Airborne coliphages from wastewater treatment facilities

Abstract

The emission (from wastewater treatment plants) of airborne coliphages that form plaques on two strains ofEscherichia coli was investigated. Two activatedsludge and two trickling-filter plants were studied. Field sampling procedures used large-volume air samplers with recirculation devices. Coliphages were enumerated by a most-probable-number (MPN) procedure. Temperature, relative humidity, windspeed, and presence of sunlight were monitored. Concurrent samples of sewage were taken during each air-sampling run. Average coliphage levels in the airborne emissions of trickling-filter beds and activated-sludge units were 2.84 x 10-l and 3.02 x 10-' MPN/m3, respectively, for all positive observations, and sewage liquor concentrations from the sources were 4.48 x 105 and 2.94 x 106 plaque-forming units/liter, respectively, depending upon the E. coli host used for assay. This work establishes minimal airborne-coliphage concentrations from the plants studied. The procedures employed will be useful in evaluating the animal virus levels in these emissions.

Animal viruses, coliphages, and bacteria in aerosols and wastewater at a spray irrigation site

“…All three types of bacterial hosts were found to be susceptible to the coliphages in all raw influent wastewater samples, but the concentrations of phages detected decreased in the lagoon and pump station samples ( Table 2). The raw wastewater E. coli ATCC 15597 (C-3000) coliphage levels, ranging from 4.9 x 104 to 1.32 x 105 PFU/liter, were similar to those obtained at trickling-filter and activated-sludge treatment facilities by Fannin et al (20). In general, the number of E. coli ATCC 13706 coliphage in Muskegon wastewater samples equalled or exceeded the number of E. coli ATCC 15597 coliphage, and both were greater than the number of E. coli ATCC 11303 coliphage.…”

“…(ii) MPN method. For assay by the most-probable-number (MPN) method, a portion (.170 ml) of the liquid sample of ELH containing the collected aerosol particles was syringe filtered through a 10% beef extract (pH 7.0)-pretreated 0.45-pum membrane filter and assayed as described by Kott (28) and Fannin et al (20), using all three E. coli hosts. The E. coli ATCC 13706 and ATCC 11303 cultures were grown in Trypticase soy broth (BBL), and the E. coli ATCC 15597 culture was grown in tryptone broth with 0.22 g of CaCl2 per liter (32).…”

“…For each set of inoculated sample tubes, two seeded bacterial lawns were prepared for each of the hosts on phage assay base agar plates (20). Each lawn was prepared and inoculated by the procedure described by Fannin et al (20). Positive results, indicated by clear zones of bacterial lysis in the areas receiving the sample, were compared with the MPN table (5) to determine the MPN/100 ml of sample.…”

Methods for Sampling of Airborne Viruses

“…LVS have also been used in other circumstances to recover low concentra-VOL. 72,2008 SAMPLING OF AIRBORNE VIRUSES 439 on April 30, 2020 by guest http://mmbr.asm.org/ tions of airborne adenoviruses and picornaviruses (12,13,38,40,51,77,94,97,121,144). These samplers are commonly used with a preimpactor attached to the air inlet to capture particles of over 15 m in diameter.…”

“…Simply flushing a toilet containing infectious particles can aerosolize significant concentrations of airborne viruses (14,136). Wastewater treatment plants (24,51) and sewage sprinklers (97,125) can also produce viral aerosols. Farm animals have also been studied for their emission of airborne viruses.…”