污泥生物炭在污泥好氧降解中的原位应用

摘要

在300,500,700℃下热解获得的污泥生物炭C300、C500和C700,分别添加至污泥中进行好氧降解反应,研究降解过程中污泥性质的变化,及反应前后污泥生物炭重金属含量的变化.结果表明,添加污泥生物炭提高了污泥降解产物的稳定性,降低了污泥中重金属的生物有效性.添加C300的产物稳定性最高、重金属生物有效性最低,相比对照工况,其产物的5日耗氧量降低了27%,Cu、Zn、As和Ni的生物有效性分别降低了24%、15%、26%和19%.反应后C300和C500中水溶性重金属含量没有显著变化,而C700中水溶性Cu、Zn和Ni的含量分别增加了16,94,4mg/kg. C300作为污泥好氧降解添加剂经济可行.%Three biochar samples were produced by pyrolysis of sewage sludge at the temperatures of 300, 500and 700℃, named as C300, C500and C700, respectively. The C300, C500and C700samples were separately mixed into sewage sludge for aerobic biodegradation, during which the variation of sludge properties was investigated, and the change of heavy metals in the biochars before and after reaction was studied. Results showed that the addition of sludge-derived biochar improved the stability of the products and reduced the bioavailability of heavy metals in the sludges. The most stable product sludge and the lowest bioavailability of heavy metals in the sludge were obtained in the trial with C300, for which the five-day oxygen consumption of the product sludge was 27% lower than that of the control, and the bioavailable contents of Cu, Zn, As and Ni were 24%, 15%, 26% and 19% lower than those of the control, respectively. The contents of water-soluble heavy metals in C300and C500before and after reaction were similar, while the water-soluble Cu, Zn and Ni in C700increased by 16mg/kg, 94mg/kg and 4mg/kg after reaction, respectively. In conclusion, adding C300 to sludge for aerobic biodegradation was recommended.