【作者】 杨小丽；

【导师】 王世和；

【作者基本信息】 东南大学 ， 环境工程， 2006， 博士

【摘要】 膜生物反应器是污水的生物处理与膜分离技术有机结合的新型污水处理技术。本文开展了膜生物反应器处理城市污水的试验研究,通过研究和分析取得如下主要成果:通过与传统活性污泥工艺的比较试验,系统考察了MBR的除污特性和反应动力学。MBR中膜的截留作用提高了系统的污染物去除能力和抗污染、pH值和温度的冲击能力。MBR系统中污泥的亚硝化、反硝化作用均呈零级反应,对应降解速率常数分别约为传统活性污泥的2.2倍和2.5倍;MBR中硝化作用规律不明显。MBR中的细菌总数、硝酸菌、亚硝酸菌和反硝化菌数量分别比传统活性污泥法高出1~2个数量级。通过170天的连续运行试验,研究了MBR在不排泥条件下处理城市污水的微环境特征。发现污泥浓度最终稳定于7000 mg/L左右;与传统活性污泥法相比,稳定阶段MBR的污泥脱氢酶活性较小,污泥沉降性能略差。MBR内出现了溶解性微生物产物的积累,但随着运行时间的延长可被进一步降解。污泥负荷与胞外聚合物浓度呈负相关;多糖和蛋白质是胞外聚合物的主要组分,二者占胞外聚合物总COD的60%以上。全面考察了MBR独特的微环境及运行条件对系统出水水质、污泥活性及系统运行稳定性的影响。系统出水COD随上清液COD的增加而增加;MBR试验运行中期,系统脱氢酶活性随上清液COD增加而明显下降。经济曝气强度随污泥浓度的增加呈指数递增;经济曝气强度下膜污染发展速率随污泥浓度变化而变化,污泥浓度过高或过低时,膜污染发展速率均加快。对MBR中微型动物群落结构随运行历程的变化进行了系统研究,并探讨了微型动物对MBR系统运行的指示作用。随着运行历程的推移,MBR中微型动物由活性污泥性生物向中间污泥性生物转变;不同微型动物种类及数量与COD去除率间的相关性不显著;而微型动物总数和肉足类动物数量与NH4+-N和TN的去除率均呈显著相关。研究得出污泥混合液中悬浮固体、胶体物质和溶解性物质所形成的膜阻力分别占总阻力的55%、39%和6%,以此为依据,考察了曝气强度、污泥浓度及进水COD浓度对膜污染的影响,建立了膜过滤阻力模型。对不同进水浓度下的膜污染发展状况进行了预测,找出了对应临界污泥浓度MLSS和临界曝气强度G的MLSS~G临界曲线。更多还原

【Abstract】 Membrane bioreactor (MBR) is a new technology combining biological treatment with membrane separation for sewage treatment. Research on MBR for municipal wastewater treatment was conducted both in laboratory and in sewage treatment plant. The following results are obtained:By comparison with conventional activated sludge process (CAS), pollutants removal characteristic and kinetic analysis were revealed detailedly. The blockage of membrane module in MBR enhances removal efficiency and ability to resist impact of pollutants, pH and temperature. Both ammonium-oxidizing and denitrifying reaction in MBR accord to zero-grade reaction formula, and the corresponding degradation rate constant was 2.2 and 2.5 times respectively over CAS. The nitrifying rule is not obvious in MBR. The amount of total bacteria, nitrifying bacteria, ammonium-oxidizing bacteria and denitrifying bacteria in MBR are higher than corresponding bacteria 1~2 order of magnitude in CAS separately.By 170 day’s continuous running test, microenvironment characteristics were investigated in MBR for municipal wastewater treatment with no biomass wasting. It is found that sludge concentration levels off at around 7000 mg/L. Dehydrogenase activity and sludge subside characteristic in MBR are inferior to CAS at stabilizing period. Accumulation of soluble microbial products (SMP) is occurred in MBR but it could be degraded further along with test progressing. Mass loading is negative correlation with extracellular polymers (EPS) concentration. EPS is mainly composed of polysaccharide and protein, and the two attribute over 60% to total COD of EPS.The influence of particular microenvironment and operation parameters in MBR on effluent quality, microbial viability and operation stabilization was discussed generally. The effluent COD is increasing with the supernatant COD increasing while dehydrogenase activity is declining obviously during the middle operation period. Economic aeration intensity is exponential increasing with sludge concentration enhancing. Membrane fouling developing is varied with sludge concentration under economic aeration intensity and it would be accelerated with too high or too low sludge concentration.The microfauna community variety in MBR along with time going was investigated, and the indicative effect of microfauna on MBR operating was discussed meanwhile. Microfauna in MBR are changed from active sludge bacteria to middle active sludge bacteria with time. The pertinence between microfauna species, number and COD removal efficiency is not obvious. The amount of total microfauna and sarcodina has great influence on the removal efficiency of NH4+-N and TN.The relative contributions of suspended solids, colloids and dissolved molecules to filtration resistance更多还原