Investigation on the response of anaerobic membrane bioreactor to temperature decrease from 25°C to 10°C in sewage...

Area of Science:

• Environmental Engineering
• Biotechnology
• Wastewater Treatment

Background:

• Anaerobic membrane bioreactors (AnMBRs) are effective for sewage treatment.
• Temperature significantly impacts biological processes in wastewater treatment.

Purpose of the Study:

• To investigate the effect of decreasing temperature on AnMBR performance for sewage treatment.
• To analyze the mechanisms of membrane fouling under low-temperature conditions.

Main Methods:

• Operation of an AnMBR for 650 days with temperatures decreasing from 25°C to 10°C.
• Monitoring of chemical oxygen demand (COD) removal, methane (CH4) production, and membrane fouling.
• Analysis of soluble microbial products (SMP) and extracellular polymeric substances (EPS) contributing to fouling.

Main Results:

• COD removal exceeded 94% at temperatures above 15°C but decreased below this threshold.
• Sewage treatment efficiency and CH4 production declined significantly at lower temperatures.
• Membrane fouling rate increased at low temperatures, with pore blocking rising from 17% to 45% due to protein from SMP and EPS.

Conclusions:

• Low temperatures (<15°C) inhibit hydrolysis and acidification, reducing AnMBR sewage treatment efficiency.
• Microbial self-protection mechanisms at low temperatures, involving SMP and EPS release, exacerbate membrane fouling.
• AnMBR performance is temperature-sensitive, requiring operational adjustments for optimal function in colder climates.