Desulfuromonas alkenivorans S-7联合稻壳处理酸性重金属废水

Combining Desulfuromonas alkenivorans S-7 with rice husk to treat acid heavy metal wastewater

为了研究硫酸盐还原菌和稻壳联合生物反应器在重金属废水处理中作用及机理。利用实验室前期分离鉴定的硫酸盐还原菌 Desulfuromonas alkenivorans S-7联合填充稻壳柱式生物反应器处理人工合成酸性重金属(Fe 3+,Mn 2+,Cr 6+)废水。比较了废水处理过程中理化特性(pH, E h , E c )及3种重金属离子变化规律,并利用FT-IR光谱仪分析了微生物和稻壳联合处理作用下重金属离子去除特性。研究结果表明:S-7能够明显提高酸性废水的pH,20 d后pH 最终稳定在6.20左右,也能使反应体系维持在较高的还原环境并降低体系的电导率。S-7菌株对3种代表性离子都有一定的处理效果,对Fe,Mn,Cr三种金属离子的去除效率分别为Fe>Mn>Cr。反应器处理前期废水中离子的去除速率较快,后期由于离子共存对废水处理的影响使废水中金属离子浓度趋于平衡,出现动态制约平衡,S-7菌株对3种重金属离子的去除机制可能存在差异。处理后期由于Cr 6+浓度上升明显,增大了SRB反应器中的重金属含量,明显影响SRB反应器的稳定性能;稻壳填充对S-7菌株生长能够稳定维持SRB反应器的厌氧环境,并且稻壳对金属离子去除也存在一定程度的物理吸附作用。FT-IR分析表明:S-7菌体处理废水时会吸附Fe,Mn,Cr离子,其中羟基、胺基、酰胺基及羧基是发生吸附作用重要的官能团;稻壳在处理重金属废水前后,稻壳的Si—O—Si和羰基在处理重金属废水中可能发挥了作用。

To study the role and mechanism of sulfate-reducing bacteria and rice husk combined bioreactor in heavy metal wastewater treatment,the sulfate-reducing bacteria Desulfuromonas alkenivorans S-7 isolated and identified in the laboratory was combined with a rice husk column bioreactor to deal with the synthetic acid heavy metal (Fe 3+,Mn 2+,Cr 6+) wastewater.The physicochemical characteristics (pH, E h, E c) and changes of three heavy metal ions in wastewater treatment process were compared.Then the removal characteristics of heavy metal ions under the combined treatment of microorganism and rice husk were analyzed by FT-IR spectrometer.The results showed that S-7 could significantly increase the pH of acidic wastewater,and the pH was finally stabilized at about 6.20 after 20 days.It could also maintain the reaction system in a high reduction environment and reduce the conductivity of the system.S-7 strain had a certain treatment effect on three representative ions,and the removal efficiency of Fe,Mn and Cr metal ions was Fe>Mn>Cr,respectively.At the early stage,the removal rate of metal ions in the wastewater treated by the reactor was relatively fast,but at the later stage,due to the influence of metal ions coexistence on the wastewater treatment,the concentration of them in the wastewater tended to balance,and a dynamic restriction balance appeared.The removal mechanism of the three heavy metal ions in the S-7 strain may be different.In the later stage of treatment,the concentration of Cr 6+ increased significantly,which increased the heavy metal content in SRB reactor and significantly affected the stability of SRB reactor.Rice husk filling could maintain the stable anaerobic environment of SRB reactor for the growth of S-7 strain,and the rice husk also had a certain degree of physical adsorption effect on the removal of metal ions.FT-IR analysis showed that S-7 bacteria adsorbed Fe,Mn and Cr ions when treating wastewater,and the hydroxyl,amine,amide and carboxyl groups were important functional groups for adsorption.The Si-O-Si and carbonyl groups of rice hull may play a role in the treatment of heavy metal wastewater.