【作者】 齐悦；

【导师】 康春莉；

【作者基本信息】 吉林大学 ， 环境科学， 2004， 硕士

【摘要】 污水回用是缓解水资源短缺的重要方法。城市污水是城市稳定的淡水资源，研究开发污水深度处理回用技术，提高污水回用率，减少了城市对自然水的需求量，削减了水环境的污染负荷，减弱了对水自然循环的干扰，是维持健康水循环不可缺少的措施。在缺水地区和干旱年份再生水的应用更是雪中送炭，是解决水荒的切实可行之策。 小型火电厂在我国占有很大的比重，北方的大多数以供热为主的火电厂机组装机容量都不大。虽然小型火电厂的用水量相对较小，但是由于许多电厂建设时期较早，污水处理技术落后，使得耗水量和废水排放量很大。采用先进污水深度处理回用技术，实现小型火电厂的废水零排放，不仅可以减少污染而且可以节约用水。这对于北方尤其是缺水地区有着非常重要的意义。 本文在对小型火电厂各用水系统水质特点进行调查分析的基础上，通过对北方某小型火电厂的污水排放工艺运行与效果的研究，论证了北票发电厂废水深度处理回用、实现电厂废水零排放工程项目的可行性。一、小型火电厂各用水系统水质特点调查分析小型火电厂的废水一般分为除灰废水、冷却系统排水、化学水处理系统排水、输煤系统废水、厂区生活废水、含油废水和杂用水系统排水等。其中除灰废水和冷却水系统排水水量占整个电厂废水的80％左右。其它废水水量由电厂的具体用水情况而定。冷却水系统排水水质较好，只是温度和COD值较高。除灰废水水质差，水中不仅COD和SS很高，还含有许多重金属元素。 <WP=58> 冷却水系统的排污可以作为低级用水系统的补水（例如冲灰系统、原煤加湿系统等）。煤场废水、冲灰废水水质较差，并且含有多种重金属，较好的措施是将洗煤、冲灰水形成闭路循环，使冲灰系统只补水，不排水。含油废水以及化学水处理系统排放的废水可以作为系统的补水水源。二、小型火电厂污水深度处理回用案例研究 以北方某电厂为例，根据小型火电厂各用水系统和排放的废水的特点，按照污水处理的技术路线必须采用一级物化预处理，二级生物处理和三级强化深度除盐处理的原则，改进技术路线如下： 1、将冷却水系统的浓缩倍率提高，减少排放量。冷却水系统的废水作为输煤栈桥用水、原煤加湿用水和燃油泵轴承用水的补水。　　2、改造为脱硫-除尘-体化系统，提高脱硫效率。新建石灰制浆系统，向脱硫-除尘-体化系统供应石灰浆。脱硫后残余的石灰进人灰沟。　　3、废水分成两部分来处理。含油废水以及化学水处理系统排放的废水作为石灰制浆系统补水。　　4、平衡水量，新建冲灰水调节池，减少水量波动造成废水外，实现了该小型电厂废水的零排放。 该电厂废水零排放工程实施后，对于水资源非常紧缺的北水地区来说，其社会和环境效益是显而易见的。 三、北票发电厂废水深度处理回用技术可行性研究北票发电厂年用水量3860000t，其中厂内用水量3300000t，家属区居民用水量560000t；北票发电厂外排污水排放106t/h，其中转机冷却水排放43t/h，生产生活水排放30t/h，循环水排污水排放25t/h,化学反<WP=59>渗透排水排放8t/h。方案一提出转机冷却水收集后直接用做转机冷却水，化学反渗透排水用做干灰加湿搅拌及燃料冲洗水和煤场喷淋水，生产生活污水经处理达工业水标准后回收做循环水补水或做转机冷却水；方案二是在方案一的基础上将循环水排污水经反渗透处理达工业水标准后做循环水及热网补水后循环水补水。方案三是在方案一的基础上，将回收的生产生活废水达工业水标准后经反渗透处理做循环水补水。 方案一总投资332.73万元，可回收废水90.23万吨/年，工程净效益为106.1万元/年，投资回收年限3.14 年。方案二总投资527.43万元，可回收废水112.13万吨/年，工程净效益为116.04万元/年，投资回首年限4.55年。方案三总投资552.73万元，可回收废水94.61万吨/年，工程净效益为90.69万元/年，投资回收年限6.10年。由于方案二具有投资收益较大，投资回收年限较短的特点，并能做到废水零排放，其经济和社会效益均十分显著。且该工程施工难度不大，在经济和技术上均是可行的，因此建议优先采用方案二。 北票发电厂污水深度处理的技术路线，符合CECS61:94《城镇及污水处理厂设计规范》所规定的污水处理工艺设计规定，和国家设计部、国家环境保护总局和国家科学技术部联合发布的“建发[2000]124号”文件印发的《城市污水处理及污染防治技术政策》中4.1条<工艺选择准则〉，4.2条＜处理工艺＞等规定。北票发电厂污水深度处理的技术路线符合一级物化预处理，二级生物处理和三度强化深度除盐处理的处理工艺设计原则。北票发电厂污水深度处理回用技术路线科学、完整、经济，各个设计参数可靠，能够确保处理后的出水水质达标。 四、结论 通过对小型火电厂用水和排水的水质特征研究，提出合理的节<WP=60>水工艺和废水资源化技术，对北票发电厂废水深度处理回用工程的可行性进行了论证，结果表明实现小型火电厂的废水零排放，是解决城市严重缺水问题的最有效途径。更多还原

