【作者】 Wisaam S.Al-Rekabi；

【导师】 何强；

【作者基本信息】 重庆大学 ， 市政工程， 2008， 博士

【摘要】 城市污水处理基础设施的高投入,城市污水厂的高运行费用,管网渗漏造成的二次污染,以及水资源缺乏地区对污水回用的需求,迫切需要运行稳定,低能耗污水处理工艺。本研究将SBR工艺与人工湿地工艺进行组合,用于处理生活污水,以得到该组合工艺处理生活污水的最佳工况条件与最优的经济运行参数,要求充分发挥人工湿地的处理效能,以降低SBR系统的能耗。在该组合工艺中,人工湿地是自然处理工艺,人工湿地中间设置自然复氧槽可提高湿地内部的溶解氧,为无能耗工艺。SBR系统是活性污泥工艺,须通过供氧来培养活性污泥和保持一定的活性污泥浓度。SBR系统的曝气强度和曝气时间是影响该组合工艺的能耗参数。常温下(气温≥15℃),活性污泥中微生物生长迅速,SBR中污泥浓度高,对有机污染物的去除效果好。为降低能耗,不断降低SBR的曝气时间,选用运行方式1、2、3,4作为运行工况,曝气时间从5h降低到2h。同时采用限制曝气,将SBR系统控制在低溶解氧状态。出水要求达到《景观用水标准》(GB/T18921-2002)。低温下(气温<15℃), SBR中活性污泥受到气温变化的影响,活性污泥中微生物活性降低,污泥浓度下降,加之秋冬季节,进水污染物浓度较春夏季高,通过延长曝气时间,来提高有机污染物的去除效果,选用运行方式5、6、7,8作为运行工况,曝气时间从6h延长到8h。出水标准要求达到《城市杂用水标准》,对总氮总磷不作要求。试验从2006年4月启动,到2007年3月结束,历时一年。根曝气时间的不同,试验运行了8个运行方式,每种方式运行20-25天。周期运行过程中,2-3天取一次水样,每次取样,SBR每间隔1小时沿时取样,人工湿地沿程取样。试验研究了常温和低温条件下,组合工艺中SBR与人工湿地对COD、氨氮、总氮和总磷等有机污染物的去除规律及最佳运行工况;低溶解氧下SBR系统的特性研究,包括同时硝化反硝化现象,脱氮除磷效果的研究;人工湿地最大处理效能,及人工湿地内植物生长特性。研究结论如下:SBR反应器启动期间,温度为14.7～26.5℃,污泥培养周期按进水1h,曝气20h,沉淀1h,出水1h,闲置1h,每天运行一个周期,排水比为1/3。运行3天后,污泥浓度明显增加。其后,调整运行周期:进水1h,曝气8h,沉淀1h,排水1h,闲置1h,每天运行两个周期。十天后出现大量菌胶团。污泥浓度达3000mg/L以上,并对COD、氨氮、TN,TP等指标进行检测。COD去除率达93%,氨氮去除率达90%, TP去除率达50%。对SBR中污泥进行镜检,发现大量菌胶团,其中有变形虫,固着型纤毛虫属,枝虫、轮虫等微生物。SBR反应器启动成功。人工湿地系统启动前对填料进行了冲洗和补充,植物被短期(3天)移出了湿地床,在重新栽入湿地系统后,湿地植物都较快的适应和恢复了生长态势。在种植植物时,重庆地区气温较高,有利于植物的生长恢复。特别是风车草,在重新栽入湿地床中2周后,就长势旺盛,发出了新芽,且每株分蘖数都增加了5～6个;美人蕉的生长趋势相对风车草要弱些,这是由于其自身的特点决定,美人蕉在冬天后大量枝叶枯萎,仍然没有得到很好的恢复,但是在经过30天左右,美人蕉也呈现良好的长势,部分美人蕉已经长至1.4米左右,比较茂盛。在进行填料清洗过程中,发现植物根系发达,其中风车草根系长达30多公分,在两种植物的根系上都附着大量填料。在各植物根区由于植物根系供氧,为微生物提供了一个好氧环境,形成的生物膜结构密实,呈褐色絮状。植物根系内部填料上生物膜的颜色骤渐变深,最终呈黑色絮体。运行20天后,对人工湿地各级填料上的生物膜进行镜检,水生美人蕉位于人工湿地的第一级,周围有机物浓度高,生物膜成黄褐色,镜检发现了大量的微生物;自然复氧区由于受光照影响,出现了大量的藻类和草履虫;随水质的不断变好,在人工湿地后段风车草根系区的生物膜发现了钟虫以及等枝虫等微型动物。在后端植物池,除镜检发现轮虫、线虫等后生动物外,还发现了肉眼可见的丝状沙虫及一些软体小虫。人工湿地内生物相十分丰富,湿地内已经建立了一个较完整的生物群落。常温下,运行方式3为最佳运行工况。此工况条件为,SBR限制曝气3h,沉淀1h,进出水2h,每天运行3个周期;人工湿地的HRT为24h,每天处理水量1.5m3,水力负荷为16.1cm/d。在进水COD、氨氮、总氮,总磷均值依次在272mg/L、47.74mg/L,65.01mg/L,5.94mg/L的情况下,出水满足《景观用水标准》(GB/T18921-2002),且组合工艺在满足出水要求的前提下,SBR反应器能耗最低,人工湿地的处理效能发挥最大。在此工况条件下,组合工艺的COD、氨氮、总氮,总磷的总去除率为95.6%、82.1%、78.1%,82.7%;其中,SBR对COD、氨氮、总氮,总磷的去除率为79.8%、52.7%、43.0%,30.0%;人工湿地对COD、氨氮、总氮,总磷的去除率为70.9%、84.3%、61.6%,88.7%。在运行方式3条件下,组合工艺中SBR对COD、氨氮、总氮,总磷的贡献率分别为90.1%、54.8%、43.0%,30.1%。人工湿地对COD、氨氮、总氮,总磷的贡献率分别为5.5%、27.2%、35.1%,70.1%。SBR去除COD和氨氮效果明显,人工湿地总磷效果明显。人工湿地对总氮,总磷的去除达到了最大效果,总氮的最大处理效能大致在2.2g/ m2·d,总磷最大处理效能大致在0.39g/ m2·d。将SBR反应器中的溶解氧浓度控制在0.5-1mg/L,曝气强度控制在1m3/h～2m3/h较为合适。将SBR反应器控制在低溶解氧状态下,COD和氨氮降解并没有受到明显影响,且出现同时硝化反硝化现象,明显放磷、吸磷现象。在运行方式3条件下,SBR中COD在第一个小时内被降解很快,一小时后COD均值在100mg/L一下,随着曝气时间的延长,COD浓度一直呈下降趋势,曝气3h后,其出水值在50mg/L以一下。氨氮的降解过程受COD浓度的浓度影响,其优先去除COD,而后去除氨氮。在曝气前一个小时,COD浓度较高,增值速度较高的异养型细菌迅速增值,COD降解速度快,使得自养型的硝化菌受到抑制,硝化速率很慢,但由于反应器的稀释作用,氨氮在进水混合初期,氨氮浓度明显下降。曝气一小时后,COD降解基本完成,氨氮降解速率增大。曝气3小时后,氨氮浓度下降20mg/L左右。总氮在低溶解氧环境下,由于反应器的稀释作用和同时硝化反硝化作用,在曝气过程中,其浓度一直曾下降趋势,曝气3小时后,浓度下降了25mg/L左右。总磷的去除过程受溶解氧的影响明显,在曝气的前1小时,由于COD的降解,氨氮的硝化,总氮的同时硝化反硝化需要消耗大量的溶解氧,在限制曝气的情况下,SBR反应器中的溶解氧浓度下降到0.2mg/L左右,反应器基本处于厌氧状态,SBR反应器中出现明显的释磷反应,总磷的浓度在第1小时内呈明显上升趋势,随着曝气时间的延长,总磷浓度开始下降,曝气3小时后,其浓度降低到4mg/L左右。在运行方式3条件下,人工湿地的COD进水浓度很低,经过人工湿地的降解出水能够满足出水要求。