Effects of Florida Leachates on Geosynthetic Clay Liners (GCLs)    

Project Duration: 

November 1st, 2017 – October 31st, 2018

Investigators:    

 Prof: Tarek Abichou, Ph.D. P.E. and Youneng Tang, Ph.D.

                             FAMU – FSU Dept. of Civil and Env. Eng.

Email: abichou@eng.fsu.edu, Phone: (850)410-6661

Email: ytang@eng.fsu.edu, Phone: (850)410-6119

Motivation and Objectives: 

MSW incinerator (MSW-I) residues are being landfilled in MSW landfills or mono-filled in Florida. Leachates from these types of waste are different from regular MSW leachate and can affect the performance of Geosynthetic Clay Liners (GCLs), widely used in Florida.  GCLs are hydraulic barrier systems in which a thin layer of bentonite (<10 mm) is fixed between two geotextiles by needle punching or glued to a geomembrane. In the first generation GCLs, sodium bentonite (Na-B), hydrates upon exposure to liquids such as deionized water and swells significantly. However, aggressive characteristics of the hydrating liquid in contact with bentonites in GCLs, such as leachate from CCPP and MSW-I landfills may alter the bentonite fabric and lead to unacceptable increases in hydraulic conductivity. Several new GCL products have been developed for these high ionic strength leachates.  Polymer-modified bentonites (PMBs) GCLs containing a blend of Na-B and various polymers have been introduced in recent years to improve the chemical compatibility and hydraulic performance of GCLs contacted with aggressive leachates. These GCLs are referred as second generation GCLs.

The main objective of this study is to test the resistance of PMBs GCLs from different vendors to aggressive leachates from MSW-I landfills and CCPP landfills from Florida, and to identify conditions where these new types of GCLs might not be adequate (such as negative gradient landfills and fluctuating groundwater table). The second objective of this study is to use conventional index tests (e.g., free swell, fluid loss) and develop new alternative index tests to predict the long term hydraulic performance of these new types of GCLs.

Methodology: 

Hydraulic conductivity of different new types of GCLs containing natural sodium bentonite (Na-B) and GCLs containing various polymers from different vendors will be measured in flexible wall permeameters. Specimens will be permeated with water, synthetic leachates, and leachates from MSW-I landfills across the state of Florida. The chemical composition of each leachate will also be characterized.  Index properties of the bentonite from each GCL will be determined and correlated to hydraulic properties of the GCL.

TAG Group Members:

TAG Meetings:

        TAG Meeting 1

TAG For Effects of Florida Leachates on GCLs (ABICHOU) 
Fri, Feb 2, 2018 10:00 PM - 12:00 AM EST 

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 TAG Meeting 1 Presentation

        TAG Meeting 2

Progress Reports:

    Progress Report 1

    Progress Report 2

    Progress Report 3