Methanogenic potential of diclofenac and ibuprofen in sanitary sewage using metabolic cosubstrates

摘要

Diclofenac (DCF) and ibuprofen (IBU) are widely used anti-inflammatory drugs and are frequently detected in wastewater from Wastewater Treatment Plants and in aquatic environments. In this study, the methanogenic potential (P) of anaerobic sludge subjected to DCF (7.11 ± 0.02 to 44.41 ± 0.05 mg L~(-1)) and IBU (6.11 ± 0.01 to 42.61 ± 0.05 mg L~(-1)). in sanitary sewage, was investigated in batch reactors. Cosubstrates (200 mg L~(-1) of organic matter) in the form of ethanol, methanol:ethanol and fumarate were tested separately for the removal of drugs. In the DCF assays, P was 6943 ± 121 μmolCH_4, 9379 ± 259 μmolCH_4, 9897 ± 212 μmolCH_4 and 11,530 ± 368 μmolCH_4 for control, fumarate, methanol:ethanol and ethanol conditions, respectively. In the IBU assays, under the same conditions, P was 6145 ± 101 μmolCH_4, 6947 ± 66 μmoICH_4, 8141 ± 191 μmolCH_4and 10,583 ±512 μmolCH_4, respectively. Without cosubstrates, drug removal was below 18% for 43.10 ± 0.01 mgDCF L~(-1) and 43.12 ± 0.03 mgIBU L~(-1), respectively. HigherPand removal of DCF (28.24 ± 1.10%) and IBU (18.72 ± 1.60%) with ethanol was observed for 43.20 ± 0.01 mgDCF L~(-1) and 43.42 ± 0.03 mgIBU L~(-1) respectively. This aspect was better evidenced with DCF due to its molecular structure, a condition that resulted in a higher diversity of bacterial populations. Through the 16S rRNA sequencing, bacteria genera capable of performing aromatic ring cleavage, β-oxidation and oxidation of ethanol and fatty acids were identified. Higher relative abundance (＞0.6%) was observed for Smithella, Sulfuricurvum and Synthophus for the Bacteria Domain and Methanosaeta (＞79%) for the Archaea Domain. The use of ethanol favored greater mineralization of organic matter and greater methane production, which can directly assist in the metabolic pathways of microorganisms.