Influence of Biochar Feedstock On Transport of Pathogenic Bacteria in Unsaturated Biochar-Amended Soil.

Recent studies have shown that biochar amendment influences bacterial transport in soils. In this study,the effect of biochar feedstock on the transport of pathogenic bacteria through fine sand under partially saturated conditions was investigated in column experiments. Biochars produced from four feed stocks including pine chips, sun hemp, dairy manure and swine manure  that were pyrolyzed at 700°C were separately added to fine sand (2% w/w) and packed in cylindrical columns. Transport of Escherichia coli O157:H7, Salmonella typhimurium, Enterococcus faecalis and Listeria monocytogenes were evaluated in separate partially-saturated columns. All four biochars significantly increased the retention of all bacteria tested with up to 100% of applied bacteria retained in the porous media. Their degree of effectiveness, however, was observed to vary  among bacterial species with highest retention observed for  L. monocytogenes.