Abstract:

Hydrothermal treatment of sewage sludge was conducted by using a stainless steel autoclave reactor at different temperature. This study aims to investigate the influence of reaction temperature on the migration and transformation of nitrogen in sewage sludge during hydrothermal treatment. The pathway of nitrogen transformation during hydrothermal treatment was also comprehensively analyzed. The results showed that nitrogen was mainly distributed into solid and liquid products after hydrothermal treatment. The percentage of nitrogen distribution in liquid products was increased with the increasing reaction temperature. During hydrothermal treatment, the inorganic nitrogen in sewage sludge was almost completely hydrolyzed to ammonia nitrogen and nitrates nitrogen. The labile protein was decomposed into organic nitrogen and ammonia nitrogen, and the organic nitrogen was further decomposed to ammonia nitrogen. However, the stable protein can be transformed into the forms of pyridine nitrogen, pyrrole nitrogen, quaternary nitrogen and nitrile nitrogen. Each form of nitrogen can be decomposed into ammonia nitrogen at a high reaction temperature. In summary, the nitrogen in sewage sludge was gradually transformed from solid products to liquid samples with the increasing hydrothermal reaction temperature, and the nitrogen remained in liquid samples major in the form of organ nitrogen and ammonia nitrogen.

Key words: sewage sludge, hydrothermal treatment, nitrogen, transformation, temperature

摘要：

采用高温高压反应釜在不同温度下进行了污泥水热实验。主要考察污泥中氮元素在水热过程中的迁移转化以及水热温度的影响，并对水热过程中氮元素的迁移路径进行了系统分析。结果表明，氮元素主要分布在固相和液相产物中，并随着水热温度的升高，分布在液相产物中的氮元素逐渐增加。在水热过程中，污泥中的无机氮形态几乎全部转换为氨氮和硝酸盐氮形态；不稳定性蛋白质氮分解为有机氮和氨氮，有机氮可进一步分解为氨氮；而稳定性蛋白质可转变为吡啶氮、吡咯氮、季氮以及腈氮形态，在较高的水热温度下均可再分解为氨氮。因此，随着水热处理温度的升高，污泥中氮元素逐渐从固相中转移到液相中，在液相产物中主要以有机氮和氨氮形态赋存。

关键词: 污泥, 水热处理, 氮, 迁移, 温度