Where there’s muck there’s brass, they say, and many at Worton Farm, near Cassington, are now hoping the old adage is true. Certainly there is no shortage of muck there — in the pungent form of all that food waste most of us in Oxfordshire are now being told to consign to special bins.
No shortage of money, either, judging by the £9m invested in the county’s first anaerobic digester, officially opened by recycling minister Lord Henley yesterday.
Formerly known as the Cassington Anaerobic Digestion (AD) Plant, it is run by Oxford Renewable Energy (ORE), a company owned 50-50 by organic recycling company Agrivert, of Radford, near Chipping Norton, and M&M Skips, based at Worton.
Agrivert commercial director Harry Waters said: “Oxfordshire has been at the forefront of pushing ahead and getting this scheme up and going.” He added: “The background to this initiative, nationally, is that the UK must meet targets set by the EU for reducing waste going to landfill. If it misses those targets it will be fined £150 for every tonne above the limit.”
Earlier this year Agrivert bid for and won the 20-year contract with the county council for processing all Oxfordshire’s organic waste, comprising what is technically called “controlled in-vessel compost” — including such nasties as chicken carcasses — and green waste. Already the none-too-fragrant pure food waste (sorted by the householder or commercial entity that produced it) has begun arriving at Worton Farm in lorries from the Vale of the White Horse, South Oxfordshire and Oxford City Councils.
From November 15, more deliveries are scheduled for the three- acre digester site — in the middle of the 120-acres between the A40 and the railway — as food-waste collections get under way in West Oxfordshire, too.
Cherwell’s waste goes to a different site in Ardley where pure food waste and green waste arrive without having been previously separated at source. The environmental case for building digesters such as this sounds convincing.
Mr Waters explained: “When running at full capacity, the digester will produce 4.5 million cubic metres of methane a year — which will be fed into a generator to produce 2.1 megawatts of electricity, enough to power about 4,000 homes. The renewable electricity generated is fed into the National Grid and is already producing enough to power 2,100 homes.”
Mr Waters says the costs to Oxfordshire council tax payers are half that of dumping organic waste in landfill. Methane is 23 times as potent a greenhouse gas as carbon dioxide and that if the waste were to go to landfill the gas given off as the stuff decomposes, would, in terms of global warming, be the equivalent of 71,000 cars on the road, each driving the UK average mileage a year.
If all goes to plan, Agrivert will build a similar digester on the edge of Benson airfield, near Wallingford.
Under the scheme, local councils bring the waste to the site in their lorries and dump it into a bunker in a closed warehouse, which keeps the smell indoors and away from the nearest neighbours, who are anyway 600 metres distant.
In the bunker, the rubbish is separated from contamination such as the plastic bags in which householders have placed it, some of which are degradable and some not.
The waste is then homogenised and pasteurised (a requirement since the last outbreak of Foot and Mouth) and stored and stirred for 50 days as a sort of sterile soup in the first two of those five huge green tanks now visible to passengers on the Cotswold Line railway.
Then it moves on to the next two tanks for another 25 days for further maturing at different temperatures.
The fifth tank is used to store the end product — something called digestate, which is sold to local farmers as a chemical-free fertiliser.
It seems that every step of the process is potentially profitable. Significantly, when fully up and running, the plant will only employ a grand total of two people on site.
The electricity produced powers the generator on site too, which also produces renewable heat — some of which is used to heat the pasteurisers and the digesters. With the help of a grant from the Department for Environment Food and Rural Affairs (Defra), more of the heat generated will be used to dry woodchip, seen as a useful fuel of the future, for use, for instance, in boilers to heat schools.
Worton Farm, owned by green industries businessman Guy Pharaon, who is also a shareholder of M&M Skips, is seen is an ideal site: close to Oxford and yet isolated.
The Cassington Anaerobic Digestion Plant is the initiative of company managing director Alexander Maddan, who served in the army in Germany and saw how energy is produced from waste there.
He said: “I was originally interested in producing energy from sewage. Then I learned about energy from food waste.
“The Germans are far ahead of us in this area.”
He added that finding the millions of pounds needed to pay for Agrivert’s half share of the plant had not been easy, even though the venture received a £1.6m grant from the Government agency Wrap (Waste and Resources Action Programme) based in Banbury.
He said: “We were committed to the purchase when the credit crunch struck and our finance disappeared. However we were able to go ahead eventually. But it was challenging.”
Agrivert, a privately owned company, has negotiated contracts in Hertfordshire, Essex, Pembrokeshire and Newcastle as well as Oxfordshire.
It also owns three sites for composting garden waste in Oxfordshire at Chipping Norton, Benson, and Hinton Waldriss.
But the Cassington anaerobic digester is the first to be built on this scale in the UK. It puts Oxfordshire among the leaders in the recycling stakes, with South Oxfordshire now showing the second highest recycling rate for any district in England and Wales.
All the expensive equipment on site, including the two generators worth about £750,000 each, was built in Germany; much of it by the specialist firm Wacherbauer.
Mr Waters said: “It’s true that Britain is way behind Germany, but we have made huge strides in the right direction in the last few years.”
He added: “Our next challenge is to start take food waste from commercial properties such as Oxfordshire schools and hospitals.
“We reckon the waste from 40 schools equals the waste of 65,000 households.”