城市污水污泥用于石漠化地区生态修复基础研究

Soil erosion has been a serious problem in the Mountainous Areas of Guizhou, where the soil nutrient deficiency and degradation of land productivity have been general. The area of rocky desertification amounts to 5 million ha in Guizhou, and the ecological restoration in the areas is imperative. Otherwise, the treatment of municipal sewage produces large amounts of sewage sludge. The sewage sludge is usually stacked in the ground environment. The sewage sludge contains pollutants such as heavy metal, and the pollutants easily lead to soil and underground water contaminations under the rain erosion and leaching. Therefore, the sewage sludge treatment is a problem of environmental protection. However, in addition to pollutants, sludge is rich in organic matter, nitrogen, phosphorus and other ingredients, which are necessary for plant growth. The key measure of ecological restoration in Karst Rocky Desertification Areas of Guizhou is vegetation reconstruction. The sewage sludge is used for ecological restoration, the sludge disposal problem can be solved, and the needs of ecological restoration on soil quality can be better satisfied..In this study, we analyze the characteristic of sewage sludge, and add sludge to soil matrix in typical Rocky Desertification Area of Guizhou. We study on soil properties and plant growth under different portions of sludge addition by simulating experiment, and explore translocation and accumulation rule of nutrient and heavy metal pollutants which contained in sludge in soil environment and the plants. Potential impact of sludge application on the environment in the process of ecological restoration is also considered. This study would provide the theoretical foundation for sludge application in ecological restoration of the Rocky Desertification Area of Guizhou.

贵州山区土壤流失严重，土壤贫瘠，土地生产力急剧退化，石漠化面积达500万公顷，生态修复迫在眉睫。另外，城市污水处理产生的大量污水污泥通常作为固体废弃物堆放在环境中。由于污泥中含有重金属等污染物质，在雨水冲刷及淋滤作用下易造成土壤和地下水污染，其处置亦是一个环保难题。然而，除重金属等污染物质外，污泥中还含有丰富的有机质、氮、磷等成分，正是植物生长所必需的营养物质。植被重建是贵州喀斯特石漠化地区生态修复的主要措施。因此，将城市污泥用于生态修复，既能解决污泥处置问题，又能更好地满足生态修复对土壤质量的要求。.本研究对污泥特性进行分析，并将污泥添加于贵州典型石漠化区土壤基质中，通过模拟实验研究污泥添加对土壤性质和植物生长的影响，并探索污泥中的养分和重金属在土壤、植物中的转运规律，同时考虑污泥在生态修复过程中对环境带来的潜在影响，为城市污泥在贵州石漠化地区生态修复中的应用提供理论依据。

城市污水污泥是生活污水处理过程中产生的固体废弃物，含有丰富的有机质、氮、磷等成分，可用于提高土壤肥力；但污泥中也含有重金属等污染物质，利用时须考虑其环境影响。污泥的合理利用，既能解决其处置问题，又能改善土壤质量。本研究以城市生活污水污泥和贵州典型石漠化区土壤为研究对象，将污泥添加于土壤基质中，通过模拟实验研究污泥添加对土壤性质和植物生长的影响，同时考虑降水产生淋溶液带来的潜在环境影响。主要研究结果如下：（1）城市污泥添加能够提高土壤持水能力，且随着添加比例的增加，土壤饱和含水率及持水时间呈增加趋势；污泥添加能够显著提高土壤养分、微生物生物量，以及土壤微生物活性、多样性及丰富度。（2）淋溶液中Cu、Zn、Cd和Pb对地下水环境的影响风险随着污泥施用比例的提高而增加，随着土壤熟化时间的延长，淋溶液中重金属对地下水环境的影响风险逐渐减小。（3）一定比例的城市污泥添加可促进类玉米和狼尾草在石漠化土壤中的生长，但超过50%的污泥添加，植物生长开始受到影响。因此，适量比例的污泥添加，可改善土壤理化性质及微生物特性，促进植物生长；但高比例的污泥添加将导致土壤重金属污染，对地下水质量亦存在潜在影响。城市污泥用作石漠化地区生态修复过程中提高土壤肥力的材料，需严格控制污泥的添加量，以污泥/土壤配比不超过50%为宜。研究结果为城市污泥在贵州石漠化地区生态修复过程中改善土壤质量的应用提供了依据。本项目在国内外学术期刊发表研究论文5篇，其中SCI论文2篇，国内核心期刊3篇，授权实用新型专利3项。