Increasing concern exists within the EU countries about the pollution of surface waters and groundwater due to point-source release of pesticides. This is because most farms have a centralized location to fill spray tanks with agrochemicals and to flush and clean application equipment. These sites, depending on the frequency of use, represent therefore a significant sources of contamination. One approach to minimize this pollution is to install a simple and low-cost biological treatment system consisting in a filtering layered bed, the so-called biobed, where toxic chemicals are bound along its profile and degraded by microbial metabolism. A biobed consists in a lined pit in the ground, usually 60 to 150 cm deep, filled by a mixture of topsoil, peat, and straw or other organic matrices that creates an environment whereby the maximum sorption of pesticides is achieved while maintaining their bioavailability and the most favorable conditions for microbial decomposition. Biobeds originated and have been used extensively in Sweden. They have been shown to effectively retain and degrade pesticide residues arising from spillages of concentrate or diluted formulations of the active substances. The aim of this project is to perfect a protocol for the construction of high-efficiency biobeds allowing the exploitation of specific microbial catalysts, sized according to the main recurrent contaminats to be treated in different circumstances, that are left adhering as continuous biofilm on needle felts made with 100% coconut husk fibers refractory to a rapid biological decay. Coconut coir is an agricultural waste obtained from the fibrous mesocarp layer of the Cocos nucifera L. fruit. It contains 38% cellulose, 28 % hemicellulose and 32.8% lignin, and possesses a sligthly sub-acidic pH of 5.2-6.3 conducive of both fungal and bacterial growth. Moreover, the high lignin content gives the coconut coir a great adsorptive capacity toward organic substances such as pesticide residues.
