农业废弃物原位防治矿山酸性水污染的机理研究

With the bulk mining of sulfur-contained minerals especially coal mine, the contamination from acid mine drainage (AMD) is becoming severe. It’s been proved that acidophilic microorganisms especially Acidithiobacillus ferrooxidans play a key role in the forming of AMD. In order to prevent and in situ control the pollution of AMD, it's vital to inhibit the growth of acidophilic microorganisms and their biological oxidation. This research based on the idea of controlling wastes with agricultural residues, focusing the mechanism of interaction between biological factors and non-biological factors in coal mine dump. Several kinds of agricultural residues such as walnut shell have been proved to be effective to inhibit the activity of Acidithiobacillus ferrooxidans in our previous experiment. The active ingredients in agricultural residues will be extracted to test their effects to morphological structure，activity of ferroxidase, proteomics and whole-genome expression of acidophilic microorganisms. As a result, the inhibiting mechanism of active ingredients of agricultural residues to acidophilic microorganisms will be discovered. In order to test the effect of selected agricultural residues of inhibiting AMD generation and the main control factors of the environment, a leaching model will be established to simulate AMD prevention by agricultural wastes in situ in the coal mines of Shanxi, Anhui and Fujian provinces. This research will attempt to discover the mechanism of AMD prevention by agricultural residues at different levels, and also try to find the high efficiency, environmental friendly, economic and feasible way to AMD control.

含硫矿物特别是煤矿的大量开采，导致矿山酸性水（acid mine drainage，AMD）污染日趋严重，嗜酸菌特别是氧化亚铁硫杆菌在AMD形成过程中起到重要的促进作用。抑制嗜酸菌的生物氧化活性，是原位防治AMD污染的关键。本课题本着“以废治废”的理念，立足于对煤矿固废堆中生物与非生物因子之间的作用机制进行研究，在预试验中发现核桃壳等几种农业废弃物对氧化亚铁硫杆菌生物氧化活性有抑制作用，拟进一步分离其有效成分，从细胞形态、铁氧化酶活性、蛋白质组和基因表达等水平分析其对氧化亚铁硫杆菌氧化活性的影响；并在山西、安徽和福建等地建立煤矿固废堆小型实验生态系统，研究所筛选农业废弃物抑制AMD形成的效果及环境主控因素，并评估其应用对周边生态环境的影响。本课题将从不同层面解析农业废弃物原位防治AMD污染的机理，试图为矿山环境AMD污染探寻高效、环保、经济、可持续性的治理方法提供依据。

本研究通过检测核桃壳、米糠、龙眼壳等十几种常见的农业废弃物对氧化亚铁硫杆菌(A. ferrooxidans)生物氧化活性的抑制效果，发现核桃壳具有良好的减缓矿山酸性水(AMD)形成的作用。通过分离核桃壳各组分发现酚类物质是抑制A. ferrooxidans的生物氧化能力的活性物质，其抑制机理为通过在核酸水平上抑制编码A. ferrooxidans菌氧化Fe2+的基因的表达，使得菌体在蛋白水平上缺乏Fe2+氧化相关的蛋白（酶），无法通过Fe2+氧化进行正常的能量代谢以及DNA的合成，导致菌体的生长繁殖受到限制，从而显著减缓了AMD形成。通过建立的煤矿固废堆原位防治实验模型，发现核桃壳处理不但能较好地抑制AMD的形成，还可以吸附大量的金属离子特别是重金属离子，综合性能比从核桃壳中提取出的酚类更优越，且这种抑制作用受气温、降水等环境因素影响不明显。本研究对矿山环境污染源进行原位治理具有重要的现实意义，预期会对矿山环境生物地球化学发展提供一定的理论创新。