兰州新区节水型生态小区规划和中水回用技术研究

发布时间：2018-08-18 17:42

【摘要】：兰州新区作为国务院批准的第五个国家级新区，由于兰州新区地处我国西北地区，属于缺水地区，建设成节水型新区是必行之路，住宅小区作为城市主体部分，建设节水型生态小区对于兰州新区的建设具有一定社会效益和经济效益，对西北地区节水型生态小区建设具有一定示范和带动作用，对缓解城市用水压力具有现实性的意义。从兰州新区的基本情况和现存问题出发，结合国内外对于节水型生态小区规划经验，为兰州新区节水型小区建设提供合理的规划方案，按照生态化、系统化、经济化和可持续化的原则对小区进行规划。首先，提高小区居民节水意识，全部采用节水器具，加强小区整个水系统监管力度。其次，，采用MBR工艺作为中水回用技术，对小区杂排水进行处理，回用于小区冲厕、绿化、洗车用水等，实现水资源利用最大化；将雨水进行收集入湖，作为人工湖补给水和回用水水源；还要加强对小区景观水体的保护，采取相应措施杜绝水体出现恶化。为了维护整个小区水系统平衡和节水型生态小区的建设，应加强管理和维护，制定相应的法律法规，提高居民节水意识。这样才能建成生态文明型、环境友好型的节水小区。本研究课题通过国内外参考文献和实践经验分析，决定采用MBR工艺作为中水回用的核心工艺，通过对一体式MBR工艺、A/O-MBR工艺和BCOR-MBR工艺进行研究，考察各个工艺对于小区生活污水处理效果，并对处理结果进行分析，一体式MBR工艺对COD、氨氮、总氮、总磷去除率分别为92.07%、99%、22.69%、26.20%，出水平均值分别为浊度全部小于0.26NTU、氨氮≤2.56mg/L、COD≤25mg/L、总氮≤49.58mg/L、总磷≤3.32mg/L，出水指标符合《城市杂用水水质标准》(GBT18920-2002）。在一体化MBR基础上增设缺氧区，采用A/O-MBR工艺，其中设计缺氧段水力停留时间为2.8h，溶解氧低于0.2mg/L，好氧区水力停留时间为6h，好氧区溶解氧一般在3-5mg/L之间。整个运行周期内，出水浊度仍然很低，出水平均值为0.24NTU，出水水质较好，可见膜的具有高效的截留作用；相比于一体式MBR，COD去除效果相近，平均去除率达93.78%，系统抗冲击能力较强并运行稳定；对于氨氮去除率同样保持很高水平，去除率高达98%以上，出水氨氮始终低于2mg/L。分析原因，由于硝化菌世代周期长，定期排泥，产生影响；对于总氮和总磷来说过，去除效果有了明显提升，总氮由原来的平均值22.69%提升到40.44%，总磷由原来平均值26.20%提升到41.39%。采用BCOR—MBR(接触氧化-MBR)工艺进行小区中水回用处理，填料采用孔隙率和比表面较大的聚氨酯泡沫，边长20-25mm的正方形聚氨酯泡沫填料，密度较水轻，浮在水面上，将其放在球形空心塑料球内部，填料填充量约占整个反应器的50%，运行条件采用一体式MBR得出的最佳参数，出水指标：COD去除率平均94.24%，后期出水COD低于15mg/L；氨氮去除率高达99.25%，出水氨氮在1.9mg/L以下；TN平均出水为44.58mg/L，出去率平均值为36.24%；总磷平均去除率为43.58%，平均出水为2.4mg/L。膜污染是MBR工艺不可避免的问题，我们通过产生膜污染原因尽量减缓膜污染，膜污染控制方法有低压操作、曝气、反冲洗、膜清洗。其中膜清洗的方法有气冲、气水反冲洗、药物清洗、超声波清洗等等。在本次试验期间采用化学清洗法进行膜清洗，除去附着在膜片表面的残留物质，减缓膜污染，实现膜通量恢复目的。
[Abstract]:Lanzhou New Area is the fifth national-level new area approved by the State Council. Because Lanzhou New Area is located in the northwest of China and belongs to the water-deficient area, it is a feasible way to build a water-saving new area. As the main part of the city, residential district has certain social and economic benefits for the construction of Lanzhou New Area. The construction of water-saving ecological community in Northwest China has a certain demonstration and leading role, which is of practical significance to alleviate the pressure of urban water use.
Starting from the basic situation and existing problems of Lanzhou New Area, combining with the planning experience of water-saving ecological district at home and abroad, this paper provides a reasonable planning scheme for the construction of water-saving ecological district in Lanzhou New Area, and plans the district in accordance with the principles of ecology, systematization, economy and sustainability. First of all, the residents of the district should be aware of water-saving and take all the water. Secondly, MBR process is used as reclaimed water reuse technology to treat the miscellaneous drainage, which can be reused for toilet flushing, greening and car washing to maximize the utilization of water resources. In order to maintain the balance of water system and the construction of water-saving ecological community, it is necessary to strengthen the management and maintenance, formulate corresponding laws and regulations, and raise residents'awareness of water-saving.
