生物硫铁复合材料处理含铬废水及铬资源化研究

研究了由硫酸盐还原菌(SRB)与其原位生成的纳米硫铁化合物组成的生物硫铁复合材料(生物硫铁)的耐铬性能和再生性能,并利用其再生特性,设计了处理高浓度含铬废水及铬资源化的还原-再生循环处理工艺.结果表明,生物硫铁处理含铬废水后,污泥中的SRB仍具有活性,能以反应产物Fe3+和S单质为电子受体,重新生成生物硫铁;而且SRB在Cr(VI)浓度600mg/L的废水中仍能存活并逐渐将Cr(VI)去除.还原-再生循环处理工艺处理含铬废水结果表明,出水Cr(VI)低于0.019mg/L,总Cr低于0.929mg/L,能达标排放.经10个循环处理后污泥中铬(Cr2O3)含量达到40.47%,铬铁比达到6.98,污泥达到冶金级(湿法冶炼铬)铬矿标准和化工级铬矿标准,可资源化利用.

Application of biological iron sulfide composites in chromium-containing wastewater treatment and chromium reclamation

The resistance to Cr(VI) and regeneration character of biological iron sulfide composites were studied. The composites consisted of sulfate reducing bacteria(SRB) and nanosized iron sulfide produced by SRB. A new reduction-regeneration recirculation process for treating chromium-containing wastewater and reclaiming chromium was developed with the regeneration character of the composites. The SRB still survived after treating wastewater containing Cr(VI), which could regenerate biological iron sulfide composites by using Fe3+, sulphur as electron acceptor. Furthermore, the SRB could also resist 600mg/L Cr(VI) and remove it gradually. The results of reduction-regeneration recirculation process for treating wastewater indicated that the contaminants in the effluent could meet the discharge standard, i.e. the concentration of total chromium less than 0.929mg/L, Cr(VI) less than 0.019 mg/L. After 10 cycles, the Cr2O3 content in sludge reached 40.47%, and the ratio of Cr2O3/FeO was 6.98. The sludge reached the chemical and metallurgical(hydrometallurgy) grade of chromite ore, which could be reclaimed again.