Recycling methods and the environment

Engineers and scientists have the task of designing appropriate recycling methods that produce goods that are of at least the same quality as the goods made from raw materials, while minimising waste produced by the plant. After all, there is no point in touting the ecological value of paper recycling plants if the harmful bleaches used to whiten the paper are released into local waterways.

In general, less energy is required to make recycled products than goods from raw materials. An extreme but common example is aluminium. Recycling aluminium from cans takes about 5 percent of the energy required to produce the same amount from bauxite. This translates to less pollution from electric plants. In fact, the energy saved by recycling a single can will run the average television for three hours. Similarly, recycling one glass bottle saves enough energy to light a 100 watt light bulb for four hours.

Also, in most cases, recycling techniques produce less direct pollution than producing goods from virgin materials. This is not always the case, though, and engineers must identify which recycling methods are better for the environment.

Making recycled paper saves forests, but producing recycled paper is often not as white as paper made from wood chips, because most recycled paper comes from old newspapers. In order to produce paper white enough to be used for business, bleaches must be used in the manufacturing process. Chemical engineers have been working on bleaches that can be considered safe to the environment. It may be possible in the future to collect waste from the bleaching processes and reuse it in some way.

Recycling plastic is possible, but only with certain types of plastic – the hardest kinds, such as those used in the casings of kitchen appliances, are not yet safely recyclable. Even the softer recyclable plastics, which are now marked with a recycling symbol, raise environmentalist concerns because of the noxious gases emitted when these plastics are burned. This is why recycling plants must carefully monitor manufacturing processes to only melt down plastics at a temperature level that causes no toxic emissions.

In some cases, engineers are only involved in recycling programmes as members of the community. Did you know that the Lions Clubs and LensCrafters have been sponsoring a glasses recycling programme for over seven years? Wearers of spectacles can aid people who are unable to afford eyecare by giving their old glasses to charity. While your prescription may not be perfect for the recipient, it could well improve their vision markedly.

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