基于植物质的复合滤床修复含重金属矿区排水及其作用机理研究

The pollutions of mining area drainage which usually contains various heavy metals and sulfate produced by exploitation and utilization of mineral resources is extremely harmful to the environment ecology, and thus needs to be treated effectively and control its transfer. Filter bed using plant biomass as adsorbent for heavy metal ions and carbon source for sulfate reduction is greatly potential in remediation of mining area drainage. While, to date, the knowledge on its long-term synthetic performance, functional process and mechanisms is unclear, leading to a shortage of principle for its application and optimization. .In this project, we plan to treat mining area drainage dynamically using hybrid filter bed (HFB) with waste plant biomass as adsorbent for heavy metal ions and carbon source for sulfate reduction to produce precipitator to remove heavy metal. The long-term operational performance of the HFB with different plant biomass species, influent pH values and pollution loads will be investigated to assess its applicability. The heavy metal removal mechanism will be revealed through investigating the dynamic adsorption characteristics of plant biomass for heavy metals, and removal forms and contents of heavy metals by the HFB. The microbial mechanism will be illustrated by analyzing the characteristic responses of functional microorganisms, and functional mechanism of the plant biomass will be explored combining with its changes of physical and chemical properties and degradation products. Furthermore, comprehensive analysis of the above-mentioned items will be conducted to reveal the functional processes and mechanisms of the HFB treating mining area drainage. The purposes of the project are to provide theoretical basis and technical support for the application and optimization of HFB based on plant biomass for the efficient treatment of mining area drainage at a low cost.

矿产资源开发利用相关活动产生的含多种重金属和SO42-的矿区排水对环境生态的污染危害极大，需对其进行有效治理和转移控制。以植物生物质为重金属吸附剂和SO42-还原碳源的滤床类系统在此方面的应用潜力巨大，然目前对于其长效综合作用效能以及作用过程和机理等还不甚明了，导致其应用和优化还缺乏有力依据。本项目拟以滤床系统动态处理矿区排水，以废弃植物质为重金属吸附剂和SO42-还原碳源生成重金属沉淀剂，通过考察不同植物质种类、pH、污染负荷作用下滤床的长效运行效能规律获得系统应用性能，通过考察植物质的动态吸附特性和重金属去除形态及含量揭示重金属去除机制，通过解析功能微生物特征响应阐明微生物作用机制，结合植物质物化性质变化、降解产物等探明植物质作用机制，并对上述内容进行综合全面分析，剖析系统作用过程和机理，旨在为应用和调控优化基于植物质的滤床类系统低成本高效修复矿区排水提供理论依据和技术支撑。

酸性矿山排水（AMD）含有大量的重金属，且呈酸性，会对周边生态环境和人类健康造成较大危害。因此，开发低成本、高效的AMD处理系统并研究其作用效能和机制十分必要。基于植物质作用下的生态滤床工艺在修复AMD方面具有较大的应用优势和前景，十分适用于偏远的矿区。本项目围绕基于植物质的生态滤床处理AMD的效能及机制开展研究，在对矿区污染基本状况进行调研的基础上，筛选出对重金属具有转化吸附解毒功能的微生物并考察其对废水中重金属的去除效能和机制，采用植物质及其生物炭产物作为基质构建生态滤床处理AMD，并投加植物质发酵液等作为外源碳以提升修复效果，构建出可高效处理AMD的生态滤床系统，进一步考察pH等关键因子对滤床处理效能的影响及其机制。通过分析重金属在滤床中的赋存形态和归趋、滤床功能微生物特征等揭示生态滤床修复AMD的作用机制。研究筛选了高效吸附Cu、Cd和转化解毒Hg、Cr的功能微生物菌株并探明了其作用机制，发现在滤床中充填植物质有利于创造微生物还原SO42-作用的环境，且可提供碳源并作为功能微生物载体，强化滤床修复AMD的生物作用途径。生物炭具有较强的重金属吸附容量和酸度中和能力，可有效提升滤床修复AMD的非生物作用途径。与砂砾相比，两种基质都能有效改善滤床中植物的生长，容纳更多的金属沉淀物。生活污水和植物质发酵液作为外源碳显著调控了滤床中的微生物群落，提高了功能菌群的丰度和作用功能，从而使滤床能高效修复AMD。pH对滤床修复AMD作用效能的影响显著，随着pH的下降，滤床的修复效能明显下降，系统中功能菌群的丰度下降，尤其当pH=2时，可修复AMD的功能微生物无法生长，滤床系统无法有效地通过生物或非生物途径修复AMD。研究开发的基于植物质的滤床系统可低成本同步处理AMD和生活污水等含有机物废水，同时可资源化利用滤床植物秸秆，且具有回收废水中资源的潜力，因此在矿区污水的减排方面具有较大的应用前景。同时，研究对滤床修复AMD的作用机制的解析为应用优化滤床修复AMD提供了有力的理论支撑。

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