生物沥浸对自然干化污泥重金属去除效果研究

重金属的去除是污泥农用需要解决的关键问题之一.本研究采用摇瓶实验,将氧化硫硫杆菌为功能微生物的生物沥浸技术应用于干化污泥重金属的去除,对山西省不同污水处理厂11个干化污泥样品进行了为期15 d的生物沥浸处理.分析了生物沥浸体系p H及SO2-4的变化情况,并对生物沥浸前后污泥中Cu、Zn、As、Cd、Cr等重金属去除率及有机质、全氮、全磷、全钾等养分的损失率进行了分析.结果表明,干污泥直接进行生物沥浸过程较为缓慢,无机酸对体系的酸化能够快速启动干化污泥的生物沥浸过程.无机酸酸化后,体系S0的生物氧化率逐渐提高,酸化速率加快,且污泥重金属去除率随着p H的降低而提高,生物沥浸过程结束后,供试污泥样品Cu、Zn、As、Cd和Cr的去除率分别为23.69%~77.62%、89.67%~97.80%、30.24%~84.31%、18.18%~97.05%和28.55%~67.11%,而污泥有机质、全氮、全磷和全钾的含量损失率分别为3%、1%、44%和8%,污泥剩余养分含量满足农用泥质标准(CJ/T309-2009)的限定值.Cu、Zn、As、Cd和Cr去除率与污泥有机质含量呈显著负相关关系(r=0.935、0.895、0.932、0.516、0.847,n=11).

Removal of heavy metals from natural dried sludge by bioleaching method

Removal of heavy metals is a key issue for utilization of sludge in agriculture. Bioleaching technology was introduced in this study for removal of heavy metals from eleven dried sludge samples which collected from different wastewater treatment plants in Shanxi province. The bioleaching process was incubated for 15 days with Acidithiobacillus thiooxidans as function microbial. The changes of system pH and SO₄^2- were investigated during bioleaching. In addition, the removal efficiency of Cu, Zn, As, Cd, and Cr, and the loss amount of organic matter, total nitrogen, total phosphorus, and total potassium were studied. The results showed that the bioleaching process was slow in original dried sludge system. However, the bioleaching process quickly started with addition of inorganic acid. After acidification, bioleaching process was significantly accelerated as the sulfur was rapidly bio-oxidized, and the removal efficiencies of sludge-borne heavy metals increased with the decrease of pH. After bioleaching, the removal efficiencies of sludge-borne Cu, Zn, As, Cd, and Cr were 23.69%~77.62%, 89.67%~97.80%, 30.24%~84.31%, 18.18%~97.05%, and 28.55%~67.11%, respectively. But the contents of organic matter, total nitrogen, total phosphorus, and total potassium just reduced by 3%, 1%, 44%, and 8%, respectively. The contents of remained nutrients met the limit value given in agricultural application standard (CJ/T309-2009). Removal efficiencies of Cu, Zn, As, Cd, and Cr were significantly and negatively related to the organic matter content of sludge (r=0.935, 0.895, 0.932, 0.516, 0.847, n=11).