MIT researchers have developed new metrics for assessing the performance of firms that recycle scrapped electronic equipment, a major source of toxic pollutants.
The metrics focus not just on how much of a firm's incoming waste is processed but also on the quality and reusability of the materials produced from it, a consideration critical to overall resource efficiency.
To assess the performance of electronics recycling firms, people have focused mainly on the most easily measured indicator: the fraction of a firm's incoming waste stream that ends up as landfill. But minimizing landfill is not enough, according to the MIT researchers.
"Recycling companies will tell their customers, 'Virtually none of your material is going to landfill.' While we recognize that that's important, we also know that not all end uses are equal," said Randolph E. Kirchain Jr., an assistant professor in the Department of Materials Science and Engineering and the Engineering Systems Division. "For example, it's preferable to take a pound of recovered plastic and use it to make new components than to use it as roadbed filler."
The quality of the recovered material determines its potential uses. If the quality is sufficiently high, the material can be reused by manufacturers, reducing the need to extract and consume new materials.
Almost a billion obsolete computers and other electronic devices are scrapped each year, and four out of five of them end up in basements or on sidewalks rather than in recycling facilities. But the electronics recycling business is expected to grow quickly. Regulations on handling large-scale electronics waste streams are becoming more stringent, and public concern is growing about the shipping of electronics to countries not equipped to handle toxic and hazardous materials.
Kirchain worked with Frank Field III, a senior research associate in the Center for Technology, Policy and Industrial Development, and Jennifer R. Atlee, a graduate student in the Engineering Systems Division, and colleagues in the Materials Systems Laboratory to develop measures of assessing electronics recycling firms. The team drew on its 10 years' experience studying another recycling industry--automobiles.
To identify recycling firms and processes that achieve good materials recovery, the researchers use price as an indicator of quality. "We hypothesize that the price that's received for those [recovered] materials is an indicator of the quality of the materials. A buyer will pay more for materials they can use in manufacturing components than for materials going into a roadbed," said Kirchain.
They also used two value-based metrics--value retention and value-added. Value retention measures how well the value of materials is maintained all the way from their first use to their recovery. Value added compares the price of the recovered material to the price the recycler paid or was paid to take it away.
In case studies of three U.S. firms, the researchers found that the value-based metrics worked well and were easy to use. The researchers stress that their materials-only analysis is just a baseline and does not incorporate the effect of device or component reuse. They also note that other criteria could be used to assess the performance of recyclers. Examples include toxicity, emissions, energy use, and operating costs. In the long run, a variety of independent metrics could lead to significant improvements in recycling efficiency.
"We're interested in measures of performance that will lead to the best electronics-recycling practices. But if we really understand the recycling process, we may also be able to help manufacturers of original equipment make design and materials choices that will make recovering, recycling, and reusing materials less expensive," said Kirchain.
This research marks the beginning of a long-term MIT effort to develop analytical methods and tools that the electronics industry can use to identify and select materials, product designs and process technologies that will improve the sustainability of materials use. It was supported by the Alliance for Global Sustainability.