氨氮的进水浓度在20mg/L左右,人工湿地中植物根系的供氧和自然复氧槽的复氧,给湿地内部形成了较好的好氧环境,出水氨氮值下降到5mg/L以下,能够达到出水要求。总氮的进水浓度在30mg/L左右,由于植物根系的传氧与自然复氧槽的复氧,为人工湿地提供了一个好氧,厌氧环境。通过其兼氧和厌氧区的反硝化过程去除硝态氮。总氮经过人工湿地的沉积、挥发、吸附、微生物作用,植物吸收其下降值在15-20mg/L,出水总氮值在15mg/L以下,能够满足出水要求。总磷的进水浓度在3.5mg/L左右,通过微生物的积累、植物的吸收和填料床基质的物理化学等几方面的协调作用,人工湿地系统的出水总磷浓度在0.5mg/L以下,具有很明显的去磷效果。在低温下,SBR运行方式8为达标运行工况。此工况条件为,SBR曝气8h,沉淀1h,进出水2h,每天运行2个周期;人工湿地的HRT为36h,每天处理水量1m3,水力负荷为10.6cm/d。在进水COD,氨氮均值在374mg/L,86.14mg/L的情况下,出水COD和氨氮值满足《城市杂用水水质标准》(GB/T18920-2002)。在此工况条件下,组合工艺的COD,氨氮的总去除率为96.3%,89.4%;其中,SBR对COD,氨氮的去除率为92.5%,68.3%;人工湿地对COD,氨氮的去除率为96.3%、89.4%。组合工艺中SBR对COD,氨氮的贡献率分别为92.5%、68.3%。人工湿地对COD,氨氮的贡献率分别为3.7%,21.1%。SBR对COD和氨氮的去除起主要作用。低温情况下,由于组合工艺对COD的降解速率下降,前置SBR只有通过不断延长曝气时间和提高曝气强度来提高COD降解速率,将COD浓度降低到一个较低水平,再利用人工湿地的深度处理使出水满足要求,人工湿地对COD的降解效果受气温影响较大,随着气温的降低,其对COD的去除率逐渐下降。由于前置SBR反应器对COD的降解,人工湿地降解COD的效能没有完全发挥,无法得出其低温下的对COD降解的最大效能。SBR中污泥所含硝化细菌的生物活性降低,氨氮处理效果下降。加之进水氨氮浓度很高,氨氮的降解速率明显下降。SBR系统不断延长曝气时间才能有效降低污水中的氨氮浓度,当曝气时间延长到8h,再充分利用人工湿地对氨氮的去除效果,才能满足出水标准。人工湿地中设置的自然复氧槽能够有效的进行复氧。复氧量随着槽长增加而增加,复氧的效果主要取决于槽长,将人工湿地四道复氧槽的平均复氧效果进行线性回归,复氧槽的复氧效果与槽长呈正向线性关系。风车草和水生美人蕉是较好的人工湿地植物。根系发达,其中风车草根系长达30多公分,在两种植物的根系上都附着大量填料。在各植物根区由于植物根系供氧,为微生物提供了一个好氧环境,形成的生物膜结构密实,呈褐色絮状。植物根系内部填料上生物膜的颜色骤渐变深,最终呈黑色絮体。风车草受季节影响不大,但水生美人蕉受季节影响较大,冬季生长情况不好,植物需要三个月清理一次。组合工艺耐冲击负荷能力强,限制曝气下,污泥浓度在3000-4000mg/L之间,且活性很高。在夏季学生离校期间,进水浓度很低的情况下,采用限制曝气,其污泥浓度能够控制在2000mg/L-3000mg/L。SBR与人工湿地组合工艺兼有两种水处理技术的优点。SBR抗冲击负荷强,自控程度高,操作简单;人工湿地运行成本低,维护简单;人工湿地具有生态效应,可美化环境,具有绿化功效,可与小区的景观相结合。同时,可以弥补两种技术各自的不足。可以缩短SBR系统的曝气时间,降低其能耗;人工湿地可以弥补SBR中氮磷去除功效;SBR系统可以弥补人工湿地湿地系统冬季处理效果不佳的问题,有效防止人工湿地堵塞,减小人工湿地的占地面积。试验得出的最佳运行工况是:常温下,SBR运行方式3(限制曝气3h,沉淀1h)与人工湿地(HRT=24h,每天处理水量1.5m3,水力负荷为16.1cm/d)组合,出水满足《景观用水标准》(GB/T18921-2002),且组合工艺在满足出水要求的前提下,SBR反应器能耗最低,人工湿地的处理效能发挥最大。在低温下,SBR运行方式8(曝气8,沉淀1h)与人工湿地(HRT=36h,每天处理水量1m3,水力负荷为10.6cm/d)组合,出水COD和氨氮值满足《城市杂用水水质标准》(GB/T18920-2002)。更多还原

【Abstract】 As water consumption increases sharply, many areas face water shortage now or in the near future. In order to overcome this crisis, a number of measures have been introduced for the effective use of this valuable natural resource. In this situation, wastewater could be considered as a water resource. However, the conventional treatment systems have focused on disposal rather than reuse. Thus the related issues of what kind of wastewater should be treated, how to treat and how to transport them should be studied.City sewage infrastructure of high input, high urban wastewater treatment plant operating costs, the net leakage cause secondary pollution and lack of water resources reuse of sewage in the demand, there is an urgent need for stable operation, low power consumption sewage treatment process. In this study, SBR technology and artificial wetlands technology combination for domestic wastewater treatment in order to get the best working conditions of combination treatment domestic sewage and the optimal economic operating parameters to give full play for constructed wetland performance and SBR system to reduce energy consumption.In the composition