生物碳固定白腐菌强化堆肥修复重金属污染底泥效果及机制

River sediment in Pearl-delta Region has been contaminated with heavy metals. A.solution proposed to enable the sediment environmental responsible is dredging, composting and reuse for land application. The action effect of heavy metals by both white-rot fungi and biochar, the effect of composting by the both two, and the interaction between the both two have provided the possibility of combining the both two to enhance ex-situ remediation of heavy metals by composting. In this project, heavy metals-contaminated sediment collected from Pearl-delta Region Rivers will be used to build enhanced composting system based on biochar-immobilized white-rot fungi, the effect of enhanced remediation of heavy metals will be explored, and a superior ex-situ remediation method of heavy metals contamination will be established by optimizing remediation process. The inherent relations among biochar-immobilized white-rot fungi, humus, pH, organic matter, and heavy metals remediation will be clarified, and the behavior mechanism of biochar-immobilized white-rot fungi in heavy metals remediation will be clarified. Microbiological community structure and metabolism changes in composting system will be analyzed to fully reveal the mechanism of composting ex-situ remediation of heavy metals contamination enhanced by biochar-immobilized white-rot fungi. The purpose of this project is to explore an accessible method to allow the reuse of heavy metals-contaminated sediment economically and environmental-friendly in land application. This is to solve the problems encountered in sediment disposal and to enhance the aquatic and ecological environment in Pearl-delta Region Rivers.

我国珠三角区域河道底泥重金属污染严重。处理污染底泥的一类环境友好型方法是将其疏浚、堆肥处理后进行资源再利用。白腐菌与生物碳对重金属的作用效应、二者对堆肥的影响以及二者之间的交互作用为结合二者强化堆肥异位修复重金属污染效率提供了可能。本项目以重金属污染河道底泥为研究对象，基于生物碳固定白腐菌构建强化型修复重金属污染堆肥体系，研究生物碳固定白腐菌对重金属污染的强化修复效果，优化修复过程，建立较优的强化型修复方法；阐明生物碳固定白腐菌、腐殖质、pH、有机质与重金属修复的内在联系，明确生物碳固定白腐菌在重金属修复中的行为机理；剖析堆肥修复体系中微生物群落结构及代谢功能变化规律，全面揭示生物碳固定白腐菌强化堆肥异位修复重金属污染底泥的作用机制。该项目旨在探寻一种低成本和环境友好型的重金属污染底泥土地再利用的方法，以解决重金属污染底泥处置方面的困难，并有效改善珠三角区域河道水质及生态环境。

项目以重金属污染的环境介质为研究对象，围绕“白腐真菌-生物炭-堆肥”与重金属毒性的相互关系，研究基于白腐菌-生物炭强化堆肥对重金属毒性控制的机制。主要开展的研究工作包括：①白腐真菌对污泥堆肥及重金属钝化的影响，为研究生物炭-白腐菌强化堆肥对疏浚底泥重金属污染修复提供理论依据和研究思路；②生物炭基吸附剂的制备及其对Pb2+和Cu2+的吸附性能，为研究生物炭特性及其与重金属去除效果与机理提供一种研究手段；③考察了生物炭-白腐菌对疏浚底泥与农业废物共堆肥进程的影响，并研究了其对堆肥过程中各种重金属生物有效性的影响效应，阐明了堆肥理化参数与重金属植物可利用度的相关性，初步揭示了生物炭/白腐真菌强化堆肥对疏浚底泥重金属毒性控制的机理。本项目发现生物炭与白腐菌可有效控制环境介质中重金属毒性，研究成果可为疏浚底泥毒性污染物控制和水环境修复提供理论依据与技术支撑。