城市污泥应用于我国北方沙地生态修复的探讨

Application of Urban Sludge in Restoration of Sandy-land in North of China:A Viewpoint

  • 摘要: 我国北方地区土壤退化和沙化严重,如何改良沙地土壤,恢复沙地植被,是当前区域生态保护工作的重点,也是推进区域生态文明建设进程的重要内容之一。针对北方沙地土壤流动性大、有机质浓度低、保水性能差等现状,在综述前人研究成果基础上,得出:城市污泥具有物源充足、有机质浓度高、NPK等营养物质富集、黏性物质浓度大、有利于促进沙地植物生长等优良特性,完全可以通过废物循环利用,实施沙地土壤改良,用以沙地植被修复与重建。但是,由于城市污泥主要来源于工业或生活污水处理厂,其中含有一定量的重金属、有机污染物和病源微生物等有害物质,直接应用可能对沙地生态环境带来潜在的环境风险。因此,必须采取污染物源头控制、生物堆肥发酵、固化/稳定化预处理等措施,制订相应的应用技术规范以及严格施用范围和施用量,并实施长期的跟踪监测与风险评价,才能确保城市污泥在沙地生态修复中的有效性。

     

    Abstract: Soil degradation and desertification were widely and severely existed in Northern China. The amelioration of the sandy soil and restoration of the sandy plants were currently the key tasks for protection of regional ecological environment, and also the important content for promotion of regional ecological civilization construction. Given the large fluidity, low concentrations of organic compounds and deficient water-retaining ability of northern sandy soil and based on review of previous literature, it was suggested that municipal sludge could be recycled and used to ameliorate sandy soil and restore sandy plants since the municipal sludge has the good properties of sufficient resources, high amount of organic compounds and glutinous matters, enrichment of nutrients (i.e., NPK, etc.), facilitating the growth of sandy plants, etc. However, since the municipal sludge is mainly originated from industrial and municipal wastewater treatment plant, it contains certain amounts of heavy metals, organic compounds, pathogenic microorganisms and other hazardous components which may provoke the potential risk to the ecological environment of sandy land if directly applied. Therefore, to ensure the availability of utilizing municipal sludge in ecological restoration of sandy land, several measures were recommended to be taken such as controlling the source of pollutants, applying the biological compost/fermentation and solidification/stabilization pretreatment technologies, formulating corresponding technical guidelines, rigidly managing its application scopes and amounts, and exerting a long-term tracked detection and risk assessment.

     

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