An anoxic/aerobic membrane bioreactor (MBR) was applied to simultaneous removals of nitrogen and carbon from food processing wastewater in a laboratory scale experiment. By continuous runs under appropriate operational conditions, COD, NH4 +-N and TN removal was over 94, 91 and 74%, respectively. The anoxic reactor and aerobic MBR contributed 40-63 and 29-46% to COD removal, and 31-43 and 47-64% to NH4 +-N removal, respectively. Nitrification in the MBR could be enhanced by adding some carriers for growth of adhesive biomass when the system was operated at a shorter sludge retention time (SRT). The maximum volumetric COD and TN loadings as high as 3.4kg COD m-3 day-1 and 1.26kg Nm-3 day-1 were achieved. Measurement results of sludge activity for nitrification were consistent with the effluent NH4 +-N concentration change.

结合连续流小试,对膜2生物反应器运行过程中，活性污泥沉降性能的变化及其对膜污染的影响进行了研究。结果表明,随着运行时间的增长，该系统内丝状菌大量繁殖，活性污泥沉降性能变差，SVI值升高。随之，膜过滤压差（过滤阻力）平均上升速率有所增加，膜过滤周期缩短。膜过滤压差的“两阶段性（平缓上升期和加速上升期）”变化规律趋于明显，平缓上升期和加速上升期的膜过滤压差上升速率随污泥SVI值的升高分别呈现下降和上升的趋势。污泥沉降性能的变化对膜污染过程产生明显影响。电镜观察表明，污泥沉降性能对膜过滤压差的影响与膜面污染层的结构和厚度有关。

自生动态膜-生物反应器是一种将粗网材料制成的组件置于反应器中进行泥水分离的生物处理工艺。粗网材料表面形成的动态膜不仅能有效去除浊度，还具有生物活性，可以降解污染物。通过微电极技术，可以研究动态膜的生物活性。为便于微电极在线测量，构建微型反应器模拟动态膜的实际过滤过程，结合微动平台，采用溶解氧微电极测量动态膜内的溶解氧分布。结果表明，动态膜在反应器运行过程中结构发生变化，出现气泡。动态膜内溶解氧浓度随深度的增加而降低，在210～215mm深度处降至0。动态膜表层微生物的比耗氧速率在反应器运行第1、5 和8天分别为3413、1016 和1214mg/（g.h）。

The influence of hydrodynamic conditions on membrane fouling was investigated. Ten experiments were dsigned and operated over a wide range of suspended solid (SS) concentrations (2-20 gl-1), iltration fluxes (4.5-271m-2h-1) and aeration intensities (10-100m3 m-2 h-1). In each experiment, the liquid cross-flow velocity was measured and the membrane filtration resistance was monitored. A modified model was set up for calculating the cross-flow velocity of the activated sludge over the membrane surface. The increasing rate of filtration resistance was deduced as a power function of the cross-flow velocities, filtration fluxes and SS concentrations, and a critical curve corresponding to a group of critical fluxes and critical aeration intensities was found. The membrane filtration resistance sharply increased at a flux over the critical flux or at an aeration intensity below the critical aeration intensity.

Synthetic wastewater was treated with a submerged membrane bioreactor to investigate the organic removal performance, as well as the behaviour of soluble microbial products during long-term operation. Satisfactory chemical oxygen demand (COD), total organic carbon (TOC) and biological oxygen demand (BOD) removal efficiencies were achieved, averaging over 90, 94 and 95%, respectively. The accumulation of TOC in the supernatant of the bioreactor and its degradation after 5 months of operation was observed. Among this accumulation, macromolecules with a molecular weight (MW)\100000 accounted for 34%. A decrease in the supernatant TOC corresponded to a shift from large to small molecules. The organic substances with a MW\100000 decreased from 34 to 16%, whereas those with a MWB30000 increased from 33 up to 52%. The accumulation proved to be inhibitory towards the metabolic activity of the activated sludge, as well as contributing to the poor membrane permeability of the mixed liquor.