A decade ago, options in closure applications changed dramatically with the debut of two unique systems: one was an exposed membrane with thin-film photovoltaic (solar energy) cells adhered to the membrane surface; the other combined geomembrane and synthetic turf layers. Both systems provided green engineering benefits, strong stormwater shedding performance, and long-term cost savings. Only one system lasted: ClosureTurf® from Watershed Geo.
It isn’t easy to introduce new approaches to sensitive applications, like landfill closure or Superfund site capping. Still, the use of synthetic turf as part of a capping system not only survived in the marketplace, it flourished.
To date, roughly 1,500 acres have been capped with the ClosureTurf system.
TRANSFORMING CLOSURE APPLICATIONS
“[The system] outperforms traditional closure methods in every category,” says Michael Ayers, Watershed Geo CEO. “It addresses landfill stability and erosion problems by providing a long-lasting, geotechnically stable and environmentally friendly final cover system that significantly reduces maintenance costs.”
The patented system utilizes a structured geomembrane (from AGRU America), an engineered turf, and a specified infill. A patented gas collection system has also been designed into many of the installations to provide additional performance for closure applications.
Importantly, ClosureTurf has been developed to last more than 100 years, which well exceeds typical post-closure monitoring periods and provides a level of support to surface capping that is expected of base lining systems within landfill cells.
As projects have popped up across the United States over the last 10 years, a number of benefits have been documented, including:
- The system installs at least twice as fast as vegetated covers
- Leachate production on larger sites has been found to be reduced by approximately 100,000,000 gallons because of the swift installation window
- Approximately 550 truck trips (275 round-trips) of soil per acre are saved with Closure Turf versus vegetated covers
- Eliminates the generally specified two-foot soil layer—this opens more than 80,000 cubic yards of potential air space for a typical 25-acre project
- Reduces the carbon footprint by approximately 80% (210,000 kg of CO²per acre) when compared with soil/vegetative covers
- 90% reduction in turbidity on many sites
- Long-term maintenance activity reduction of greater than 90%
Furthermore, the system has shown its durability. ClosureTurf has survived multiple weather events with no erosion damage. This has included a record 500-year-rain event in Pensacola, Florida.
REVISITING SOLAR ENERGY
Watershed Geo has earned awards for its work from the Solid Waste Association of America (SWANA), the American Public Works Association (APWA), the American Council of Engineering Companies (ACEC), and the Industrial Fabrics Association International (IFAI).
While landfills have been a common site for the ClosureTurf system, large remediation projects have emerged among the closure applications, including a 200-acre Superfund site with the US Environmental Protection Agency.
All of this work and the growing site data have expanded the company’s investment in the technology. Additional product lines have been developed, such as the HydroTurf ® advanced revetment technology for high hydraulic shear protection and the VersaCap® system, which provides an intermediate, wind- and erosion-resistant cover that supports landfill gas (LFG) collection.
Interestingly, Watershed Geo is also reinvesting in a solar energy system. The new system will be unveiled in 2019. The company promises it will “[combine] the most advanced, proven panel technology with a rackless, direct surface attachment system that can be used on the top decks and side slopes of a ClosureTurf foundation.”
Ten years ago, Watershed Geo’s approach proved to be more accessible and implementable than solar caps, during that unique window in which alternative designs were welcomed. Now, the company seems positioned to make solar energy collection truly successful in closure applications as well.