Methane fermentation is widely used to dispose of sewage sludge at wastewater treatment plants (WWTPs), due to production of renewable energy in the form of biogas. Antibiotics present in wastewater may accumulate in a sewage sludge. The aim of the present study is to investigate the impact of three antibiotics from different classes in three different doses on methane production from sewage sludge. For this purpose, metronidazole (MET), amoxicillin (AMO), and ciprofloxacin (CIP) are individually added to anaerobic reactors with sewage sludge collected from municipal WWTP. The antibiotics’ highest concentration (1024 mg kg⁻¹ of AMO; 512 mg kg⁻¹ of MET and CIP) lowers methane production and methane content in biogas. MET exerts the most marked effect and lowers methane production to 36.8 ± 3.7 mL CH₄ kg⁻¹ volatile solids. Tested antibiotics probably inhibit methanogenic archaea, which results in volatile fatty acids (VFAs) accumulation. Addition of MET results in accumulation of many kinds of VFAs with the highest concentration of acetic acid (17.52 ± 1.85 g L⁻¹). The addition of of AMO results in accumulation of butyric acid only (253.00 ± 15.89 g L⁻¹). However, addition of CIP results in accumulation of mainly acetic acid (7.58 ± 0.82 g L⁻¹) and isovaleric acid (2.01 ± 0.41 g L⁻¹). Next, synergistic effect of these antibiotics in a low concentration of 16 mg kg⁻¹ of AMO, 8 mg kg⁻¹ of MET, and 2 mg kg⁻¹ of CIP is measured in semi‐continuous conditions and causes inbibition of methane production and accumulation of VFAs.

中文翻译：

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甲硝唑，阿莫西林和环丙沙星在污水污泥甲烷发酵中的个体协同作用

由于产生沼气形式的可再生能源，甲烷发酵被广泛用于废水处理厂（WWTP）的污泥处置。废水中存在的抗生素可能积聚在污水污泥中。本研究的目的是研究三种不同剂量的三种不同类别的三种抗生素对污水污泥甲烷产生的影响。为此，将甲硝唑（MET），阿莫西林（AMO）和环丙沙星（CIP）与从市政污水处理厂收集的污水污泥分别添加到厌氧反应器中。抗生素的最高浓度（AMO为1024 mg kg ^-1； 512 mg kg ^-1（例如MET和CIP）降低了沼气中的甲烷产量和甲烷含量。MET发挥最显着的作用，并将甲烷生成量降低至36.8±3.7 mL CH ₄  kg ^-1挥发性固体。经过测试的抗生素可能会抑制产甲烷菌，从而导致挥发性脂肪酸（VFA）积累。MET的添加导致乙酸浓度最高（17.52±1.85 g L ^-1）的多种VFA积累。AMO的添加仅导致丁酸的积累（253.00±15.89g L ^-1）。但是，添加CIP会导致主要是乙酸（7.58±0.82 g L ^-1）和异戊酸（2.01±0.41 g L ^-1）积累）。接下来，在半连续条件下测量这些抗生素在16 mg / kg A ^- 1、8 mg / kg ^-1 MET和2 mg ^-1 CIP的低浓度下的协同作用，并导致甲烷生成和VFA的积累。