Pyrolysis trial heats up for estates disposal
One London council is testing an innovative thermal treatment system to reduce waste at source from housing estates. Dean Stiles reportsWandsworth Borough Council has just begun trials on a pioneering project to treat waste from housing estates at source. The scheme, which started last month, uses the AutoBin system - a small-scale pyrolysis plant fed by waste from communal rubbish chutes located in blocks of flats.
Residents using the system will dispose of their waste in the normal manner via the rubbish chutes. But instead of collection from paladins at the chute exit, waste will be fed into the AutoBin system. This typically will consist of two PyroPure thermal treatment units working side by side at different times, and together they can handle 16kgs of waste reducing it to 300g of ash that is flushed daily into the sewage system.
The process was developed by waste technology company Morgan Everett and is marketed by Connaught Environmental, which provides housing maintenance and estate management services to UK social landlords and local authorities.
"Through carefully scrubbing waste gases and treatment of waste water we can utilise the existing sewage system for final disposal," says Ted Brown, chief executive officer for Morgan Everett. "It makes sense to use a carbon neutral facility that's available almost everywhere - that should be a significant factor for a London borough like Wandsworth."
Recyclable materials like bottles are filtered from the waste stream before processing and taken with other recyclables from the site. Brown explains: "The application deals with waste at the point of first creation. Half the cost of waste disposal is transport - this is a cost that we can significantly reduce. Additionally there is the environmental benefit of reduced pollution from less vehicle journeys."
"We are looking to achieve considerable cost savings with this process," adds Councillor Malcolm Grimston, Wandsworth Borough Council's cabinet member for environment and leisure. "This is one of the reasons why we are participating in this pilot project. We have some very precise questions on how reliable the technology is, any potential downsides, and whether it can deliver the environmental and economic benefits anticipated."
Economics make sense
Brown is clear about the financial benefits of such a system: "We have checked the economics and they make sense against costs of service and the increasing costs of landfill. The obvious environmental benefits would be in addition to these financial ones. The system is moving from proving itself in laboratory conditions to proving itself in a real life location. This process will be carefully monitored and will take several weeks."
By treating at source, the system also cuts down on the amount of refuse entering the waste stream in the first place. "These blocks of flats produce considerable amounts of refuse. Although we are getting increased recycling rates from such estates, a lot of waste still goes to landfill. If we can prevent more getting into the waste stream that's a clear advantage," points out Grimston.
He adds that the council will still continue with recycling and is confident the trial won't reduce the amount of material put out for recycling by residents. He does expect a significant reduction in the amount of black bag waste going into collections with the Morgan process.
Connaught Environmental's managing director, Darren Frost, says the system has tremendous potential for the company improving its service provision to local authorities by providing waste treatment and disposal.
"We are eagerly awaiting the results of the field trials and expect to use the Morgan AutoBin system as part of our waste management package for councils and social landlords," he says. "The application of the this technology will radically alter the way we and councils deal with waste. It will be cheaper because it removes the need for collection and transportation of rubbish - it is more hygienic and is better for the environment."
Dean Stiles is a freelance journalist
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