Pesticide removal from waste spray-tank water by organoclay adsorption after field application; an approach for a formulation of cyprodinil containing antifoaming/defoaming agents

Purpose Many studies report depuration data of water containing pesticides based on study performed using active ingredients. Nevertheless, the major part of the commercial formulations contains additives/adjuvant or are manufactured with the technology of microencapsulation which may influence the depuration processes. Therefore the main objective of this work was to develop and test a pilot scheme for decontaminating water containing pesticides, for substances formulated with antifoaming/defoaming agents. Methods The Freundlich adsorption coefficients of formulation of new generation fungicide cyprodinil onto the organoclay Cloisite 20 A have been determinate, in laboratory, in order to predict the efficiency of this organoclay on removing the fungicide from the waste spray-tank water. Subsequently, the adsorption tests were repeated in the pilot system in order to test the practical operation of the depuration scheme. Results The results obtained from the laboratory adsorption tests have been successfully confirmed by the results in the adsorption tests with the pilot system, with a removal of cyprodinil higher than 96% over a few hours. The passing of the organoclay - cyprodinil suspension trough a layer of biomass has shown a 100 % recover of the organoclay at the surface of the biomass in one week. Regarding the waste disposal, for instance the organoclay composted after the treatment, cyprodinil doesn’t show any significant dissipation after 90 days. Conclusion The depuration scheme developed showed to be efficient for decontaminating water containing pesticides, for substances formulated with antifoaming/defoaming agents, but additional treatments for the adsorbed residues still appear to be necessary even for moderate persistent pesticide as cyprodinil. Furthermore, a significant conclusion of this study concerns the high influence of pesticides formulation on the decontamination process of water containing these compounds, which should be taken into account for the development of innovative decontamination systems, especially for practical applications.