A Comparison of Three Types of Compost Materials for the Reduction of Bacterial Pathogens

Abstract

This study compared three compost materials, sand, soil, and stall waste, for their ability to inactivate pathogenic bacteria. For this purpose, a series of mounds were constructed for large-scale testing during the first summer of the project. This was followed by small-scale testing for two winter trials and a second summer trial. In all trials Escherichia coli and Salmonella spp. were used as indicator organisms, either in unison or individually. Large-scale testing showed complete inhibition of indicator organisms in sand compost mounds. Soil and stall compost mounds showed little to no inhibition of coliforms over the course of both trials. In small-scale winter trials, ANOVA testing showed no significant difference between compost types using turbidity to measure bacterial growth. During the small-scale summer trial, stall compost completely inhibited the Salmonella population by day 9; however, by the end of the trial there was no statistically significant difference between compost types.