Bentofix® X2-type multicomponent GCL paves the way for brownfield redevelopment – Smart barrier technology for sustainable urban transformation
Brownfield remediation
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Fig. 1: Secutex® R 501 installed over Bentofix® X2 NSP 4900 and topped with clean soils
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Fig. 2: Installation of Bentofix® GCL across slurry wall
From industrial legacy to new beginnings
Naue’s Bentofix® X2 NSP 4900 Geosynthetic Clay Liner (GCL) played a key role in the remediation of a former industrial site in Sighthill, north of Glasgow. The site is being redeveloped for a major urban project including around 800 new homes, infrastructure, green space, retail and community facilities.
The challenge: Galligu and chemical contamination
The site was home to St. Rollox Chemical Works for 167 years, once Europe’s largest chemical works. When it closed in 1964, the land was heavily contaminated, especially with galligu – a waste product from the Leblanc process used to manufacture soda ash. For every 8 tonnes of product, 7 tonnes of calcium sulphide waste were produced and left in heaps, emitting toxic hydrogen sulphide gas.
Around 700,000 m³ of galligu and hydrocarbon waste needed to be safely contained and capped across the 50-hectare site.
The solution: Multifunctional capping system with Bentofix® X2
The remediation design required a low-permeability capping barrier meeting several criteria:
- Immediate and permanent gas barrier
- Chemical resistance and long-term durability
- Prevention of freshwater ingress
- Connection to 1,800 metres of deep slurry walls
- Full performance retained during steel piling
Based on site-specific chemical analysis, Naue confirmed the long-term compatibility and provided a warranty for Bentofix® X2 NSP 4900. Naue also recommended using Naue Secutex® R 501 as a protective and filtering layer above the GCL.
The product: Bentofix® X2 NSP 4900
Naue Bentofix® X2 is a needle-punched composite with a uniform core of natural sodium bentonite between a woven and a nonwoven geotextile. A 0.2 mm polyethylene coating is extruded onto the woven side during manufacturing, providing for immediate gas impermeability and additional protection of the bentonite.
The product provides a reliable moisture and gas barrier, resists delamination and delivers hydraulic performance equal to or better than compacted clay. Edge impregnation with bentonite and printed alignment marks ensures watertight overlaps.
Added protection with Secutex® R 501
To protect the GCL during cover soil installation and to ensure filtration and separation, Naue’s nonwoven needle-punched Secutex® R 501 was installed above the Bentofix® layer.
Result: A safe and future-ready site
In total, 140,000 m² of Bentofix® X2 NSP 4900 and Secutex® R 501 were installed. The system provided a safe, cost-effective and high-performance solution for this challenging brownfield remediation – supporting the regeneration of Sighthill into a modern, sustainable neighbourhood.
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