A landfill base lining system describes the engineered barrier installed beneath a waste disposal facility to prevent leachate and contaminants from migrating into subsoil and groundwater. Inadequate base sealing can result in irreversible groundwater contamination and regulatory non-compliance. Bentofix® geosynthetic clay liner and Carbofol® HDPE geomembrane form the certified sealing barrier, protected by a Secutex® geotextile, with the leachate collected in a mineral drainage layer above the sealing system – together delivering a complete, certified base lining solution.
Naue geosynthetic lining systems are installed wherever reliable containment, long-term groundwater protection and regulatory compliance are required.
Base lining for new MSW cells requiring compliant leachate containment and groundwater protection.
Composite liner systems for Class I and II hazardous waste landfills with enhanced leachate management.
Robust base sealing for industrial waste sites with variable chemical exposure and high leachate loads.
Cost-effective geosynthetic lining for inert waste disposal sites where the availability of mineral barrier material is limited.
Landfill base lining involves large areas, steep side slopes and repeated construction traffic before waste placement. Naue geosynthetic products are designed to meet demanding installation requirements and support safe, efficient execution under variable site conditions and tight construction programmes.
A compliant landfill base lining system typically combines several functional layers. Each layer addresses a specific engineering requirement. Understanding which layers are mandatory and which are optional, based on site conditions, is essential for cost-effective and regulation-compliant design.
Key principle: The GCL acts as the mineral barrier. The HDPE geomembrane provides the primary polymeric seal. Secutex® protects the geomembrane from mechanical damage. A mineral drainage layer (gravel) above the sealing system collects and removes the leachate. Together, they form a fully integrated base lining system.
| Function | Naue product |
|---|---|
| Mineral barrier (GCL) | Bentofix® GCL (e.g. NSP 4900 or Bentofix® X) |
| Primary polymeric barrier | Carbofol® HDPE geomembrane (2.5 mm per DepV, Germany; 1.5 mm typical EU industry minimum) |
| Leachate drainage | Mineral drainage layer (gravel 16/32) + Secutex® filter/separation |
| Geomembrane protection | Secutex® nonwoven geotextile |
| Slope stability (steep slopes) | Bentofix® needle-punched GCL |
Product selection for a landfill base lining system depends on waste classification, subsoil permeability, leachate aggressiveness and regulatory requirements. The following table provides a structured decision guide based on four key criteria.
| Criterion | Bentofix® GCL only | Carbofol® HDPE only | Composite system (GCL + HDPE) |
|---|---|---|---|
| Subsoil / subgrade type | Suitable where the subsoil provides secondary containment backup; native clay present | Suitable where rigid, impermeable primary barrier is required regardless of subsoil | Recommended for most landfill classes: GCL provides the mineral layer, HDPE the primary seal above |
| Leachate aggressiveness | Standard leachate (non-hazardous MSW); normal sodium bentonite suitable | For aggressive leachate or risk of ion exchange, Bentofix® X (PE-coated GCL) adds chemical protection | Composite provides a dual barrier: HDPE as the primary barrier; GCL as the secondary self-sealing backup layer |
| Regulatory / waste class | Inert waste or lower-class sites where single-layer GCL meets local requirements | Where polymeric barrier alone is accepted under national regulations (e.g. certain Class I applications) | Mandatory for Class II/III hazardous waste under EU Directive 1999/31/EC; also required under BAM specifications in Germany |
| Slope gradient | Suitable on slopes up to 1V:2.5H using needle-punched Bentofix® types | HDPE geomembrane suitable on all slope gradients; requires textured surface for steep slopes | Composite on steep slopes: use Bentofix® + Carbofol® textured MF/MF for adequate interface friction |
Benefit for planners and compliance
Bentofix® GCLs can provide significantly lower hydraulic conductivity than compacted clay liners in landfill base sealings. Hydraulic conductivity is equivalent to or better than 1 m of compacted clay - in a layer only 7 mm to 15 mm thick. Bentofix® GCLs hold LAGA certificates of suitability for German landfill Classes I and II. Carbofol® HDPE geomembranes carry BAM Approval No. 08/BAM IV.3/08/15 for waste containment.
Benefits for procurement and finance
Bentofix® GCL delivers the sealing performance of about 1 m of compacted clay in a 7-15 mm layer, eliminating the need to import large volumes of compacted clay - a major cost driver on sites without suitable native clay. This significantly reduces material procurement, transport and placement costs, and the thinner sealing layer frees up cell volume.
Benefits for site managers and contractors
Bentofix® NSP 4900 is supplied in 5-metre-wide rolls. No specialist bonding equipment is required. Carbofol® geomembranes are welded on site using standard hot-wedge or extrusion methods. Secutex® protection geotextiles are simply rolled out above and/or below the geomembrane.
