Effect Of The Hydraulic Retention Time On The Sludge Mixed Liquor Properties And Membrane Fouling Of Split Anaerobic Membrane Bioreactor

Anaerobic membrane bioreactor(Anaerobic Membrane Bioreactor, AnMBR)is a new, highly efficient and stable wastewater treatment process, which effectively combines anaerobic biological treatment technology and membrane separation technology, and achieves the complete separation of the hydraulic retention time(HRT)and sludge retention time(SRT). It is a great potential of anaerobic treatment technology, with high methane conversion rate, long sludge age, low sludge production, high the sludge concentration, a strong resistance to shock loading, small footprint, and ease of automation control. Now, with the matures of anaerobic biological treatment and membrane separation technology, some scholars have studied the operating conditions and membrane fouling for the split and integrated AnMBR, but not yet have a consistent conclusion. In the study, Xi’an Hans brewery wastewater was the influent of the small test split–AnMBR, explored the reactor the best operating conditions and the impact of HRT on the sludge mixed liquor properties and membrane fouling, and tried to provide reference for achieving the process optimization and controlling membrane fouling of AnMBR by controlling HRT.The main results were as follows:(1)In the start-up phase, AnMBR ran well. Controlling the reactor temperature was at 35 ± 2 ℃, HRT was 48 h, the COD concentration was at 1000 ~ 3000 mg/L. The reactor finished start-up only 17 days. COD removal rate was between 83.33~96.94%, the reactor effluent VFA, alkalinity, and pH were within a reasonable range. But the system did not have a basic nitrogen and phosphorus removal.(2) In the stable operational phase, obtained that HRT was 40 h, organic load(OLR) was 2.24 kgCOD/(m3·d), sludge load(F/M)was 0.58 kgCOD/(kg MLVSS·d), the system can get better treatment effect and lower membrane fouling rate. This condition was the best operating conditions.(3)When HRT between 40 ~ 16 h gradually reduced, resulting in a higher OLR and F/M, which affected the metabolic activity of anaerobic microorganisms, and maked extracellular polymeric substances( EPS), soluble microbial products(SMP),and sludge particle size increase; the protein of EPS and SMP,and the sludge particle size had greater impact on the cake resistance(Rc),their increase prompted the formation of cake layer, increased Rc, then increased the membrane filtration resistance(Rt), which led to the rapid growth of trans membrane pressure(TMP), accelerated the process of membrane fouling.(4)HRT had significant impact on sludge mixed liquor properties and membrane fouling of the anaerobic membrane bioreactor. By optimizing the HRT to ensure the treatment effect and control membrane fouling.