Geomembranas

Geomembranas are impermeable synthetic liners designed to restrict water, liquid or gas movement. They are typically made from polymers such as high‑density polyethylene (HDPE), low‑density polyethylene (LDPE), polyvinyl chloride (PVC), polypropylene (PP), and sometimes vinylidene chloride (VDC). The polymer film is often reinforced with mats or fibers to improve mechanical strength and tear resistance.

In the 1960s, geomembranes began to appear in civil engineering projects, initially for landfill cover systems. By the 1970s their applications expanded to include leachate collection and liners for mining tailings. The 1990s saw the introduction of technical geomembranes for industrial waste containment, stormwater management and irrigation projects. Today they are widely used in landfills, waste treatment plants, containment ponds, mining pits, agricultural drainage, and in treatment wetlands.

A key performance metric for geomembranes is their permeability, which is typically on the order of 1×10^-10 to 1×10^-12 centimeters per second. Tensile strength and elongation at break are measured by ASTM D-1629 for HDPE and LDPE and by ISO 1927 for PVC. UV resistance, temperature tolerance, and chemical compatibility are also evaluated; for example, PVC geomembranes are more suitable for acidic or alkaline environments, whereas HDPE offers superior resistance to oil and petroleum products.

Installation methods include self‑adhesive, mechanically joined, or bonded by heat or ultrasonic welding. Proper compaction of the sub‑grade, drainage layers and anchoring systems are essential to prevent ponding or failure. Geomembranes must be inspected for punctures or leaks, and access points are required for ongoing monitoring.

The environmental assessment of geomembranes focuses on their life‑cycle impacts, recyclability and potential for degradation. While they provide an effective barrier to prevent pollution, improper disposal or puncturing can lead to leakage. In many regions, regulations require geomembrane thickness and material verification, often through coating or thickness testing. Their widespread use has led to standardization efforts such as ASTM D-4151 (geomembranes for landfill leachate control) and ISO 10776 (liners for temporary and semi‑permanent containment).