A landfill base lining system is an engineered barrier installed beneath a waste disposal facility. It prevents leachate and contaminants from migrating through the subsoil into groundwater. A compliant system typically combines a geosynthetic clay liner (GCL), an HDPE geomembrane, a geotextile protection layer and a mineral drainage layer for leachate collection above the sealing system. The system must comply with national and EU regulations throughout the operational and post-closure phases of the landfill.
Bentofix® GCL acts as the mineral barrier layer and is suitable where a self-sealing secondary containment function is required. Carbofol® HDPE geomembrane provides the primary polymeric barrier. For most regulated landfill classes - particularly Class II and III hazardous waste under EU Directive 1999/31/EC - a composite system combining both is mandatory. For inert or lower-classification sites, a single GCL layer may meet local requirements. Contact Naue for a project-specific recommendation.
The key references are: EU Landfill Directive 1999/31/EC and Council Decision 2003/33/EC (waste acceptance criteria); EN 13257 (geotextiles for solid waste applications); EN ISO 10318 (geosynthetic terminology and standards); BAM certification requirements (Germany); USEPA Subtitle D (MSW) and Subtitle C (hazardous waste) in the USA; Naue provides BAM-approved products and supports regulatory documentation for project-specific compliance.
The main savings come from replacing thick mineral sealing layers with thin geosynthetics. Bentofix® GCL provides a hydraulic conductivity equivalent to or better than 1 m of compacted clay in a layer only 7 mm to 15 mm thick, eliminating the need for large volumes of imported compacted clay - which is frequently unavailable on site and expensive to transport and place. Because the thin GCL replaces a thick clay layer, the available cell volume increases, improving the economic return on landfill infrastructure investment.
Bentofix® GCL panels are unrolled and overlapped at the joints. No adhesive or welding is required. Carbofol® HDPE geomembrane panels are welded using standard hot-wedge or extrusion fusion equipment. Secutex® protection geotextile is installed above and/or below the geomembrane and can also serve as the filter/separation layer beneath the mineral leachate drainage layer. Naue provides installation guidelines, design support and quality assurance documentation.
Geosynthetic sealing systems significantly reduce the volume of mineral sealing materials required. Bentofix® GCL replaces roughly 1 m of compacted clay with a 7 mm to 15 mm layer, eliminating the import of large clay volumes and cutting the associated extraction, transport and installation emissions. Thinner sealing layers also increase the available waste disposal volume within the same footprint, extending landfill service life.
Yes. Carbofol® HDPE geomembranes hold BAM approval (Approval No. 08/BAM IV.3/08/15) for landfill use in Germany. Bentofix® GCLs hold LAGA certificates of suitability for German landfill Classes I and II. All products comply with EN ISO 10318 geosynthetic standards and EN 13257 requirements for solid waste applications. For individual project certifications or third-country compliance documentation, contact Naue’s Engineering and Design Department (EDD).
Yes. Bentofix®, Carbofol® and Secutex® have been installed in a lot of of landfill projects worldwide, including the Ennigerloh central landfill in Germany, the Armstrong Waste Management landfill (Scotland, UK), the Bukit Tagar sanitary landfill in Malaysia and the Hong Hua Ling landfill expansion in Shenzhen, China. Reference projects are available in the case studies.
Bentofix® GCL achieves a hydraulic conductivity of k = 1.2 x 10⁻¹¹ m/s, which is equivalent to or better than the performance of 1 metre of compacted clay. This is achieved in a layer thickness of only 7 mm to 15 mm. The self-sealing sodium bentonite core swells upon hydration to close minor imperfections, ensuring long-term barrier integrity without the need for specialist compaction equipment or quality-controlled clay material.
The mineral drainage layer (gravel) above the sealing system provides continuous leachate collection and removal. By draining leachate efficiently away from the barrier, it reduces the hydrostatic head acting on the geomembrane and GCL. A lower leachate head means lower hydraulic pressure, decreasing the risk of liner uplift and extending the service life of the barrier. A Secutex® filter/separation geotextile keeps the drainage layer functional by preventing clogging over the service life.
The design of landfill base lining systems is based on recognised regulatory frameworks and project-specific boundary conditions. Naue’s Engineering & Design Department (EDD) provides design support to help you identify the optimal system configuration for your site - compliant, traceable and cost-effective.
Naue Bentofix® is a geosynthetic clay liner (GCL) for waterproofing in landfill engineering, groundwater protection and hydraulic applications.
Naue Bentofix® X geosynthetic clay liner is a multicomponent PE-coated GCL for landfill, waterproofing and slope sealing.
Naue Carbofol® is a HDPE liner for landfill sealing, mining containment, and groundwater protection.
Naue Secutex® is a mechanically bonded nonwoven geotextile for separation, filtration and protection in roads, railways and hydraulic engineering projects.
