Effects of temperature and temperature shock on the performance and microbial community structure of a submerged anaerobic membrane bioreactor

► Temperature and temperature shock affected the performance of SAnMBR. ► Temperature shock resulted in a temporary increase in biogas production. ► An increase in temperature resulted in a lower membrane flux and lower COD removal efficiency. ► Microbial community structure was affected by temperature variations. Effects of temperature and temperature shock on the performance and microbial community structure of a submerged anaerobic membrane bioreactor (SAnMBR) treating thermomechanical pulping pressate were studied for 416days. The results showed that the SAnMBR system were highly resilient to temperature variations in terms of chemical oxygen demand (COD) removal. The residual COD in treated effluent was slightly higher at 55°C than that at 37 and 45°C. There were no significant changes in biogas production rate and biogas composition. However, temperature shocks resulted in an increase in biogas production temporarily. The SAnMBR could tolerate the 5 and 10°C temperature shocks at 37°C and the temperature variations from 37 to 45°C. The temperature shock of 5 and 10°C at 45°C led to slight and significant disturbance of the performance, respectively. Temperature affected the richness and diversity of microbial populations.