《巴黎协定》的签署意味着控制地球变暖问题已全球化。化粪池是在尚无集中式污水处理设施情况下出现的一种原始市政污水处理单元,曾在解决城市卫生问题方面起到一定积极作用。但在集中式污水处理厂普遍兴建的今天,化粪池的作用则显得有些微不足道,甚至是在帮倒忙,产生的负面作用很大。除截留碳源(COD)外,化粪池还将截留的COD厌氧转化为严重的温室气体甲烷(CH4);不能有效逸散时CH_4还会带来巨大的爆炸隐患。测算表明,我国城市/ 城镇化粪池产生的CH_4总量高达3 000*10~4t CO_2当量/a,与市政集中式污水处理厂CH_4和N_2O直接碳排放量(2 512*10~4 tCO_2当量/a)和总碳排放量(3 985 *10~4 t CO_2当量/a)处于同一水平。因此,化粪池CH_4排放量是一种不可小觑的隐性碳排放源。只有国家层面规范十分明确,才能真正废止化粪池使用,使之全面退出历史舞台。
英文摘要:
Signing the Paris Agreement means that the global warming has been an issue around the world. As a primary unit of municipal wastewater treatment coping with sanitary problem, septic tanks appeared when there was no centralized wastewater treatment facilities. However, under the current condition with centralized wastewater treatment facility, the septic tank plays negligible or negative role. Septic tanks could not only intercept carbon sources (COD) but also convert the intercepted COD into greenhouse gas methane (CH_4) under anaerobic condition. CH_4 could cause potential explode if it could not escape effectively from septic tanks. It has been calculated that the annual amount of CH_4 produced from septic tanks in China has been up to 30 million tCO_2(eq)/a, which is at the same level as the direct emissions of CH_4, N_2O [25 million tCO_2(eq)/a] and the total carbon emissions [40 million tCO_2(eq)/ a] from centralized wastewater treatment plants. Therefore, the carbon emission of CH_4 from septic tanks is actually a ' recessive' carbon source which is usually neglected. As long as the norms from the government specification are clear and definite,septic tanks can be abandoned and out of usage any longer.