The paper and pulp industry uses a lot of water during pulping, washing, bleaching, and paper-making processes. This creates a large volume of wastewater that is dark in colour, strong in Odor, and filled with high organic and chemical loads. One of the main challenges in this industry is treating black liquor, a highly polluted by-product that comes out during the pulping stage. It contains lignin, chemicals, and other substances that make the wastewater extremely tough to handle with regular treatment methods. This wastewater usually has high COD, BOD, TDS, and colour, and conventional systems like biological ETPs or chemical treatments often fall short. Plus, the effluent changes in nature depending on the process, making it even more difficult to manage.