梭状菌促进酸性矿山废水硫酸盐还原法处理效果的影响机理

Acid mine drainage (AMD) is currently one of the most serious water and soil pollution sources due to its large discharge. Sulfate reducing bacteria (SRB) makes excellent prospects for treatment AMD, with advantages of high efficiency and low cost. But til now, SRB has not got extensive use because it is sensitive to certain specially conditions (eg. high proton concentration, undissociated organic acid, and heavy metal ions). Clostridium was always coexist with SRB in acid condition. Our results showed that, the clostridium sp. ZJ-29 could improve the treatment performance of SRB treating AMD, but the improvement mechanism is unclear. In this study, the growth characteristics of clostridium and SRB were investigated in the certain specially conditions, that the SRB was always inhibited. The present works were to investigate the pathway of organic matter oxidation and the substance transfer mode between clostridium and SRB, and to evaluate the protection of the biofilms and extracellular polymeric substances on SRB. As for improving treatment performance on AMD, the parameters of clostridium cooperating SRB will be optimized. Results of this project would provide theoretical basis for the biological treatment on the AMD.

酸性矿山废水排放量大，危害严重。利用硫酸盐还原菌进行处理在成本和效果方面展现了良好前景。然而受制于多种抑制因素（低pH、有机酸、重金属），硫酸盐还原菌处理酸性矿山废水并没有广泛应用。梭菌属在酸性环境中与硫酸盐还原菌存在伴生现象，且前期结果表明，分离获得的梭状菌能够促进硫酸盐还原菌对酸性矿山废水的处理效果，但其作用机理尚不明晰。因此，本研究针对硫酸盐还原系统中常见的抑制因素，开展其对梭状菌与硫酸盐还原菌的生长特性的影响；研究梭状菌与硫酸盐还原菌对有机物的代谢途径、种间物质传递方式、生物膜形成能力及EPS的保护作用，阐明极端酸性条件下梭状菌促进硫酸盐还原菌生长的作用机制；在此基础上，进一步研究梭状菌与硫酸盐还原菌协同作用对AMD处理的提升效果。为硫酸盐还原菌处理酸性矿山废水提供理论依据。

酸性矿山废水排放量大，危害严重。利用硫酸盐还原菌进行处理在成本和效果方面展现了良好前景。然而受制于多种抑制因素（低pH、有机酸、重金属），硫酸盐还原菌处理酸性矿山废水并没有广泛应用。梭菌属在酸性环境中与硫酸盐还原菌存在伴生现象，深入研究梭状菌对硫酸盐还原菌生长的促进机制，有助于丰富和加深对极端酸性 AMD 条件下微生物协同作用过程的认识，同时也能为高效、稳定的 AMD 生物处理提供科学依据。本项目以前期分离到的梭状菌Clostridium sp. ZJ-29与硫酸盐还原菌Desulfovibrio sp. WF-83构建工作菌株。对酸性环境中，梭状菌促进硫酸盐还原菌生长的作用机制做了深入研究。取得的主要结果如下：1）梭状菌对酸性冲击与金属毒性的耐受力优于硫酸盐还原菌。梭状菌能提高硫酸盐还原菌的活性，在低pH（4.0）与10mg/L Cu2+环境中，硫酸盐还原效率能提高12.5%。2）梭状菌对硫酸有还原菌的促进主要通过降低乙酸毒性、进行种间氢传递起作用。实验结果表明，梭状菌能代谢乙酸产H2与CO2。硫酸盐还原菌与梭状菌共培养时，分子态乙酸浓度得到有效降低，消耗乙酸提供的电子中有9.5%通过H2流向硫酸盐还原反应。不存在种间接触时，梭状菌与硫酸盐还原菌共培养能将硫酸盐还原效率提高至12.2%。存在种间接触硫酸盐还原效率的进一步提高至15.6%。梭状菌EPS对硫酸盐还原菌的生长有一定促进作用，投加梭状菌EPS能使硫酸盐还原效率提高3.4%。3）以连续投加梭状菌的方式考察梭状菌强化对硫酸盐还原菌处理AMD的效果的影响。结果表明：梭状菌强化能使反应器内的乙酸得到进一步去除，平均乙酸浓度由1514 mg/L降低至1115 mg/L，出水平均pH由未强化时的6.8提升至7.1。这也使硫酸盐还原效率也得到了提升，出水硫酸盐浓度能够最低能够降低至91.9 mg/L，产660.6mg/L的硫离子。