Enhanced anaerobic degradability of highly polluted pesticides-bearing wastewater under thermophilic conditions

摘要

This work presents a sustainable and cost-competitive solution for hardly biodegradable pesticides bearing wastewater treatment in an anaerobic expanded granular sludge bed (EGSB) reactor at mesophilic (35 degrees C) and thermophilic (55 degrees C). The reactor was operated in continuous mode during 160 days, achieving an average COD removal of 33 and 44% under mesophilic and thermophilic conditions, respectively. The increase of temperature improved the biomass activity and the production of methane by 35%. Around 96% of pesticides identified in raw wastewater were not detected in both mesophilic and thermophilic effluents. A dramatic selection of the microbial population in anaerobic granules was caused by the presence of pesticides, which also changed significantly when the temperature was increased. Pesticides caused a significant inhibition on methanogenesis, especially over acetoclastic methanogens. Aerobic biodegradability tests of the resulting anaerobic effluents revealed that aerobic post-treatment is also a feasible and effective option, yielding more than 60% COD reduction. (C) 2017 Elsevier B.V. All rights reserved.