process constructed wetlands is a natural process, we setting aeration natural trough in constructed wetland in order to improve the dissolved oxygen within constructed wetland so not need energy for this process. The Sequencing Batch Reactor (SBR) is the name given to a wastewater treatment system based on activated sludge and operated in a fill-and-draw cycle. The most important difference between SBR and the conventional activated sludge systems is that reaction and settle take place in the same reactor. Activated sludge in the SBR need dissolved oxygen and must maintain a certain level of activated sludge concentration, SBR system aeration intensity and aeration time have a big impact in the combination process and energy consumption.At ambient normal temperature conditions T≥15oC, the SBR system running three cycles per day, the volume of wastewater treating is equal to 1.5m3/day, constructed wetland and hydraulic retention time approximately is equal to one day. The SBR system is running four operation cyclic modes (first, second, third and fourth) and aeration time reduced from 5 to 2 hours, at the same time adopt restrictions aeration, SBR system will be controlled low dissolved oxygen state DO in the range (0.5-1) mg/L, in this condition we do (COD, Ammonia, TN and TP) tests in order to meet with "Urban Landscape Water Standards"(GB/T18921-2002).At ambient low temperature conditions T < 15oC, the SBR system running two cycles per day, the volume of wastewater treating is equal to 1m3/day, constructed wetland and hydraulic retention time approximately is equal to 1.5 day, in the condition of low temperature we do the same tests before as (COD, Ammonia, TN, TP) but the difference in this condition the standard adopted is "City of miscellaneous water standards" (GB/T18921-2002) which not required to meet with TN and TP effluents, also this condition specified by extended aeration time and cyclic modes her represented by fifth, sixth, seventh and eighth as selected operating modes.This research report’s on the performance of sub-surface horizontal Constructed Wetland (CW) pilot plant in polishing effluent from the Sequencing Batch Reactor (SBR) containing activated sludge in order treat and water reuse. In this study the sequencing batch reactor received and pretreated part of the wastewater from the student’s hostels at the Chongqing University at B campus in P.R. China, Chongqing is located in the Three Gorges Reservoir area.Domestic wastewater firstly inter to settling tank from student’s hostel as a primary treatment to remove some pollutants that easy removed by settling operation and filter putting in the head of pipe carrier to SBR, in the SBR run eight operation cyclic modes, after this operation supernatant withdrawn by absorbent pump to constructed wetland which consisted of three S-shape cell and aeration beds to enhance dissolved oxygen for removal different pollutant that remains in the effluent from SBR.The experiment started in