Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
J Hazard Mater. 2012 Jun 30;221-222:170-7. doi: 10.1016/j.jhazmat.2012.04.028. Epub 2012 Apr 18.
Bio-acidification caused by bio-oxidation of energy substances during bioleaching is widely known to play an important role in improving sludge-borne metals removal. Here we report that bioleaching also drastically enhances sludge dewaterability in a suitable pH level. To obtain the optimum initial concentrations of energy substances and pH values for sludge dewaterability during bioleaching, bio-oxidation of Fe(2+) and S(0) under co-inoculation with Acidithiobacillus thiooxidans TS6 and Acidothiobacillus ferrooxidans LX5 and their effects on sludge dewaterability and metals removal during sludge bioleaching were investigated. Results indicated that the dosage of energy substances with 2g/L S(0) and 2g/L Fe(2+) could obtain bio-oxidation efficiencies of up to 100% for Fe(2+) and 50% for S(0) and were the optimal dosages for sludge bioleaching. The removal efficiencies of sludge-borne Cu and Cr could reach above 85% and 40%, respectively, and capillary suction time (CST) of bioleached sludge decreased to as low as ∼10s from initial 48.9s for fresh sludge when sludge pH declined to ∼2.4 through bioleaching. These results confirm the potential of bioleaching as a novel method for improving sludge dewaterability as well as removal of metals.
生物浸出过程中能量物质的生物氧化导致的生物酸化作用，被广泛认为在提高污泥中金属去除方面起着重要作用。在这里，我们报告生物浸出在合适的 pH 值下也能极大地提高污泥的脱水性能。为了在生物浸出过程中获得最佳的能量物质初始浓度和 pH 值，以实现污泥脱水性能的优化，我们研究了嗜酸硫氧化菌（TS6）和氧化亚铁硫杆菌（LX5）共接种时 Fe(2+)和 S(0)的生物氧化及其对污泥脱水性能和金属去除的影响。结果表明，投加 2g/L S(0)和 2g/L Fe(2+)的能量物质剂量可使 Fe(2+)的生物氧化效率达到 100%，S(0)的生物氧化效率达到 50%，是污泥生物浸出的最佳剂量。污泥中携带的 Cu 和 Cr 的去除效率分别可达 85%以上和 40%以上，并且通过生物浸出使污泥 pH 值下降至约 2.4 时，生物浸出污泥的毛细吸水时间（CST）从初始的 48.9s 降低到约 10s。这些结果证实了生物浸出作为一种提高污泥脱水性能和金属去除的新型方法的潜力。
