In this study, we present an innovative and sustainable approach for transforming surplus Lignocellulosic biomass into biochar and integrating it as a substrate in vertical flow constructed wetlands for municipal wastewater treatment. This research provides a mechanistic understanding of biochar production pathways, links between production conditions and physicochemical properties, and their implications for wastewater treatment. Ultimately, this work aims to advance next-generation constructed wetlands through the strategic integration of biochar to improve treatment efficiency and system sustainability.