One of the State’s largest water users, Intel in Co Kildare, has introduced a new “nano water filtration system” designed to save almost half a billion litres of mains water a year.
Between its actual manufacturing process and facilities for its 4,500 staff, some 5,000 construction workers and the estimated 2,000 suppliers visiting the plant each day, Intel currently takes in a staggering 600 million litres of water a month, from the Irish Water network.
Since setting up in Leixlip in 1989 the US multinational has invested some €15 billion in the Leixlip plant with the new extension now nearing completion, set to cost a further €17 billion.
The plant manufactures microprocessors for the technology industry, a process that is heavily dependent on ultra-pure, clean water. Its primary use in semiconductor manufacturing is to rinse the surface of the silicon between each of the manufacturing steps. As chips become more complex, more steps are added to the process and more water is required.
As well as using water directly in the manufacturing, sanitation and catering processes, water is also used indirectly in the manufacturing process for humidification, cooling, and scrubbing emissions. The water purity levels need to be about 1000 times higher than would be required in a hospital operating theatre.
Water savings are to be made in future by refining the water which would have been returned to the Irish Water network. The new “nano filtration system” is a first for Intel globally.
The new system, along with a bog rewetting project in the Leixlip water catchment area in the Dublin mountains, is designed to ensure Intel is “net water positive” (returning more water to the environment that it consumes) by 2030.
In May 2021 Intel and the National Parks and Wildlife Service launched a blanket bog restoration project in the Wicklow Mountains National Park. The project involves 60 hectares being re-wetted to increase and restore water storage levels in the Liffey headwaters, by up to 90 million litres.
Already, some 88 per cent of water used by Intel is returned to the Liffey, via the Irish water wastewater treatment plant in Leixlip.
Energy engineer Ronan Kearney explained that when water arrives at the Leixlip campus it is held in water tanks where it must be refined before it is sent to the factory.
“Water is brought from the on-site tanks to our ultra-pure water (UPW) filtration system. As the water goes through the first stage of UPW filtration, some 25 per cent of it is lost due to the nature of how it is filtered.
“The new nanofiltration system will capture this lost volume of water and enable the vast majority of it to be reused in the softened water system which serves other functions on-site, for example in the scrubber systems which remove particulates from industrial exhaust or gas streams,” he said.
Ultrapure water engineer Irene O’Callaghan explained nanofiltration is a membrane filtration process used to soften and disinfect water. It primarily removes “divalent ions”, such as calcium and magnesium, hardness from the water while allowing most of the monovalent ions to pass through. This removes the bulk of the hardness without using any additional regeneration chemicals.
While the water from nanofiltration is not pure enough for the ultra pure manufacturing processes, its use elsewhere will cut the amount of mains water taken in by 484 million litres of water per year.