3.8 Problems with Material Production: Waste

 

 

3.8 Problems with Material Production: Waste

The energy used to produce the materials for engineering projects is only half the problem. We must also consider what happens to the products after theirin-uselife is over. Some materials can be reused or recycled to go back to thein-usestream, however a large majority will end up as waste, and will need to be disposed of.


Example: Computers in the USA

30 million computers are thrown away each year in US (~14% are recycled now). Heavy metals present in the computers pollute water. Other materials will pollute the environment, and the space they take up put pressure on land usage. Tackling waste flows can reduce environmental impact and save money.

The electronics and automobile industry are beginning to design for the end of life

(Source: MIT Opencourseware [see reference 3])

Image sourced from MIT opencourseware under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License
http://dspace.mit.edu/bitstream/handle/1721.1/39134/1-964Fall-2004/NR/rdonlyres/Civil-and-Environmental-Engineering/1-964Fall-2004/7304E211-2A38-4420-90C5-9669E185203F/0/lec1_introduction_jao.pdf


The following passage states some facts about waste in the UK:

The UK produces around 335 million tonnes of waste per year. Of this, 30 million tonnes is household waste and the majority (nearly 70 per cent) is not recycled. In landfill, biodegradable waste, such as food and garden waste, produces methane (CH4), a powerful greenhouse gas. There are more than 1500 landfill sites in the UK and, in 2001, they produced 25 per cent of the UK's methane emissions. Methane is a more powerful greenhouse gas than carbon dioxide. Along with the unnecessary carbon emissions associated with creating waste in the first place, this means that household waste contributes to climate change. Recycling more, preventing waste food and composting at home all help to reduce this impact.

(Source Open University [see reference 5])

Above text sourced from The Open University under a Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence
http://labspace.open.ac.uk/mod/oucontent/view.php?id=426564&section=1.2.2


Note that only 30 out of a total of 335 million tonnes of waste per year are from the domestic setting. The rest will be industrial waste, where an engineer will be in a position to influence.

The following talk gives a good description of the harms of plastic pollution.

http://www.ted.com/talks/dianna_cohen_tough_truths_about_plastic_pollution.html

Often engineers are only concerned with getting a product to the market, and what happens to the product after it finishes its life is left to waste management systems and companies. With more thought put in during the design phase, products can be manufactured for ease of dismantle, re-use or more effective recycling at the end of their life.