April 2006 to the end of March 2007, lasted one year. Test operation of the eight cycles, each cycle run 20-25 days. The primary objective of this investigation was to optimize eight operations cyclic modes of existing (SBR) to elevate the water quality of the treated sewage wastewater to the level meet with "landscape water standards" and "miscellaneous city water quality standards". Both SBR and constructed wetland treatment systems were employed for the experimental tests. Under condition of normal temperature as T≥15°C the best cyclic mode given a good results for Total Nitrogen TN is third cyclic mode because the average concentration value of TN effluent which resulted from SBR and constructed combined treatment process is equal to 14.21 mg/L can be met with "urban landscape water standards." Because these standards recommended by 15 mg/L achieving it, also the average concentration value of TN effluents (8.14 and 11.52) mg/L from first and second cyclic modes respectively which can met with this standards, but we considered two reasons first one is decreasing a power that consumed by SBR to operate pump for aeration as shown before the first and second cyclic modes is 4 and 5 hours respectively while the aeration time take 3 hours in third cyclic mode, the second reason is the effect role of constructed wetland to smooth out TN effluent that come from SBR as depicted from TN removal efficiency in first and second cyclic modes is 28.59% and 31.86% respectively while TN removal efficiency in constructed wetland was 35.12% more than before so that choose third cyclic mode as the best cyclic mode in TN removal.Under condition of normal temperature as T≥15°C the best cyclic mode given a good results for Total Phosphorus TP is third cyclic mode because the average concentration value of TP effluent which resulted from SBR and constructed combined treatment process is equal to 0.47 mg/L can be met with "urban landscape water standards" Because these standards recommended by 0.5 mg/L achieving it, also the average concentration value of TP effluents (0.27 and 0.34) mg/L from first and second cyclic modes respectively which can met with this standards, TP removal efficiency by constructed wetland is 61.95% also higher than 31.65% and 48.63% which represented first and second cyclic modes respectively, by considered two reasons explained in the preceding paragraph choose third cyclic mode as the best cyclic mode in TP removal.For ammonia removal under condition of normal temperature as T≥15°C in this case the average effluent value of ammonia is 5mg/L can achieve "urban landscape water standards". As shown from results the average ammonia effluent of combination SBR with constructed wetland in (first, second, third and fourth) cyclic modes were (2.14, 2.93, 3.54 and 4.21) mg/L respectively all these values achieve reuse standards but by considering SBR power reducing and constructed wetland impact in ammonia removal so that consider fourth cyclic mode