过硫酸盐化学氧化-强化生物降解耦合修复石油污染土壤研究

Soil contamination is a serious problem in China. Development of innovative chemical reagents with independent intellectual property rights is the key technical work to solve the soil contamination problem in China. Coupling of chemical oxidation and bioremediation is a new concept of remediation technology, but the theoretical feasibility of this coupling technology is still in controversy and several important knowledge gaps need to be filled. This research project plans to investigate the effectiveness of persulfate oxidation coupled with enhanced biodegradation for the remediation of petroleum-contaminated soil. The theoretical research objective of this project is to reveal the synergistic mechanisms of persulfate oxidation and biodegradation. The technological research objective is to develop an innovative chemical reagent of the coupling remediation technology and optimize the reagent injection method. Petroleum-contaminated soil will be used as the treatment target. Advanced analytical and molecular technologies such as high-resolution mass spectrometry, metagenomic DNA sequencing, and microarray GeoChip will be used in this study. The impacts of persulfate oxidation on the microbial community, soil physical-chemical properties, and the contaminant biodegradability will be explored respectively. The overall impacts of persulfate oxidation on contaminant biodegradation and the potential synergistic mechanisms between the two processes will be explored. The theoretical feasibility of this coupling technology will be assessed. Methods to stimulate the regeneration of degrading microbial community following chemical oxidation will be explored. Based on above knowledge, the reagent formulation of the combining technology will be developed and the reagent injection method will be optimized. Through this study, an innovative persulfate oxidation coupled with enhanced bioremediation technology with intellectual property right owned by our country is expected to be obtained.

我国面临着严峻的土壤污染问题，开发具有自主知识产权的修复药剂是解决我国土壤污染问题的关键性核心技术工作。化学氧化与生物降解耦合联用是一种新颖的技术概念，但这两种技术耦合的可行性仍然存在着不小的争议，一些机理问题尚有待解答。本课题拟以过硫酸盐氧化耦合生物修复技术为攻关对象，以揭示两个过程的耦合增效机理为理论目标，以开发性能优异的复合修复药剂并优化药剂投加工艺为技术目标。拟以石油污染土壤为研究对象，借助高分辨率质谱、宏基因组测序、基因芯片等先进的实验手段，从过硫酸盐对微生物种群、对土壤理化性质、对石油生物课降解性等角度揭示化学氧化与生物降解这两个过程间的相互作用及耦合增效机制，从理论上探明两者耦合是否具有可行性。进一步研究促进化学氧化胁迫下微生物活性恢复的人工强化方法，在此基础上开发复合修复药剂并优化药剂投加工艺，最终形成一套具有我国自主知识产权的过硫酸盐氧化-强化生物降解耦合修复技术工艺包。

我国面临着严峻的土壤污染问题，开发具有自主知识产权的修复药剂是解决我国土壤污染问题的关键性核心技术工作。化学氧化与生物降解耦合联用是一种新颖的技术概念。本研究发现过硫酸盐氧化可以实现易降解和难降解组分的同步降解。热活化过硫酸盐的预氧化可以将了高碳数难生物降解组分降解成分子量较小易生物降解的组分，从而提高了这类物质的耦合修复效果。HtPS、HtPS+Y1、HtPS+Y2对C18-C22组分的最终降解率分别为42.46%、62.02%、73.5%，相较对照组提高19.56%-31.04%。以华北平原常见的壤土为例，过硫酸盐氧化土壤后并未能显著提高溶解态氮磷营养物的含量，因此过硫酸盐污染通过氧化土壤中天然有机质或矿物释放无机营养物从而促进生物降解活性。通过外加营养盐，可以有效促进微生物降解活动和石油烃的去除率.我们配置和比选了12种生物刺激的药剂，找到的效果最好的Y3和Y4药剂可作为过硫酸盐氧化的耦合增效助剂使用。通过16S rRNA扩增子高通量测序发现过硫酸盐氧化后土壤微生物的丰富度和群落均匀度均明显下降。虽然PS氧化后整体物种丰度下降，但在处理后的优势菌群中却富集了更多种类的石油烃降解菌，包括类芽孢杆菌属、黄单胞菌属、节杆菌属、假单胞菌。含水层种的无机阴离子对于过硫酸盐氧化降解苯系物具有显著的影响，其中CO32-、HCO3-、Cl-、Br-对过硫酸盐氧化降解苯系物有显著的抑制作用，而H2PO4-、NO3-、SO42-几乎不影响苯系物的降解。综上所述，本研究认为过硫酸盐氧化与生物修复的耦合联用可能是可行的，下一步可在实际污染场地开展现场研究和示范。