Waste reduction programme means concrete plant is set on sustainability

The Sittingbourne facility of Supreme Concrete, part of the concrete division at Ibstock plc, is approaching the end of a transformational two-year journey of process waste reductions.

Such is the turnaround that major outcomes have been achieved, including a 50% cut in the use of mains water. The initiatives are providing a significant contribution to the environmental targets set out in Ibstock’s Sustainability Roadmap 2025.

Core business at Supreme Concrete’s Sittingbourne plant – the biggest site in Ibstock’s concrete group – is the manufacture of pre-stressed T-beams for suspended block and beam flooring systems, as well as lintels of various shapes and sizes for doorways and window openings.

Slick production process

Supreme Concrete has three factories at the Sittingbourne site and around 70 people are headquartered at the facility, 45 of whom are directly associated with its finely-honed manufacturing operations. The production process for a pre-stressed T-beam, for example, begins with steel wires pulled along a 1.5m-wide stainless-steel bed, and each of the factories has six beds of various lengths from 90 to 150m.

The steel wires are positioned, cut and tensioned, before a concrete T-beam profile is cast over the top. Curing time is 10-17 hours, depending on the product and factory. De-stressing the product entails cutting the wires so they pull inwards, ensuring the concrete is extremely strong in compression. Finally, the product is cut to the required length.

Despite this slick process, some issues were recognised regarding waste and wastewater that the site wanted to address in line with Ibstock’s Sustainability Roadmap, which was launched in 2018. To contribute towards the group’s overall goals, the need for a significant shift in culture was plainly evident, as Factory Manager Tom Malcolm reveals.

We wanted to restructure and refocus our maintenance team to drive reductions in water usage and product waste,” he says. “This strategy allowed us to undertake initiatives such as rebuilding our reclaim system. After products are cut we wash the dust down with water, which creates a slurry paste that runs along the production bed. Previously, this slurry had to be moved offsite by tanker and sent to landfill at significant cost, but now we process it on site.”

More effective reclamation

The reclaim system works by separating liquid and solid matter, with the latter sent to a filter press where it becomes a ‘mat’ of concrete and returned to the site’s stock of recycled materials. Moreover, the water is reused in the site’s mixer, reducing the need to draw from mains by 50%.

This substantial improvement sits well with the company’s Sustainability Roadmap 2025. The most recent update states that 74% of Ibstock’s water use now comes from a recycled or recovered source, with several of its factories today operating a closed-loop system. Communicated within the roadmap is a wide range of clear targets for the business, not just reductions in water use and CO2 (per tonne of production), but zero waste to landfill, for example.

A further successful initiative at Sittingbourne centres on the amount of raw concrete waste sent offsite in skips. Through efficiency improvements and the aforementioned culture change – ensuring operators focus on factors such as quality and offcuts – the generation of raw waste has been reduced by 80%. And nothing is sent offsite.

Instead of sending out the small amount of concrete waste we still produce in costly skips, we’re now utilising an area on-site that allows an external team to come in and crush any beams that have failed our stringent quality checks into <10mm aggregate,” explains Mr Malcolm. “This aggregate can be reused in our process as a substitute for limestone. Also, the steel wire in the beams is retrieved as part of the crushing process and sold to a local scrap dealer for recycling.”

Further waste reduction planned

But the success story for Supreme Concrete’s Sittingbourne site does not end there. A new cutter due for imminent arrival is set to reduce waste even further.

In the case of a T-beam that has been chipped or damaged during transportation around the facility, the entire length becomes waste,” says Mr Malcolm. “However, when the new stand-alone table saw arrives, we’ll be able to remove damage from the end of a beam by simply cutting it down and returning it to stock, recovering 90% of the product.”

The transformational journey at Supreme Concrete has been supported by substantial investment levels.

As part of our rolling programme of site modernisation, we’ve probably invested just short of £1 million over the past 18 months,” concludes Mr Malcolm. “However, in my opinion, one of the most effective investments cost very little. By empowering our employees we’ve provided staff with the chance to move up, or around the facility. In the past, we’ve probably been guilty of keeping people in their roles, chiefly because they’re very good at what they do. However, presenting a key performer with a new opportunity, perhaps involving more responsibility, has been the catalyst for the real culture change.”

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