城镇生活污水厂CO_(2)释放过程中碳同位素组成变化  

Changes in carbon isotope composition during CO_(2)release from urban sewage treatment plants

作　　者：刘建华 吴洋洋 刘健[3] 刘运涛 LIU Jianhua;WU Yangyang;LIU Jian;LIU Yuntao(Ecological Environment Promotion and Technology Center,Pingdingshan Ecological Environment Bureau;The Fifth Institute of Geo-Exploration,Henan Bureau of Geo-Exploration&Mineral Development;SINOPEC Star Petroleum Corporation Limited)

机构地区：[1]平顶山市生态环境宣传和技术中心 [2]河南省第五地质勘查院有限公司 [3]中国石化集团新星石油有限责任公司

出　　处：《环境工程技术学报》2025年第2期446-453,共8页Journal of Environmental Engineering Technology

基　　金：国家自然科学基金项目(42073009,41573095)。

摘　　要：生活污水中含有大量有机质,污水处理过程中有机质降解产生大量CO_(2),是大气CO_(2)重要的源,借助溶解性无机碳碳同位素组成(δ^(13)C-DIC)能够有效阐明水体有机质降解机理和释放CO_(2)过程。但污水厂污水处理过程中的δ^(13)C-DIC变化以及碳同位素分馏情况尚不明确。选择某生活污水处理厂作为研究对象,在污水处理厂不同处理单元采集污水样品,借助溶解性无机碳碳同位素技术和瑞利分馏模型,判断碳同位素分馏机制及CO_(2)释放过程。结果表明:1)污水厂进水的溶解性无机碳(DIC)部分来自碳酸盐岩溶解,DIC浓度〔(7.62±0.16)mmol/L〕为全处理流程中最高,方解石饱和指数最大(0.404)且趋于沉淀,随污水处理过程进行方解石趋于溶解方向;2)污水厂出水δ^(13)C-DIC(均值为−10.45‰±0.28‰)最高,进水δ^(13)C-DIC(均值为−12.40‰±1.07‰)并非最低,且高于生物处理区(厌氧、缺氧区和好氧池),这是因为污水中有机质降解和方解石溶解产生并释放CO_(2),导致生物处理区污水DIC浓度降低,污水DIC来自有机质降解产生的溶解CO_(2)占比增高,以及污水δ^(13)C-DIC明显降低;3)从好氧区开始,有机物在好氧细菌的作用下快速消耗,CO_(2)大量逸出,DIC浓度显著降低,导致污水中δ^(13)C-DIC升高并伴随着强烈的同位素分馏过程,通过计算得到碳同位素分馏系数为0.9927。研究结果可为优化城镇生活污水厂碳排放核算提供支撑。Domestic sewage contains a large amount of organic matter.In the process of sewage treatment,the degradation of organic matter produces a large amount of CO_(2),which is an important source of atmospheric CO_(2).With the help of dissolved inorganic carbon carbon isotope composition(δ^(13)C-DIC),the degradation mechanism of organic matter in water and the process of releasing CO_(2)can be effectively elucidated.However,the changes ofδ^(13)C-DIC and carbon isotope fractionation in the process of sewage treatment are not clear.A domestic sewage treatment plant was selected as the research object,and sewage samples were collected in different treatment units of the sewage treatment plant.The carbon isotope fractionation mechanism and CO_(2)release process were judged by means of dissolved inorganic carbon carbon isotope technology and Rayleigh fractionation model.The results showed that:(1)For the influent of wastewater treatment plant,the concentration of dissolved inorganic carbon(DIC)was the highest in the whole treatment process,which was(7.62±0.16)mmol/L,and partly from the dissolution of carbonate rocks.The saturation index of calcite was the largest(0.404)and tended to precipitate,and the calcite tended to dissolve with the wastewater treatment process.(2)The effluentδ^(13)C-DIC(mean value−10.45‰±0.28‰)was the highest,and the influentδ^(13)C-DIC(mean value−12.40‰±1.07‰)was not the lowest,but higher than that in the biological treatment area(anaerobic,anoxic and aerobic tank).It was due to the degradation of organic matter and the dissolution of calcite to produce and release CO_(2),resulting in a decrease in the DIC concentration of sewage in the biological treatment area,an increase in the proportion of dissolved CO_(2)from the degradation of organic matter in sewage DIC,and a significant decrease in sewageδ^(13)C-DIC.(3)From the beginning of the aerobic zone,the organic matter was rapidly consumed under the action of aerobic bacteria,a large amount of CO_(2)escaped,and the DIC concentrati

关 键 词：生活污水处理厂 CO_(2)排放 碳同位素 同位素分馏 瑞利分馏模型 

分 类 号：X703[环境科学与工程—环境工程]