Abstract Light expanded clay aggregates (LECA) have been increasingly used as substrate material for constructed wetlands given their phosphate removal capacity, mechanical strength, hydraulic conductivity and their plant rooting and biofilm growth supporting structure. This review summarizes the current literature on LECA-based constructed wetlands. Removal performances for main wastewater parameters phosphate, nitrogen species, suspended solids and oxygen demand are tabulated. Both, physical and biological water purification processes in LECA wetlands are discussed. Additional emphasis is on design and layout of LECA wetlands for different types of wastewater, under different climatic conditions and to improve treatment performance in general. LECA life cycle considerations include sourcing, production energy demand, reuse and recycling options for spent wetland substrates, for example as soil amendment. Research and development opportunities were identified for structural and compositional LECA modification to obtain tailored substrates for the use in water treatment and specific treatment tasks. Beyond traditional wastewater contaminants the fate of a wider range of contaminants, including organic trace contaminants, needs to be investigated as high Fe, Al and Ca oxides content of LECA substrates provide adsorptive sites that may facilitate further biological interactions of compounds that are otherwise hard to degrade.

中文翻译：

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轻膨胀粘土骨料（LECA）作为人工湿地基质——综述

摘要 轻质膨胀粘土骨料 (LECA) 因其磷酸盐去除能力、机械强度、导水率及其植物生根和生物膜生长支撑结构而越来越多地用作人工湿地的基质材料。本综述总结了基于 LECA 的人工湿地的当前文献。主要废水参数磷酸盐、氮种类、悬浮固体和需氧量的去除性能被制成表格。讨论了 LECA 湿地的物理和生物水净化过程。额外的重点是在不同气候条件下为不同类型的废水设计和布局 LECA 湿地，并总体上提高处理性能。LECA 生命周期考虑因素包括采购、生产能源需求、废湿地基质的再利用和回收选择，例如作为土壤改良剂。确定了结构和成分 LECA 改性的研究和开发机会，以获得用于水处理和特定处理任务的定制基材。除了传统的废水污染物之外，还需要研究更广泛的污染物（包括有机痕量污染物）的归宿，因为 LECA 底物的高 Fe、Al 和 Ca 氧化物含量提供了吸附位点，可以促进化合物的进一步生物相互作用，否则这些物质很难被降级。确定了结构和成分 LECA 改性的研究和开发机会，以获得用于水处理和特定处理任务的定制基材。除了传统的废水污染物之外，还需要研究更广泛的污染物（包括有机痕量污染物）的归宿，因为 LECA 底物的高 Fe、Al 和 Ca 氧化物含量提供了吸附位点，可以促进化合物的进一步生物相互作用，否则这些物质很难被降级。确定了结构和成分 LECA 改性的研究和开发机会，以获得用于水处理和特定处理任务的定制基材。除了传统的废水污染物之外，还需要研究更广泛的污染物（包括有机痕量污染物）的归宿，因为 LECA 底物的高 Fe、Al 和 Ca 氧化物含量提供了吸附位点，可以促进化合物的进一步生物相互作用，否则这些物质很难被降级。