Managing thousands of tonnes of “heavily contaminated liquid” each week at two closed landfill sites is set to cost Glasgow’s council almost £1.4 million per year.

A new contract is expected to be awarded for the collection and disposal of landfill leachate at Cathkin and Summerston landfill sites.

The council has a “statutory obligation” to “protect the environment, ” and officials have recommended Clearwater DC 2001 Ltd are handed the contract to carry out the work after five bids were received.

It would be a 24-month deal at £1.375 million per year, with an option for a further 12 months.

In a report to the city’s contracts and property committee, officials state the council is “responsible for the management of a number of closed landfill sites throughout Glasgow and the surrounding areas.”

They add: “Despite these landfill sites no longer accepting biodegradable waste for a considerable period of time, the council has a statutory obligation to ensure environmental impacts associated with these landfill sites are managed correctly to protect the environment.”

Landfill leachate is a “heavily contaminated liquid which continues to form for many years after a landfill site stops receiving biodegradable waste.”

It occurs when “water percolates through the waste mass and the breakdown of waste releases moisture.”

The report reveals Cathkin, on average, produces around 1,000 tonnes and Summerston produces around 1,500 tonnes of landfill leachate per week. The successful firm will need to provide treatment and capacity to collect and dispose of the liquid.

Officials add the sites are designed to use bacteria to break down leachate into a “compliant chemical composition for discharge to sewer (Cathkin) or the River Kelvin (Summerston).”

They advise the council, alongside landfill consultants, is developing a strategy to “move to a more sustainable way of dealing with landfill leachate.”

“Until this is finalised and implemented leachate disposal, via external suppliers for treatment and disposal is essential,” the report adds.

The council has an annual budget of £1.56 million for dealing with landfill leachate. Officials say a cost reduction of almost £800,000 has been achieved, when “compared to the current rates paid for this service.”