摘    要

本设计是以相关的资料为依据，设计一座城市污水处理厂，其日处理量为10万立方米。主要处理来自东北某工业区的生活污水，要求处理后出水水质达到《城镇污水处理厂污染物排放标准（GB18918-2002）》中的一级A类标准。根据资料污水BOD/COD=0.462，可生化性较好,重金属及其他难以生物降解的有毒有害污染物一般不超标,污水中主要污染物指标BOD、COD、SS值为典型城市污水值，氮超标，磷含量较低，作为处理过程中的营养物质，不需要单独处理，故本设计采用了氧化沟工艺。

此工艺污染物去除效率高，运行稳定。能较好的耐受冲击负荷。污泥沉降性能好。缺氧、好氧两种不同的环境条件和不同种类微生物菌群的有机配合，能同时具有去除有机物、脱氮的功能。脱氮效果受混合液回流比大小的影响。在脱氮去除有机物的工艺中，该工艺流程最为简单，总的水力停留时间也少于同类其他工艺。管理维护简单运行费用低，国内工程实例多，工艺成熟，容易获得工程管理经验

关键词：城市污水；氧化沟；脱氮

Abstract

This design is based on the relevant data and designs a municipal sewage treatment plant with a daily capacity of 130,000 cubic meters. It mainly deals with the domestic sewage from DongBei province, and requires that the water quality of the discharged water should meet the first level standard of the pollutant discharge standard (gb18918-2002) of the urban sewage treatment plant. BOD/COD =0.462 according to the data, can be better biological sex, hard to biodegradation of toxic heavy metals and other harmful pollutants are generally not overweight, sewage main pollutant indexes in the BOD, COD, SS value for typical urban sewage, nitrogen, phosphorus content is low, as nutrients, in the process does not need to be treated separately, this design USES the oxidation ditch process.

The removal efficiency of this process is high and stable. Can withstand shock load better. The sludge settling performance is good. The two different environmental conditions and the organic cooperation of different kinds of microbial flora can simultaneously remove the organic and nitrogen removal functions. The effect of denitrification is affected by the ratio of the mixture reflux ratio. In the process of removing organics from nitrogen removal, the process is the simplest, and the total hydraulic retention time is less than that of other processes. Management and maintenance simple operation cost low, domestic engineering examples are many, process mature, easy to obtain project management experience.

Keywords：Urban sewage; oxidation ditch; denitrification