<p>The amelioration of water quality and the effective management of waste are two critical environmental obstacles. Biochar (BC) has the potential to serve as a promising solution for addressing both of these issues. In this regard, this review article elucidates the potential of BC as a sustainable approach to overcome the challenges associated with water remediation and waste management. The study focuses on the biomass-based synthesis of BC and its composites, with optimum experimental parameters (pyrolysis temperature, activation methods, and precursor materials) to enhance the performance. Afterward, the article provides a comprehensive discussion on BC-based water pollutant removal processes (adsorption and advanced oxidation processes) along with the significance of modification strategies. The review also evaluates current BC-based products, discusses their market potential, and identifies key challenges in commercialization. Thus, this article offers new insights into sustainable water remediation and waste management processes by following the principles of sustainable development goals (SDGs).</p> Graphical Abstract <p></p>