Systematic monitoring of raw leachates (RL) from the operating landfill “Khmet'yevo7rdquo; during December, 2001-June, 2002 with regard to heavy metals (HM) revealed that these RL were moderately contaminated with Fe, Zn, Pb and Cd (Cu is present in non-dangerous concentrations). This contamination depends on season - the winter leachates are less polluted compared to the summer ones. For removal of HM together with removal of bulk COD, the UASB reactors were applied where, besides elimination of the major part of organic matter, concomitant precipitation of HM in the form of insoluble sulphides inside the sludge bed occurred due to development of the process of biological sulphate reduction. Both removal processes were quite efficient even during operation under submesophilic and psychrophilic conditions (20-10°C). The subsequent submesophilic aerobic-anoxic treatment of submesophilic anaerobic effluents led to only 75% of total inorganic N removal due to COD deficiency for denitrification created by a too efficient anaerobic step. On the contrary, psychrophilic anaerobic effluents (richer in COD compared to the submesophilic ones) were more suitable for subsequent aerobic-anoxic treatment giving the total N removal of 95 and 92% at 20 and 10°C, respectively. The final effluent is approaching the current national standards for direct discharge of treated wastewater.

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