Projects

Upgrading Drainage Systems to Increase Portlaoise Wastewater Capacity

Tetra Tech is engineering the main drainage improvements scheme in Portlaoise to enhance wastewater capacity and support future growth.

The aim of this project was to upgrade the existing wastewater treatment plant at Portlaoise, on behalf of Laois County Council, from 12,000 Population Equivalent (PE) to 39,000 PE, with a new collection system and a new sludge treatment facility.

As Consulting Engineers for all stages of the Portlaoise Main Drainage Sewer Improvement Works Contract, we dealt with the preparation of the preliminary report and EIS, all the way through to the procurement stages to construction supervision and handover to Laois County Council.

The Contract involved laying approximately 20km of pipeline of varying diameter throughout the town and environs of Portlaoise. In order to upgrade the existing foul and storm sewers, pipeline routes were identified both through private and institutional properties as well as along roads and across railway lines.

The project was awarded the Engineers Ireland Environmental Infrastructure Award in November 2011.

Challenge

Upgrading of the existing wastewater treatment plant at Portlaoise, County Laois from 12,000 PE to 39,000 PE, a new collection system and a new sludge treatment facility for the County through constant water ingress and non-cohesive soils.

Solution

Given that significant sections of the sewers were constructed within existing streets and roadways careful attention was given to traffic management, programming of works to avoid busy road use periods and minimising both the number and duration of road closures. 

Ongoing communication continued during the construction stage with landowners, resident groups, Chamber of Commerce, traders and other affected parties to inform parties as to when and where works were planned and measures that were proposed to mitigate the impact of such works. We worked closely with the Local Authority and their resident engineer staff throughout to maintain effective communications with the general public and other interested parties.

					Benefits				

									20km of large sewers
5km of rehabilitated live sewers
2 crossings of a major railway line
3 major pumping stations constructed
								

At a glance

Client

Laois County Council

Location

Portlaoise, Ireland

Services

Civil and structural engineering, environmental impact assessment (EIA), geotechnical engineering, health and safety, planning, project communications, project management, transport engineering, water services

An aerial view of the Portlaoise wastewater treatment plant in a green field setting

An industrial facility with large, metal pipes and machinery

The project featured in this article was undertaken by RPS, A Tetra Tech Company and originally published on RPSgroup.com. In March 2026 RPS rebranded to Tetra Tech.