Residents of the Gaeltacht in west Cork were placed at risk of consuming inadequately disinfected water over an extended period last year, a report by an environmental watchdog reveals.
An audit by the Environmental Protection Agency of drinking water supplied by the Ballymakeera Water Supply Scheme located near Ballyvourney (Baile Mhuirne) found that people were exposed to potentially infected water for almost five months largely due to a problem caused by poor internal communications within Irish Water.
The examination by EPA inspectors found that the ultra-violet disinfection system, used to kill bacteria, at the water treatment plant in Ballymakeera was switched off on February 27 last year.
The audit also found that the disinfection system used at the plant did not allow sufficient contact time for chlorine to adequately disinfect the water in the Ballymakeera water supply which provides drinking water to a population of almost 700 including Ballyvourney (Baile Mhuirne/) and Cúil Aodha.
“A lack of communication of the relevant information internally in Irish Water resulted in a delay in the full extent of the deficiency in the disinfection system until July 18, 2018. This put the consumers of the supply at risk from inadequately disinfected water,” the EPA said.
The audit acknowledges that Irish Water fast-tracked the installation of a new UV disinfection unit at the plant once it became aware of the problem.
The EPA recommends that the company should conduct a full review of its procedures for identifying any inefficiency in the disinfection process of its water treatment plants. It claims such a review should also cover Irish Water’s communications with the HSE and the EPA.
The audit was carried out after Irish Water had informed the EPA on July 20 last year that the drinking water supply at Ballymakeera was not being adequately disinfected. It found inadequate disinfection arose when the treatment plant pumps, which pump water from a reservoir two kilometres away, were operating as the water had insufficient time to be treated with chlorine. The pumps operated for 15 hours per day.
Over months following the February 27 shut-down of the UV disinfection system at Ballymakeera, supplies were only monitored for Cryptosporidium – a parasite that causes gastroenteritis – as staff from Irish Water’s compliance division were unaware there was an issue about inadequate contact time.
The realisation that consumers were potentially exposed to inadequately disinfected water only occurred when officials from the company’s process optimisation and asset operations division visited the treatment plant in July as a result of the summer drought and issues with the UV unit. Although all tests were clear, Irish Water acknowledged to the EPA that the supply had been at risk from Cryptosporidium due to a problem at the source of the supply.
A new UV unit installed at Ballymakeera will automatically shut down the supply to consumers if water quality drops below a certain limit.