厌氧消化是剩余污泥稳定化处理的常用技术，针对厌氧消化过程中污泥水解速率慢、甲烷产率低的瓶颈问题，本项目提出将内源生化合成FNA的技术方法与污泥两相厌氧消化工艺相耦合，由产酸相消化液提供质子，产甲烷相消化液氨氮亚硝化提供亚硝酸盐，FNA制取全过程无需外源加碱、加酸；并以FNA对污泥进行预处理融胞提高污泥厌氧消化效率。研究重点解决以下科学问题：(1)阐明污泥中有机质与氮源在回流循环中竞争与再分配机制；(2)阐明FNA预处理污泥的融胞机理。该耦合工艺能够显著提高污泥水解酸化速率及甲烷产率，减少污泥排放量；同时，本项目既节约FNA的生产成本，也降低了污水处理系统氮循环负荷，对于提高污泥资源化利用水平具有重要理论意义和应用价值。

Anaerobic digestion (AD) is widely used for the stabilization of waste activated sludge (WAS). In view of the two key problems limiting the application of AD process: low hydrolysis rate of sludge and low methane production yield. The combining process of inner-source free nitrous acid (FNA) production and two-phase anaerobic digestion (TPAD) is proposed for improving digestion properties of WAS. The proton is provided by digester liquor of acidogenic phase, the nitrite is provided by nitritation of ammonia from digester liquor of methanogenic phase, and the whole FNA production process do not need the additional alkaline and acid. The produced FNA is used to pretreat WAS to enhance the efficiency of anaerobic sludge digestion. In this study, the key scientific problems include: (1) To clarify the mechanism of competition and redistribution of organic matter and nitrogen source in reflux cycle system. (2) To elucidate the melting mechanism of FNA pretreatment sludge. The combining process can improve sludge hydrolysis rate and methane production yield, and reduce sludge discharge. In addition, it can save FNA production cost and decrease nitrogen recycle loading of wastewater treatment system, which has great contribution for sewage sludge reuse both in theory and in practice.