三峡大坝是世界上最大的综合水利枢纽工程，具有发电、航运、防洪及供水 等显著综合利用效益。三峡库区是指受长江三峡工程淹没并有移民任务的 20 个县 （市）的地区。近年来，随着国家投入的迅速增加，库区经济有着显著的增长， 但与此同时，经济的发展、人口增加和城市化进程加快给库区水环境带来了巨大 压力。 三峡大坝于 2010 年 10 月 24 至 26 日成功进行了 175 米试验性蓄水，相比蓄 水前，三峡库区水力学条件发生变化。库区流场的变化直接导致污染源至受纳水 体的直线距离减短，污水自净能力下降，在同样的污染物排水负荷下，收纳水体 中污染物浓度增加，次级河流及近岸污染带水环境污染日益严重。虽然目前库区 已建成多座城市污水处理厂，并且也取得了一定的效果，但由于库区大部分属于 经济基础比较薄弱地区，环境保护投资不足，库区仍然面临严峻的治污局面。加 之小城镇数量众多，部分小城镇紧邻水体，其污染更不可小视。因此，对三峡库 区小城镇水污染进行治理迫在眉睫。 本文通过对库区典型小城镇给排水设施，居民用水特征等进行实地调研以及 对三峡库区小城镇生态污水处理工艺的运行现状进行了调研和统计分析的基础 上，提出在三峡库区运用沟渠生态系统处理小城镇生活污水在技术和经济上是可 行的。报告主要得出以下结论。 （1）三峡库区小城镇给水排水特征 三峡库区小城镇的给水基础设施比较完备，排水基础设施还有待完善，污水 管网生活污水收集率较低，目前污水主要以室内排水管网-化粪池-沿街暗渠-镇周 边明渠和室内排水管网-化粪池-污水收集管网-污水厂两种方式进入受纳水体。 本文所调查小城镇人均生活用水量仅为 65.8 L/d，分别是《室外给水设计规 范》(GBS0013—2006)和《城市居民生活用水量标准》(GB/T 50331-2002)中相关 规定值的 0.39～0.66 倍和 0.47～0.66 倍。库区小城镇最为普遍的用水模式是室内 有淋浴设备和给排水卫生设备的用水模式。 （2）运用生态工艺在处理小城镇污水在技术和经济上可行 从理论角度分析生态工艺具有良好的生活污水处理能力，其处理效果受多因 素影响。通过实例论证所选生态工艺在三峡库区均能满足当地污水处理的要求。 污水处理厂排放的废水中氨氮、总氮、悬浮物、化学需氧量、生化需氧量、总磷 等监测指标均符合《城镇污水处理厂污染物排放标准》（GB18918—2002）一级 B 类标准要求。运用生态工艺处理小城镇生活污水在工艺上和经济上是可行的。 II （3）沟渠生态系统处理小城镇生活污水 自然沟渠对 COD Cr 、TN、TP 的去除率分别为 47.6%、20.6%、18.9%。对 COD 的去除效果最好，且各段中暗流段对各指标的去除率最高。自然沟渠对 N 的去除 主要以颗粒态为主。沟渠内部有硝化反硝化能力，但对 NH 4 + -N 的去除主要以吹脱 为主。天然沟渠对 P 的去除主要以颗粒态吸附、过滤为主，且去除效果主要集中 在暗流区和缓流区，对 DP 的去除效果不高。 强化沟渠系统对有机物和 SS 有较强的去除能力，同时对氮磷的去除效果也不 错。强化沟渠稳定运行时，经系统处理稳定出水的 SS、CODcr 以及总氮分别达到 了《城镇污水处理厂污染物排放标准》（GB18918-2002）中的一级 A 标和一级 B 标；TP 和 NH 4 + -N 也能达到二级标准，接近一级 B 标。 本文提出一种结合三峡库区山地地形的污水处理工艺。这种工艺按顺序或者 交叉构建格栅分流槽、沉砂池、接触氧化池、人工湿地、稳定塘、跌水装置。这 种生态污水处理系统处理效果良好且稳定，不受外部动力条件的约束，极大的节 约了能源，节省了运行成本。另一方面，这种工艺结合了当地的沟塘系统，在处 理污水的同时也有一定的景观效应。因此，沟渠生态工艺在库区具有推广意义。 关键词，三峡库区，山地小城镇，生活污水，沟渠，生态处理 III ABSTRACT Three gorges reservoir area is located in the upper-middle of Yangtze river which is the key development zone of Yangtze river basin economic development from the east to the west. Its development has important strategic significance to carrying out the strategy for western development and promoting the development of the Yangtze River economic belt. But the economic development, population increase and the urbanization bring enormous pressure to the water environment The three gorges dam successfully storage water to 175meters by experimental in 2010 October 24 th to 26 th pared with before, hydraulics conditions is changing, self-purification declining, Reservoir flow field changes resulting in slick shortened, and increasing of the width; in this case, in the same exclusively conditions water pollutant concentration increases, water environmental pollution heavier. After years of management, three gorges reservoir area has established many wastewater treatment plants and has made some achievements. But due to the environmental protection foundation was weak, environmental protection investment limited, reservoir still faced with severe pollution problem. Together with part small towns are numerous, small towns close to water, its pollution more is not taken lightly. Therefore, the three gorges reservoir area small towns’ water pollution treatment is imminent. According to the research achievements of water supply and drainage facilities and residents used water features by typical small towns; on the investigation statistical analysis basis of wastewater treatment process operation status, this paper put forward that in three gorges reservoir