More than 2,800 tons of paper left out by householders for recycling is being dumped in landfill sites every year.

Paper collected in the same containers as plastic bottles and metal cans is being contaminated by food and liquid waste, making it unusable for recycling.

At present, 11 of Scotland’s 32 councils use mixed collection schemes. A further eight are considering adopting similar practices, according to a report by Remade Scotland, a Scottish government-funded agency set up to promote recycling.

Mixed collections are a cheaper alternative to kerbside sorting — in which householders leave different recyclable materials in separate containers — because they can be picked up by refuse workers in a single run.

Figures provided by local authorities reveal that, across Scotland, at least 2,880 tons of paper from mixed kerbside collections is being dumped. Critics say the system causes additional damage to the environment because the paper has to be sorted using industrial blowers and electric magnets that waste energy.

According to Glasgow city council, 2,400 tons of paper from its household collections have been dumped in landfill sites over the past year — 5% of total waste. South Lanarkshire said just over 3% — or about 480 tons — of its paper and card collections was sent to landfill.

South Ayrshire and West Dunbartonshire said 5% and 3% respectively of paper ended up in landfill. North Lanarkshire, Scottish Borders and Highland said 10%, 3% and less than 2% respectively of their mixed waste was dumped but were unable to provide a figure for paper. Falkirk said 4%-6% of its mixed waste was sent to landfill, but the figure included material that could not be recycled. West Lothian and Inverclyde were unable to provide information.

North Ayrshire, which said all its paper was recycled, and Highland use both kerbside sorting and mixed collection. Highland said it was considering expanding its mixed collections.

Recycling firms working for councils question council figures and claim as much as 15% of paper from mixed collections is sent to landfill.

Malcolm McArdle, the managing director of Alloa Community Enterprise, a recycling contractor working with four local authorities, said he does not process paper from mixed collections but that it was not uncommon for up to 15% of paper collected in this way to be dumped in landfill.

“I can tell you that between 10%-15% will not be reusable — that is based on industry figures,” he said. “Separate collections are the better solution but it is cheaper to chuck everything in the back of a lorry.”

McArdle added that councils had to rely on contractors being open and honest when reporting their recycling rates.

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