Methane Gas Harvesting at the McCommas Landfill - Dallas, TX

Enhanced Leachate Recirculation

at the McCommas Bluff Landfill - Dallas, TX

Eco Park - Training Center

 The City of Dallas is undertaking a new project that the McCommas Bluff Landfill in south Dallas.  In conjunction with CP&Y they have started an Enhanced Leachate Recirculation Project (ELR).  Basically water is circulated through a series of pipes into the landfill at various elevations to enhance the work of micro-organisms in decomposing waste material.  As waste decomposes it takes up less space thus reducing the amount of total volume in the landfill.  The City is expecting to recover approximately 30% of airspace within the landfill.  One of the by-products of organic waste decomposition is methane gas which is captured, filtered and transfered by pipelines to be used as a fuel gas.  They are expecting about 5 million cubic feet per day of methane production.  Enough to power up to 30,000 homes. (above) A view of the Downtown Dallas skyline from atop the McCommas Bluff Landfill.

(left) One of the tanks that holds stormwater to be pumped though the black pipes in the foreground up to the top of the landfill where it is distributed by a series of perforated pipes.  As the water filters down through the landfill it enhances decomposition of organic matter but also picks up chemicals that are present within the landfill.  The water that filters out of the bottom of the landfill is called leachate.  The recovered leachate is taken to a wastewater treatment plant to be cleaned before it is released back into nature.

The landfill uses crushed glass as a media to distribute the stormwater within the the leach field.  The perforated distribution pipes run through a layer of crushed glass that is spread over the area to be treated.

 (left) Pump station number 2 has to holding tanks for water that is collected from stormwater holding ponds on the landfill property.  These pumps feed to other leach fields in the landfill.  the leach fields are created in "lifts".  A layer of garbage is covered with broken glass on top of which the perforated distribution pipes are laid.  The pipes are then covered with more crushed glass which is followed by a 2-3' layer of "soft" household garbage.  Other harder waste can crush the water pipes so the soft trash acts as a buffer.  More waste is added on top of the soft trash layer and then the process is repeated.

One of our former classmates manages this project for the city.  (right) John shows us one of the pump stations that pumps water from the stormwater retention ponds up the the holding tanks which then distribute the water into the landfill.

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What's that smell???