In the present study, the BCR (Community Bureau of Reference) sequential procedure has been applied to determine the zinc partition in sediments taken from a river situated in the Southwest of Romania, in a region subject of intense mining activities. The sampling was performed during three sampling expeditions, organized in the spring, summer, and autumn, 2007. The zinc concentration in different fractions was normalized, its concentration being related to the concentrations of some metals (such as Al or Fe) that are naturally present in sediments. The zinc-contaminated sediments from the investigated area have been evaluated by means of combining the analysis data from the BCR sequential extraction with the normalization to the Al content. The most important zinc collector in the samples taken during the three sampling expeditions is the easily soluble fraction, next being amorphous iron and manganese hydrated oxides fraction, followed by organic matter fraction.
A two-stage aerobic Sequencing Batch Reactor system (SBR) designed and constructed by INCD-ECOIND�s specialists was used for treatment of the wastewater discharged from drugs fabrication (conditioning operations), with variable concentrations of organic load: COD = 1200-3300 mg O2/L, BOD5 = 490-1570 mg O2/L. After acclimation period, the 1st stage and 2nd stage SBRs were able to achieve COD and BOD removal, with global efficiencies ranging from 63-97% and 82-99% respectively (HRT = 9 h). The effluent quality is in compliance with the discharge standards (GD352/05 - NTPA002). The paper also presents laboratory-scale experimentation carried out for the processing of excess biological sludge (stabilization/conditioning, leaching tests) in order to find out its subsequent destination.
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