The rise in material and mining costs coupled with concern about processing consumer waste have inspired the prospect of mining landfills for materials. Although landfill mining is not a new idea—particularly in developing nations where scavenging garbage dumps is not uncommon—the notion that the procedure be conducted in earnest by developed nations is surprising.
"By 2020 we might have 9 billion people on the planet, we could have a very big middle class driving millions more cars, and we could be in a really resource-hungry world with the oil price climbing and a supply situation in Libya, Russia and Saudi [Arabia], where natural gas is limited," British waste-management expert Peter Jones told The New York Times in 2008. "It is those drivers, those conditions, which will encourage the possibility of landfill mining.”
Ivan Cornejo, a materials-engineering research professor at the Colorado School of Mines in Golden, Colo., is putting such a possibility into practice. Cornejo and his research team are studying the minerals that may be extracted from food waste and other garbage common to municipal landfills. The team found that discarded items such as eggshells, banana skins, apple cores, corn husks contain valuable elements that may be used to create new products like glass, which is composed of silica and additives like the calcium oxide, potassium oxide, and magnesium oxide present in food waste.
“I know that calcium is abundant in many shells and bones,” Cornejo told PBS in October. “I said, ‘Well, why not use that?’ For the last year and a half, I haven’t bought any chemicals from commercial places. Everything we use in the lab is from waste.”
Cornejo and his colleagues have already demonstrated the successful conversion of food waste into new types of glass. The results represent a compelling link between biological and technical nutrients—terms used to distinguish usable vegetable and mineral waste, which are rarely considered to be connected and are therefore recycled in different streams. In addition, extracting minerals from vegetables is safer than conventional mining because plants filter out toxins, such as mercury and arsenic, that are otherwise present.
Although landfill mining is still in the preliminary study phase, Cornejo’s research delivers a powerful message about future resource utilization that has many advantages, including: a reduction in environmentally-disruptive mining and related toxins; the presence of fewer landfills and waste dumps; the resourceful utilization of food waste; and the development of new materials with novel properties.
In short, a process to convert landfill waste into new materials, if conducted at a significant scale, would be nothing short of revolutionary with many environmental, social, and economic benefits.
Blaine Brownell, AIA, is a regularly featured columnist whose stories appear on this website each week. His views and conclusions are not necessarily those of ARCHITECT magazine nor of the American Institute of Architects.