The Caja Del Rio Landfill is continuing the construction of its next solid waste disposal cell, Cell 5B. A total of 25 successful blast events occurred from October 7, 2013, to February 21, 2014. The blasting and excavation of 279,000 cubic yards of basalt rock is complete.
The subgrade soil will be prepared for the installation of a geosynthetic liner. The liner is a low permeable barrier which is constructed under the landfill before disposal to contain leachate and prevent groundwater contamination. The liner system includes a layer of a low-permeability, geosynthetic clay (GCL) liner on the bottom. The GCL liner acts as a primary seal at a specified moisture content to provide additional protection for the liner system. Over this layer, a 60-mil, high-density polyethylene (HDPE) secondary plastic liner is installed to cover the bottom and sides of the landfill cell. The HDPE liner is smooth on the landfill bottom and textured on the landfill sides to increase friction and prevent slipping. The liner, which is resistant to chemicals and damage, is then welded together and tested to ensure a continuous seal in accordance with regulatory requirements. A blanket of geotextile fabric, composed of synthetic fibers, is laid above the liner and a geonet made of mesh-like plastic is added under the geotextile on the sides of the landfill to prevent fine clay particles from clogging the leachate collection layer and promote removal of leachate from the liner surface. Normally, the entire leachate collection layer would be comprised of two feet of basalt gravel on the liner that collects leachate and allows it to drain by gravity to the leachate collection pipe system, but this cell is different. For the first time in New Mexico, glass cullet from bottles processed at the Buckman Road Recycling and Transfer Station will provide a beneficial use as a portion of this drainage layer.
The liner installation of the new cell is scheduled to begin in September of 2014 and completed by December. The new cell will have a surface area of approximately 10 acres with a disposal capacity of 4 years. Estimated cost of building the new cell is $3.6 million with $1.6 million of this for the blasting and removal of basalt. The Agency has contracted CDM Smith of Albuquerque, NM to design and prepare the technical plans and specifications for the liner installation.