area use ditches ecosystem towns sewage treatment in technology and economy is feasible. This article mainly following conclusions: (1) Features of water supplied and drained in small towns in three gorges reservoir area In the small towns of three gorges reservoir water infrastructure is relatively completed, drainage infrastructure remains to be perfect; sewage collection rate of sewage pipe network is lower. Currently Two way sewage into the reservoir mainly by two ways, which are indoor drainage pipelines - septic tank - dark canal - open channel or Indoor drainage pipelines - septic tank - sewerage pipeline - wastewater treatment plant. IV Water for domestic use has a large proportion in total in urban life-water quantity of water. Small town’s per capita life-water quantity is only 65.8 L/d, which is just 0.47~0.66 of townsman life-water quantity standards (GB/T 50331-2002) and 0.39 ~ 0.66 of the outdoor water design rules (GBS0013-2006).Drainage sanitation and shower facilities of water reservoir model in door are the most common mode of water using in small towns. (2) The ecological processes in small towns sewage treatment is feasible in technology and economy From a theoretical perspective analysis of ecological technology, it has good sewage treatment ability and the treatment effect by multiple factors. Through example this paper demonstrates the selected ecological process in three gorges reservoir area all can satisfy the requirements of local sewage treatment. Sewage discharge of wastewater In the ammonia nitrogen, total nitrogen and floaters, chemical oxygen demand (COD), BOD, total phosphorus or other monitoring indexes accord with the urban sewage treatment plants standards for pollutants discharge (GB18918-2002) level 1 class B standard requirement. The ecological processes in small towns sewage treatment is feasible in technology and economy (3)Use ditches ecosystem for small towns’ sewage treatment The removal of CODcr, TN, TP were 47.6%, 30.0% and 18.9%, respectively. Through the analysis about the existence of pollutants in the inlet and outlet wastewater we can obtain that the main way of pollutants removal in the upland ditch is particulate-intercept and adsorption. The removal rates of PN, PP were 60.6% and 49.6%, respectively. The writer trying to make a technology that combines the ditch optimization and pond-wetlands in series based on the study, which can be used to treat the urban domestic wastewater and lessen the pollution. Enhanced ditch system has strong ability to remove organic and SS, and nitrogen and phosphorus removal efficiency of pretty good also. SS ,CODcr and TN in effluent has respectively achieves first-level A standard and the first-level B standard and TP and NH4+-N achieve the secondary standard of 《Discharge standard of pollutants for municipal wastewater treatment plant》(GB18918-2002). Conclusion: this paper put forward a kind of wastewater treatment process combined with the three gorges mountain terrain. This kind of ecological sewage system treatment effect is good and stable, and is not affected by external dynamic conditions of constraint, greatly saves energy, save operating costs. On the other hand, V this technology combined with the local ditch pond system, in the treatment of wastewater c