Influence of temperature and temperature shock on sludge properties, cake layer structure, and membrane fouling in a submerged anaerobic membrane bioreactor

Effects of temperature and temperature shock on sludge properties, cake layer structure and membrane fouling of a laboratory-scale submerged anaerobic membrane bioreactor (SAnMBR) was studied over 416 day using various analytical tools. Polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) analysis indicated that there were significant differences in species diversity and richness among different operating temperatures and cake ages in cake sludge. The bound extracellular polymeric substances (EPS) in bulk sludge, soluble microbial products (SMP), and colloidal particles content increased with an increase in operating temperature. Temperature shocks had modest impact on bound EPS and SMP in bulk sludge. The particle size of the cake layers decreased with an increase in operating temperature and increased with an increase in cake age, while the quantity of bound EPS in the cake layer decreased with an increase in operating temperature and cake age. The extent of membrane fouling increased with an increase in the operating temperature, whereas temperature shocks temporarily decreased fouling resistance. (C) 2012 Elsevier B.V. All rights reserved.