Tests were conducted for excess sludge treatment by supercritical water oxidation method at different pressures. Removal ratio of chemical oxygen demand (COD), total nitrogen, and ammonia were investigated. Variations of total phosphorus in sludge and orthophosphate concentrations of liquid were analyzed. Composition of solid product was discovered. It was showed that the removal ratio of COD and total nitrogen was improved via increasing reaction pressure. The maximum of COD and total nitrogen removal ratio was 95.80% and 85.27%, respectively. Total nitrogen was mainly due to ammonia and ammonium ion. The maximum of ammonia and ammonium ion removal ratio was 50.81%. An orthophosphate removal ratio of 97.23% in liquid was achieved at reaction pressure of 27 Mpa. Phosphorous element in sludge was mainly transformed into orthophosphate residue via supercritical water oxidation process. The residue was mainly consisted of O, Si, Al, Fe, P, S and Ca. The advantage of harmlessness and bulk reduction was obvious for excess sludge treatment by supercritical water oxidation method.%在不同压力条件下,采用超临界水氧化法处理剩余污泥.对化学需氧量(COD)、总氮、氨氮的去除效果及总磷、正磷酸盐的变化规律进行了研究,并对处理后的固体产物进行了分析.结果表明,随着反应压力增大,反应后出水水质较好,COD去除效果提高,COD去除率最高为95.80％；随反应压力增大,总氮去除效果提高,总氮去除率最高为85.27％；总氮主要以游离氨和铵离子形式存在,氨氮去除率最高为50.81％.反应压力在27 MPa时,液相中正磷酸盐的转化率达到97.23％.反应后污泥中的磷元素主要以磷酸盐形式存在于污泥残渣中.处理后残渣主要还包含O、Si、Al、Fe,P,S和Ca.超临界水氧化技术处理剩余污泥具有较好的无害化和减量化效果.
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