贠丹丹,王陆军,郝同,梁硕,王聚灿,赵乔华
(北京沃尔德斯水务科技有限公司,北京 102300)
摘 要:目前水体环境污染严重,国家环保力度加大,新的标准愈加严格,城市污水处理厂必须进行提标改造。针对内蒙古某污水处理厂存在的现实问题,提出改造难点,并根据水质指标分析探索出提标改造路线为原处理工艺出水+磁混凝沉淀池--深床反硝化滤池--臭氧氧化池--消毒—中水回用,使污水厂达到地表IV类水标准。污水深度处理效果明显,适用于对出水水质要求高,出水回用工程。选择深度处理工艺时,要根据处理水质、工程规模和出水水质要求进行分析实验确定。
关键词:城市污水处理厂;提标改造;IV类水标准。
Analysis of Technical Route for Upgrading the Current Effluent Standard of Urban Sewage Treatment Plants to Environmental Quality Standard for Surface Water Class IV
Abstract: At present, due to severe water pollution, Our country is investing more efforts and taking new and more strict standards to protect environment. Under such circumstances, urban sewage treatment plants have to be upgraded. As for the issues in a Inner Mongolia sewage treatment plant, We pointed out the difficulties in the current plant transformation, analyzed data of water quality and discovered a new transforming route(original process+magnetic coagulation tank+Deep-bed denitrification filter tank+ozone oxidation+sterilization→reclaimed water), by applying which, the quality of effluent can meet the standard of surface water class IV. This process is perfectly suitable for reclaimed water projects or projects demanding high water quality of effluent because of its outstanding efficiency in sewage advanced treatment. When we have to choose a process for advanced sewage treating, we should always take the quality of influent water quality, scale of the project and the quality of effluent water into account, analyse the data and find the best solution.
Key words: Urban sewage treatment plant; upgrading; Surface water quality Class IV standard.
1 背景
目前水体环境污染严重,我国环保力度不断加强,制定了节能减排目标,同时将城镇污水处理厂的污染物排放指标不断提高[1-3]。从2003年7月1日起《城镇污水处理厂污染物排放标准》(GB18918-2002)开始实施,该标准对污水处理厂的出水COD、BOD5、SS、TN、NH3-N、TP及大肠杆菌有了更严格的规定。2006年提出修改单公告[4],明确指出“城镇污水处理厂出水排入国家和省确定的重点流域及湖泊、水库等封闭、半封闭水域时,必须执行一级A标准”。
各地区根据地方情况制定了当地水环境污染物排放限值,如天津标准把TN定为10mg/L,氨氮为1.5(3.0)mg/L。此外,还有环渤海流域标准、环太湖流域标准、巢湖流域标准、广州的类五类标准等都是在国家地表水四类和三类水的标准下适当放宽TN和氨氮的标准下形成各自的标准。之后《地表水环境质量标准》(GB3838-2002)IV类、III类水的提出,进一步对各污染物指标更严格的限定(相关排放标准表1列出)。