The 30,000 tonne-capacity LondonWaste Ltd plant at Edmonton had received complaints from neighbouring householders in June and July this year.
” We had a sudden amount of wet and dense material delivered. Our procedures couldn't deal with it. That has now changed, we are confident it is all in the past.“
– Alexander Maddan, Agrivert Ltd
The problem stemmed from a batch of green waste received in May. Because of the wet weather, the material started to break down anaerobically at the Edmonton plant. The odours peaked in late May and early June because of the summer heatwave.
As a result, Enfield council's environmental health regulators served an enforcement notice on London Waste ordering them to remove the “large” batch of compost.
Mike Hainge, Enfield's assistant director of environment said: “After discussions with London Waste and the Environment Agency a notice was issued to ensure works were carried out to remove the batch of compost that had been identified as the source of the odour. This would have taken another three weeks to go through the maturing process.
“This would have proved intolerable for residents and we have to act in their best interests,” Mr Hainge.
Investigation
The Edmonton facility was officially opened in March this year, but began operations back in September 2005. It was built by Oxfordshire composting company Agrivert, which also operates the plant on behalf of LondonWaste.
Composting experts at Agrivert have been working with LondonWaste to tackle the odour problems, and the German composting engineering firm Biodegma GmbH was brought in to investigate the problems.
Biodegma recommended that retention times for material kept in the plant's composting tunnels should be extended for higher volumes of grass cuttings and kitchen waste. It also advised a seasonal adaptation of aeration and a more vigorous blending procedure.
Agrivert
The company's managing director, Alexander Maddan, told letsrecycle.com today that the offending material had now been cleared and procedures changed.
Mr Maddan conceded that the operation of the plant had not reacted quickly enough to the unexpectedly wet green waste received in May. However, he insisted that procedures had now been changed to avoid the problem in future.
The Agrivert managing director said: “We were running for nine months without anyone knowing we were here – but then in May/June came in and we had a sudden amount of wet and dense material delivered. Our procedures couldn't deal with it. That has now changed, we are confident it is all in the past.”
Mr Maddan said the complaints from residents had come because by the time the company had realised the problem, the offending batch had been maturing for three weeks. And, he added, “By the time we worked out how to deal with it, it had been there for six weeks. That's the problem you have with a continuous operation like this.”
Changes
He said procedures had been altered as a result of the episode, explaining: “We have improved our aeration and improved our mixing, using an enzyme. We are very pleased with it.”
The offending material was speeded through the composting process in eight weeks' rather than the usual 10, with Agrivert applying specially to the Environment Agency to allow the shortened maturation period. Mr Maddan said the composted batch has now been sent for agricultural use.
LondonWaste is the waste contractor for the North London Waste Authority, collecting waste from the London boroughs of Barnet, Camden, Enfield, Islington, Hackney, Haringey and Waltham Forest.
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