American Council of Engineering Companies Award - Denton ELR

Awarded By - American Council of Engineering Companies

In a collaborative effort between CP&Y, Inc., and the City of Denton, a unique technique called Enhanced Leachate Recirculation (ELR), a term coined by CP&Y, is being used by the City to achieve a more viable and sustainable approach to the usage of their current landfill. In turn, it has positioned the City and CP&Y as key players in potentially influencing the EPA and Texas Commission on Environmental Quality (TCEQ) in modifying Municipal Solid Waste regulations.
The ELR design concepts and operations accelerate the decomposition of the waste thereby reducing the potential for long-term environmental concerns posed by conventional landfills. The concepts of bioreactors and enhanced leachate recirculation designed by CP&Y have the potential of changing the standards and regulations of both the EPA and TCEQ. CP&Y designed and defined to the TCEQ an Enhanced Leachate Recirculation Landfill as a MSW landfill which incorporates purposeful, controlled addition of clean water, leachate and landfill gas condensate to the waste mass, facilitating more rapid stabilization of decomposable organic materials, while maintaining waste mass moisture content below 40% by weight. CP&Y designed the necessary infrastructure to implement this ELR system and the City of Denton has constructed, and is operating the initial ELR cell at their landfill, making them home to the first operational ELR cell in the State of Texas.
The City is currently operating a leachate and landfill gas condensate recirculation system with enhancements in the form of surface water and treated wastewater effluent. The liquids are injected into the landfill via a series of recirculation lines and recirculation beds (constructed of shredded tires or other media), and landfill gas is collected through a series of vertical gas wells and horizontal gas collection lines. This landfill gas is utilized by a third party landfill-gas-to-energy developer that operates electrical generators on site; producing electricity that is introduced into the electrical grid system of the Denton Municipal Electrical Utility. To date, only two facilities in Texas are using the ELR technology, both of which were permitted and designed by CP&Y.