Geosynthetics, the way forward for Sustainable Waste Management

About fifty years back, waste management looked very different. Plastics were far less common, and most other waste could be recycled, composted or burnt. Today waste is more varied and more hazardous, the risk to soil and groundwater is better understood, and waste regulations are much stricter. Geosynthetics are now a standard part of how landfills and waste sites meet those rules.

Geosynthetics have been part of civil and environmental engineering for more than three decades, in uses as different as containing aggressive chemicals, building mechanically stabilised earth walls and working in harsh climates. Their range of applications keeps growing.

Waste management is one of the largest of those applications. Geosynthetics in a waste facility perform six functions: separation, filtration, reinforcement, barrier, protection and drainage. The table below shows which products do which job.

Waste Management with Geosynthetics:

Landfill Lining Solutions: Leachate from landfills can be hazardous, and as waste volumes rise, so does the risk of groundwater contamination. Geosynthetic clay liners, geocomposites and geomembranes form the lining systems at municipal solid waste landfills, bioreactor landfills, construction and demolition debris sites, industrial hazardous waste landfills and nuclear waste facilities. A typical composite liner is an HDPE geomembrane over a GCL or compacted clay, with a protection geotextile above it. Ocean supplied a Geosynthetic Clay Liner 6 MM for a landfill project in Odisha.

Leachate drainage systems: Drainage geocomposites and geonets have the strength, chemical resistance, durability and low creep that a leachate drainage layer needs, and they are a cost-effective alternative to thick layers of drainage gravel.

Capping systems: Every landfill needs a cap to keep rainwater out and stop landfill gas escaping into the air. Geosynthetic clay liners and drainage geocomposites are widely used in caps: the GCL forms the barrier, and the geocomposite drains rainwater off the cap and collects and conveys gas beneath it.

Gas collection systems: In the cap, a geonet or drainage geocomposite under the barrier layer collects the gas produced as waste decomposes and carries it to vents or extraction wells, so gas pressure cannot build up under the liner and lift or rupture it.

Dewatering: Geotube dewatering uses durable geotextile tubes that filter and retain solids, and is used to dewater sediment from site runoff, sludge and wastewater. The slurry is dosed with flocculants and pumped into the permeable tube; the water drains out through the geotextile pores under the pumping pressure while the solids stay inside. The filtrate can be treated and returned to waterways, and the dried solids reused or disposed of.

Ocean Geosynthetics works with clients on waste containment systems designed to meet regulatory guidelines, supplying geomembranes, GCLs, geotextiles and drainage geocomposites for landfills and waste sites.

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