【作者】 周东凯；

【导师】 王文兴； 海热提；

【作者基本信息】 北京化工大学 ， 环境工程， 2013， 博士

【摘要】 随着最严格水资源管理制度的实施,全国范围内,节水减排和水生态环境修复任务更加艰巨,污水处理厂提标改造势在必行。研究开发新型污水处理材料、工艺、技术以及强化现有工艺的处理能力形势迫切。生物膜法污水处理技术在治理点源污染和面源污染的实际应用中获得了普遍认可,对挂膜填料的改进研究受到了广泛关注。聚丙烯腈基的活性碳纤维(PAN-ACF)和活性碳纤维毡(PAN-ACFF)具有比表面积高、生物亲和性好、化学性质稳定等优异性能,作为生物膜法挂膜填料的相关研究倍受期待。1.以PAN-ACF填料为生物膜载体,对模拟生活污水和化工废水进行了小试实验。PAN-ACF用量为40g,比表面积为1200m2·g-1。(1)在模拟生活污水小试实验中,考察了水力停留时间(HRT)和回流比(R)对COD、 NH4+-N、TN去除率的影响。首先测试了HRT为16、12、8、4、2h时的污染物去除率,当HRT为8h时的去除率最高；设定HRT为8h,调节R为1:2、1:1、2:1、4:1,COD、NH4+-N、TN去除率在R为1：1时达到最大值,分别为94.8%、98.0%、62.2%,填料贡献力为1.99(gCOD·d-1)·g-1、0.20(gNH4+-N·d-1)·g-1、0.12(gTN·d-1)·g-1。测试了HRT为8h、R为1：1时4种浓度下填料生物膜抗有机负荷冲击能力,当进水COD浓度为1478.3～1652.4mg·L-1时,填料贡献力最大,为6.43(g·d-1)·g-1。(2)在化工废水小试实验中,进水COD为1900±50mg·L-1, BOD/COD为0.3,考察了DO和HRT对COD去除率的影响,HRT分别为20、15、10、5h,DO分别为3.0、4.0、5.0、6.0mg·L-1。结果表明,当13h<HRT<19h、5.0mg·L-1<DO<6.0mg·L-1时,COD去除率高于75%；当进水COD为1851.3～1947.3mg·L-1, HRT为15h、DO为6.0mg·L-1时,COD去除率最高,平均为75.3%,单位质量填料贡献力为6.1(gCOD·d-1)·g-1。小试实验还发现, PAN-ACF负载生物膜的生物相非常丰富；PAN-ACF表面含有大量的亲水、亲脂活性官能团,有利于提高生物亲和性；填料负载生物量大,挂膜后质量增加了6倍多；填料干燥后仍可重复使用,使用寿命长。2.以PAN-ACFF和超细丙纶、涤纶纤维为原材料,制作了外夹层包裹内芯的复合填料(CFF)。以CFF为生物膜载体,对生活污水进行了中试实验。(1)制作了“环状毛圈+超细纤维网布+PAN-ACFF内芯”的纤维丝复合填料,比表面积为1450+100m2.g-1,填料束干重为70g.m-1。(2)将活性污泥法与生物膜法进行了整合,制作了“初沉池+预缺氧池+厌氧池+缺氧池1+缺氧池2+好氧池+二沉池”的改进型UCT反应器(MUCT),总有效体积0.54m3,体积比V预缺氧池：V厌氧池：V缺氧池：V好氧池=1：1：2：5。设置了“好氧池到第二缺氧池”(R1)、“二沉池到第一缺氧池”(R2)、“第一缺氧池到预缺氧池”(R3)三套回流系统。缺氧池、厌氧池MLSS为2.5土0.5g·L-1,好氧池MLSS为1.5+0.5g.L-1。反应池放置了CFF填料,总质量为3.36kg,填料束投放数量为T预气氧池：T厌氧池：T缺氧池：T好氧池为2：2：4：16。(3)考察了进出水污染物浓度。设定了三种工况：HRT为12、8、6h,分段进水比为1：9、2：8、3：7,R1为200%、300%、400%,R2=R3为20%、40%、60%,厌氧池、缺氧池、好氧池、二沉池的污泥停留时间(SRT)分别为6、10、10、7d。在工况3时,COD、NH4+-N和TP去除效果最好,进水日负荷分别为1384.8±80.4、113.3±8.9、25.1±2.5g.d-1,去除率分别为93.2±0.8%、87.4±2.1%和90.2+3.7%。出水的COD浓度达到了GB18918-2002一级B标准,NH4+-N接近一级B标准,TP达到了二级标准。填料贡献力为384.2±23.5(gCOD·d-1)·kg-1、29.5±2.6(gNH4+-N·d-1)·kg-1和6.8±0.9(gTP·d-1)·kg-1。(4)考察了MUCT生物膜反应器中含氮化合物浓度变化规律。三种工况下,NO3--N和NO2--N进水浓度低,出水浓度高,在工况1时累积率最高,在工况3时累积率最低。三种工况中NH4+-N的净去除百分比分别为31.4%、52.7%、78.0%。中试实验认为,MUCT生物膜反应器对污染物有较好的去除能力,在常温下实现了N02--N的高累积率；CFF不需定期反冲洗,在清水中漂洗、浸泡后可重复使用。3.以CFF为生态基对生活社区纳污人工湖进行了水生态功能修复工程实验。初步形成了“纤维丝复合填料+人工曝气+EM菌剂”的生态基技术,人工湖的水质在较短时间内由GB3838-2002劣五类提升为五类。总之,论文尝试性的制作了活性碳纤维填料和纤维丝复合填料,并以其作为微生物挂膜载体分别进行了应用研究,达到了预期效果；制作的MUCT生物膜反应器具有稳定的污染物去除能力,机理分析和工艺参数改进还有待进一步深入。更多还原

【Abstract】 The excessive emissions of nitrogen and phosphorous compounds to waterbodies can give rise to eutrophication, oxygen depletion and even water source toxicity for life. Accordingly, the total nitrogen (TN) and total phosphorous (TP) removal from contaminated waters has become an imperative demand according to public health and environmental protection. Actually, the more stringent regulations for nitrogen and phosphorous removal from wastewater have been implemented in China. Without a doubt, it is a markedly hard challenge to reduce wastewater discharge and restore water environment for the society as a whole. Particularly, it is imperative for the sewage treatment plants to expand scale and upgrade technical level. Thus, the wide investigation has been carried out with regard to the new wastewater treatment materials and process