Employing an early contractor involvement framework facilitated collaboration between Uisce Eireann, Glanua and the entire project supply chain, boosting efficiency, innovation, and sustainability on the new Boherbue Wastewater Treatment Plant.
The village of Boherbue in northwest county Cork has undergone considerable expansion in recent years, resulting in increased demand for housing. This growth has presented infrastructural challenges, particularly for the original wastewater treatment facility, which struggled to cope with the surge in population. Additionally, the plant had fallen short of EPA treatment standards, underscoring the pressing need for an upgrade. Of particular concern was the risk of discharge of treated wastewater into the river Brogeen, a protected conservation area that serves as the habitat for the freshwater pearl mussel.
In collaboration with Uisce Eireann and Cork County Council, Glanua undertook a comprehensive project to modernise and enhance the capacity of the treatment plant. This initiative would address the immediate needs of Boherbue’s growing community and ensure compliance with environmental regulations.
EARLY CONTRACTOR INVOLVEMENT
The project, delivered under the Early Contractor Involvement (ECI) framework, aimed to address the overloaded and outdated infrastructure while ensuring compliance with regulatory standards and meeting the evolving needs of the community. The project was groundbreaking because of the multifaceted approach taken by Glanua to efficiently treat wastewater, reduce carbon emissions, and protect natural ecosystems.
GROUNDBREAKING PROJECT
Key features of the upgraded facility include new inlet works, a stormwater tank, biological treatment processes and tertiary solids removal systems. Leveraging the ECI framework allowed for the integration of innovative solutions such as solar energy, natural sludge drying reed beds and the preservation of existing constructed wetlands for stormwater overflow. This innovative approach set a new standard for sustainable wastewater treatment and ensured long-term environmental benefits for Boherbue and its natural surroundings.
HEALTH & SAFETY
Glanua prioritised safety throughout the project with meticulous planning and early-stage involvement of safety protocols such as Access Lifting and Maintenance (ALM) workshops a Hazard and Operability (HAZOP) study to reduce risks. Following project completion, the site obtained an impressive Safety Management Score of 98.88%.
INNOVATION
Innovation was central to the project’s success with advancements in wastewater treatment technologies and practices. Adopting the ECI framework facilitated enhanced collaboration between Glanua, the client and the extended supply chain, promoting efficiency, innovation and sustainability throughout the project lifecycle.
Effective project management was crucial in delivering a multifaceted solution. The innovative design, integrating sustainability initiatives such as sludge drying reed beds, solar technology, and reuse of constructed wetlands, along with modular off-site construction for precast tanks and steel modular buildings, marked a pioneering project approach. The project was completed on time and budget, with commissioning completed in March 2024.
The innovation in this project also lies in its comprehensive integration of advanced treatment processes and renewable energy solutions, surpassing conventional wastewater treatment solutions. By combining a new biological treatment process and tertiary solids removal with the incorporation of sludge drying reed beds and a solar panel farm and reuse of the existing constructed wetlands, the project adopts a multifaceted approach to enhance sustainability and reduce carbon emissions.
SLUDGE DRYING REED BEDS
The implementation of sludge drying reed beds (SDRBs) significantly increases sludge concentration to up to 40% dry solids (DS) after 10 years of operation. This revolutionary approach reduces sludge export volumes by more than tenfold compared to conventional methods, thereby minimising transportation and dewatering costs while substantially reducing the carbon footprint of the Boherbue WwTP. SDRB sludge can also be directly land spread without the need for additional chemical conditioning, further enhancing its environmental benefits.
There are numerous benefits to the inclusion of sludge-drying reed beds instead of using traditional sludge management practices. These include, but are not limited to:
– Reduction of the carbon footprint of the plant by approximately 45T over a 10-year period.
– Carbon capture via natural plant growth
– Up to 25% organic matter removal due to mineralisation
– Dewatering process completed with zero energy consumption.
– At full design loads, the SDRBs will remove over 49 20,000-litre tankers from the road per annum.
The construction of the SDRBs commenced in early February 2023, incorporating earth embankments and precast concrete wall sections for formation. Each cell was meticulously lined to ensure water tightness, with feed and drainage pipework installed for optimal functionality. Reeds were planted in late April to establish and grow during the summer months, aided by the importation of sludge to promote growth. This comprehensive approach ensures the effectiveness and sustainability of the SDRBs in treating wastewater and reducing the carbon footprint of the Boherbue WwTP.
CONSTRUCTION METHODS
Throughout the entire design process, Glanua, in collaboration with Uisce Eireann’s PMO team, evaluated several project aspects, such as energy efficiency (BEP), total expenditure costs and environmental impact. These included:
– Energy efficiency of all motors and equipment (BEP).
– Process and equipment selected on total expenditure costs, which includes CAPEX, OPEX and Capital replacement at end of life.
