EDITOR’S NOTE: CETCO Lining Technologies has published on its website a paper from Christos Athanassopoulos, P.E., CETCO, and Richard J. Vamos, Ph.D, P.E., DAI Environmental, Inc., on “Carbon Footprint Comparison of GCLs and Compacted Clay Liners.” We republish here the company’s synopsis of the paper and link to the full article (PDF). It is fascinating to discover how great an impact geosynthetic clay liners can have on reducing the carbon footprint of construction when measured against the thickness of compacted clay required to equal GCL performance. The reduction in truckload traffic alone (550 for CCL, 3.5 for GCL in this analysis) represents a significant carbon footprint savings. Athanassopoulos and Vamos’s work includes excellent comparative tables of the carbon footprint aspects of site work and two appendixes demonstrating the full methodolgy used to reveal these project savings. A version of this paper has also been presented at a Geosynthetic Research Institute (GRI) conference.
– Chris Kelsey, Editor, Geosynthetica
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An Introduction to “Carbon Footprint Comparison of GCLs and Compacted Clay Liners”
CETCO and DAI Environmental performed an analysis comparing the carbon footprint of a conventional compacted clay liner to a GCL for a hypothetical RCRA Subtitle D municipal solid waste landfill. The analysis found that, for a landfill liner site located 1,610 km (1,000 miles) from the GCL manufacturing plant and 16 km (10 miles) from the clay borrow source, a conventional compacted clay liner is expected to produce a 34% larger carbon footprint than a GCL. The largest single component of the overall carbon footprint for both options is transportation. It is estimated that, in order to line a one-hectare area (2.5 acres), over 550 truckloads of clay would be required, compared to only 3.2 truckloads of GCL.
Repeating the analysis over ranges of different haul distances found that in order for the compacted clay liner option to produce a lower carbon footprint than the GCL option, the clay borrow source would need to be within approximately 9 km (5.5 miles) of the job site. This assumes that the GCL manufacturing plant is located 1,610 km (1,000 miles) from the job site. If the GCL plant is located 3,000 km (1,860 miles) from the job site, then the clay borrow source could be within approximately 14 km (8.7 miles) of the job site and still offer a lower carbon footprint. If the GCL plant is located 100 km (62 miles) from the job site, then the clay borrow source would need to be within 2.5 km (1.6 miles) of the job site to produce a lower carbon footprint.
As is the case with evaluations of cost effectiveness, carbon footprint evaluations are sitespecific, depending greatly on the relative distances of the project site to the clay borrow source and to the GCL manufacturing plant. Accordingly, project-specific analyses are strongly recommended.
Read the full paper here (PDF)