and old system optimizing. Especially, the biofilm technology has attracted great attention in the wastewater treatment. Here, polyacrylonitrile-based activated carbon fiber (PAN-ACF) and activated carbon fiber felt (PAN-ACFF) are investigated as biofilm carriers in wastewater treatment process considering the characteristics of high specific surface area, good biocompatibility, and chemical stability.1. PAN-ACF40g with the specific surface area1200m2·g-1as the biofilm carrier was used to wastewater treatment in two small-scale tests for artificial sewage and organic industrial wastewater.(1) The influence of hydraulic retention time (HRT) and reflux ratio (R) on chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), and TN removal was studied in the aerobic biofilm reactor for artificial sewage treatment. The evaluation on various HRT showed that the highest removal efficiencies of COD, NH4+-N, and TN was obtained at8h in contrast to the HRT of16,12,4, and2h. The removal efficiencies according to various R displayed that the removal of COD, NH4+-N, and TN reached maximum with the R of1:1compared to R of1:2,2:1, and4:1; and the average values were94.8%,98.0%, and62.2%, respectively; wherein the filler’s contribution power per unit mass was1.99(gCOD·d-1)·g-1,0.20(gNH4+-N·d-1)·g-1, and0.12(gTN·d-1)·g-1. In addition, the COD removal efficiencies at four influent levels was measured at HRT=8h and R=1:1and the results showed that the highest (6.43(g·d-1)·g-1) filler’s contribution power per unit mass was obtained at the influent COD of1478.3-1652.4mg·L-1.(2) In small-scale experiments for organic industrial wastewater treatment with the influent BOD/COD of0.3. The COD removal efficiencies were tested at different dissolved oxygen (DO) of3.0,4.0,5.0, and6.0mg·L-1; and HRT of20,15,10, and5h. The results showed that the COD removal efficiencies were higher than75%with13<HRT<19h and 5.0<DO<6.0mg·L-1. when HRT and DO was5h and6.0mg·L-1respectively, the influent COD concentration varied in1851.3-1947.3mg-L"1with the highest average COD removal rate75.3%and the filler’s contribution power per unit mass was6.1(gCOD·d-1)·g-1.(3) To sum up, the small-scale tests indicated that the microbial populations in the PAN-ACF biofilm reactor were very rich. Besides, PAN-ACF filler greatly increased from60to463.6g after hanging biofilm. The dried fillers can be reused again as biofilm carriers.2. The pilot-scale experiments for sewage treatment in MUCT biofilm reactor.(1) A complex fiber filler (CFF) carrier was produced with the characteristics of specific surface area1450±100m2·g-1, dry weight70g·m-1, and sized Φ5×50cm. The CFF was composed of an outer-coat made by polypropylene net-cloth with loops (ultra-fine polypropylene and terylene fiber) on outer surface and an inner-core made by PAN-ACFF.