Study On Anaerobic Self-forming Dynamic Membrane Bioreactor For Low Strength Wastewater Treatment

Anaerobic self-forming dynamic membrane bioreactor is a novel wastewater treatment process,which combines self-forming dynamic membrane bioreactor with anaerobic wastewater treatment.Besides having stable water-quality, small footprint, low sludge yield, integrated automatic control,and easy operation, it also has low maintenance and operation costs and is easily converted into energy.Anaerobic self-forming dynamic membrane bioreactor (ASFDMBR) was applied to low strength municipal wastewater treatment at ambient temperature.The feasibility and stability of the anaerobic self-forming dynamic membrane bioreactor in municipal wastewater treatment were investigated.The metabolic and interception ability and components of the self-forming dynamic membrane (SFDM) were also studied.The physical and chemical characteristics of sludge were investigated in-depth. Changes of sludge properties their effects on SFDMBR's performance were mainly studied.This study was performed as follows:1)SFDM can be formed in short time and maintain a stable permeate flux 5 L/m2·h at a 5 cm water head drop.ASFDMBR had a low effluent COD 38.4 mg/L on average and a good COD removal efficiency as high as 89.5%,when the influent COD was 368.6 mg/L.SFDM had a considerable metabolic ability with a COD removal efficiency of 7%,as well as a good interception capacity. FTIR revealed that protein, polysaccharide and humic acid were the components of SFDM.2) Sludge concentration exerted a great impact on the formation of SFDM:flux dropped faster and reached a steady state in a shorter time during the SFDM formation as the sludge concentration increased.The higher the sludge concentration, the lower the permeate flux.3) Sludge properties had appreciable impact on SFDMBR performance.EPS had much effect on physical,chemical or biological characteristics of sludge and ultimately affect the SFDM formation, flux and effluent water quality.4) Analysis of sludge components on the non-woven fabrics(NWF) surface showed that quantity of protein, polysaccharide and RH had little difference.VSS/SS and RH were higher than that of mixed liquor, which suggested that sludge on the NWF surface had higher organic components and higher relative hydrophobicity; Sludge particle size was the key factor affecting SFDM.Sludge particle with higher hydrophobicity in a particle size range 32μm-62μm were the major part of SFDM.