Dublin City Council last night responded to reports that diluted sewage sludge was being discharged into Dublin Bay by insisting that wastewater quality levels set in the building contract for the €300 million Ringsend wastewater treatment works were being adhered to.
A report on RTÉ 1 news that, on certain days, as much as one-quarter of the sludge was diluted with water before being discharged has prompted concern among residents, who say they have had to deal with bad odour problems since the plant opened last year.
Dublin City Council said last night that some sludge was being remixed into the final treated wastewater before it left the site while performance testing was being done, but insisted it was not discharging sludge directly into the sea.
According to Mr Michael Phillips, city engineer, the remixing of some of the sludge into the treated wastewater before it left the plant was a temporary measure and "above board".
"The final treated wastewater leaving the site meets the standard set out in the contract. Water in the bay is cleaner now than at any time in the past, and when the plant is fully commissioned in the next few weeks, this measure will no longer be needed."
He said water quality in the bay was so improved that the council was applying to An Taisce for Blue Flag status for Dollymount Strand.
Mr Damien Cassidy, chairman of the Ringsend, Irishtown and Sandymount Environment Group, said: "I am concerned but not surprised. We foresaw these problems, and always said that one site to treat the sewage from two million people was a bad idea."
The Green Party last night called on the council to explain how it intended to deal with the "fiasco". Mr John Gormley, Green TD for the area, said: "It now appears that the plant, when running at full capacity, can't cope properly with the amount of sewage it receives."