某城市城镇污水处理厂COD排放现状评价分析

基于统计学的方法理论,分析北方某城市11家采用二级处理或二级强化处理工艺的城镇污水处理厂3 a例行监测数据,得到该城市城镇污水处理厂化学需氧量(COD)的排放浓度呈Delta-对数正态分布.在此基础上,借鉴美国水污染物排放限值制订方法,对该城市城镇污水处理厂COD任意一天排放和月均排放情况进行评价分析,得到其任意一天最大值低于《城镇污水处理厂污染物排放标准》(GB 18918-2002)中一级A标准(50 mg·L-1)要求,同时提出了月均排放评价结论,并对相关结论进行了讨论.本研究所探索的方法体系和结论可为相关污染物排放标准的制修订提供参考.

Assessment on the COD Discharge Status of Municipal Wastewater Treatment Plant in a City of China

Based on the statistical theory, the paper collected routine monitoring data for 3 years of 11 municipal wastewater treatment plants with secondary treatment or enhanced secondary treatment in a northern city in China, and analysis of the discharge concentration distribution of COD showed a Delta-lognormal distribution. On this basis, referring to the formulation methods of water pollutant discharge limits used in the USA, the paper studied and assessed the discharge status of COD of the municipal wastewater treatment plants in the city, including the daily maximum and the monthly average discharge status, and came to the conclusion that the daily maximum discharge status met the first grade A class discharge standard (50 mg ·L^-1) required by the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002). Meanwhile, the assessment conclusion was obtained for the monthly average discharge status, and the conclusions were discussed. The assessment method and the conclusions in this paper might provide reference for formulation and revision of water discharge standards.