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Geosynthetics: A key toward sustainability

February 1st, 2009 / By: / Updates

Papers from two 2008 conferences prompted our thoughts vis-à-vis the important role that geosynthetics can, and should, play toward sustainability.

The first conference was the 4th European Geosynthetics Conference (EuroGeo4) held in Edinburgh, Scotland, Sept. 7-10. The paper by Belton, et al.1 hit the sustainable issue head-on by illustrating how geotextiles and geogrids save large quantities of natural materials, mainly stone aggregate for highways, railroads, parking lots, and building foundations. They also describe the use of “site won” materials such as the use of on-site soils for use in walls and slopes rather than using imported sands and gravels. In addition they bring into context the carbon footprint of both materials and the processes involved in obtaining these materials, e.g., transportation from quarries to construction sites.

At the same conference, Robinson and Quirk2 presented details of the UK’s Aggregate Levy Tax in the amount of £1.60 per tonne. This incentive should readily propel the widespread use of geosynthetics for the same applications, as just mentioned. In this context, geosynthetics could even be considered to be a negative cost material. Interestingly, the intent of this tax was to increase the use of recycled materials but it appears to more immediately play into the use of geosynthetics, to all of our advantage. Robinson and Quirk give several tables of aggregate thickness saved using geogrids in highway base courses. They also illustrate aggregate savings when using geodrains, fin drains, and geocomposites in walls and bridge abutments. Lastly, they describe the many uses of these drainage geosynthetics in waste containment. Landfills require drainage of leachate at their base, drainage of water at the surface, and sometimes drainage within the waste mass itself.

A second 2008 conference, the Global Waste Management Symposium, was held at Copper Mountain Conference Center in Colorado on the same days as EuroGeo4. At this conference, there was a session on “Sustainable Waste Management and Climate Change.”

The papers were focused on methane gas capture and its use for power cogeneration, but two other papers brought carbon credits into landfill situations directly. Maillet3 described the use of carbon credits to finance solid waste projects in developing countries and Welsh4 in his keynote address presented the trading of carbon credits. Interestingly, one ton of carbon currently is valued, and trades at, $40 on the Chicago Carbon Exchange.

This reminded the writers of a comment from an audience participant at the GRI-21 Conference in Cancún last March. He approaches small cattle farmers and offers to completely finance the building of concrete holding basins, which have a geomembrane floating cover for encapsulation of the animal waste. As the waste rapidly degrades, the methane is used to power a generator for on-farm use. Everything is free to the farmer/rancher, even the power usage. What the entrepreneur wants is the carbon credits to sell or trade on the open market!

For us at GSI, we believe that carbon footprints, carbon taxes and trading, and the entire sustainability effort can, and should, be a powerful incentive for using geosynthetics in myriad future applications.

Y. Grace Hsuan, Professor, George R. Koerner, Director Designate, Robert M. Koerner, Director, GRI.

Footnotes

1Belton, J., et al. (2008), “Using Geosynthetics to Meet the Challenge of Improving Material Resource Efficiency,” Proc. EuroGeo4, Scotland, Paper #128.

2Robinson, P. N. J. and Quirk, C. M. (2008), “The UK Aggregate Levy and Its Implications to Geosynthetics,” Proc. EuroGeo4, Scotland, Paper #80.

3Maillet, B. K. (2008), “The Use of Carbon Credits to Finance Solid Waste Infrastructure Projects in Countries with Developing Economies,” Global Waste Management Symposium, Cooper Conference Center, Colorado, (presentation only).

4Welsh, M. (2008), “The Potential for National Carbon Emissions Trading to Reduce Greenhouse Gas Emissions,” Global Waste Management Symposium, Cooper Conference Center, Colorado, (presentation only).

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