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Nitrate Reduction, Sulfate Reduction and Methanogenesis Interrelation in Fixed and Suspended Bed Batch Reactors
並列摘要
This study was focused on the interrelation among nitrate reduction, sulfate reduction and methanogenesis in fixed bed and suspended reactors. Dried stems of the cactus Opuntia imbricata were used as substratum for biofilm growth. Three anaerobic treatment systems: Biofilm and Macerated Anaerobic Sludge (BMAS), Biofilm formed by macerated anaerobic sludge (B) and Macerated Anaerobic Sludge (MAS) were studied. Experiments were carried out in batch reactors containing 250mL of synthetic wastewater (0.5, 1.2 and 7.6g/L of nitrate, sulfate and acetate, respectively). The nitrate reducing rate was of 6.0, 5.9 and 3.29g NO_3^- l^(-1) d^(-1)×10^(-1) for BMAS, B and MAS systems, respectively. The sulfate reducing rate was two times higher for BMAS and B systems (11.5 and 11.3g SO_4^(2-) l^(-1) d^(-1)×10^(-2), respectively) than MAS system (4.8 g SO_4^(2-) l^(-1) d^(-1)×10^(-2)). Methanogenic rate was 1.5 times higher for BMAS and B systems (4.2 and 3.8g CH_4 l^(-1) d^(-1) ×10^(-1), respectively) than MAS system (2.15g CH_4 l^(-1) d^(-1) ×10^(-1)). In MAS system, the processes were not simultaneous but in stages, contrary to observed in the removal of nitrate, sulfate and organic matter in the biofilm containing systems. Biofilm containing systems carried out nitrate reduction, sulfate reduction and methanogenesis processes more efficiently than MAS system.