Cost savings, both short and long – term, can be recognized in several ways with ClosureTurf.
ClosureTurf allows an additional two feet of airspace because the soil layer is eliminated, if the landfill is permitted by the final cover top elevation. The value of the airspace can be realized in many ways, including additional income with the gained two-feet expansion, lower annual bonding obligations, lower the cost per ton of those bonding requirements and potentially receive a one-time significant credit to their financial bottom line.
With the benchless design approach, the following items can reduce overall costs:
- Reduction/elimination of diversion berms and down slope channels
- Reduction/elimination of energy dissipation devices
- Reduction/elimination of sediment storage and water quality volumes
- Detention of storm water rather than retention allowing for smaller pond volume
- Reduction/elimination of maintenance
Elimination/Reduction of Deep Gas Wells
Deep gas wells extending to within feet of the base liner were designed so that their expected radius of influence to collect gas would overlap. One aspect of a gas design not often discussed was that the “radius of influence” of each gas well was not a 2D object as drawn, but rather it was a 3D area of influence. The gas that migrated above the well screen and beyond the vertical radius of influence would certainly cause pressure to build on the final cover system. Deep gas wells also introduced many new problems. The change in temperature at ~200 feet deep versus the surface temperature caused large quantities of condensate. Condensate, simply stated, is instant leachate. Since the wells must be designed to allow the free flow of gas, they are prone to watering in both from the percolation of leachate and the creation of leachate as the deep well produces condensate. This is a major reason why deep wells must be replaced from time to time. With the patented surficial gas management system used in conjunction with ClosureTurf, landfill gas is collected without the expense of these deep wells, potentially eliminating or at least greatly reducing the need all together.
Borrow pits necessitate the destruction of land. ClosureTurf greatly reduces the destruction of native, undisturbed land that is only being destroyed to provide soil for a landfill cover. Eliminating the need for a borrow pit makes environmental as well as economic sense. Depending upon the proximity of borrow sources, soil can be a costly item to get on site. ClosureTurf eliminate this layer and reduces the need for construction vehicles to transport.
ClosureTurf makes it easy to install in small, incremental closures. This closure method reduces both fugitive emissions and the infiltration of leachate which provides significant savings for the owner.
Accelerated Project Schedule
The consistency offered by a standardized system such as ClosureTurf provides efficiencies that can be easily realized, from pre-design through construction. A significantly larger amount of closure acreage can be constructed using ClosureTurf than a traditional soil cover, effectively allowing more projects to be constructed with a given set of fixed resources. Typically, ClosureTurf installs 2 to 3 times faster than traditional covers.
Post Closure Care
The annual maintenance costs for ClosureTurf runs, on average, more than 90% lower than those for a traditional soil and vegetated cover system. The following is an example of a maintenance activity comparison.
4 events per year
|Erosion Control||2 events per year|
|1/3 area once per year||Not Required|
1/3 area once per year
|Soil/Sand Replacement||Typical 1 ton/per acre per year avg. – Per EPA (Soil Replacement)||<2% total area per 5 years (Sand Infill Replacement)|
|Pond Clean-Out||Avg. once per every 4 years|
|Major Storm Repair||4 hours equipment after 1 event/year||Not Required|
|Site Inspection||1 inspection per quarter||Every 5 to 10 years|
|Financial Assurance||-2% per year||-2% per year|
- Over a 30-year period, the average cost to maintain a prescriptive soil cover is estimated to be $1,200 – $1,500 acre/year. ClosureTurf averages around $250 acre/year.
- Several ClosureTurf sites have experienced hurricane-force winds and multiple 100- year The most severe storm event occurred at a 25-acre closure in Pensacola Florida, with the storm occurrence exceeding 500-years (25+ inches of rain over 24 hours). The required maintenance to bring the installation back to specification was performed solely with 1 infill spreader and a 3- man crew over 2.5 days.
- The projected long-term performance is well in excess of 100 years for the turf and 400 years for the geomembrane. As part of a redundant protection approach, the engineered turf backing is designed to resist UV from potential Any infill that may be dislodged due to unanticipated concentrated flows or settlement does not require immediate or even annual infill addition (suggest a 5–year evaluation of infill condition). ClosureTurf eliminates on-going maintenance in perpetuity for soil versus over 100 plus years of stability.
- Sites experience less erosion (5 to 10 tons per acre per year for soil versus a negligible amount for ClosureTurf).
- ClosureTurf provides predictability of final cover performance and post-closure maintenance costs. This predictability is assured independently of site-specific or weather-related Furthermore, this predictable performance is economically competitive with typical methods.
Landfill Gas Collection
The ClosureTurf Surficial Gas Collection System is designed to allow LFG to rise to the waste surface. The collection points across the surface which are integrated into the geomembrane component can relieve the gas actively or passively based on specific site needs and desires. This collection mechanism provides for an increased quantity of gas collected as well as an increase in quality of gas collected all because gas collection can be performed at the surface of a landfill. Surface collection also reduces potential oxygen intrusion through wells and supports a safer gas management system with much lower exposure to oxygen migration into the landfill.
Reduction of Leakage
The HELP Model and JP Giroud Model analyses prove ClosureTurf has significantly less leakage than traditional soil covers.