[vc_row][vc_column width=”3/4″ offset=”vc_col-lg-8 vc_col-md-8″][vc_empty_space height=”24px”][vc_column_text]Glanua is delighted to be a finalist in the 2023 ICE awards for the upgrade of Mallow Waste Water Treatment Plant (WWTP) and associated Pumping Station and Storm Water Storage on behalf of our client, Uisce Eireann (Irish Water).
The €20 million investment which commenced in 2021, is to ensure compliant standards of wastewater are discharged to local streams, rivers and the sea to a standard set by the Environmental Protection Agency (EPA) and also to enhance the water quality of the Blackwater River which the treated wastewater enters.
[/vc_column_text][vc_empty_space height=”39px”][vc_column_text]This is one of the first projects delivered for Irish Water under the widely acclaimed Early Contractor Involvement (ECI) Model. The ECI model encourages engagement with contractors from the start of the project cycle to provide input into design and planning phase, right through to construction and final handover. To date it has been a highly successful initiative in building a culture of trust, collaboration and engagement between Glanua, Irish Water, and the local community while also driving enormous benefits such as innovation, collaboration, efficiency, and risk reduction in project delivery.
In 2019, Mallow WWTP had a capacity of 18,000 population equivalent (PE), and the Mallow Pumping Station had no stormwater storage facility meaning discharges of stormwater to the Blackwater River were common after heavy rainfall. The upgrade of Mallow WWTP involved increasing the capacity of the plant to 22,000 PE initially, with an ability of future expansion to 24,595 PE. As part of the upgrade, a new Mallow Bridge Wastewater Pumping Station, storm tank, and rising main meant excess stormwater would no longer overflow into the Blackwater River and instead would flow to the newly constructed Storm Tank with a capacity of 2,400 m3.
Innovation and sustainable design solutions were at the forefront of the upgrade at Mallow WWTP. BIM was adapted early in the project to ensure that all designs and hazard and operability studies (HAZOP) were completed using 3D Models and clash detection. This early-stage involvement allowed the Glanua team to create a robust and innovative design that included pragmatic and sustainable solutions.
- The use of Design for Manufacturing Assembly (DFMA) was an integral part of our solution. By optimising the design ahead of construction, we manufactured and assembled the control building offsite, significantly reducing the time, costs, and risk of traditional onsite construction.
- The new Mallow Bridge Pumping Station was built adjacent to the existing pumping station which had to be kept operational throughout the build. A 400 mm existing rising main as well as pumped overflow passed adjacent to the footprint of the new pumping station and needed to be protected throughout the construction of the pumping station. The existing rising main was diverted from footprint of works prior to storm tank works, whilst maintaining treatment.
- A dual 450 mm sewer rising main was also constructed from the new pumping station to convey flows to the existing plant. Due to the route of the pipeline a design solution for install on a near-vertical cliff face, a height of 24m had to be developed. Initial specimen design had the pipes fixed to the face of the cliff, Glanua in conjunction with Uisce Eireann design teams redesigned this to utilise augur boring for the install of the pipe. A rig was set up 25m from the face of the cliff at an angle of 40 degrees from the toe of the cliff. The rig drilled two bores 32m long which both landed within 50mm of the design location.
- The construction of the Mallow Bridge Pump Station required the install of a 16m deep rectangular tank with ground conditions changing from river gravels to Limestone rock at a depth of 4m. The excavation was also within 20m of the banks of the with the depth of dig 6m below river bed level. Initial specimen design had 18m long secant piles surrounding the perimeter of the tank. During the final design we altered this to utilise the ground conditions to our advantage utilising a mass gravity concrete retaining wall to support the overburden from ground level to the rock level. This resulted in significant savings in time and works scope.
- One of the most significant challenges of this project was that the discharge of water during construction works posed an environmental risk as the site was within 20 metres of the Blackwater River. To ensure water disposal was planned and managed correctly a detailed and robust groundwater and surface water management plan was developed collaboratively with Glanua site teams, Uisce Eireann representatives and specialist environmental consultants.
- A 2400m3 storm tank was designed to finish with the contours of the existing undulating site. As a result a stepped roof was required with the bottom “step” becoming surcharged as the tank was filling. This was a non standard design solution and was one of the first tanks of it’s type in the country designed for the roof to surcharge. Now that the tank is completed none of the finished structure can be seen with the exception of a retaining wall for access and maintenance.
The primary objective of the Mallow WWTP upgrade was to ensure that all discharges from the WWTP are of the required EPA standard at all times. In addition, modernisation and improvement of the wastewater infrastructure will ensure that cleaner and safer effluent is discharged from the plant and will accommodate further growth in the area. The project was delivered on-time and on-budget through the ECI Programme and the team are preparing to handover the project to the Irish Water team.
The Mallow Bridge Pump Station and WWTP Upgrade is up for 2023 Project of the Year at the ICE Awards. To vote for this project click here ICE Awards 2023 | Project of the Year [/vc_column_text][vc_empty_space height=”39px”][vc_row_inner][vc_column_inner offset=”vc_col-lg-12 vc_col-md-12″][vc_gallery interval=”10″ images=”4756,4757,4758,4759,4760,4761,4762,4763″ img_size=”medium”][/vc_column_inner][/vc_row_inner][vc_empty_space height=”39px”][/vc_column][vc_column width=”1/4″ offset=”vc_col-lg-offset-1 vc_col-md-offset-1″][vc_empty_space height=”24px”][vc_column_text]
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