Full Description

The identification and quantification of pathogens in raw and treated wastewater is important formonitoring the efficiency of treatment processes. An assessment of the efficacy of wastewatertreatment also has implications for influent water quality for drinking water operations. Treatedwastewater effluent may harbor infectious pathogenic microorganisms such as enteroviruses,Cryptosporidium and Giardia even after standardized treatment processes. The development ofmethods to recover Cryptosporidium, Giardia, and enteroviruses from sewage have not been wellestablished. Consequently, detailed investigations of the impact of treated sewage on surface waterhave not been reported. In this study, ultrafiltration and immunomagnetic separation (IMS)methodologies were optimized to determine and quantify the presence of the target organisms in raw(influent) and treated sewage at three wastewater treatment facilities: Las Cruces, New Mexico; El Paso, Texas;and, Juarez, Mexico. One liter influent grab samples were centrifuged and the pellets were processed byIMS and indirect fluorescent antibody (IFA) for Cryptosporidium and Giardia and the supernatant wasprocessed by ultrafiltration for phage. Raw sewage seeded recoveries of Cryptosporidium and Giardiaranged from 42-81% (SD 3-10) and 27-53% (SD 6-10), respectively (n=3 for each site). The recoveryfor endogenous phage in raw sewage ranged from 32-50% (SD 10-45) (n=2-4 for each site). Ten litereffluent grab samples were concentrated by ultrafiltration and the pellets were processed by IMS andIFA for Cryptosporidium and Giardia and the supernatant was further concentrated by spin columnfor phage. Three replicate challenges were done for each site and recoveries of Cryptosporidium andGiardia ranged from 12-25% (SD 4-14) and 1-30% (SD 0.5-21), respectively. Results from this studywill help evaluate the impact that treated wastewater may have on pathogen loads in environmentalwaters. Includes 23 references, tables, figures.

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Edition: Vol. - No. Published: 11/15/2004 Number of Pages: 14File Size: 1 file , 300 KB