固相碳源强化微生物除钒过程及其机理探究

Heavy metal (vanadium (V)) contaminated groundwater is a serious threat to drinking water safety and human health. The biological treatment is considered to be promising for V contamination remediation. However, there is little concern about the process and practical application of V bioremediation by using solid carbon sources, and the mechanism is unclear. The project intends to select efficient solid carbon sources for microbial V removal, with the dissolution characteristics of packing materials investigated. The filling ratio and mode of the solid carbon source and packing materials will also be optimized. Based on this, the V bioremediation system will be constructed by employing selected mixed microbial cultures as inocula. Moreover, the related operating parameters will be investigated for optimizing the reactor performance and the degradation process will be also simulated with the mechanism model built to establish the system control modes. By employing biochemistry and molecular biology methods such as metagenomics, the structure and evolution of microbial communities in the reactors will be analyzed. The biochemical characteristics along with the height of V removal reactors will be studied to reveal the V bioremediation mechanisms in the system. The functional species in reactors will be cultured to reveal V(V) reduction mechanisms of specific microbes. In the project, the efficient technology of microbial V removal enhanced by solid carbon source will be developed, with mechanisms investigated. The obtained results suggest a theoretical foundation for the remediation of V(V) contaminated groundwater and provide technical support for practical applications.

地下水重金属钒污染严重威胁人类的饮水安全和身体健康。含钒地下水污染的微生物修复技术具有广泛应用前景，但对基于固相碳源的微生物除钒作用过程及实际应用关注较少，其作用机理尚未明确。本项目拟遴选高效微生物除钒的固相碳源，探究辅助填料的溶出特性，确定固相碳源与辅助填料的最优填充比例及模式；遴选适宜的混合微生物接种体，构建固相碳源强化微生物除钒系统，研究运行参数的影响，优化微生物除钒反应器性能，通过建立除钒过程模型，探究除钒系统的调控模式；利用生物化学及宏基因组学等分子生物学手段，解析反应器中微生物群落组成结构及演变规律，研究除钒系统沿程生化特性，阐明除钒机制，从反应器中发现并纯培养功能性微生物，揭示其还原五价钒的作用机理。本项目研发的固相碳源强化微生物除钒工艺及其调控机制，可为我国地下水重金属钒污染治理和修复提供理论与技术支持。

地下水重金属钒污染严重威胁人类的饮水安全和身体健康，开发简单、高效、适用性强的处理技术具有重大的社会、经济和环境意义。本项目主要遴选出了可强化微生物高效去除五价钒（V(V)）的固相碳源—秸秆（98.6%, 120 h）；V(V)被还原后沉淀析出物为四价钒，系统中具有耐金属和纤维素降解功能的微生物分布广泛，占主导地位。随秸秆粒径降低和投加碳源量增加，V(V)去除效率提高；Enterobacter、Clostridiaceae和Brevibacillus等均可能为钒还原菌（VRB），并发现ABC转运蛋白基因富集和酶活性上调。遴选了适宜的辅助填料，陶粒的钒吸附效果最为明显（84.9%, 168 h）；麦饭石的生物富集效果最好（＞99.9%-V(V), 144 h）。确定了惰性填料-陶粒和活性填料-麦饭石的最优填充比例为1：3，其生物还原系统具有最高的钒去除效率（97.5%）；证实了麦饭石中微量元素溶出对微生物生长和V(V)还原的促进作用。通过在秸秆中加入麦饭石并接种不同污水处理厂活性污泥，遴选了适宜的混合微生物接种体；污泥所含VRB在实验前期可以被大量富集并通过产生膜蛋白抵御环境中高浓度V(V)，后期则通过对V(V)生物还原作用来维持系统长期稳定运行。构建了秸秆强化微生物除钒连续流系统，并深入解析了除钒系统沿程生化特性。优化了柱反应器的填料（秸秆-麦饭石-陶粒）填充方式，分段填充时除钒效果最佳（97.8%）；探究了不同HRT对除钒效果的影响并优化了除钒性能；证实了环境中V(V)刺激了EPS产生，其在结合钒和保护微生物方面起到关键作用；溶解性有机质主要成分为类蛋白质（可结合V(V)并保护细胞）和类腐殖质（可促进还原系统中电子转移）。基于一体化秸秆-麦饭石协同强化生物除钒反应器的长期运行和调控，出水循环运行调控模式有利于后续提高反应器的除钒性能；并利用生物化学及宏基因组学等分子生物学手段，进一步揭示了除钒机制。本项目研发的固相碳源强化微生物除钒工艺及其调控机制，可为地下水重金属钒污染有效治理和修复提供科学依据。