There are 2.4 billion people without improved sanitation and another 2.1 billion with inadequate sanitation (i.e. wastewater drains directly into surface waters), and despite improvements over the past decades, the unsafe management of fecal waste and wastewater continues to present a major risk to public health and the environment (UN, 2016). There is growing interest in low cost sanitation solutions which harness natural systems. However, it can be difficult for wastewater utility managers to understand under what conditions such nature-based solutions (NBS) might be applicable and how best to combine traditional infrastructure, for example an activated sludge treatment plant, with an NBS such as treatment wetlands. There is increasing scientific evidence that treatment systems with designs inspired by nature are highly efficient treatment technologies. The cost-effective design and implementation of ecosystems in wastewater treatment is something that exists and has the potential to be further promoted globally as both a sustainable and practical solution. This book serves as a compilation of technical references, case examples and guidance for applying nature-based solutions for treatment of domestic wastewater, and enables a wide variety of stakeholders to understand the design parameters, removal efficiencies, costs, co-benefits for both people and nature and trade-offs for consideration in their local context. Examples through case studies are from across the globe and provide practical insights into the variety of potentially applicable solutions.

Water quality standards across the world are being re-written to promote healthier ecosystems, ensure safe potable water sources, increased biodiversity, and enhanced ecological functions. Treatment wetlands are used for treating a variety of pollutant waters, including municipal wastewater, agricultural and urban runoff, industrial effluents, and combined sewer overflows, among others. Treatment wetlands are particularly well-suited for sustainable water management because they can cope with variable influent loads, can be constructed of local materials, have low operations and maintenance requirements compared to other treatment technologies, and they can provide additional ecosystem services. The technology has been successfully implemented in both developed and developing countries. The first IWA Scientific and Technical Report (STR) on Wetland Technology was published in 2000. With the exponential development of the technology since then, the generation of a new STR was facilitated by the IWA Task Group on Mainstreaming Wetland Technology. This STR was conceptualized and written by leading experts in the field. The new report presents the latest technology applications within an innovative planning framework of multi-purpose wetland design. It also includes practical design information collected from over twenty years of experience from practitioners and academics, covering experiments at laboratory and pilot-scale up to full-scale applications. Scientific and Technical Report No.27

Los estandares de calidad del agua alrededor del mundo estan siendo actualizados para garantizar ecosistemas saludables, asegurar recursos hidricos para potabilizacion, incrementar la biodiversidad, y mejorar las funciones ecologicas. Los humedales para tratamiento son utilizados para depurar una variedad de aguas residuales o contaminadas, lo que incluye, aguas residuales municipales, escorrentia agricola y urbana, efluentes industriales, y efluentes de los vertederos de excesos en alcantarillados combinados, entre otros. Los humedales para tratamiento son particularmente adecuados para la gestion sostenible del agua porque pueden manejar cargas variables en los afluentes, pueden ser construidos con materiales locales, tienen pocos requerimientos de operacion y mantenimiento en comparacion a otras tecnologias, y pueden proveer servicios ecosistemicos adicionales. La tecnologia ha sido exitosamente implementada en paises desarrollados y en vias de desarrollo. El primer Reporte Cientifico y Tecnologico (STR, por sus siglas del ingles, Scientific and Technical Report) sobre la tecnologia de humedales fue publicado en el 2000. Con el desarrollo exponencial de la tecnologia desde entonces, la generacion de un nuevo STR fue desarrollada por el Grupo de trabajo de la IWA sobre la integracion de la tecnologia de humedales (IWA Task Group on Mainstreaming Wetland Technology). Este STR fue conceptualizado y escrito, junto con su traduccion al castellano, por expertos lideres en la materia. Este nuevo reporte presenta las ultimas aplicaciones de la tecnologia dentro de un marco de planificacion innovador del diseno de humedales para multiples propositos. Tambien, incluye informacion practica para el diseno recolectada a partir de 20 anos de experiencias de profesionales y academicos, que abarca experimentos a escala de laboratorio, piloto y real.