【Abstract】 Sewage reuse plays an important role in relieving water resources shortage. Urban sewage reuse, which is a key factor for sustaining stable freshwater resources, could improve wastewater reuse rate and decrease need for natural water resources, and at the same time, it could diminish pollution load for water environment and disturbance for natural water cycle. Especially in water-shortage areas and drought season, it is a feasible measure for solving water scarcity.Small-size power plants occupy a quite big proportion in China. In the northern part of China, most power plants are used for heat supply, which have small installed capacity and only need little water quantity. But because most power plants are built early, which wastewater treatment technique is quite lag, and often discharge much wastewater. So sewage advanced treatment and reuse technique is useful measure to economically use water and realize zero pollution. Based on the analysis on quality characteristics of different water systems in small-size power plants, this paper studies on the operation and effect of sewage discharge technique, and provides sewage advanced treatment and reuse technique, which tries to realize wastewater zero discharge.一、Analysis on Quality Characteristics of Different Water Systems Insmall-Sizepower PlantsWastewater in small-size power plants includes many types, such as wastewater from eliminating ash, discharge water from cooling system, discharge water from chemical water treatment system, wastewater from transferring coal system, residential wastewater from factory community, wastewater with oil and discharge water from other systems, etc. Among which, wastewater from eliminating ash and cooling system occupy 80% of the total discharge water, and others are decided by the actual condition of the power plant. Generally, discharge water from cooling system has better water quality, which only has higher temperature and COD value, but wastewater from eliminating ash has worse water quality, and has higher COD, SS and other heavy metal elements. Wastewater from cooling systems could be used for recharge water for low-level water system like rinsing ash system. Wastewater from coal <WP=62>factory and rinsing ash system has worse water quality and many heavy metals, so it is better to set up closed cycle within washing coal and rinsing ash water. Wastewater with oil and discharge water from chemical treatment system could be used for recharge water for system.二、Case Studr on Sewage Advanced Treatment And Reuse Technique in Small-Size Power PlantAccording to characteristics of different water systems and discharge wastewater, the paper takes a northern power plant as the example, and improve original technical route of sewage treatment, which includes physical-chemical treatment pretreatment, secondary biological treatment of wastewater and tertiary advanced wastewater treatment. The improved technique route is the followings:1. Improve concentrated rate of cooling system and diminish discharge quantity. Wastewater could be used for transmitting coal, watering and washing coal and fuel pump.2. Set up the integrated systems of desulfurizing and diminishing ash, and construct calcareousness-slurry systems, which could supply calcareousness slurry to integrated system, and calcareousness left after desulfurizing are dumped into ash ditch.3. Wastewater treatment is divided two parts. Wastewater with oil and wastewater from chemical water treatment are used for recharge water to calcareousness-slurry systems.4. Balance water quantity and build adjusting pond for washing calcareousness water to diminish wastewater because of water quantity fluctuation and realize zero discharge. 三、Feasible Research on Sewage Advanced Treatment And Reuse Technique in Beipiao Power PlantAnnual water quantity in Beipiao Power Plant is 3860000t, among which factory and residential occupy 3300000t and 560000t respectively. Discharge wastewater is 106t/h, among which cooling water is 43t/h, product and living water更多还原