CHANGES are being requested for the anaerobic digester on Duchy of Cornwall land west of Dorchester.

The plant, which was opened by the King, is seeking to up the number of vehicles visiting the site, off the Monkeys Jump to Martinstown road, compared to the original planning permission.

At the peak, in the autumn, this could amount up to 40 trips by lorry or tractor and trailer each day, although the application says this is less than 1per cent of all HGV traffic on the adjacent A35 and A37 and only happens over a very limited period.

Figures with the application papers seek to vary the original planning agreement, dating back to 2011, which refers to 40,000 tonnes of material per year, and to vary the mix of materials going through the plant to include rye and oats.

The new site operators, IXORA, would like the planning documents to reflect the annual amount in and out of the site, bringing the total to 60,000tonnes, which is already being routinely reached.

A planning agent said: "Although it is recognised by IXORA that the facility comfortably operates at this increased capacity without adversely impacting the local highway local amenity, they are keen to regularise the planning conditions so they align with the operational capacity of the site."

The Rainbarrow Farm plant, set up to provides renewable heat and power to the Poundbury estate, now feeds directly into the public gas supply network, using locally-produced material to generate the gas and using most of the left-over material, after processing, directly onto local farmland as fertiliser.

Figures produced with the application show a range of material being brought to the site for processing, almost all from within ten miles. These include dairy cow slurry, chicken manure, potato waste, from Weymouth, and grass and maize silage.

Of these maize is the biggest bulk material brought to the site, amounting to almost 300 tonnes per day when it is being harvested, usually in September and October.

Added together the existing use amounts to almost 35,000 tonnes per year brought into the site and 27,000 exported from it , averaging 10 vehicle trips each day in winter and up to 30 trips per day in autumn, the busiest period. Peak figures will be higher than this, and out of harvest season, lower.

The applicants say that actual vehicle movements have been more than anticipated in 2010 when the original planning consent was granted, amounting to 54,000 tonnes of imported material alone in 2023.

"This is significant because it demonstrates that vehicle movements in excess of those originally anticipated in 2010 can comfortably be accommodated within the purpose-built site access and local roads without any adverse effect on highway safety or capacity," said the application to change the capacity to 60,000 tonnes which, in practical terms, is already taking place.

"It is reasonable to conclude that that the increase in feedstock would have no material effect on highway safety or operational capacity," said the report to Dorset Council.