The Perkins Landfill located in Payne County, Oklahoma is currently closed and in the post closure-monitoring period. Aquaterra developed a work plan for submittal to the Oklahoma Department of Environmental Quality (ODEQ) to mitigate leachate seeps at the facility. The work plan included installing passive landfill gas (LFG) vents and planting vetiver grass within the leachate seep areas. The work plan was approved and implementation began in 2011. Passive LFG Vents Aquaterra provided oversight during the installation of 16 passive LFG vents. The passive LFG vents were installed using a 36-inch bucket auger on a track-mounted rig and were constructed of 6-inch diameter SDR 11 HDPE pipe and 1 to 3-inch diameter washed gravel. Vetiver Grass Planting Aquaterra personnel planted various plots of vetiver grass in rows at the locations of existing and previous leachate seeps. The grass was planted with a 2-foot spacing between each plant and row. Vetiver grass is native to Asia and has been used worldwide for various reasons, including soil stabilization, wastewater treatment, and leachate mitigation. The variety used for this application is USDA approved as a non-invasive plant because it produces an infertile, sterile seed. Vetiver grass can tolerate: temperatures from 5 to 115 °F; pH ranges from 3 to 10; very high salinity; high metals concentrations; agricultural chemicals; high nitrogen levels; high phosphorous levels; wide range of soil types; and planting on steep slopes. Vetiver grass typically grows to a height of 5 to 10 feet, with a root depth equal to or greater than
Read more →See the Cascade System In Action Here The Kansas Department of Health and Environment (KDHE) State Water Plan Program and the City of Frankfort, Kansas contracted with Aquaterra to design/build a remediation system to address the source area of contamination affecting the City’s three public water supply (PWS) wells. The source area is a farm approximately ½‑mile north of the well field where historically grain storage bins had been located. As requested by KDHE in the fall of 2008, Aquaterra researched alternative methods to conventional air stripping towers or tray aerators, and proposed a cascade aerator for the groundwater treatment technology. The cascade system is essentially a waterfall where the contaminated well water cascades down the waterfall, which aerates the water and transfers the contaminant (in this case, carbon tetrachloride – CCL4) from the water to the ambient air. The advantages of the cascade system over conventional systems was the reduction of the required maintenance due to hard water fouling of tray and tower aerators that would not be an issue with the cascade aerator, and the reduction in motors and system complexity that reduced long term energy costs and equipment replacement. The primary disadvantage of the system was that the cascade could not operate for approximately three months during the winter. Following a meeting with KDHE and City personnel to discuss the design scope and preliminary plan, Aquaterra was authorized to proceed with the final design of a 25 gallon per minute (gpm) system and to evaluate green alternatives
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