A food treatment centre to handle Oxfordshire's kitchen waste could be up and running within 18 months.

Oxfordshire County Council announced tonight it was inviting tenders from companies to build "one or more" plants to process food and green waste collected from homes across the county.

County Hall said it hoped to sign a contract worth about £20m with the successful bidders by March, with the multi-million-pound facility accepting kitchen waste from April 2009.

The authority said it wanted "one or more facilities" to process about 30,000 tonnes of mixed garden and food waste every year.

Faced with widespread anger over the introduction of fortnightly waste collections, Oxford City Council expects a countywide food recycling scheme to win over the public.

For those living in the city, food waste collections could come as early as next year with the Town Hall expected to pilot a small-scale service.

Most residents' concerns about vermin and rotting rubbish spilling on to streets have centred on the disposal of food.

The creation of a multi-million-pound treatment plant would see waste from kitchens converted into a compost-like material or used to generate electricity.

City councillor Jean Fooks, executive member for a cleaner city, said: "We are hoping to introduce food waste collections in parts of the city next year to see how we can make it work.

"This will help us prepare for the new facility. It would be nice if we are able to collect food waste weekly. It is what we want and it is the issue most people are really bothered about."

Roger Belson, Oxfordshire County Council's cabinet member for sustainable development, said: "I am very pleased that we are making progress with this scheme, which is essential to keep costs low for Oxfordshire taxpayers by diverting as much waste as possible from landfill."

The county's food waste plant is likely to see the creation of a giant composter, which involves put- ing food in vast closed containers and pumping air in.

Chipping Norton-based recycling company Agrivert was the first company to confirm that it would be tendering to build a giant composter on land between Yarnton and Cassington.

Harry Waters, sales director of Agrivert, said the company had already spent thousands of pounds designing a plant and finding a suitable location.

He said: "We hope that acquiring planning permission will give the council confidence in what we are proposing. With our plant in north London, we have a proven record."

The centre would recycle about 40,000 tonnes of kitchen and green waste and would cost more than £5m to build on a two-hectare site close to the A40.

The food waste treatment contract is running alongside a tendering process for a far more costly plant to treat non-compostable waste.

Major incineration companies dominated a shortlist drawn up the county council in July of firms bidding to build a residual waste plant in the county, possibly a large-scale incinerator.

Energy from waste, as incineration is sometimes known, remains a controversial option that critics claim brings health risks and adds to global warming.