钼胁迫下复合基人工湿地基质层除钼机理与系统微生物响应特征研究

Molybdenum pollution has emerged in recent years, which caused by weathering, leaching and dissolution in alkaline Mo tailings. So it has important scientific value to study Mo pollution control technology in the source control by using ecological restoration methods. However, molybdenum removal mechanism by the substrate beds in constructed wetland is one key science problem of biological remediation technology of Mo pollution. Early studies showed that the constructed wetland composed of ferric and alum water treatment residuals (FARs) and modified pomelo peel (MPP) of solid waste can remove Mo pollution to some extent for a short period, which caused by rainfall washout. However, the stability of Mo removal in the combined system has not been considered. The mechanism of substrates and microbes on Mo removal, as well as community characteristics of wetland microbes, has not been clearly demonstrated. To solve these problems, this project proposes to use the two aforementioned wastes as one compound-substrate to treat simulated Mo tailings wastewater. Analyzing the long-term efficiency of Mo removal by using a compound apparatus, applying integrated approaches of static sequencing batch experiments, micro universe constructed wetland model, Miseq high-throughput sequencing technology, mesoscopic system, and spectroscopy measurement, etc. This research also analyzes the structural change of molybdenum-resistant microbes before and after Mo removal, discusses Mo transformation rule inside and outside the microbes, and discusses the response feature and reciprocity relation of the microbial communities. The research results not only can provide technical support for optimization of substrates and microbial community structure in constructed wetland. Moreover, an efficient Mo removal technique to treat non-point source pollution of dilute heavy metals by using industrial wastes is also demonstrated.

碱性钼尾矿在风化淋滤溶出作用下产生的钼污染在近些年已初步显现，研发生态修复技术进行源头控制具有十分重要的科学价值，而人工湿地基质层（基质-微生物）除钼机理是其生态修复技术的关键科学问题。前期研究表明给水厂铁铝泥（FARs）和改性柚子皮（MPP）复合基人工湿地对降雨冲刷导致的水体钼污染在短期内有一定去除，但未考虑系统长期除钼稳定性，且基质与微生物除钼机理不明，微生物群落响应特征模糊。本项目从MPP-FARs联合对模拟钼尾矿排水处理入手，应用静态序批式吸附实验、微宇宙人工湿地模型、Miseq测序平台、介观分析及波谱学测试等手段，探明基质除钼机理与复合基人工湿地长期除钼效能；剖析钼作用前后抗钼菌结构的变化特征，揭示钼在菌体内外的转化规律；分析钼污染下人工湿地微生物群落的响应特征。研究成果不仅为除钼人工湿地基质优选、微生物群落优化提供技术支撑，也为以废治废处理低浓度重金属面源污染技术提供理论依据。

碱性钼尾矿在风化淋滤溶出作用下产生的钼污染在近些年已初步显现，对其污染防治技术研究具有重要的科学价值。本项目从复合基质对模拟钼尾矿排水处理入手，应用静态序批式吸附实验、微宇宙人工湿地模型、Miseq测序平台等手段，探明了复合基人工湿地长期除钼机理与效能。重点研究了废弃物吸附材料的制备及其除钼机理；分析了复合基人工湿地除钼效能及其去除机理,并对钼污染下人工湿地微生物群落的响应特征进行了深入研究。研究成果不仅为除钼人工湿地基质优选、微生物群落优化提供技术支撑，也为以废治废处理低浓度重金属面源污染技术提供理论依据。具体研究结论如下：（1）以自来水净化厂残留物为研究对象，研究了不同改性方法对水体重金属钼去除的效能和机理。研究表明改性后的材料吸附钼遵循伪二级动力学模型和 Langmuir等温吸附模型，同时静电吸附作用和表面络合是该吸附过程的主要机制。（2）采用温室盆栽试验方法，对比研究了根瘤菌对紫花苜蓿富集土壤中钼的强化作用。结果表明钼污染下根瘤菌促进了紫花苜蓿的生长及其钼富集能力，土壤钼转运系数和富集因子与对照组相比均有明细提高。根瘤菌一方面促进了重金属钼由水溶态向中间过渡态的转变，同时增大了土壤残渣态钼的比例。（3）经500天的连续运行，人工湿地基质层对钼去除贡献率最大，RDA分析表明，腐霉菌、匿杆菌、装甲菌和芽单胞菌与钼去除最为密切。以上研究为钼胁迫下人工湿地基质、植物优选，以及系统微生物响应特征提供了新的参考和见解。