造纸废水有机氯在人工芦苇湿地中的归趋与生物响应机制

Nowadays the research and application of constructed wetland focused more on the removal efficiency of pollutants in the pulp and paper wastewater, while taking less account of the transportation law and the ecological role of the absorbable organic halogens (AOX) in the wetland ecosystem. Based on the early correlative studies, the aim of this application is first to assay contents of AOX and varieties of physical and chemical parameters about the environment and the organism in the water and the soil of an reed wetland systems with about 2000ha area，which have run for disposing paper water for 12a. Thus we can obtain various foundation data about environmental quality of wetland ecosystem after sewage irrigation each year. Secondly, connecting with the laboratory test, we are going to establish a Fugacity Model to clarify the environmental fate of AOX in the constructed wetland. Simultaneously, the diversity of microbial community structure is to be explored by the method of PCR-DGGE technique and 16S rDNA genomic library. Finally, a response relation model is to be established between the distribution of AOX and the diversity of microbial community structure in wetland ecosystem, by which we will approach to the process and mechanism of response action at the genomic level. Furthermore, the effect of AOX in paper water on the wetland soil is also be clarified at the enzymatic level by studying the activity of typical soil enzyme.

目前对于造纸废水人工湿地处理技术的研究和应用侧重于造纸废水中各类污染物的去除效率，而忽略了对废水中的特征污染物可吸附有机氯(AOX)在湿地生态系统中的迁移规律及生态作用过程。本申请在前期研究的基础上，以已运行12a、面积近2000ha的用于处理造纸废水的芦苇湿地系统为研究对象，分析该湿地系统的水土环境和生物体中AOX含量及各种理化参数，获得经逐年污灌后湿地生态系统环境质量的基础数据，结合实验室的小试试验，建立逸度模型，阐明AOX在人工湿地中的环境归趋。同时，应用PCR-DGGE技术和16S rDNA基因组文库方法探讨湿地土壤微生物群落结构多样性的变异规律，建立湿地生态系统中AOX分布与微生物群落结构多样性的响应关系模型，从基因组水平上阐明土壤微生物群落结构多样性对造纸废水AOX的响应过程及其机制。通过土壤典型酶活性研究，从酶学水平阐明造纸废水AOX对湿地土壤的影响规律。

以造纸废水灌溉的人工芦苇湿地处理系统为研究对象，结合模拟人工湿地试验，系统研究土壤理化性质、酶活性、微生物群落及其相互作用，重点探讨AOX的环境归趋及微生物群落结构的演替。研究表明，随着年限的增加，土壤中AOX浓度升高，表层AOX含量高于底层，含量一般在10-60mg/kg。土壤的转化酶、脲酶和多酚氧化酶的活性显著提高，多酚氧化酶、脲酶与AOX的相关性较高。土壤微生物的Shannon-wiener多样性指数和Simpson多样性指数增大，其中Shannon-wiener指数增加更为显著，与AOX含量有一定的相关性（R2=0.4588）。基于16S rRNA的元基因组的菌群结构和多样性分析表明，土壤中的细菌列属于46个门，含量最丰富的包括Proteobacteria，Chloroflexi，Bacteroidetes和Planctomycetes。分离得到的可培养细菌27种，其中，Lysinibacillus fusiformisWTXJ1-4是具有优势降解造纸废水和AOX潜力的兼性好氧细菌；菌株Bacillus cereus WTXJ1-16能高效降解造纸废水中的典型污染物四氯愈创木酚。模拟系统试验研究表明，土壤中AOX和TX分别从11.3 mg/kg和388.9 mg/kg增加至17.9 mg/kg和490.0mg/kg，对土壤纤维素酶、多酚氧化酶和转化酶活性具有明显促进作用（P < 0.05），对脲酶活性有一定程度抑制，对磷酸酶活性具有明显抑制作用（P < 0.05）；细菌活性受到抑制、多样性降低，Shannon指数从2.372降低至1.541，DGGE图谱中主要条带通过克隆测序和Blast比对鉴定为Lysinibacillus fusiformis、Paenisporosarcina quisquiliarum、Erythrobacter flavus和Uncultured bacterium。土壤真菌生长代谢活性在初期受到抑制，但随着时间延长，土壤真菌群落多样性增加。DGGE图谱中鉴定主要为Scopulariopsis brevicaulis、Amyloporia xantha和Uncultured fungus。课题从基因组水平上阐明土壤微生物群落结构多样性和酶学水平阐明土壤酶对造纸废水有机氯响应过程与机制，研究成果对相关工程应用风险控制提供理念依据。