Tata opts for wiser waste

Tata Steel produces 45,000m3 of metals-laden effluent per year at its pre-finished steel production site in Shotton, Wales.

The steel is primarily used for the domestic appliance and construction industries

However, the effluent plant is now 40 years old, having been built in 1976, and was designed to cater for a time when the site was an integrated steel plant.

“The existing treatment plant was designed to cater for a completely different duty to what is expected of it now,” says Tata Steel project engineer Jason Davies.

“This, along with its age meant that operating and maintaining the facility, was becoming more challenging and costly, and even though the treatment process itself was achieving compliance, it was inefficient and no longer fit for purpose,” Davies adds.

To combat this, Shotton’s own projects team worked with colleagues from Tata’s Swinden Technology Centre to establish a method of treating the metals laden effluent.

Tata Steel then engaged Siltbuster Process Solutions (SPS) to design and supply the necessary equipment, which consisted of mixed reaction tanks, a lamella clarifier, pumps and dosing systems and associated control.

From there, SPS designed, built and commissioned a full-scale pilot plant for treating of the main effluent flow at the Shotton production site.

The aim of the pilot plant is to test a new treatment process for the site and meet the site’s longer-term needs.

SPS was chosen to work on the project largely because of its involvement in a temporary groundwater project at Shotton during 2014.

“We worked closely with Tata’s projects team on interpretation of results from the test work already undertaken, and from there, were able to agree scope of supply and make progress,” says Clwyd Jones, SPS business development manager.

The pilot plant, which was installed by SPS, Tata and Tata’s other nominated subcontractors, has already shown the new treatment process to be much more efficient than the one it replaces.

SPS also says it occupies a very small footprint by comparison, uses far less process chemicals and generates a very small fraction of the existing plant’s filter cake volume.

“The pilot plant has exceeded expectation in terms of treatment capacity, and has enabled us to verify the new treatment process,” Davies says.

“We now have the confidence to use this as the basis to move forward with plans to fully replace the old treatment facilities in due course.”

According to SPS, the pilot plant will continue to operate until a project to replace existing treatment facilities is approved and completed. That work is scheduled to take place this year.