Uso de materiais lígneo-celulósicos, como fonte de carbono para bactérias redutoras de sulfato, na remoção de metais pesados

Abstract

When wetlands reach maximum treatment capacity to remove heavy metals, removal can still take place through precipitation as sulphides, due to biological reduction of sulphate. To achieve this goal, anaerobic conditions must be attained, a sulphate source must exist, and an adequate carbon/energy source must be present. In the present work, the seaweed Sargassum filipendula and sugarcane bagasse (ligneous-cellulosic materials) have been selected as carbon sources, due to their high content of slow degradation organic compounds and high availability as waste materials. Experiments were simultaneously conducted in continuous operation in two columns (0.5 L each), one containing the seaweed and/or sugarcane bagasse and another containing the materials inoculated with an anaerobic sludge. In this work, the removal of cadmium and zinc was studied, due to their presence in effluents from mining/metallurgy operations. The rehearsals were accomplished under three different experimental conditions in what refers to the amount of anaerobic mud inoculated in the reactor and employed material as carbon/energy source. The results obtained indicated that the inoculated reactor was able to treat the effluent more efficiently than the non inoculated reactor, considering the time-course of the tests