In Cradle to Cradle they mention monstrous hybrid materials. These are materials that combine biological and technical nutrients. The example discussed was a leather shoe. Leather shoes used to be biodegradable when tanned with vegetable chemicals, but in the past 40 years the industry has moved to chromium tanning. This mixture of technical nutrients with natural ones in effect prevents these nutrients from being reclaimed by nature or people.
Perhaps it is because I have spent the past 5 years studying electronics, but this mention of monstrous hybrids scared me. It made me think, “… are electrical circuits monstrous hybrids?” And if so does that the world will have to say goodbye to electronics in order to make a sustainable world? While I am not sure it falls in their definition of a monstrous hybrid material (there doesn’t seem to be much of a biological component), I could defiantly see circuits being a product from which little can be reclaimed. If the goal of a sustainable designer is to make their products cradle to cradle there must be something done with electronics. I see no way to convince the world that they must give up their computers, cameras, cell phones, alarm clocks, or TVs. (In addition electronics could hold some form of environmental benefit. Bits and bytes are virtually an unlimited resource.)
So I decided to dive a little deeper into this topic. Firstly let’s look at printed circuit boards’ material make up. As there is great variability in the function of circuits there is also a wide variety of materials. This summary is a very broad summary of PCBs. The boards they are printed on act as insulators for the circuits. Typically they are of paper-plastic composite materials. FR-2, FR-4, and Kapton are some typical examples. The traces connecting the various electrical components are typically made of copper with outer covering for beter soldering contacts. Upwards of 24 different layers can be found in a board. Though double layer is a more typical number Other metals such as silver, lead, and gold are also used at times. This is the board before adding any electrical components such as integrated circuits, resistors, capacitors, etc…
There are processes out there to reclaim materials from electronics. The process is fairly involved:
[source]
They are able to reclaim valuable metals such as gold, silver, and copper. Though in doing so there are considerable hazardous materials that are also collected. Due to the toxicity, this is typically done overseas in countries with less stringent working conditions. This certainly raises issues concerning the sustainability of this process. There are other alternatives to this expensive recycling process. The non-metal portions of the boards can be added in “plastic wood” and concrete to act as a strengthening component. I have also seen products such as clipboards and other knickknacks in stores made from circuit boards without their electrical components. Then there is also the occasional use of scrap electronics in craft and art projects. Anyone notice the circuit board egg on University Ave.?
As sustainability becomes a more prevalent issue more people are looking at ways of handling our electronics waste. I read in one of the articles, that electronic waste is the fastest growing streams of waste. In Europe they have the Waste Electrical and Electronic Equipment Directive. This requires manufacturers to take responsibility for the collection and ecologically friendly disposal or reuse of equipment. Perhaps involving the manufacturers is the correct direction for electronics waste. They would know best how to reuse their own components, and it may force them to begin considering the full lifecycle of their product when in the design process.
Sustainability around electronics certainly seems like it should be a big issue. Though in my brief research of the end of life options for electronics, it seems like there isn’t that much focus in this area. In broadening my search to sustainability of electronics during it’s life (not just at its end) there seems to be a little bit more information. The most popular emphasis is on its energy consumption. While energy is certainly an important issue, perhaps we should also be thinking about how to preserve the technical nutrients of our electronics.
Sources:
http://p2library.nfesc.navy.mil/P2_Opportunity_Handbook/2_II_8.html
http://www.ami.ac.uk/courses/topics/0113_prei/index.html
http://www.environment-agency.gov.uk/business/444217/444663/1106248/?version=1&lang=_e
http://www.iaer.org/aboutrecycling.htm
http://www.treehugger.com/files/2007/03/how-to-green-your-electronics.php
June 11, 2007 at 6:57 am |
Reading this post reminded me of a discussion in Will’s car on the way to the Sunnyvale Smart Station a couple of weeks ago. We were talking about the sustainability of silicon, and wondering if an increase in electronics use meant that we might one day find ourselves in a resources crunch, combing the earth for precious silicon deposits. Someone pointed out that silicon was actually one of the most abundant elements in the earth’s crust, so that put an end to the speculation and convinced us that silicon would probably remain a standard in microchip production because of the abundance of the material.
So, along the lines of a green circuit board, how green is a microchip? Even if silicon is readily available, what other resources does it take to create a chip? And are any of those inputs recaptured and reused after the chip’s life? An article from a couple of years ago in the American Chemical Society’s journal discussed this very issue. In the article, they state that to produce a two gram chip it requires at least 3.7 pounds of fossil fuel and chemicals, broken down as “3.5 pounds of fossil fuels, 0.16 pounds of chemicals, 70.5 pounds of water and 1.5 pounds of elemental gases (mainly nitrogen).” The ratio of fossil fuel and chemical inputs by weight for the silicon chip is 630 to 1. In comparison, the ratio for a car is 2 to 1. In the article, the comparison is made that if you buy a new computer every two years for ten years, it would take 28 giga-joules of energy to produce those computers; if you bought one new car in that period, it would take 46 giga-joules. While it still takes more energy to produce the car, “the two are not so far apart, which is rather counter-intuitive given how much larger the automobile is.”
Making matters worse, at the end of their useful life, silicon chips are not recycled in any way, and are merely tossed into landfills. While they are not taking up as much space as other materials in landfills, they still represent a significant waste of material, chemical, and energy inputs. And as the number of silicon chips embedded in all sorts of devices increases, this waste will become even more significant.
Sources:
http://www.eurekalert.org/pub_releases/2002-11/acs-ttp110502.php
http://www.newsfactor.com/perl/story/19992.html
August 23, 2009 at 5:10 am |
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September 11, 2009 at 3:27 am |
This written is too abstruse! how is to cover a printed circuits with green tree?