生活污水处理厂甲烷的释放通量及其影响因素

摘要

An increaseing emissions of greenhouse gases has contributed to global warming, which has caused a deterioration of the agricultural ecological environment. Methane ( CH4 ) is an tipical greenhouse gas and domestic sewage is an important contributor.China has a large population and a large domestic sewage dis?charge.Therefore,the generation of methane in domestic sewage treatment plant is a problem urgent to be stud?ied.Samples were analyzed from each structure of the sewage treatment plant in Nanjing City. The results showed that the main structure of methane emission were oxidation ditch,anaerobic zone,rotary grit chamber, secondary settling tanks and anoxic zone. The methane emission of these five structures was accounted for 94. 69％ of the total discharge.It is estimated that 12625.61 kg/yr of methane will be released by this WWTP. Based on the chemical oxygen demand( COD) removal,CH4 emission factor was estimated to be 0.0457 kg/kg (CH4/COD).COD,temperature and dissolved oxygen are important influencing factors of methane flux.%温室气体的排放量增加,加剧全球气候变暖,最终导致农业生态环境恶化.甲烷是一种典型的温室气体,生活污水是其中一个重要的贡献源.中国人口众多,生活污水排放量巨大,因此亟需对生活污水处理厂产生甲烷情况进行研究.本研究对南京市某污水处理厂的各个构筑物进行了采样分析,结果表明,该污水厂的主要甲烷释放构筑物为氧化沟、厌氧区、旋转沉砂池、二沉池和缺氧区,这5个构筑物中的甲烷释放量贡献占整体释放量的94.69％.经估算,该污水处理厂每年释放12625.61 kg甲烷,根据化学需氧量的去除量,测算出甲烷排放因子为0.0457 kg/kg(CH4/COD).化学需氧量、水温和溶解氧是影响甲烷释放通量的重要影响因素.