Duckweed as a Circular Economy Solution for Treating Agro-Industrial Wastewaters

Water pollution resulting from nutrient-rich wastewater (WW) discharged by industries such as distilleries, sugar mills, and dairy farms poses significant ecological and public health challenges. Conventional treatment methods often fail to effectively reduce nutrient loads, contributing to environmental degradation. This review critically examines the use of duckweed (Lemna spp.), a fast-growing aquatic plant, as a sustainable solution for wastewater remediation. Duckweed demonstrates a high capacity for nutrient uptake, particularly nitrogen (N) and phosphorus (P), while simultaneously producing protein-rich biomass suitable for animal feed. The review synthesizes findings on the effectiveness of duckweed-based systems in reducing chemical oxygen demand (COD) and biological oxygen demand (BOD), and explores their integration into circular economy models that couple wastewater treatment with resource recovery. Additionally, it addresses current limitations in system design, scalability, and long-term implementation, highlighting areas requiring further research. Overall, duckweed-based wastewater treatment offers a costeffective, eco-friendly strategy to enhance environmental sustainability and food-feed security.