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There’s a 23-foot tall man in England who can’t talk, but still has a lot to say. He is the WEEE Man, a sculpture shaped like a man, built out of the equivalent of a lifetime’s worth of electronic waste generated by an average U.K. citizen—more than 3 tons worth. He was created as part of efforts in the U.K. to increase public awareness about the growing problem of electronic waste. And since this problem is worldwide, the WEEE Man’s message is relevant to the global population of electronics producers and consumers.
Acting on that message is not easy. Computers, for example, contain a multitude of materials and must be dismantled and the various parts sorted before they can be recycled. Then, once sorted, some of those parts are difficult to make useful again.
Plastics used in computer bodies and cord casings pose a problem because there is variation in composition from one model to the next, making them complex to handle. They also are likely to contain brominated fire-retardants and/or polyvinylchloride (PVC) that become health hazards if they leach out of landfill waste. So, what progress is being made to find effective recycling methods for computer plastics?
An article published in the August issue of Energy and Fuels is evidence of one new direction (2006 , 20, 1536–1549). In it, W. J. Hall and P. T. Williams of the University of Leeds researchers report their investigation into using pyrolysis as a possible method for converting polymeric computer bodies into reuseable materials.
Pyrolysis uses high heat (typically between 400 and 800 ºC) in an inert atmosphere (oxygen is excluded), to take polymers down to smaller molecular building blocks. This is a different approach than other recycling methods that are used to grind, melt, and then extrude plastics into items such as lawn furniture and fences. Grinding and melting methods do not break polymers down to building block units.
Pyrolysis, by contrast, breaks bonds and induces chemical rearrangements. The released small molecules form either oils or gases. Those in the oil category potentially can be used as chemical feedstock for making new plastics; some oils are useful as fuels. Gaseous products, such as methane, propane, and butane, can be collected for use as fuels.
However, as the British researchers found, pyrolysis of computer bodies leads to complex results that complicate its potential use as a recycling method. They tested five computer housings, and each resulted in a different mix of products. All of the housings primarily formed oils consisting of numerous compounds, some of which contained bromine or chlorine.
Brominated and chlorinated products are undesirable because they cannot be used as chemical feedstock or as fuels. And, according to the authors, it would not be economically feasible to try to isolate the useable compounds out of the complex product mix. Instead, they suggest that further research is needed to modify the method to include a means for removing brominated and chlorinated substances during the pyrolysis process.
While work on this continues, the computer shells being discarded right now do have another recycling option. As mentioned earlier, there are grinding and sorting methods that can convert these plastics into feedstock for other products. Some commercial enterprises are even making this route economically attractive.
If you have an old computer that needs to move out of your office or home, you have several options for dealing with it. Several computer manufacturers now have take-back programs. If you own a Dell, a Hewlett-Packard, an IBM, Gateway, or a Macintosh, check out that company’s take-back policy: http://www.computertakeback.com.
If you cannot take advantage of a take-back program, there are numerous charitable organizations that may be able to put your computer into a school, community organization, or home of a needy individual: http://www.epa.gov/epaoswer/hazwaste/recycle/ecycling/donate.htm.
If your model is so old that it has no more functional life left, your local recycling center can probably help you determine where to take it to be recycled. The following Web site allows you to enter your zip-code to receive information about where you can recycle just about anything, including computers: http://www.earth911.org/master.asp.
The EPA also offers some information and guidelines about recycling your old computer: http://www.epa.gov/epaoswer/hazwaste/recycle/ecycling/faq.htm.
Learn about what U.S. state and federal governments are doing to produce legislation on this issue: http://www.ncsl.org/programs/environ/cleanup/elecwaste.htm.
This article first appeared on September 25, 2006.
