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| Heavy metals removal from sewage sludge and dewaterability improvement by bioleaching |
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Abstract 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.
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Received: 11 July 2012
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CHEN Huan-Yu, LIU Jing-Qing, WEI Zong-Yuan, ZHANG Hui-Hui, HE Xiao-Fang, ZHOU Xiao-Yan, QIU Shang-De, HU Bao-Lan, LOU Li-Ping. Radial differences in contaminant distribution in large-diameter pipe scales of main pipelines in drinking water distribution system[J]. CHINA ENVIRONMENTAL SCIENCECE, 2015, 35(9): 2706-2712. |
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