Autoclaving goes commercial in Yorkshire

A commercial-scale autoclave and recycling plant will be up and running shortly, offering an attractive treatment option for local authorities. Dean Stiles reports

The UK’s first commercial-scale autoclave and recycling plant is due to go live this April in Rotherham, capable of handling 100,000 tonnes per annum of household waste. Sterecycle has already built the plant off-site and installation is now underway at the six-acre facility in Yorkshire.

The £10M plant will take in a mixture of commercial and household waste, and managing director Duncan Grierson says that the company is currently in discussions with a number of local authorities to take their waste. According to Grierson, autoclave technology has lower capital costs than other waste treatment processes and is a more environmentally attractive option.

“We can recycle and recover around 80% of the typical domestic waste stream. The benefits of this system are that we are not destroying waste – we are cleaning it up and turning into new products, to achieve recycling as well as diversion targets,” he explains.

He points out: “Technologies like incineration and gasification only achieve diversion – they are destructive technologies. In particular, they destroy the plastics that are hydro-carbon based. We recover better quality recyclates than from MBT processes, plus we produce a higher quality organic fraction which has real value and greater flexibility as to it use.”

Under the Sterecycle patented process, steam is used to clean the waste before mechanically separating it into sterile non-organics and an organic biomass fibre. With further processing, the fibre can be used as a soil conditioner, for making paper pulp, or as a clean renewable energy source with high calorific value.

“This recovered fibre is a high quality biomass and has many uses including land remediation or as a renewable energy source,” explains Grierson. “A major advantage of the autoclave process is the high quality biomass generated. We can achieve 98% pure biomass, which is much higher than the refuse-derived fuel from mechanical biological treatment.”

A more local option

While the financial model for autoclave projects is more complex than for incineration because it depends on the markets for back-end products, Grierson says there are scale advantages with autoclaves plants commercially viable at 100,000 to 150,000 tonnes, which is much smaller than most incineration plants.

This means facilities can be more localised and it also makes planning applications easier. So far, Sterecycle has raised £20M of equity finance from leading environmental investors including Goldman Sachs International, Impax Group and Ailsa3Ventures. With a credit facility of £100M, the company now intends to finance, build and operate a further five plants across the UK in the next five years.

Sterecycle was recently named as one of Europe’s leading low-carbon climate pioneers, ranked number five out of the top 50 companies by CNBC European Business. “To receive such an accolade is proof that our technology has an important role to play in reducing climate change. Our solution has a carbon benefit,” says Grierson.

Dean Stiles is a freelance journalist

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