生物除铬(VI)效果及机理探讨

以特定污泥挂膜的自制厌氧生物滤床系统具有良好的去铬(VI)能力。恒流泵最佳流量为47mL/min,外加碳源使废水COD约140mg/L,铬(VI)的浓度由60mg/L左右降到0.5mg/L以下(一级排放标准),需要4h,而对照组(未加碳源)需要14h。铬(VI)浓度由64.66mg/L提高到75.53mg/L时,对系统负面影响甚微,提高到95.47mg/L时,系统出水达标所需时间延长到7.5h。添加微量金属离子与未添加微量金属离子的情况相比,处理效率提高21.26%。分析试验表明:铬(VI)的去除途径可能是由生物还原作用将六价铬还原为三价铬,形成氢氧化铬沉积于微生物表面。

Cr~(6 ) REMOVAL FROM WASTEWATER BY A BIOSYSTEM AND ITS MECHANISM

A self-made anaerobic bio-filter bed, which was inoculated with special sludge, showed a high efficiency in removing hexavalent chrome. When the optimal flux of the pump was 47mL/min and the COD in the wastewater was about 140 mg/L, it took 4 h to decrease the concentration of Cr6 from above 60mg/L to under 0.5mg/L, while the time of the control group(without carbon source added) was 14 h. When the concentration of Cr6 was increased from 64.66mg/L to 75.53mg/L, the negative effect, was less, and when the concentration of Cr6 reached 95.47mg/L, the time was prolonged to 7.5 h. As compare with the contol system, the added trace metal system showed clear superiority that the removal rates of Cr6 was increased by 21.26%. Some analysis also showed that hexavalent chrome was likely to be bio-deoxidized to trivalent chrome and form sediment of chrome hydroxide on the surface of microorganisms.