Paper Title
Packed-Bed Column with an Immobilized Bacteria Consortium for Pesticide-Containing Wastewater Treatment

Abstract
Pesticide-containing wastewater generated in agroindustrial postharvest activities, like fruits processing or equipment washing, represents an environmental problem, when they are disposed without previous treatment. Considering the complexity of these toxic molecules, new and efficient alternatives for pesticides degradation are necessary. In this context, we evaluated encapsulated bacteria strains for degradation of a mixture of the pesticides atrazine (ATZ), chlorpyrifos (CHL) and iprodione (IPR) in a continuous system. Selected strains (C1 and C4) were obtained from a biopurification system (BPS) used during the last three years to treat a mixture of the above-mentioned pesticides and, were individually encapsulated in alginate beads. Glass columns (10x4 cm) packed with the immobilized consortium (15% w•v-1 each strain) were feed at flow rates of 0.5 and 1 mL•min-1 with a pesticide mixture (ATZ, IPR, and CHL) at a concentration of 50 mg•L-1 and were operated for 120 h. Samples from each treatment were taken periodically and pesticides and metabolites were analyzed by HPLC. The main results showed high degradation capacity of the bacteria consortium for the three pesticides. The different flow rates did not influence degradation capacity in the continuous mode and, high degradation of ATZ (74.92%), IPR (99.13%) and CHL (81.86%) was observed during the columns operation. Also, a decreased half-life time and an increase of pesticide dissipation rate were observed. Therefore, an adequate design for pesticide-containing wastewater treatment using adapted microorganisms to high pesticides concentration will allow decrease environmental contamination and toxicology effects by pesticides. Keywords - Packed-Bed Column, Bacteria Consortium, Pesticide-Containing Wastewater, Treatment