Circular economy and payment for ecosystem services: A framework proposal based on water reuse

Water scarcity forces the use of non-conventional water sources, to satisfy water demand, such as the effluent of wastewater treatment plants (WWTPs). Water reuse helps to close the urban water cycle and reduce pressure on available water resources, providing a bases for circular economy in the water sector. Under an ecosystem services (ES) point of view, if water reuse is considered the best management option in water scarcity areas, WWTPs are responsible for the ES of provisioning. One of the main requirements for the ES of provisioning is to guarantee the reclaimed water quality due to this water being discharged back into the ecosystem. Hence why removing pollutants, such as pharmaceutical and personal care products (PPCPs), is necessary to reduce the environmental impact of reused water. Considering the lack of legislation about PPCPs in effluents, this study proposes the use of the Payment for Ecosystem Services (PES) approach as an innovative solution to provide reclaimed water without PPCPs considering both the environmental and institutional context and the importance of WWTPs as non-conventional water sources. This study contributes to consider the PES as a water cycle management tool and its suitability to be used to remove PPCPs is highlighted, with the purpose of promoting water reuse in water scarcity areas under circular economy approach.