生物沥浸去除污泥重金属及改善脱水性能研究

从天然矿山酸性废水中富集制备了3种嗜酸性细菌混培物,开展了污泥生物沥浸实验,研究了沥浸去除污泥重金属(Cu、Zn、Cd)同时改善脱水性能的效果.结果表明,3种嗜酸性细菌混培物均可有效去除污泥中的重金属(P<0.01).沥浸12d后,改进型Starkey培养基富集的嗜酸性细菌混培物对Cu和Cd的去除率分别达到82.0%和82.9%,9K培养基富集的嗜酸性细菌混培物进行生物沥浸处理对Zn的去除率可达到87.5%.同时,生物沥浸还可以显著改善污泥的脱水性能(P<0.01).经过12d沥浸,污泥的离心脱水率可由73.1%上升到90.0%.显微观察和能谱分析结果显示,污泥脱水性能的改善是因为生物沥浸能使污泥结构由絮体状变成明显的颗粒状,并可形成以铁、氧和硫为主要元素组成的次生矿物规则晶体.

Heavy metals removal from sewage sludge and dewaterability improvement by bioleaching

Three kinds of mixed culture of acidophilic bacteria were enriched and prepared from natural acid mine drainage and used in bioleaching experiments. The heavy metals (Cu, Zn and Cd) removal from sewage sludge and the improvement of sewage sludge dewaterability in bioleaching processes were investigated. The results showed that all the three prepared mixed culture of acidophilic bacteria could efficiently remove heavy metals from sewage sludge (P<0.01). After 12 days of bioleaching, 82.0% of copper and 82.9% of Cd could be removed by the mixed culture of acidophilic bacteria enriched by modified Starkey medium, and 87.5% of zinc could be leached out when inoculating the mixed culture of acidophilic bacteria enriched by 9K medium. Meanwhile, the bioleaching processes could also significantly enhance sewage sludge dewaterability (P<0.01). The centrifugal dehydration efficiency of sewage sludge rose from 73.1% up to 90.0% after 12 days of bioleaching. The microscope observation and energy spectrum analysis demonstrated that the dewaterability improvement of sewage sludge was attributable to the changes of particle structure from flocculent to obvious granular and the formation of the secondary minerals mainly consisting of iron, oxygen and sulfur elements in the bioleaching processes.