Irish Water wants to increase capacity of the system serving Newbrige to facilitate growth of the town.
It needs to upgrade the Upper Liffey Valley Sewerage Scheme by laying 9.9km of new pipes between Kilbelin, south of Newbridge, and the Oberstown waste treatment plant, which is to the west of Naas. The project would also entail the construction of pumping and stormwater storage tanks at Kilbelin, Little Connell and Newhall.
It requires land owned by businessman Dermot Cox, Rosetown Stud, Athgarvan, Newbridge, and occupied by Thurles Wholesale Cash and Carry, with registered offices at Kilbelin.
Both parties lodged objections to compulsory purchase orders (CPOs) sought by Irish Water.
Both said the sewerage project would severely restrict truck movements on the site and pose health and safety risks to workers and customers of the cash-and-carry.
The storage tank at Kilbelin would pose a health and food safety risk and adversely affect worker and customer perceptions. These were likely to lead to closure of the cash-and-carry which is a major employer in the local economy, it was claimed.
The location of the proposed tank would also negate a proposed approved extension to the cash-and-carry business, it was also claimed.
Last November, An Bord Pleanála recommended the CPO be confirmed without modification.
In their legal challenge, Mr Cox and Thurles Wholesale Cash and Carry say the board inspector erred in law by saying the project was not a type of development which required an environmental impact assessment (EIA).
They also say, among other things, the inspector failed to consider the fact that the planning permission for the cash-and-carry extension is due to expire in early 2019. If the applicants had to wait until after the construction of pumping and storage tank, the permission will have long expired.
They say the board failed to impose any condition to make a possibility of exploring an alternative siting of the pumping station/tank. The board abdicated its requirement to ensure the CPO did not disproportionately interfere with their property rights.
Last month the High Court granted a stay on the project pending determination of judicial review proceedings.
On Monday, Irish Water applied to have the case dealt with through the fast track Commercial Court because of its urgency. Mr Justice Brian McGovern admitted it to the commercial list and set a provisional hearing date in July.
In an affidavit as part of the application to admit the case to the commercial list, Brian Sheehan, an engineer employed by Irish Water's parent company, Ervia, said the improvement works were urgently needed because the treatment plant at Oberstown in Naas has already been specifically referenced in infringement proceedings by the EU against Ireland in the Court of Justice of the EU.