The Production And The Effect Of Extracellular Polymeric Substances On Membrane Fouling In Membrane Bioreactor

Membrane Bioreaetor (MBR) is an effective technology of wastewater treatment. It have been widely used in wastewater treatment for it's higher efficiency,less surplus sludge volume calculation,high volume loading and easy operation and so on.However,membrane fouling is a main obstacle to the wide application of MBR. Aetivated sludge extracellular polymeric substances (EPS) has been reported as an important a fetor goveming membrane fouling.The topic of the research focus on the constitutes of EPS and membrane fouling in different controlled conditions.This paper study the transformation of the constitutes of EPS and membrane fouling,in different aeration intensity(0.2m3/h and 0.6 m3/h),SBR(5,10,15,20d),and also study the effects of MBR and PAC-MBR in distribution and membrane fouling. The experimental results show that:(1)In different aeration intensity(0.2m3/h and 0.6m3/h),The value of protein, polysaccharide and p/c in TB-EPS and LB-EPS increase first and then decrease with the increase of time in suspended activated sludge. Total amounts of LB-EPS in biofilm decrease all the time.(2)The effects of different aeration intensity to the components of LB-EPS is strong,but is slight to the component of TB-EPS.(3)Membrane fouling included two stages in different aeration:the early(1-20d)and the late(after 20d).In the period of the early, the membrane fouling of the higher aeration is more serious.Hower, In the period of the later, the result is totally opposite.It is decided by the aeration intensity and the characteristics of the activated sludge.(4) The amount of LB-EPS, The value of protein and polysaccharide in LB-EPS decreased, then increased a little latterly with the change of SRT. While The value of protein in TB-EPS decreased, The value of protein in TB-EPS increased with the increase of SRT.(5) With the increase of SRT, the amount of TB-EPS changed a little. the amount of TB-EPS and EPS decreased in the beginning,then increased a little latterly.(6)The removal efficiency of COD is more higher in PAC-MBR.In the beginning,COD decreased fast and maintained for a moment, then increased a little latterly.All in all, The removal efficiency of COD in PAC-MBR is more higher than the one in MBR.(7) The removal efficiency of NH4+-N is similar in the two bio-membrane reactors.At the beginning of opertation, The removal efficiency of TN is alsosimilar in the two bio-membrane reactors.During the lasting operation,The removal efficiency of TN in PAC-MBR is more higher than the one in MBR.