Based on the analysis of domestic and foreign references and practical experience, this study decided to adopt MBR process as the core process of reclaimed water reuse. Through the study of integrated MBR process, A/O-MBR process and BCOR-MBR process, the effect of each process on residential sewage treatment was investigated, and the treatment results were analyzed. The removal rates of D, ammonia nitrogen, total nitrogen and total phosphorus were 92.07%, 99%, 22.69%, 26.20% respectively. The average effluent turbidity was less than 0.26NTU, ammonia nitrogen < 2.56mg/L, COD < 25mg/L, total nitrogen < 49.58mg/L, total phosphorus < 3.32mg/L. The effluent indexes were in accordance with the water quality standard for urban miscellaneous water (GBT18920-2002).
On the basis of integrated MBR, anoxic zone was added, and A/O-MBR process was adopted. Hydraulic residence time was 2.8 hours, dissolved oxygen was less than 0.2 mg/L, hydraulic residence time in aerobic zone was 6 hours, and dissolved oxygen in aerobic zone was generally between 3-5 mg/L. Compared with the integrated MBR, the removal efficiency of COD is similar, the average removal rate is 93.78%, the system has strong impact resistance and stable operation; the removal rate of ammonia nitrogen is also maintained at a high level, the removal rate is as high as 98%, and the effluent ammonia nitrogen is always lower than 2mg/L. For total nitrogen and phosphorus, the removal efficiency has been significantly improved, total nitrogen from the original average 22.69% to 40.44%, total phosphorus from the original average 26.20% to 41.39%.
BCOR-MBR (Contact Oxidation-MBR) process was used to treat the reclaimed water in the residential area. The packing was made of polyurethane foam with larger porosity and specific surface area. Square polyurethane foam filler with 20-25mm side length was used. The packing was placed on the hollow plastic sphere and the density was lighter than that of water. The filling amount was about 50% of the whole reactor. The optimum parameters were obtained by the integrated MBR, and the effluent indexes were as follows: COD removal rate was 94.24%, COD was lower than 15mg/L in the later stage; NH3-N removal rate was 99.25%, NH3-N was lower than 1.9mg/L in the effluent; TN effluent was 44.58mg/L, the average effluent rate was 36.24%; total phosphorus removal rate was 43.58%, and the average effluent was 2.4mg/L.
Membrane fouling is an unavoidable problem in MBR process. Membrane fouling can be mitigated as much as possible through the causes of membrane fouling. Membrane fouling control methods include low pressure operation, aeration, backwashing and membrane cleaning. Membrane cleaning methods include air-washing, air-water backwashing, drug cleaning, ultrasonic cleaning and so on. Cleaning, removal of residual substances attached to the membrane surface, slowing membrane fouling, achieving membrane flux recovery purposes.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：X703;TV213.4

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