Tata Steel Goes from Pilot to Permanent with Siltbuster
Siltbuster Process Solutions (SPS) has designed, built, installed and commissioned a new effluent treatment plant for Tata Steel’s Shotton Works, doubling the treatment capacity at the site. Following the process optimisation, the turnkey solution can now treat up to 40 m3/hr, removing at least 80% of the total Zinc.
Tata Steel invited SPS to tender for the project after the water treatment experts successfully delivered a full-scale treatment pilot plant to the Shotton site in 2015. This pilot enabled Tata to test the chemical treatment process it had in mind for its effluent and scope the ideal permanent treatment solution for its needs.
According to Rich Matthews, General Manager at Siltbuster Process Solutions, this ‘pilot to permanent’ approach is a growing trend:
“Companies are increasingly using our modular plant to test out ways of optimising the processes and chemistry behind their effluent treatment by running our pilot system in parallel (or as a side stream) with their existing plant. During the pilot, companies not only refine their treatment processes, but they also become familiar with our technology, team and approach. The fact our test plant can then be scaled-up to a permanent solution makes the transition so much easier for the customer. It de-risks the plant upgrade process; clients know our system and know it will work.”
In the case of Tata, the SPS pilot plant worked so well during the trial that Tata was able to wind down its current, ageing treatment plant, rather than running the two in parallel. This, together with the way the modular solution worked – it was energy efficient, could cope with varying effluent in terms of volume and type, and minimised waste – made SPS an obvious candidate when Tata was ready to install a permanent solution.
Occupying a quarter of the footprint of the old plant and yet doubling the treatment capacity, the permanent treatment plant which SPS has designed and built for Tata consists of modular process stages, including a 4-stage mixed reaction tank, a lamella clarifier, pre-packaged chemical dosing plus housing for a motor control centre panel, with associated instrumentation and pumping stages.
Tata operates three production lines at Shotton, manufacturing approximately 600,000 tonnes of pre-finished steel per year in the form of coated strip for building envelope, domestic and consumer applications. Tata’s effluent at the site has a variety of heavy metals present predominantly zinc but includes other trace metals too. When treating this effluent previously Tata’s treatment plant generated Gypsum (calcium sulphate) which is problematic to equipment and both difficult and expensive to remove. With the new SPS system, Gypsum is no longer formed, during effluent treatment, so processing costs are reduced. Instead, the dissolved metals are precipitated by chemical reactions during the mixed reaction tank stages before being settled out and separated by the lamella clarifier. The treated water can then be safely discharged to watercourse.
The new plant, which was delivered on time and within budget, works on every front as
Bill Duckworth, Tata Shotton Works Manager, says: “The new treatment plant will increase the volume of effluent that can be treated, it will reduce waste, reduce our energy consumption, and it will make the process more efficient and controlled.”
Richard Sidebottom, Tata Shotton Director Engineering Downstream Operations recently visited the treatment plant and commented: “I found it particularly encouraging to see the new technology that has been introduced which will support our production plans well into the future.”
The project presents another example of modular standard products, supplied by Siltbuster, being used to treat a variety of effluent streams. The deployment of a smaller system as a pilot, optimised the process selection and provided certainty to the project.