitable reduction of some naturally occurring pathogenic viruses such as adenovirus...

Detection of Infectious Human Adenoviruses in Tertiary‐Treated and Ultraviolet‐Disinfected Wastewater

“…The MS2 coliphage, a male-specific RNA phage, was studied in both the pilot-unit and collimated UV experiments. This phage (ATCC, 15597-B1, American Type Culture Collection, Manassas, Virginia) was propagated in liquid culture using an enrichment method previously described (Thompson et al, 2000;Yanko et al, 1999). The stock cultures used ranged in concentration from 10 9 to 10 10 plaque-forming units (PFU)/mL as determined using the double-agar layer method (Adams, 1959) with Escherichia coli HS(pFamp)R (Debartolomeis and Cabelli, 1991) as the host bacteria.…”

“…During the seeded MS2 pilot-study experiments, grab samples (0.1 to 1.0 L) were taken before and after UV disinfection. Analysis of the pilot-study samples was done using a modified most probable number of infectious units (MPNIU) enrichment method (Kott, 1966;Thompson et al, 2000;Yanko et al, 1999), with E. coli HS(pFamp)R as the host bacteria.…”

UV disinfection costs FOR INACTIVATING Cryptosporidium

“…Compiled data on UV dose and corresponding inactivation of Cryptosporidium indicate that 40 mJ/cm 2 is a conservative UV dose that will achieve a minimum of 2‐log inactivation (Bukhari et al, 1999). A dose of 140 mJ/cm 2 will achieve at least 2‐log inactivation of most viruses (Meng & Gerba, 1996; Thompson et al, 2000).…”

Membrane Bioreactor (MBR) Piloting at a Water Reclamation Plant in Los Angeles County

“…Details of the analytical procedure for hormones may be found in Vanderford et al (2003). Indigenous coliphage was analyzed by the Districts' laboratory using methods described in the literature (Kott, 1966;Yanko et al, 1999;and Thompson et al, 2000). All other water quality parameters measured in this study were analyzed in accordance with Standard Methods (APHA et al, 1992) or by EPA approved methods.…”