BIOLIXIVIACION DE METALES DE SEDIMENTOS ANAEROBICOS DEL RIO RECONQUISTA (ARGENTINA) COMO ESTRATEGIA POTENCIAL DE REMEDIACIÓN

NATALIA PORZIONATO; ROBERTO CANDAL; GUSTAVO CURUTCHET

Ciudad de Mexico

Simposio; International Symposium on Environmental Biotechnology and Engeeniering; 2014

CINVESTAV

Anaerobic sediments of watercourses which are subject to industrial pollution have a tendency to accumulate contaminants, mainly heavy metals. In oxidizing conditions, generated by dredging or rainfall, the accumulated metals mobilize to the water column with a negative impact on the ecosystem. The biocatalyzed oxidation and reduction of sulphur compounds in the sediment are the key reactions that lead to this solubilization. These bioprocesses of mobilization and inmobilization of metals are the same as those that could be used for remediation of heavily contaminated sediments. The aim of this work was to study the application of bioheaps leaching as a strategy for the remediation of anaerobic contaminated sediment of the Reconquista River basin, and to evaluate the effect of adding different concentrations of elementary sulphur on the mobility of metals from the bioheap to the aqueous solution. The potential for remediation by bioleaching was demonstrated through bioheap tests of containing 100 g of anaerobic sediment with 340 mg Kg-1of zinc and 116 mg Kg-1 of cooper. The system was compiled into columns of 6 cm high and 21 cm diameter, using perlita to improve drainage, and adding increasing concentrations of elementary sulphur (1%, 2%, 5% w/w) to achieve an increased level of acidification. After 3 months of acidification generated by periodic watering, extraction of 70% of the initial Zn and 43% of the initial copper was achieved with the addition on the surface of the bioheap of 5% w/w of elementary sulphur. Furthermore, we succeeded in enriching, isolating and identifying the bacterial strains responsible for the mobilization-immobilization processes of metals from sediment. We conclude that, given the feasibility of acid drainage, which the consequential increasing of bioavailable and dangerous metals in oxidizing conditions, it should not be indiscriminately manipulate the sediments from polluted watercourses as Reconquista River, being possible to carry out its remediation by a simple and economically viable manner using bioheaps leaching.