Landfill mining and reclamation (LFMR) is a process whereby solid wastes, which have previously been land filled, are excavated and processed.
Processing involves a series of mechanical processing operations designed to recover one or more of the following: recyclable materials, a combustible fraction, soil, and landfill space. The combustible fraction can be used to generate electricity. LFMR can be used as a measure to remediate poorly designed or improperly operated landfills and to upgrade landfills that do not meet environmental and public health specifications. [World Resources Foundation, undated, http://www.enviroalternatives.com/landfill.html ] Though not widely practiced, LFMR has gradually been gaining acceptance since the 1980s.
In 1997, the EPA published an 8-page brochure on landfill reclamation that summarized potential benefits and drawbacks. [ http://www.epa.gov/osw/nonhaz/municipal/landfill/land-rcl.pdf ] Benefits include reducing pollution or the risk of pollution from substandard landfill or dump sites, reclaiming soil for use at the landfill (as a cover material) or offsite, extending the life of the landfill by reducing the volume of waste on-site and/or reducing the area of land the landfill occupies, recovering materials such as aluminum and ferrous metals, or producing energy at municipal waste-to-energy facilities. Drawbacks include the risks of uncovering hazardous wastes or releasing flammable gases such as methane or hydrogen sulfide. The EPA document includes representative case studies of LFMR projects in Collier County, Florida (starting in 1986), Edinburgh Landfill in New York (1990-1992), and the Frey Farm Landfill in Lancaster County, Pennsylvania (1991-1996).
In October 1993, the New York State Department of Environmental Conservation included landfill reclamation in that state’s solid waste management regulations. The Florida Department of Environmental Protection published a guidance document on the disturbance and use of old closed landfills or waste disposal areas in 2001 and updated it in 2009 and 2011. [ http://www.dep.state.fl.us/waste/quick_topics/publications/shw/solid_waste/Dump-Guidance-03Feb11.pdf ]
Typical equipment used in simple LFMR operations includes excavators, screens, and conveyors. Higher-tech LFMR operations recover additional materials and improve the purity of recovered materials, and therefore require more equipment than simple operations.
A LFMR project that has attracted a great deal of attention recently is being implemented at the landfill site of Remo Milieubeheer NV in Houthalen-Hechteren, Belgium. A waste-to-energy company, Advanced Plasma Power (APP), based in the United Kingdom, formed a joint venture with Group Machiels, a global waste management firm.
[ http://www.waste-management-world.com/index/display/article-display.articles.waste-management-world.waste-to-energy.2011.05.Plasma_Power_Goes_Large_at_Landfill_Mining_Project.QP129867.dcmp=rss.page=1.html ] The process to be used is called the “Gas plasma process,” a gasification and plasma conversion technology that converts the waste stream into a clean, hydrogen-rich syngas and a vitrified recyclate product called Plasmarok that can be used as a building material or replacement aggregate. According to APP, the process destroys harmful gases, leaving the high-quality syngas to be used to generate electricity.
As fossil fuels become increasingly scarce and more expensive, the first and most cost-effective response of the waste management system is likely to be to boost the rate of recycling, especially of metals and plastics, before they reach a landfill. This is because the process of landfilling materials degrades their purity and economic value. Increased mining of landfills may be a secondary effect, depending on the net energy balance of the LFMR process and the potential to generate electricity from combustible waste materials.
Stay tuned as we extend our thoughts to recovering valuable metallic products from landfills or ‘Urban Mining”.
Conceived, Developed and Written by Geoff Young, Dr. Subodh Das and Austin McKinney on February 10, 2012
All rights Reserved by Phinix, LLC
www.phinix.net skdas@phinix.net
