Efficient methanogenic degradation of alcohol ethoxylates and microbial community acclimation in treatment of municipal wastewater using a submerged anaerobic membrane bioreactor

•AE was all degraded and converted into CH4 by anaerobic microbes in SAnMBR.•Sludge acclimation to AE greatly changed the microbial community structure.•Tolerance ability of methanogenic activity to AE was greatly enhanced.•Higher concentration of AE caused an increase of membrane fouling rate.

The effect of alcohol ethoxylates on the treatment of municipal wastewater by a submerged anaerobic membrane bioreactor was investigated by a 400 days operation including the treatment efficiency, methanogenic activity of sludge and microbial community structure. The results indicated that alcohol ethoxylates (5.0-200 mg/L) was efficiently degraded and converted into methane due to the similar COD removal 95.5-98.8% and rising biogas production rate (2.30-4.25 L/d) compared with control (96.8% and 2.55 L/d). The microbes in sludge could copy with the presence of alcohol ethoxylates in wastewater by releasing more SMP and EPS, which caused a higher membrane fouling rate. Moreover, via long term acclimation, the specific methanogenic activity of sludge was greatly enhanced due to the changes of microbial community structure. Hence, the sludge self-acclimation to alcohol ethoxylates was responsible to the efficient methane recovery in treatment of municipal wastewater.

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