Biodrying comes to Shanks in UK first
Shanks is pre-treating municipal waste in its East London facility with a unique biodrying process which can eliminate 30% of moisture contentLast month the UK's first commercial biodrying facility was commissioned and handed over to Shanks Waste Management in conjunction with the East London Waste Authority.
The biodrying system, which treats municipal waste by using heat to extract its water content, was developed by Italian firm Ecodeco, and this is the first installation for the company outside Italy.
According to Duncan Bowett, managing director of Synmet UK, which integrated the waste processing and recycling plant at Shanks, the biodrying process can eliminate around 30% of the moisture found in municipal solid waste (MSW) before any other treatment.
"Biodrying converts waste into recoverable and usable products. But, as importantly, it stops the biological activity of MSW and the emission of greenhouse gases such as methane that would otherwise end up in landfill," he says.
The black bin waste is taken from London boroughs such as Tower Hamlets by Shanks as part of its long-term private finance initiative contract for the East London Waste Authority. The waste gets loaded into one of three halls at the contractor's east-London facility - each hall has a capacity of 75,000 tones per annum.
Micro-organisms which are naturally present in municipal waste take around a fortnight to reach optimum temperatures. But the biodrying process generates heat, which releases moisture from the waste. This moisture is then sucked out of the hall by creating a negative-pressure environment. With the moisture gone, the micro-organisms can no longer grow.
The waste is then transferred from the sorting hall into a single separating system, designed and built by Synmet. It includes various separation technologies - trommel screening, fine screening, shredding, magnetic separation and air technology. Once separated, what's left is solid recovered fuel - a renewable energy source that can be used by power plants and direct end-users such as cement kilns.
According to Bowett, certain technical "challenges" had to be overcome - both at the design and implementation stages - to integrate the three lines from the halls into one separation plant.
"It involves technology that's new, not just to the UK, but also for the rest of the world. In fact, there are only a handful of companies throughout the world who could achieve what we've done," he claims, adding: "The plant has been set up in such a way that makes it more reliable. If one hall goes down, the others keep going."
Bowett believes that Shanks's biodrying plant will be used as a template for future waste innovations and will set the benchmark on a cost-per-tonne basis. Shanks is working on more biodrying plants in Dumfries and Galloway, which are anticipated to open in 2007.
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