As computers become more ubiquitous it becomes more apparent that these computers will continue to generate a significant amount of problems related to their disposal. As modern operating systems and software require more horsepower the need for users to replace their computers will increase which only increases the amount of waste computers. There are several ways in order to keep these old computers out of the waste stream and ways to safely handle the computers after they have entered the waste stream. Another problem is with the computers that find their way to the dump, without passing through a method to reuse or recycle them, is the lead used in the solder. Lead has been used for years in consumer electronics and now people are looking for alternatives.
One major aspect of waste computers that needs to be strongly looked into is the reuse of computers. The vast majority of computers reach their end of life fully operational, baring small problems like virus infections and part damage. The easiest way to reuse the computer is to give it to someone else who may not need as new of a computer. Most companies purchase computers in large blocks but the machines that are replaced can replace other older computers[1]. This allows the computer to be used for a few years longer than it would have normally. Another way in which these computers see more use is by placing them in “schools, non-profits, and charities”[3]. Because computers are very modular devices and units can easily be swapped out in order to upgrade the computer[1]. The computer can be easily broken down into the casing, motherboard, memory, power supply, hard drive, and CD-ROM drive which can either be replace, if they are broken, or used in a different computer[1].
Eventually a computer will reach a point where it can no longer be used due to age or damage and will need to be recycled. The simplest method is to just shred the computer which can recover up to 400 g of precious metals found in the components[1]. This allows for all part of the computer to be treated as the same and because of this the labor costs are very lower[1]. The other option is the complete remanufacturer of the computer but this option has a very high labor cost associated with it[1]. Neither of this options are idea because remanufacturing a computer is not usually desirable due to the rapid development of computer technologies and shredding a computer destroys any portion of the computer that may be usable[1]. Another problem is that comparison to other “post-consumer products (i.e. Glass bottles, steal cans, scrap cars, etc.)”[2] the waste generated by computers is so new that recycling companies are not prepared to handle it[2]. So much so that the EPA of Taiwan proposed “Scrap Computer Treatment Guidelines” for recyclers interested in processing computers[2]. There are several parts of a computer that are considered hazardous and toxic by many governments on earth including the phosphor coatings of cathode ray tubes (CRTs), batteries, capacitors, LCDs, and the plastic containing flame-retardant bromine[2]. The fear is that the chemical that can leach out of these parts will find their way into the drinking supply near the dump where they were disposed of [2].
One of the major environmental impacts of dumping computers into landfills is due to the fact that the solder used in the components of the circuit boards is comprised of a tin-lead alloy and over time the lead can leach from the solder. Usually the lead, which is a toxic substance, finds it’s way into the drinking water[4]. In fact, it has been speculated by some historians that the fall of the Roman Empire could have been due to the lead used in the citie’s drinking water pipes[5]. In order to combat this the industry is trying to move away from lead based solder with limited success. Because tin-lead solder has been used for a very long time it has been difficult to find a replacement[4] and there are several criteria that they are judging replacements with including (but not limited to): a melting point similar to Tin-Lead solder, good fatigue resistance, relatively non-toxic, and cost[4]. Much work has gone into replacing the lead in conventional solder with with other elements with limited success. The main problem is that lead is relatively cheap when compared to other elements because of it’s abundance in the Earth’s Crust and potential replacements are usually at least twice as expensive[5]. One problem is that tin-lead solders have a low melting point and potential replacements have a higher melting point which increases the thermal stress that is put on electronic parts[6].
There are several possible solutions to replacing lead based solder. One possibility is using just tin for solder. Currently, tin is mostly used by the electronics industry and by using only tin the consumption of tin increases from 60,000 tonnes per year to 80,000 tonnes per year[4]. This may seem like a large increase but it still within the amount of excess tin mined every year[4]. The viability of tin as a replacement is so good that Sandia National Lab considers 100Sn solder to be a valid replacement for current tin-lead solders[4]. Another possibility is replacing the solder completely by using new techniques to make electrical interconnections. One possibility is using electrically conductive adhesive materials[6]. The idea behind electrically conductive adhesive materials is to use an adhesive to attach the circuit elements to the circuit board[6]. In many situations these adhesives work just as well as solder except in situations where there is very high current or in areas of high humidity[6].
A major issue that needs to looked at seriously is the fact that replacements for tin-lead solder may also pose potential problems. A study found that tin-silver-copper, tin-silver, tin-copper, and tin-antimony solders all leached chemicals[5]. Due to the low solubility of tin salt in water tin did not leach significantly[5]. Because silver and antimony are both likely to be used in any tin-lead solder this may cause problems in the future for lead-free solders[5].
The effects of electronics on the environment need to be full realizes as these devices become garbage faster and faster. Computers can be reused where normally they would be thrown out. This will help radically with the amount of waste that is generated due to these devices. Non-toxic methods of construction also need to looked into which will keep people from becoming sick.
Bibliography
- Ferrer, Geraldo. “The Economics of Personal Computer Remanufacturing”. Resources,
Conservation, and Recycling, Volume 21, Number 2, October 1997, pp 79-108. - Lee, Ching-Hwa, Ssu-Li Chang, King-Min Wang, Lih-Chyi Wen. “Management of scrap computer
recycling in Taiwan”. Journal of Hazardous Materials, Volume 73, Issue 3, 28 April 2000, pp
209-220. - Matthews, H. Scott, Francis C. McMichael, Chris T. Hendrickson, and Deanna J. Hart. “Disposition
and End-of-Life Options for Personal Computers”. Green Design Initiative Technical Report
#97-10, Carnegie Mellon University, July 7, 1997. - Lee, Ning-Cheng. “Getting Ready For Lead Free Solders”. Soldering & Surface Mount
Technology, Volume 9, Number 2, 1997, pp. 65-69. - Lee, Ning-Cheng. “Lead-Free Soldering – Where The World is Going”. White paper.
- Toon, John. “Replacing Lead-Based Solder: Molecular Wires and Corrosion Control Boost
Performance of Electrically Conductive Adhesives”. Georgia Tech Research News. Published
March 13, 2005.
A great and informative article. Donating, dropping off or getting a electronic recycling company to pick them up for you, are a much more substainable solution.
I definately recommend using a company that doesn’t just recycle computers, but offers data destruction, WEEE documentation and after a repair and refurbishment process sends the donated IT equipment for reuse. The environmental advantages for reuse over recycling are many but not always understood.
The use of lead in computers does create a potential hazard and ergo the necessity to ensure an environmental friendly computer disposal system.