IESI Corporation/Weaver Boos Consultants
Turf Type 1 – Field Green
The final ClosureTurf closure design at Weatherford is a “True Green Closure”, with benefits including but not limited to CO2 emission reduction, reduction of soil erosion, water conservation, reduction of nitrates oxides, and improved water quality.
In 2010, engineers at IESI Corporation, Weaver Boos Consultants, and Watershed Geo took on an environmental concern facing landfills in western Texas: How can landfills be closed properly while maintaining and supporting the required vegetative growth?
The answer? An engineered turf system called ClosureTurf.
ClosureTurf is a patented, three component system comprised of a structured geomembrane, an engineered turf, and a specialized sand infill. The foundation of the system is an impermeable, highly transmissive structured geomembrane. It provides for the highest interface friction values available in the market. The engineered turf component gives the system its natural look and feel of grass while protecting the geomembrane from extreme weather conditions for the long term. The specialized sand infill component is placed between the blades of the engineered turf and allows the system to be trafficked while also providing additional protection from weathering. When required, ClosureTurf’s patented surficial gas system is included with the system to vent landfill gas emissions. ClosureTurf is fast and easy to install for an aesthetically pleasing, cost-effective landfill closure solution.
According to IESI, if Weatherford Landfill had been closed using the traditional EPA Subtitle D closure method, approximately 400,000 c.y. of soil would have been required for the site’s infiltration layer and for vegetative soil/ protective cover layers along the 76.6 acre waste footprint. This would have required soil being imported from across the main road adjacent to the site, which would have resulted in over 33,000 diesel truckloads of soil and the accompanying air emissions to haul this material. Not only this, but the post closure care of the sandy soil types available in the area would have required extensive erosion monitoring and maintenance. These issues are compounded even more along the western part of Texas where vegetative growth is limited due to arid conditions.
Unlike traditional soil closures, the ClosureTurf system provides a very sustainable approach to closing landfills by eliminating soil, removing the need for vegetative maintenance, fertilization, and the inherent erosion issues associated with a soil and vegetative cover.
The use of ClosureTurf, as is typically the case with geosynthetic projects, provides a significant opportunity to reduce CO2 emissions at levels 5 times lower than Subtitle D covers. The figure below shows the comparison of traditional closures and ClosureTurf in regard to CO2 footprint.
According to IESI, using ClosureTurf as the final closure at Weatherford Landfill has accomplished several environmental improvements and is leading the way on environmental leadership in the State of Texas in the following ways:
- Erosion of landfill sideslopes is controlled with the combination of geomembrane and artificial grass
- With no vegetative growth to worry about, and irrigation system or source of water is not needed
- Now that the entire area is properly covered and no soil layers are exposed, there is no erosion for silty or turbid water to flow off site. During rain events, only clean water flows off of the exposed cover system
- With the soil layers being taken out of the final cover system, every site can have huge savings on the need for large amounts of borrowed soil, extra stormwater basins, tree clearing, and gravel needed to repair site haul roads
- With the entire landfill properly covered and protected from the elements, no sideslope repairs due to washout are require
- No chemicals needed for grass growth or weed control
- The ClosureTurf system was designed to trap gas and emissions under the geomembrane’s “impermeable barrier”, allowing for sub-surficial gas controls and the proper transportation of gas to the onsite flare for destruction
“This new closure system immediately addresses a high priority environmental need facing TCEQ (Texas Commission of Environmental Quality) on a daily basis: How do we regulate and design landfill cover systems to meet the State’s vegetative growth requirements in final closure and during operations? Now with the success of ClosureTurf and the Weatherford landfill closure, the State has viable long term cost saving approach to landfill capping that is environmentally beneficial, visually pleasing, and self-sustaining. Since ClosureTurf was installed, there has been no need for expenses associated with site maintenance, grass cutting or stormwater controls. Additionally, local residents get to see a huge landfill sideslope constructed with visual aesthetics similar to a Country Club’s well-manicured facility versus barren sideslopes and annoying maintenance issues.” – IESI