URBAN WATER MANAGEMENT IN THE FRAME OF CIRCULAR ECONOMY: THE ROLE OF CONSTRUCTED WETLANDS

Climate change, depletion of natural resources and world population explosion are alarm bells for the future that must push humanity to turn to a more sustainable use of natural resources, particularly water. Water management solutions focusing on the protection of existent global water resources from pollution and the application of efficient water managements methods are fundamental steps but are no longer enough. There is the need to enlarge the prospective, to consider all the resource cycles together and to change the economy structure, from linear (‘take-make-use-dispose’) to circular. The use of resources must be thrifty, the efficiency of industrial processes must be improved, and the waste valorised and considered as new precious secondary raw material to be recycled to the process and reused. As a consequence, the wastewater collection, treatment and reuse has become urgent, especially considering that 80% of worldwide wastewater are untreated or not correctly treated and directly discharged into the water bodies. Wastewater management is included in SDG 6 (Clean Water and Sanitation) and it aims to “ensure availability and sustainable management of water and sanitation for all”. In detail, the SDG 6 focus on the entire water cycle, including the management of water, wastewater, and ecosystem resources. A new water scheme must be implemented, in which the waste paradigm must be substituted with a resource-oriented paradigm. It must be sustainable and integrated, composed of smart collection and natural-based processing of all resources contained in wastewaters (water, contained substances, energy) with the purpose of further reuse and marketability. Application of circular economy principles can help achieve this, but this will require mapping the interactions of the water cycle, how it is used, and where within the river basin and urban water cycles value can be extracted and new enterprises established. The paper explores the role of constructed wetlands as a promising nature-based technology for wastewater treatment in the framework of circular economy. Constructed wetland recreates the removal processes developed in natural wetlands, utilizing complex biochemical, physical, and physiological removal processes. The functions of these systems can be various, as water treatment plants, wildlife habitat, water storage, recreational facilities, landscape engineering and ecological areas. The potential applications of constructed wetlands are outlined and an in-depth study on recreative applications of natural swimming pools technology are presented, in order to reveal their function in aesthetically improving the urban environment and creating recreational areas.