The incinerator has been shut down temporarily.

The facility, called the energy from waste plant by the government, has been blocked by a large tree stump about three feet in diameter.

Spot-checks to detect oversized items of waste delivered to the plant are now set to increase in frequency following the third blockage in less than a week.

The Department of Infrastructure has highlighted the problems being experienced and said that it will explore options to recover additional costs.

Work is being carried out to resolve the issue and waste will continue to be received and temporarily stored at the site ahead of the planned start-up of the facility tomorrow (Saturday).

Problems arise when non-conforming waste is delivered to the incinerator, mainly in skips. This can include tree trunks and stumps and large pieces of metal, such as settee or bed frames. Blockages affect the ’deslagging’ part of the process that quenches and clears the bottom ash and any unburnt, non-conforming waste.

Clearing blockages can take up to 48 hours and cost thousands of pounds as the plant must be cooled before engineers can safely access the blocked section.

The incinerator was brought back online towards the end of May after a planned period of maintenance, but has been forced to shut down again on three separate occasions in the space of seven days because of blockages.

The operator of the plant carries out spot checks to identify items that should not be introduced to the incineration process.

It is expected that these checks will be stepped up in a bid to prevent a repeat of the blockages experienced in recent days.

The Department of Infrastructure has also indicated that it will look at recovering the additional costs associated with managing non-conforming wastes delivered to the plant.

Infrastructure Minister Ray Harmer MHK said: ’Clearing a blockage can be a lengthy and costly exercise.

’The energy from waste plant has to be shut down and allowed to cool before the offending items can be removed, which also disrupts the supply of electricity from the facility.

’I would urge people and businesses to act responsibly and not send any non-conforming waste to the site.’

The facility suffered third blockages in less than a week.