Bentofix® X2 Lining Solution at Gordonvale Sludge Lagoons
The Project
As part of the Cairns Water Security Stage 1 project, initiated under the Cairns Water Security Strategy by Cairns Regional Council, construction of four sludge lagoons and one emergency lagoon was undertaken at the Gordonvale Water Treatment
Plant. This project forms an important component of the region’s long term water security planning, providing improved sludge management infrastructure to support the reliable operation of the water treatment facility.
Global Synthetics worked closely with the project team during the design phase, providing technical input to assist in the selection of the most appropriate containment lining solution. During the design process, the interface friction characteristics
of the lining system were assessed and clarified. Based on these findings, Naue Bentofix® X2 NSP4900 PE (Polyethylene) coated geosynthetic clay liner (GCL) was selected as the preferred GCL due to its enhanced interface friction performance and long-term containment capabilities.
The Challenge
The sludge lagoons required a robust and reliable containment system capable of delivering long term environmental protection while withstanding the demanding conditions associated with sludge storage. The lining solution needed to provide an extremely low permeability barrier, be suitable for large scale installation and comply with the project’s stringent engineering and environmental requirements. A key project objective was also to optimise the overall lagoon construction while maintaining the required engineering performance. This included identifying opportunities to reduce construction materials and associated installation costs without compromising long term integrity.
The Solution
Global Synthetics supplied Bentofix® X2 NSP4900, an advanced PE coated GCL designed to provide superior hydraulic performance and long term containment. Bentofix® X2 NSP4900 GCL incorporates high quality sodium bentonite encapsulated between durable geotextiles. When hydrated, the bentonite forms a self-sealing, low permeability barrier, delivering exceptional hydraulic performance. The unique X2 liquid applied PE coating technology helps maintain long term hydraulic performance and allowed for a reduced cover soil thickness to be used. Other traditional water storage lining solutions such as HDPE geomembrane liner solutions were considered and assessed but when the overall costs were compared to a PE (polyethylene) coated Bentofix® GCL, it was clear that the Bentofix® solution provided not just a technically sound solution but also an economical one. The use of Bentofix® X2 NSP4900 GCL delivered several key project benefits, including:
- Excellent hydraulic barrier performance with extremely low to no permeability.
- Reduced protective cover thickness from 500mm to ~300mm (~40%), significantly lowering construction costs.
- Rapid installation compared with traditional compacted clay liners.
- Consistent factory manufactured quality.
- Durable long term environmental protection for critical water infrastructure.
Project Outcome
The successful installation of the Bentofix® X2 NSP4900 GCL lining system contributed to the delivery of five new containment lagoons that will support the ongoing operation of the Gordonvale Water Treatment Plant and the broader objectives of the Cairns Water Security Strategy. By combining technical design support with an advanced geosynthetic lining solution, Global Synthetics helped deliver a containment system that not only met the project’s environmental and engineering requirements but also reduced construction costs through a significant reduction in protective cover fill.
Need advice on lining solutions for water or wastewater infrastructure? Contact Global Synthetics today.
Photo credit: Koppen Construction
