The study looked at the pollutants in wastewater from tanneries, focusing on their harmful effects on the environment, especially on surface water and aquatic life. The effluent from tanneries contains a large amount of pollutants, including toxic substances like trivalent chrome and sulphide. Bacterial action can break down some components, but the effluent still has a high oxygen demand. Nitrogen in the effluent mainly comes from ammonia used in the tanning process.