Enhancing Biodegradation of Glyphosate Using Biofilter System.

Pesticides and other anthropogenic pollutants once introduced into the environment are subject to biological and nonbiological transformations processes. A variety of biological, chemical, and physical methods have been used for degradation and detoxification of pesticides. Conventional clean- up methods are costly and not always effective. Agrichemical storage and handling practices have been targeted as a potential point source contamination of soil and groundwater. Use of “biofilters” to contain and biodegrade pesticides may be a cost-effective alternative. A biofilter is an in-ground treatment unit designed to contain spills of pesticides and degrade the chemicals through microbial activity. Microbial activity may be enhanced by altering conditions conducive to degradation. This objective of this study is to develop a biofilter system that adapts to the soil and environmental conditions of Missouri to treat and dispose of selected pesticide wastes on farm, and gain understanding of biofilter technology.  Four biofilter mixtures consisting of top soil, straw and peat with different mixing ratios were tested in a laboratory scale experiment. Glyphosate was added into biofilter mixtures contained in glass jars. The herbicide-degrading potential of the biofilter substrate mixtures was determined by measuring residual herbicide concentration. Degradation kinetics over 3 months was analyzed. Preliminary results showed that after 3 months, glyphosate concentration and degradation half-life (DT₅₀) was lowest in biomix containing 12.5% straw, 62.5% soil and 25% peat. Future studies include additional degradation experiments and sorption experiments of different herbicides in biofilter materials, identification of microbes in the biofilter, and eventually establishment of an on-farm biofilter.