The industrial city of Jamshedpur consumes huge volumes of water, mainly for steel production, and is ranked fourth in the country in terms of per capita water consumption. However, during the steel production process, about 40 million litres per day (mld) of industrial wastewater is generated and discharged directly into the Subarnarekha and Kharkai rivers. Due to the unrestricted discharge of metals and chemicals, the quality of water in these rivers has deteriorated. This has rendered the river water unfit not only for consumption but also for non-potable uses such as industrial activities. In light of this problem, Jamshedpur Utilities and Services Company (JUSCO), a subsidiary of Tata Steel that facilitates the provision of civic services in Jamshedpur, has deployed a technology called zero liquid discharge (ZLD) to eliminate the discharge of effluents into nearby waterbodies. With this technology, the utility aims to efficiently recycle 40 mld of sewage and use it for various non-potable purposes. So far, two treatment plants based on the technology have been developed in the city.
JUSCO’s ZLD plants
To ensure 100 per cent waste-water recycling, JUSCO decided to set up a ZLD facility in the city. As part of the project, two sewage treatment plants (STPs) with a combined capacity of 40 mld capacity have been constructed at Bara and Kharkai. The secondary-level STP at Kharkai has a capacity to treat 10 mld of waste-water. Meanwhile, the tertiary treatment plant at Bara near Sidhgora has a capacity to treat and recycle 30 mld of waste-water.
Construction work on the ZLD project was commenced in 2016. Under Phase I, the 10 mld Kharkai treatment plant was completed and inaugurated in July 2016. The plant is currently treating sewage generated in the Bistupur, Kadma, Sonari, Northern Town and Circuit House areas. The construction work on the 30 mld Bara treatment plant was completed in July 2018. The plant was developed at a cost of Rs 250 million under the second phase of the project. It will treat both domestic and industrial waste. Both the plants have been developed using ZLD technology.
Further, as part of the project, a sewerage network of nearly 500 km has been laid across the city. Besides, 10 automated sewage pumping and control centres have been constructed in the Sonari, Circuit House Area, Baridih, Baradwari, Bistupur, Burma mines, Bhuiyandih, Uliyan (old) and Uliyan (new) and Sakchi (near Subarnarekha Flats) areas.
Understanding ZLD
For ZLD, the sewage and tertiary treatment plants use advanced wastewater treatment technologies to purify and recycle waste-water. The treatment process involves a series of steps including ultra filtration, reverse osmosis, evaporation or crystallisation and fractional electrode ionisation.
First, waste-water is collected and treated in various types of tanks. Microorganisms break down impurities, and solids and liquids are separated. The resultant waste-water is treated using ultrafiltration and reverse osmosis technologies that help in concentrating the dissolved solids. Up to 90 per cent of the water treated can be recycled for non-potable uses such as in boilers or cooling towers. The remaining liquid is subjected to evaporation technologies, which precipitate the dissolved solids and remove them. The water vapours formed at the evaporation stage are condensed and further purified using electrode ionisation that removes all impurities. These condensed vapours are then returned to the system as purified water, which is sent to industries through pipelines.
Effluent from JUSCO’s ZLD facilities is recycled and reused in non-potable applications. There is no discharge into the environment or waterbodies for treatment in common effluent treatment plants.
Conclusion
This initiative will help JUSCO achieve the twin objectives of pollution control and waste-water treatment for non-potable uses. The 40 mld of treated waste-water can be effectively used by about 20,000 households in Jamshedpur for various non-potable purposes including washing clothes and utensils.
The successful implementation of the ZLD facility in Jamshedpur can serve as an example for other cities and can be replicated in areas under JUSCO’s jurisdiction. Industries too can set up ZLD facilities of smaller capacities on factory premises to meet their pollution emission standards and evade penalties while running their operations in full swing.