Research On EPS,SMP And Biodiversity In Membrane Biological Reactor

Sludge characteristics, which are the remarkable factors affecting the membrane fouling in Membrane biological reactor(MBR), determine the effluent quality and separation properties of the membrane to a large extent. Extracellular polymeric substances(EPS),soluble microbial product(SMP) and biodiversity are three important indexes of the sludge characteristics.This research synthesize the three aspects of EPS,SMP and biodiversity to study the sludge characteristics in MBR. The main content is divided into two parts:The first part is to study the sludge characteristics in the MBR of Tianjin Hospital University. There is not excessive SMP accumulation in the whole operation process, and the content of the EPS is steady in the sludge initial growing stage and recovery-to-mature stage. But in the sludge wash-out stage, an sharp increasing and violent variations in EPS and SMP appears, which indicate that EPS and SMP are the cushioning substances for the microbial to defend the attack from adverse external environment. Through the PCR-DGGE profile,Shannon index,the similarity of communities and the cluster analysis,we find that the microbial structure can preferably reflect the operation of the MBR, and the microbial structure can adjust itself according to the operation of the MBR.The second part is to carry a trial under the oligotrophic environment using the sludge from the MBR of Tianjin University. We observe not only the buffer action of the EPS and SMP, but also the utilization of the EPS and SMP when the microbial lack of nutrition combining PCR-DGGE technology and biodiversity analysis. The clone and sequence results reflect that most of the dominant species are uncultured bacterium. Some of the bacterium properly has something to do with the degradation and mutual conversion of the EPS and SMP.