Ringsend plant output to be tested to gauge effect on bathing water

Move towards greater UV disinfection with growth of year-round swimming

Bathing-ban notices are regularly issued for beaches in the summer months when sewage discharges or storm water overflows result in water pollution making swimming unsafe. Photograph: Nick Bradshaw

Bathing-ban notices are regularly issued for beaches in the summer months when sewage discharges or storm water overflows result in water pollution making swimming unsafe. Photograph: Nick Bradshaw

 

Irish Water is to extend testing and treatment of effluent from the Ringsend sewage plant to determine if it is negatively affecting bathing-water quality in Dublin Bay.

The move follows growth in the popularity of year-round sea swimming, with some bathers reporting bouts of vomiting and skin infections following dips in the bay during the off-season when testing and treatment levels are reduced.

Bathing water-quality is monitored during the swimming season, which runs from June to mid-September. Bathing-ban notices are regularly issued for beaches in the summer months when sewage discharges or storm water overflows result in water pollution making swimming unsafe.

However, for the rest of the year swimmers are likely to be unaware if the waters are safe to enter.

Similarly, the licence of the Ringsend sewage plant requires Irish Water to operate an ultraviolet (UV) light disinfection system to protect bathing waters during the summer season, but not for the other eight months of the year.

Irish Water

In a joint letter, Minister for Housing Darragh O’Brien and Minister of State for Heritage Malcolm Noonan said Irish Water is to operate the UV system past the bathing season and implement testing “across the rest of 2021”.

The letter to Green Party councillor, Donna Cooney, said “sea swimming has increased in popularity over the past year while people have been confined to their homes and we want people to be safe while enjoying their pastime”.

Ms Cooney said the move was a “step in the right direction” to extending the bathing season year-round.

“I have been asking for additional testing outside the standard bathing season, so I am pleased Irish Water has come around to this, and to having additional UV treatment, which they have previously said was too expensive and unnecessary outside the bathing system,” she said.

Bacterial loads

“UV treatment kills bacteria. It’s the same system that’s used for drinking water, so its use will help prevent people getting sick.”

Irish Water confirmed it would undertake the monitoring and treatment programme, but that “bacterial loads” were affected by a number of factors including “misconnections” from homes, storm water overflows, urban run-off, fouling from dogs and birds, and “human litter and waste” on beaches.

“Current modelling has shown that the only designated bathing beach that might possibly be marginally improved by turning on the Ringsend UV beyond the normal bathing season is Dollymount Strand, ” it said.

“Irish Water have recently met with a number of stakeholders to discuss the modelling that has been carried out to date. It was agreed that we need to be able to justify the turning-on of the UV beyond the normal bathing season by ensuring that doing so will have a positive impact on bathing water quality.”

The sampling and treatment programme would build “a better understanding of all impacts”, it said.

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