Vertical Barriers/Slurry Walls Bio-Polymer Trenches Permeable Reactive Barriers Soil Mixing Jet Grouting Wetlands Site Remediation Dam Grouting MGP Sites Levee/Dam Reinforcement & Repair

Collection of Contaminated Groundwater

Selma, VA: Bio-Polymer Trench, Kim-Stan Landfill


Geo-Con completed a leachate interceptor trench via the bio-polymer trenching method at the Kim-Stan Landfill Superfund Site in Selma, VA. The interceptor trenches were installed as part of the landfill closure, to intercept and collect and treat leachate generated from the landfill and channel it into a treatment system.

The 1,645 linear foot trench was installed to depths of up to 30 feet below ground surface (bgs). Bio-polymer slurry was produced in Geo-Con's high speed/high shear colloidal batch plant and piped to the trenches via high density polyethylene (HDPE) pipe. The three-foot wide trenches were excavated using a CAT 275 excavator.

The interceptor trenches included the installation of 22 foot wide overlapping HDPE liner panels on the down-gradient wall of the trench to form a continuous HDPE vapor/groundwater barrier. A 4 foot wide strip of Bentomat was sewn to the overlaps in the HDPE panels to ensure a water-tight seal. Geotextile was placed in the trench to completely encapsulate the 3/4-inch washed-gravel backfill and folded over the top of the backfill to allow capping material to be placed on top of the 3/4-inch stone.


Additionally, a 48-inch (diameter), 30-foot long manhole was installed in the trench containing two 6-inch schedule 80 PVC pipes to accommodate the pumps that will be installed in the future. Geo-Con also installed a 6-inch perforated HDPE pipe one foot off the bottom of the trench to serve as a collection channel for groundwater/leachate to be sent to the pump station for treatment. Nine 4-inch HDPE pipes were installed at pre-determined intervals to serve as clean-out pipes for the collection pipe. Additionally, seven 6-inch HDPE pipes were placed in the trench to serve as gas vents. Finally, two overflow pipe matrices were placed in the trench.

The project was completed ahead of schedule and with zero health and safety related incidents.


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