As a step towards achieving environmental excellence, Tata SteelRss Sukinda Chromite Mine has set up a state-of-the-art effluent treatment plant (ETP) of capacity 108 million litres/day that treats both surface runoff and mine water to almost drinking water specifications. This is said to be the biggest ETP in the region and the largest single-location ETP in India.
The Tata Steel operates the chromite mines at the Sukinda Valley producing chrome ore which is converted into ferrochrome and sold to customers across the world. A large quantity of water, generated during mining and due to rainfall, needs to be handled during the mining operations. The Sukinda Valley experiences about 110 cm to 180 cm of rainfall annually, of which 80% is during the monsoon season i.e. between June and September. Water coming in contact with chromium ore preferentially leaches out soluble hexavalent chromium from the ore body. As a result, water from the mine contains 0.2-4 mg/l of hexavalent chromium against a safe limit of 0.05 mg/l for human consumption; requiring all water to be treated before its release from the mines.
The treated water in the ETP is recycled as an input to the water treatment plant for drinking water purpose.