硫酸盐还原菌利用不同生物质碳源对酸性矿山废水的处理

Treatment acid mine drainage by sulfate reducing bacteria using different biomass carbon sources

  • 摘要: 针对多组分酸性矿山废水(Acid Mine Drainage,AMD)污染严重,治理费用高的特点,基于硫酸盐还原菌(Sulfate Reducing Bacteria,SRB)处理AMD具有成本低、适用性强、环境友好等诸多优点,从长期受煤矸石淋溶水污染的土壤中纯化培养一株SRB,并采用廉价易得的玉米芯、甘蔗渣和花生壳作为SRB生长碳源分别构造1号,2号,3号组动态柱,进行处理AMD的模拟实验,以探讨SRB利用生物质碳源处理AMD的有效性和规律性。各动态柱分别按照正交试验最优配比进行装填,其中,1号柱中SRB生物量和60目玉米芯按固液比分别为106.8∶100(mg∶ mL)和35∶100(g∶ mL)装填,2号柱中SRB生物量和100目甘蔗渣按固液比分别为71.2∶100(mg∶ mL)和4.5∶100(g∶ mL)装填,3号柱中SRB生物量和100目花生壳按固液比分别为106.8∶100 (mg∶ mL)和4.5∶100(g∶ mL)装填。实验结果显示,以100目甘蔗渣为碳源的2号柱处理AMD的效果较好,对SO2-4,Fe3+, Mn2+,Cr6+,Cr3+平均去除率分别为61.63%,99.81%,72.35%,96.8%,100%,而体系出水的pH值和ORP值分别为6.38~7.30 ,-246 mV,表明SRB以甘蔗渣为碳源时的生长代谢活性优于玉米芯和花生壳,甘蔗渣可实现较持久的碳源供应。通过反应前后生物质材料的SEM和XRD分析表明,大量的Fe元素主要通过生物质材料的化学吸附方式被去除,而Mn和Cr元素主要通过与硫酸盐还原菌的代谢产物反应生成金属硫化物沉淀除去,少部分金属元素通过生物质材料的物理吸附被去除。同时,反应前生物质材料表面结构完整,反应后的生物质材料结构被破坏并附着纳米级金属硫化物沉淀。

     

    Abstract: In terms of the serious pollution of multi-component Acid Mine Wastewater (AMD) and the high treat-ment cost,the treatment of AMD based on Sulfate-Reducing Bacteria (SRB) has many advantages such as low cost,applica- bility and environmental friendliness. A strain of SRB was purified and cultured for a long time from soil contaminated with coal gangue leaching water. Using cheap and easy-obtained corncob,bagasse and peanut shells as the carbon source for SRB growth,the dynamic columns 1,2 and 3 were constructed respectively and the simulation experiment of AMD was carried out. Each dynamic column was filled according to the optimal ratio of the orthogonal test. Column 1 filled with SRB biomass and 60 mesh corncob was loaded at a solid-liquid ratio of 106. 8 ∶ 100 (mg ∶ mL) and 3. 5 ∶ 100 (g ∶ mL). Column 2 filled with SRB biomass and 100 mesh bagasse was loaded at a solid-liquid ratio of 71. 2 ∶ 100 (mg ∶ mL) and 4. 5 ∶ 100 (g ∶ mL). Column 3 filled with SRB biomass and 100 mesh peanut shell was loaded at a solid-liquid ratio of 106. 8 ∶ 100 (mg ∶ mL) and 4. 5 ∶ 100 ( g ∶ mL). The results showed that Column 2 with the 100 mesh bagasse as the carbon source performed better in repairing AMD. The average removal rates of SO24- ,Fe3+ , Mn2+ ,Cr6+ and Cr3+ were 61. 63% ,99. 81% ,72. 35% ,96. 8% ,100% ,respectively. The pH and ORP values of the system effluent were 6. 38-7. 30 and -246 mV,respectively. Therefore,as a carbon source,the growth and metabolism activity of the bagasse was better than those of corncob and peanut shell. Bagasse could supply carbon source for a lon- ger time. The SEM and XRD analysis of the biomass material before and after the reaction showed that the element Fe was mainly removed by chemical adsorption of the biomass material,and the elements Mn and Cr were mainly removed by precipitation of metal sulfides formed by reaction with metabolites of sulfate-reducing bacteria. A small part of the metal element was removed by the physical adsorption of biomass material. The surface structure of the biomass materi- al before the reaction was complete,but,it was destroyed and the nano-scale metal sulfide precipitate was attached on it after the reaction.

     

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