产脲酶微生物矿化修复重金属污染土的机制研究

微生物矿化固定重金属技术环境友好、可就地取材，为重金属污染土修复及土体环境质量改善带来了新的机遇。本项目以修复重金属污染土体为研究目标，以重金属污染土中分离优选的高产脲酶微生物与巴氏芽孢杆菌为对象，对微生物矿化修复重金属污染土的机制进行了全面系统深入的研究。通过Batch试验，阐明环境因素对酶活性的影响，探索重金属离子矿化过程中的酶催化机制，优化筛选微生物矿化固定重金属的最佳条件；通过室内土柱模型试验并结合现场试验，模拟不同工况并优化参数，确定微生物矿化固定重金属的最佳工艺，提高重金属污染场地的修复效果。在此基础上，对修复后的场地进行风险评估，确立有效指导工程实践的产脲酶微生物矿化修复重金属污染土的关键技术参数。通过重金属形态分析、结晶动力学分析，结合微细观测试技术，阐明微生物矿化固定重金属的机理。研究成果不仅具有重要的理论意义和技术创新价值，而且具有典型的生态效益、社会效益和经济效益。

Immobilization of heavy metals using microbes is an environmental-friendly technique, which can utilize local indigenous microbes, brings new opportunity for remediation of heavy metal contaminated soils and improvement of soil environmental qualities. In order to remediating heavy metal contaminated soils, urease-producing microbes with excellent activity isolated from heavy metal contaminated soils and another bacteria Sporosarcina pasteurii will be used to study the mechanism of remediating heavy metal contaminated soils by urease-producing microbes. Firstly, Batch experiments will be conducted to clarify the effects of environmental factors on urease activity, to explore the catalyzing mechanism of urease, to choose the optimum conditions for immobilizing heavy metals. Then, soil column experiments in the laboratory and field experiments will be carried out, and parameters will be carefully selected to determine the best treatment method to improve the remediation effects. In addition, risk assessment will be studied after remediation, and key technical parameters will be determined to remediating heavy metal contaminated soils via biomineralization induced by urease-producing microbes for better guiding engineering practice. In the end, mechanism of remediating heavy metal contaminated soils via biomineralization induced by urease-producing microbes will be revealed through analysis of heavy metal speciation, analysis of crystallization kinetics, and microcosmic test methods. The results will be of significant theoretical value and technical innovation value, and will have profound meaning for ecosystem, society and economy.