Bacterial Pathogen Occurrence and Persistence in Livestock Mortality Biopiles

Abstract

Abstract:Properly managed biopiles can be used for slaughterhouse-residual degradation and bacterial pathogen inactivation, which otherwise represent a major health risk in the environment. Biopiles were used to dispose of slaughterhouse-residuals and determine the occurrence and persistence patterns of indicators of pathogenic bacteria. The indicator bacteria included the family Enterobacteriaceae, total coliforms, Escherichia coli, nalidixic acid-resistant E. coli, and Streptococcus fecalis. The slaughterhouse-residual biopiles remained static for 164 d in 2006 and 141 d in 2007. In biopile effluent samples, exponentially decreasing populations of the indicator bacteria were observed. Indicator bacteria presence in biopile and soil samples suggested their retention and persistence in, but not migration from, the media. Though the family Enterobacteriaceae, total coliforms, and Escherichia coli shared behavioral correlations, they exhibited different fates in all media compared to S. fecalis, which was observed to persist and re-grow. The behavior of inoculated nalidixic acid-resistant E. coli suggested that inactivation was the primary process in the biopiles. However, the biopiles constituted continual sources of the indicator bacteria due to their persistence in isolated and protected locations, and changes in dominant species. While biopiling slaughterhouse-residuals was effective to inactivate >99% (log reductions) of indicator bacteria, tertiary methods and biopiling phases should be employed to ensure inactivation of pathogenic bacteria in animal waste biopiles. The fate of bacterial indicators in this system exhibited trends not-as-yet observed for animal waste biopiling activities, which generates numerous questions for further research.

Effect of Cornstalk Biochar Immobilized Bacteria on Ammonia Reduction in Laying Hen Manure Composting

“…The trends of temperature in each group were similar, and all experienced three processes: A rising temperature period (0-3 days), a high temperature period (3-9 days), and a cooling and decomposing period (9-15 days). The reactor temperature exceeded 50 °C during the whole high temperature period, consistent with the "Sanitation Health Standards" (GB7959-87) requirements [33]. The highest composting temperatures in the control treatment, cornstalk biochar group, free load group, mixed load group, and separate load group were 55.2 ± 3.5, 54.6 ± 0.6, 54.7 ± 3.7, 53.6 ± 1.4, and 54.1 ± 1.5 °C, respectively, while the temperature of each group was not significantly different (p > 0.05).…”