|Abit jr, Sergio|
|Peng, Huazhong, cai|
Submitted to: Environmental Science and Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/28/2012
Publication Date: 6/28/2012
Citation: Abit Jr, S.M., Bolster, C.H., Peng, H., Walker, S. 2012. Influence of feedstock and pyrolysis temperature of biochar amendments on transport of Escherichia coli in saturated and unsaturated soil. Environmental Science and Technology. 46:8097-8105. Interpretive Summary: Biochar is a charcoal-like material generated by the thermal degradation of organic matter in the absence of air, a process referred to as pyrolysis. Given its high carbon content and its recalcitrant nature, there has been much interest in using biochar to sequester carbon from the atmosphere by incorporating it into soils. Moreover, given its ability to sorb various contaminants, biochar is seen as potential soil amendment for reducing environmental pollution. In this study we evaluated whether biochar amendments can affect E. coli retention in soil. We compared transport behavior of E. coli through soils amended with biochar produced from two feedstocks (poultry litter and pine chips) and pyrolyzed at two temperatures (350 and 700 'C). Biochar addition significantly affected the retention and transport behavior of two E. coli isolates through our sandy soil. In general, biochar addition resulted in large reductions in the amount of E. coli leached from our soil suggesting that biochar addition to soils may help reduce groundwater contamination from pathogenic microorganisms.
Technical Abstract: Recent research has shown that biochar amendment could enhance bacterial retention in soils. We evaluated the effects of biochar feedstock, pyrolysis temperature and application rate on soil retention of Escherichia coli. We compared how biochar produced from poultry litter and pine chip pyrolyzed at 350'C and 700'C affects bacterial transport through a water-saturated and partially saturated (~50% saturated) fine sand when applied at rates of 1 and 2 % (w/w). Biochar addition significantly affected the retention and transport behavior of two E. coli isolates through a sandy soil. A higher rate of biochar application and use of biochar pyrolyzed at 700oC reduced bacterial fractional recoveries (fr). Pine chip biochars proved more effective –reducing fr by up to 5 orders-of-magnitude. Addition of poultry litter biochar pyrolyzed at 700oC also significantly reduced fr while that pyrolyzed at 350oC enhanced transport. Bacterial surface properties influenced transport and de-saturation generally reduced fr.