Around 220,000 households across Northern Ireland have today been warned to boil their water before using it for cooking and drinking after coliform bacteria were found in a sample.
Northern Ireland Water issued the alert, which affects around half the homes in the province, and warned of a potential problem with water quality at the Dunore Point treatment plant on the shores of Lough Neagh.
The warning affects a wide area including Belfast and large parts of counties Antrim and Down.
The company has been collecting further samples as part of a follow-up investigation but said it would take up to 24 hours for these to yield results. It said it had also examined its water treatment processes and had not found any problems.
Northern Ireland Water interim director of operations David Dangerfield told the Belfast Telegraph: “We were notified of the problem towards the end of Sunday afternoon. We take thousands of water quality samples across our water treatment works and the water distribution systems and yesterday a sample was reported to us which suggested there may be a problem with water quality from the Dunore Point Water Treatment Works, which is close to the international airport and takes water from Lough Neagh.
“We liaised with the health authorities from yesterday evening and into the night. In conjunction with the health authorities we are advising customers to boil water for cooking and drinking, really as a precautionary measure at this stage.
“We have been working since then through the night to take further samples from the water treatment works and our water distribution system.
“We’ve also checked our operations and everything appears to be normal.”
The samples suggested contamination by coliform bacteria, micro-organisms which are found widely in the environment including soil, Mr |Dangerfield said.
“We use them as an indicator of a potential problem within the treatment process. If we pick up coliforms in a sample like this the first thing we do is check the water treatment process.
“There is nothing wrong with the water treatment process that we can see,” he said.
“One of the other things we do is sample the water treatment works and take samples across the water distribution system to see whether those samples confirms the results that we already have.
“The samples are being analysed today and we should have the results back by early evening and depending on what we find we will take further action. We hope to have the results very quickly.
“It takes 24 hours to get a results on some of the things we are looking for so we are hoping that by the end of the day we will get some of the results back.”
A number of sewage treatment works discharge waste water into Lough Neagh but Mr Dangerfield said the large Dunore Point water treatment works, which was commissioned within the last 12 months, is more than capable of treating the water to drinking water standards.
“It uses dissolved air flotation to remove material and sediment from the raw water and after the treatment process it is disinfected using chlorine,” he said. “Modern water treatment plants such as Dunore Point are more than capable of treating water in Lough Neagh and to the very high |standards our customers expect.
“In 2008 we had the highest quality of drinking water in Northern Ireland ever and I have no concerns that Dunore Point is appropriate for treating Lough Neagh's water.”