15N示踪技术定量解析污水地下渗滤系统氮的去除机理及迁移转化动力学模型研究

The subsurface wastewater infiltration system (SWIS), as one of land treatment systems, is an ecological and reusable process used for decentralized domestic wastewater treatment in China. Compared to the conventional activated sludge and biofilm processes, this system has better performance in organic substance and phosphorus removal, lower construction and operational costs, and easier management and maintenance. However, nitrogen removal is deficient and nitrogen becomes the most difficult removing matter in SWIS. Conventional mass balance method impossibly provides the interal information and investigates the process and mechanisms during nitrogen removals. This project will use 15N isotope tracer technique to quantificationally analyze the contribution ratio and removal rates of ammonia volatilization, ammonification, nitrification, denitrification, plant absorption and soil substrate adsorption on nitrogen removal; to study the transferring, transformation and end-result of organic nitrogen, ammonia nitrogen, nitrite nitrogen and nitrate nitrogen; to identify the process, mechanisms and influence factors during nitrogen removal in SWIS. In addition, the project will bulid migration and transformation dynamical model of organic nitrogen, ammonia nitrogen, nitrite nitrogen and nitrate nitrogen, so as to describe the process of nitrogen removal comprehensively and dynamically.This project will provide theoretical foundation for the research on intensified nitrogen removal and regulation of operational parameter, enrich the theory system and technology meaning of wastewater treatment, and at the same time it will play a significant role in reducing pressure of wastewater treatment in China.

污水地下渗滤系统（SWIS）是一种适合中国国情的低耗高效的分散污水生态处理与资源化技术。由于系统的脱氮效率低，氮的去除成为限制该技术广泛应用的瓶颈。SWIS为隐蔽工程，传统的质量平衡方法难以提供脱氮过程的内部信息，从而无法有效的探究系统氮去除的过程及机理。本研究拟采用15N示踪技术定量解析SWIS中氨挥发、氨化、硝化、反硝化、植物吸收和土壤基质吸附作用对污水中各种形态氮去除的贡献率及去除速率；探明有机氮、氨氮、亚硝态氮及硝态氮在SWIS中迁移转化和最终归宿；揭示SWIS各种形态氮去除的过程、机理和影响因素，从而构建SWIS各种形态氮的迁移转化动力学模型，全面动态描述系统的脱氮过程。本项目将为SWIS强化脱氮技术的研究和关键运行参数的调控提供理论基础，促进SWIS在分散生活污水处理中的应用，同时对丰富分散污水处理的理论体系和技术内涵具有重要的科学意义。

污水地下渗滤系统（SWIS）是一种适合中国国情的低耗高效的分散污水生态处理与资源化技术。由于系统的脱氮效率低，氮的去除成为限制该技术广泛应用的瓶颈。SWIS为隐蔽工程，传统的质量平衡方法难以提供脱氮过程的内部信息，从而无法有效的探究系统氮去除的过程及机理。本研究采用15N示踪技术定量解析SWIS中氨挥发、硝化反硝化、植物吸收和土壤基质吸附作用对污水中各种形态氮去除的贡献率；揭示了影响SWIS各种形态氮去除的因素，构建了SWIS各种形态氮的迁移转化动力学模型，全面动态描述系统的脱氮过程。氨挥发、硝化反硝化作用、植物吸收和土壤基质吸附作用对SWIS氨氮的去除贡献分别3.6%-5.7%、69.4%-74.3%、1.3%-3.6%和12.3%-13.2%。氨挥发作用去除的有机氮量占2.4%-6.2%，硝化反硝化作用去除的有机氮量占41.9%-55.2%，土壤吸附吸附作用去除的有机氮量占15.6%-18.5%，植物吸收作用去除有机氮占2.4%-3.7%。硝化反硝化作用去除的硝态氮量占61.3%-68.5%，土壤吸附作用去除的硝态氮量占11.8%-17.9%，植物吸收作用去除硝态氮占15.7%-20.7%。硝化反硝化作用是SWIS各形态氮去除的主体作用。基质氧化还原电位，进水水力负荷、COD/N比和有机负荷影响SWIS氮的去除。构建的氨氮、有机氮和硝态氮的迁移转化动力学模型能反映实际SWIS工程出水中3种主要氮形态的浓度。本项目将为SWIS强化脱氮技术的研究和关键运行参数的调控提供理论基础，促进SWIS在分散生活污水处理中的应用，同时对丰富分散污水处理的理论体系和技术内涵具有重要的科学意义。