The Irish Times view on Dublin’s bathing water quality: new pointers for action

Irish Water’s latest research shows the key areas to be addressed to improve water cleanliness

Dublin Bay sea swimmers may feel deflated by Irish Water’s decision not to extend the treatment, using ultraviolet (UV) irradiation, of effluent leaving the Ringsend wastewater treatment plant beyond the summer season.

The utility’s licence requires it to operate the UV system during what is defined as the bathing season, which is June to September. Swimmers had worked hard to persuade the minister with responsibility, Minister for Housing and Local Government Darragh O’Brien, to consider extending the bathing season to apply this extra protection for those taking a dip year-round.

O’Brien asked Irish Water to undertake a study into the efficacy of extending the UV disinfection. Irish Water has completed this work, which involved taking more than 3,000 samples during four months of using the UV system in the winter, and has concluded that it made no discernible difference to water quality.

This may be down to the different weather conditions in the winter which can affect the operation of the UV system – though there is no guarantee that the UV system is making a perceptible difference in the summer either.

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However, what the research has achieved is to increase the store of knowledge, through rigorous and robust research, of the actual causes of pollution in Dublin Bay which may be resulting in illnesses among swimmers.

Some of these problems fall within the remit of Irish Water. The drainage system, which overflows during times of severe rain, requires investment. There is a widespread problem of housing “misconnections” where pipes which should feed into the sewerage network have been connected to the general drainage system.

However, the worst culprits, according to the research, and the issue which is proving the most intransigent is that of dogs, or rather their irresponsible owners who allow their pets to defecate on beaches and don’t pick up after them. Until this is tackled effectively by local authorities, sea swimmers’ illnesses are likely to continue.