Regeneration of DDT Contaminated Soils by Co-Composting

Application of biotechnology for pesticides elimination through diverse biotransformation, biodegradation or mineralization processes is an important task in agriculture. Among these processes, bioremediation, using living organisms, such as bacteria, fungi, actinomycetes, worms and plants, amended with agricultural residues has shown a high decrease of pesticides, and their derivatives, among other compounds, that affect soil productivity. Bioremediation technologies rely on physical, chemical, geological and biological soil characteristics, as well as on environmental conditions. Depending on the methodology, bioremediation technologies are divided into: Biostimulation (addition of nutrients or appropriate conditions), Bioaugmentation (addition of native or exogenous organisms), Phytoremediation (plant application), Landfarming (nutrients addition); their applications are classified as: Ex-situ, In-situ and On-site. In Mexico more than 50% of these biological technologies are applied in contaminated soils, due to their sustainability. In this work a biological technology, based on "Solid Cultivation On-site", (Mexican Patent No. 291975), using coffee grain and straws, low humidity and aeration, is described for the removal of the organochloride pesticide DDT and their metabolites. The technology was previously tested at commercial scale for hydrocarbons removal, creating a suitable soil for recreational use. Other applications of the mentioned biological technology were on soils for bean, pumpkin and corn crops, which resulted in high quality products.