A hammermill is used to shred old automobiles, as well as other old bulky metal appliances. The hammermill works in essence like a wood chipper, and like the wood chipper it leaves residue behind. This residue is called Automobile Shredder Residue (ASR) and consists of; glass, polymers, plastics, rubber, dirt, and small amounts of metal. This residue is considered hazardous in some countries because it has been known to also contain; polychlorinated biphenyls (PCB’s) which are used in coolants, lead from batteries, and cadmium. In North America alone it is estimated that Automobile Shredder Residue accounts for almost 5 million tons of waste that occupies landfills each year.
Impact of Automobile Shredder Residue on the environment
Automobile Shredder Residue is made of both hazardous and non-hazardous wastes. These wastes are in many cases not separated before they are dumped at the land fill, mainly because the process is expensive, or there may not be sufficient evidence to suggest that harmful levels of hazardous wastes, are contained in the mixture. This method of dumping the entire residue into a landfill severely impacts on the environment, as much of the hazardous elements contained in ASR, are not being dumped properly, and eventually the build up could lead to contamination of groundwater, or other bodies of water. The dumping of ASR also highlights our disregard for recycling valuable products, and the hopes of saving on energy costs. It is estimated that recycling the 5 million tons of ASR dumped every year would be the equivalent of saving 24 million barrels of oil every year.
Recycling Automobile Shredder Residue
Much of the Automobile Shredder Residue in today’s world is sent to landfills, but it is estimated that up to 60% of this waste can be salvaged, and recycled for use in other areas. According to the American Recycler a particular company; Argonne has spent close to $ 5 million developing a workable process of effectively recycling ASR into useful polymers. The process involves the separation of the components of the residue to leave the polymers, the polymers are then separated and grouped according to compatibility, and these polymers are then reused in other areas.
While Argonne is only one of the highlighted companies to investigate the usefulness of ASR, it is certain that many other companies will follow suit in the future. Argonne is funded by the United States Department of Energy and this is certain to be an inspiration for other companies who may want to try their hands at ASR recycling.