VERMICULTURE扴 EFFECTIVENESS AS AN ALTERNATIVE TO STANDARD USEPA CLASS A STABILIZATION METHODOLOGIES

摘要

A study was performed by the Orange County Environmental Protection Division torntest the feasibility of vermicomposting as a viable method for obtaining United StatesrnEnvironmental Protection Agency (USEPA) Class A pathogen stabilization in domesticrnwastewater residuals (biosolids). The study was conducted at the City of Ocoee抯rnWastewater Treatment Facility in Ocoee, Florida. The City of Ocoee抯 Class Brnbiosolids were used as the earthworm substrate.rnTwo rows of biosolids were heavily inoculated with USEPA抯 four human-pathogenrn(pathogen) indicators, fecal coliform, Salmonella spp., enteric virus and helminth ova.rnThe row that served as the test was seeded with earthworms, Eisenia foetida. Thernquantity of E. foetida was calculated at a 1:1.5 earthworm biomass to biosolids ratiorn(this is for a 24-hour period) and then adjusted for the amount of days in the testrnperiod.rnThe results of testing indicated that all of the pathogen indicators in the test rowrnrealized a greater reduction than in the control row within 144 hours. In this time, therntest row samples showed a twenty-one fold reduction in fecal coliforms; the controlrnrow only had a five-fold reduction. The test row samples showed a twenty-eight foldrnreduction in Salmonella spp.; the control row had a sixteen-fold reduction. The testrnrow samples showed a fifteen-fold reduction in enteric virus; the control only had arnsix-fold reduction. The test row samples showed a six-fold reduction in helminth ova;rnthe control row only had a one-fold reduction.rnThe USEPA required three to four-fold reduction in the indicator organisms wasrnstatistically obtained. These results suggest that vermicomposting may be used as anrnalternative method for stabilization of Class A biosolids.