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Monday, November 2, 2009
Convention Center, Exhibit Hall BC, Second Floor
Abstract:
Bacterial pathogens may survive and persist in environmental media from hours to years. Their re-growth has also been reported in soil, water, and compost due to inadequate pathogen elimination, animal grazing, compost pile turning, contaminated equipment, and re-wetting of carbonaceous media. In soil, bacterial survival tends to be confined to the top 10 cm and is maximized at field capacity, high organic matter content, and neutral pH. Persistence and confinement in soil, however, prevents bacteria from infiltrating media with which humans or animals interact, encouraging inactivation by other means.
Pathogen survival in the environment depends on many factors, of which temperature is primary. Biopiling, however, confers additional inactivation means, such as toxicity from the products of decomposition (e.g. organic acids), and microbial antagonism (e.g. predation, antibiotic production), and competition. As well, the anaerobic biopile environment encourages pathogen degradation due to alkaline pH and the presence of volatile fatty acids, ammonia, and sulphide. Conversely, bacteria may withstand such pressures by generating biofilms or inhabiting protected, non-thermophilic zones that are often available in aggregate compounds. Other factors also play significant roles, such as moisture content and nutrient availability.
In this research, slaughterhouse-residuals were biopiled for disposal and pathogen inactivation purposes. Due to bacterial pathogen resiliency in the environment and their associated health risks, a main objective was to quantify the occurrence and magnitude of indicator bacteria in different media during the biopiling process. The evaluation of indicator bacteria re-growth dynamics, and the effect of biopile turning on their persistence and transport, represented associated objectives. Findings will be highlighted.
Pathogen survival in the environment depends on many factors, of which temperature is primary. Biopiling, however, confers additional inactivation means, such as toxicity from the products of decomposition (e.g. organic acids), and microbial antagonism (e.g. predation, antibiotic production), and competition. As well, the anaerobic biopile environment encourages pathogen degradation due to alkaline pH and the presence of volatile fatty acids, ammonia, and sulphide. Conversely, bacteria may withstand such pressures by generating biofilms or inhabiting protected, non-thermophilic zones that are often available in aggregate compounds. Other factors also play significant roles, such as moisture content and nutrient availability.
In this research, slaughterhouse-residuals were biopiled for disposal and pathogen inactivation purposes. Due to bacterial pathogen resiliency in the environment and their associated health risks, a main objective was to quantify the occurrence and magnitude of indicator bacteria in different media during the biopiling process. The evaluation of indicator bacteria re-growth dynamics, and the effect of biopile turning on their persistence and transport, represented associated objectives. Findings will be highlighted.