best one met with standards this cyclic mode specified by two hour aeration this mean less power consumed by SBR and ammonia removal efficiency by constructed wetland is 57.52%.By considering COD removal under normal temperature condition as T≥15°C in this case the average effluent value of COD is 20 mg/L can achieve "urban landscape water standards". As shown from results the averages COD effluent of combination SBR with constructed wetland in (first, second, third and fourth) cyclic modes were (8, 11, 16 and 17) mg/L respectively all these effluent values can achieve reuse standards but also by considering SBR power reducing and constructed wetland impact in COD removal, so that considered fourth cyclic mode best one met with standards this cyclic mode specified by two hour aeration this mean less power consumed by SBR and ammonia removal efficiency is by constructed wetland 16.11%.As mentioned before we do optimization to chose best operation cyclic mode under normal at low dissolved oxygen, so considered third cyclic mode as the best one satisfied“urban landscape water standards”for TN, TP, ammonia and COD removals by combination SBR with constructed wetland for domestic sewage treatment processes under normal temperature condition when T≥15°C, The results showed that the removal efficiency that has been achieved by combined SBR with constructed wetland systems were (79.78%+9.93%), (52.74%+39.84%), (43.02%+35.12%) and (30.14%+61.95%) for COD, Ammonia, TN and TP respectively, third cyclic mode characterized by follow: SBR characterized by one hour (fill), three hours (aeration), one hour (settle), one hour (discharge) and two hours (idle) while constructed wetland characterized by (Hydraulic Retention Time) is 24 hours, (Hydraulic Load Rate) is 16.1cm/d and sewage treatment is 1.5m3 per day.Within low temperature condition when T < 15°C we have four operation cyclic modes also as (fifth, sixth, seventh and eighth) and the standards in this case is "City of miscellaneous water standards" which different of the standards in the case of low temperature condition and in this case just ammonia and COD satisfied "City of miscellaneous water standards" without TN and TP, so that by consider COD removal under low temperature condition the average effluent value of COD is 20mg/L can achieve "City of miscellaneous water standards" so as shown from results the average COD effluent of combination SBR with constructed wetland in (fifth, sixth, seventh and eighth) cyclic modes were (12, 19, 16 and 14)mg/L respectively all these values achieve reuse standards but by considering SBR power reducing and constructed wetland impact in COD removal, so consider sixth cyclic mode best one met with standards this cyclic mode characterized by three hour aeration after that two hour anoxic and then one hour aeration this mean less power consumed by SBR compared with (fifth, seventh and eighth) cyclic modes and COD removal efficiency by constructed wetland is 6.98%.By