– The impact on the local environment was carefully assessed for all design options considered during the planning phase.
MODULAR AND OFF-SITE CONSTRUCTION
Modular/off-site construction was used to reduce the carbon footprint and on-site safety risks, with precast panels and BCAR-compliant steel modular buildings used to promote efficient delivery and enhance safety.
Precast panels were instrumental in constructing the main aeration tank, reducing construction time and mitigating safety risks compared to traditional insitu methods. Precast wall sections were used to separate the SDRB sections to reduce the footprint size and, again, to reduce construction time and safety risks. Throughout the project, precast process tanks were used extensively, contributing to streamlined construction processes and improved safety measures.
A BCAR-compliant steel modular building was used for the control room, laboratory, and caretaker’s office facilities. This has a significantly lower carbon footprint than that of a conventional block-built structure and, in turn, significantly reduced health and safety risks during construction due to fabrication being completed before assembly on site.
SUSTAINABILITY
Boherbue WwTP showcases Glanua’s commitment to sustainability across various dimensions, including environmental, social, and economic considerations.
The inclusion of SDRBs demonstrates its dedication to environmental sustainability. These beds offer an innovative solution for sludge management, reducing the environmental impact of waste disposal while also providing opportunities for ecological conservation. By using nature-based solutions to treat and manage sludge, Glanua minimised the carbon footprint associated with traditional disposal methods, thereby mitigating environmental harm. The SDRBs also significantly reduce operational costs, providing a long-term, cost-effective solution.
The integration of solar technology underscores Glanua’s commitment to renewable energy and carbon reduction. By harnessing solar power to supplement the energy needs of the WwTP, the contractor reduced reliance on fossil fuels and contributed to the transition towards a more sustainable energy future. This reduces operational costs and mitigates greenhouse gas emissions, thereby supporting climate action efforts and environmental preservation.
Socially, Glanua’s decision to reuse existing wetlands demonstrates its commitment to maintaining and sustaining biodiversity in the Boherbue community. By incorporating natural elements into its design, it not only minimised disruption to local ecosystems but also to the overall health and vitality of the local environment.
It can also be said that the project’s sustainability footprint extends to additional community benefits, such as job creation and improved wastewater infrastructure, enabling Boherbue to support its growing population and contribute to the economic growth of the surrounding area.
SOLAR TECHNOLOGY
The use of solar technology underscores the project’s commitment to renewable energy sources, contributing to further reductions in carbon emissions. By leveraging these innovative technologies and practices, the initiative sets a new standard for sustainable wastewater treatment, offering a replicable model for other treatment plant projects. This holistic approach improves operational efficiency and promotes environmental stewardship, paving the way for a cleaner and more sustainable future in the wastewater sector.
50Kw solar panels have been installed. These will produce 42,500Kwh of electricity per year. This alone will introduce a carbon saving of 13.7T/CO2 per year, which is significant compared to a traditionally built wastewater treatment plant of this kind.
REUSE OF CONSTRUCTED WETLANDS
Integrating the existing constructed wetlands into the wastewater treatment facility, which was core to the design development, brought many benefits, ranging from low operational costs and support for diverse ecosystems to sustainable water management. They also improve the water quality of streams and rivers in surrounding areas, creating conditions for aquatic life to thrive. The wetlands also create a scenic location in the village, promoting biodiversity and providing a habitat for small animals.
IN CONCLUSION
Boherbue WwTP upgrade works is a flagship project for sustainable and carbon-saving treatment processes and will serve as a reference project for future similar projects within the industry. By demonstrating the feasibility and benefits of integrating renewable energy, advanced treatment technologies, and ecological conservation practices, this project sets a precedent for industry-wide innovation and best practices. It complies with stringent EPA discharge consent standards while minimising impact on the existing landscape, demonstrating a commitment to environmental sustainability, operational efficiency, and community well-being, making it a catalyst for positive change within the wastewater treatment sector and beyond.
Speaking about the project, Darran O’Leary, Programme Manager, Uisce Éireann, said: “We are delighted to have delivered this important project for the community of Boherbue. The modernisation and improvement of the wastewater infrastructure will accommodate further growth in the area and ensure that cleaner and safer treated wastewater is being discharged into the Brogeen River. It also adds biodiversity value to the area and remains sensitive to the surrounding landscape. This, coupled with the use of solar energy, demonstrates our commitment to putting sustainability at the heart of everything we do”.
Andrew Young, Managing Director, Municipal, Glanua, commented: “Glanua’s vision, captured in our tagline ‘For a cleaner planet’, reflects our commitment to environmental stewardship and the protection of natural habitat. Through innovative and sustainable technologies, we ensured that the stringent emission limit values were achieved on Boherbue WwTP, while simultaneously reducing carbon emissions and safeguarding the natural environment, establishing it as one of Ireland’s most environmentally friendly wastewater facilities.”