(2) A step-feeding pilot-scale modified University of Cape Town process (MUCT) included pre-anoxic/anaerobic/anoxic-l/anoxic-2/oxic tank. The total volume of the MUCT biofilm reactor was0.54m3, whereas the volume ratio of Vpre-anoxic:Vanaerobic:Vanoxic:aerobic was1:1:2:5. Three reflux systems were included as follows:nitrification liquor recycle (R1), sludge return (R2) and nitrosation liquor recycle (R3). The mixed liquor suspend solid (MLSS) was2.5±0.5g·L-1in the anoxic and anaerobic tanks, and1.5±0.5g-L"1in the oxic tanks. Each tank was filled with the CFF fixed-bed with the total filler mass3.36kg and the dosing ratio of Tpreanoxic:Tanaerobic:Tanoxic:Taerobic was2:2:4:16. (3) The inlet and output concentrations of COD, NH4+-N, NO3-N, NO2-N, and TP were tested by three kinds of working conditions, which included: HRT:12,8, and6h; the step-feeding ratios between pre-anoxic tank and anaerobic tank:1:9,2:8, and3:7; R1:200%,300%, and400%; R2=R3:20%,40%, and60%. The sludge residence time (SRT) of anaerobic/anoxic/aerobic/secondary settling tank were6,10,10, and7d, respectively. The influent loads were1384.8±80.4gCOD·d-1,113.3±8.9gNH4+-N·d-1, and25.1±2.5gTP·d-1. During working condition3, the removal rates of COD, NH4+-N, and TP were93.2±0.8%,87.4±2.1%, and90.2±3.7%, respectively, which is the highest among three working conditions. During the treatment, the effluent COD concentration achieved Grade1level-B of "Cities Sewage Treatment Plant Pollutant Discharge Standard"(GB18918-2002); the effluent NH4+-N concentration was close to Grade1level-B; and the effluent TP concentration reached the Grade2. As for the filler’s contribution power per unit mass, it was384.2±23.5(gCOD·d-1)·kg-1,29.5±2.6(gNH4+-N·d-1)·kg-1,6.8±0.9(gTP·d-1)·kg-1.(4) The NO3--N and NO2--N concentrations in the MUCT biofilm reactor were measured in3working conditions. The results showed that the influent NO3--N and NO2-N concentrations were low and the effluent concentrations were high. The highest accumulative rate was achieved in working condition1and lowest accumulative rate was in working condition3. The net removal rates of NH4+-N were31.4%,52.7%, and78.0%, respectively among three working conditions.(5) To sum up, the pilot-scale tests showed that the MUCT biofilm reactor performed well on pollutants removal with CFF which showed the advantage of easy cleaning for reuse and need no periodic backwashing. However, sludge emission was carried out regularly for all the tanks in order to obtain high biological phosphorus removal.3. The engineering experiments with the CFF as biofilm carrier. A new ecological technique "CFF+aeration+EM bacterial agent" was developed from a contaminated artificial lake treatment, by which the water quality was markedly promoted from Inferior Grade5standard to Grade5standard according to "Environmental Quality Standards for Surface Water"(GB3838-2002). More importantly, a large number of fish appeared and the project successfully passed the government test after one month.In summary, PAN-ACF and CFF as biomembrane carrier were first developed and successfully used in wastewater treatment apparatus. Furthermore, the novel MUCT biofilm reactor with combined advantages of activated sludge and biofilm method has displayed some potential in pollutants removal. However, further studies are also needed on the mechanism discussion and parameters optimization.更多还原