considering ammonia removal under low temperature condition as T < 15°C in this case the average effluent value of ammonia is 10 mg/L can achieve "City of miscellaneous water standards" as shown from results the averages ammonia effluent of combination SBR with constructed wetland in (fifth, sixth, seventh and eighth) cyclic modes were (16.33, 25.27, 14.54 and 9.14) mg/L respectively just one of these effluent values can achieve reuse standards, this one is eighth cyclic mode this cyclic mode characterized by eight hour aeration.In order to chose the best cyclic mode under low temperature condition T < 15°C as explained in the foregoing two paragraphs we choose sixth cyclic mode as best cyclic mode that achieved "City of miscellaneous water standards" (GB/T18920-2002)in the case of COD removal by combination SBR with constructed wetland treatment processes but eighth cyclic mode also can achieve that, also we choose eighth cyclic mode as best cyclic mode that satisfied "City of miscellaneous water standards" in the case of ammonia removal but in this case sixth cyclic mode couldn’t achieved "City of miscellaneous water standards", so that under this reasons considered eighth cyclic mode as the best one satisfied these standards for ammonia and COD removals by combination SBR with constructed wetland for domestic treatment processes under normal temperature condition when T < 15°C, the results showed that the removal efficiency that has been achieved by combined SBR with constructed wetland systems were (68.33%+21.06%) and (92.51%+3.74%) for ammonia and COD respectively.Eighth cyclic mode characterized by follow SBR characterized by one hour (fill), eight hours (aeration), one hour (settle), one hour (discharge) and one hours (idle) while constructed wetland characterized by (Hydraulic Retention Time) is 36 hours, (Hydraulic Load Rate) is 10.7cm/d and sewage treatment is 1m3 per day.In the constructed wetland ,Cyperus alternifolius plant which planted in the second and third constructed wetland cells is not affected by seasonal changes, but aquatic Canna plant which planted in the first wetland cell is great affected by seasonal changes especially in winter season the growth was bad compared with Cyperus alternifolius plant, the plants need a three-month liquidation.Cyperus alternifolius and aquatic Canna is a good wetland plant, plant root system, the long of Cyperus alternifolius roots more than 30 centimeters, in the two plants root system contain large attachment filler. In the plant root zone due to oxygen plant roots, provide an aerobic microbial environment, biofilm formation of dense structure, a brown flocculent.The concentration of sludge is about (3000-4000) mg/L under restrictive aeration DO (0.5-1) mg/L, while in the case of school holidays within summer and winter holidays almost student leaved hostels for a period so that the influent concentration will be low and concentration of sludge be less than before is about (2000-3000) mg/L.更多还原