Methyl Orange Degradation In Anaerobic Baffled Membrane Bioreactor And Membrane Fouling Analysis By Streaming Potential

Printing and dyeing wastewater is a kind of organic water,which is difficult to be degraded.Meanwhile,dyes discharged into water may destroy the ecological system,in order to deal with methyl orange effectively,ABR is combined with MBR as anaerobic baffled membrane bioreactor(ABMBR),to take degradation of methy orange.At the same time,we identified typical organic membrane foultants produced during the degradation of methyl orange.Then,we took systematic study to the methanism of membrane fouling through analysis of streaming potentials.The detail information is shown as follows:(1)The degradating effect of methy orange was tested in ABMBR.After treatment process of ABR,methy orange was decolorated markedly,while the removal of total organic carbon(TOC)was not obvious.There was about 70% of TOC could be removed after MBR treatment,which indicated that pretreatment of ABR degraded molecules into small ones,creating favorable conditions for MBR.The analysis of degradation pathways and intermediates indicated that methy orange was degraded into eight intermediate products,degradation pathways including aromatic ring oxidation?demethylation and desulfonation were proposed.This system was operated for 110 days under stable condition and only 0.19-0.32 g MLSS/m~2 of filter cake accumulating on membrane surface.EPS analysis of cake layer indicated that,the quantity of polysaccharide(735.32 ± 0.89 mg/g VSS)and protein(258.73 ± 0.41 mg/g VSS)was approach to that quantity of volatile substances in cake filter,although less filter cake presented on membrane surface.Therefore,polysaccharide and protein could be viewed as typical organic membrane foultants in the process of methyl orange degradation..(2)The research of methyl orange degradation by ABMBR indicated that,the main typical organic membrane foultants were polysaccharide and protein.Meanwhile,We took humid acid into account.So,this study researched streaming potentials of polysaccharide ? protein and humid acid on polyvinylidene fluoride(PVDF)micro-filtration membrane surface to evaluate their adsorption differences,and then reflected membrane fouling potentials among different pollutants.It was found that the order of streaming potentials in the adsorption process was sodium alga acid(SA)> sodium humate(SH)> bovine serum albumin(BSA),therefore,as for PVDF membrane,the pollution potentials of polysaccharide and humic acid were greater than that of protein.No obvious relationship was observed between zeta potential/particle size and adsorbance.For BSA and SH,adsorption was intensified under acid and alkaline conditions,respectively.There was no obvious effect of p H on SA adsorption.In order to confirm the relationship between adsorption and membrane fouling future,fast filtration tests were carried out with 250 m L of 25 mg/L of four different kinds of solutions(SA?SH?BSA and the three mixed)via the PVDF membranes.After surface cleaning with tap water,pure water flux recovery after SH and SA filtration was less than that of BSA,indicating the humic matter and polysaccharide could cause more serious membrane fouling,which was completely consistent with the results of streaming potentials.Those results indicated that the stronger adsorption capacity,the more serious of membrane fouling.