Research On Characteristic Of SMP And It's Influence On Membrane Fouling In Membrane Biological Reactor

Soluble microbial products(SMP) produced with wastewater treated by membrane biological reactor(MBR) has an evident effect on running of the reactor. To realize the characteristic of SMP, to provide referrence for optimizing efficiency of reactor working, a MBR was used to treat manmade wastewater. The mechanism of output and decompose of SMP was investigated, as well as the characteristic of SMP and mechanism of membrane fouling aroused by SMP.As the running of MBR, the concentration of SMP ascended initially, and then descended continually. The molecule weight of SMP in reactor taken on two crest distributing, but SMP in effluent contained more low MW fraction. The infrared spectrum indicated that protein, polysaccharid and hydroxyketone was the basis of SMP, and humic acid, alcoholysis sulfuration taken a lower proportion in SMP. When the concentration of SMP in a lower scope , the intensify of membrane had an more evident effect than SMP on the efflent quality. SMP could stimulate microorganism accelerate the degradation of organics, and the activation was pro rata to the concentration of SMP. The SMP cumulated in reactor had an an evident effect of TMP.Under nutrient deficiency,production of SMP could be divided into two regions: dissolved of EPS produced SMP and splited of dead cell proucted SMP. Compared with the second region, SMP produced in the first region could de degradation easily, and it contained lower quantity of macromolecules. SMP produced in either region could stimulate microorganism to accelerate the degradation of organics.Multianalysis method was used to study the relationship of resistance of membrane filtrate, MLSS and concentration of SMP . The relationship was deduced as R1 0 = 2. 2877(E+11) ?SMP0.0 70484?MLSS0.285220. The result indicated that the resistance of membrane filtrate was pro rata to the concentration of SMP and MLSS. Compared to MLSS, SMP taken an unconspicuous effect.The development of membrane fouling could be divided into two regions.In the first region,membrane fouling was mainly caused by the jam and adsorption of membrane hole. Increasing of concentration of SMP could aggravate the jam and adsorption of membrane hole. In the second region, sediment layer formed on the membrane facies. During the filtration, SMP could fill in the interspace of microorganism floccule and decreased the interspacial ratio, the drag index of sediment layer decreased with the increasing of concentration of SMP. The resistance of sediment layer in the second region was the dominant fouling factor.