Life cycle assessment of constructed wetlands for wastewater treatment: Environmental, social and economic opportunities and challenges

During the last decades, constructed wetlands (CWs) have gained popularity since they are a low-cost and nature-based alternative for wastewater treatment and reuse. This review focuses on the environmental, economic and social benefits of CWs under a life cycle perspective. The performed Life Cycle Assessments of these technologies showed that, regardless of the model, configuration or type of wastewater treated, CWs have lower environmental impacts compared to conventional solutions (e.g. activated sludge system) due to low energy requirements, no chemical consumption, and avoidance of off-site management and transportation practices. In terms of costs, CWs can reduce the costs associated with wastewater treatment and management. However, future economic analyses should also account for externalities and a full life-cycle cost profile. Moreover, more efforts should be made to define the social benefits of this technology (e.g. local employment generation, landscape enhancement, public perception), considering all the potential stakeholders (e.g. workers, local communities, value-chain actors, users).