A Review on Innovative Strategies Towards Sustainable Drug Waste Management Through Algae-Based Systems

Drug removal from urban wastewater (UW) is a topic of growing interest. The new European Directive addresses this problem by introducing quaternary treatment by 2045, as part of the "Zero Pollution" plan from a One Health perspective. In this context, the role of microalgae remains very promising in achieving clean and safe effluents, although its cost-benefit ratio needs to be carefully evaluated. The purpose of this review is to disclose the latest approaches to drug removal and energy recovery from UWs adopting different algae (Chlorella spp., Galdieria spp., and Scenedesmus spp.), to provide a detailed background for further research towards the development of new effective strategies on UW remediation while producing clean energy. We examined the most recent studies, considering most drugs found in wastewater, their management, as well as strategies used to recover energy while being mindful of a circular economy. There is growing interest in algae-based systems. The latest findings on algae-bacteria consortia show that it could be a better alternative to suspended biomass and represent a way to manage drug waste. This finding suggests that large-scale experiments should be conducted to confirm the potential benefits of such waste treatments.