Recycling Problems
1. The idea of a circular economy is aimed at reducing discarded waste and maximizing use out of all available resources. The central concept of a circular economy is to reuse resources as much as possible, recycling discarded resources and products into new ones whenever possible. Thus everything will circle back from refuse into future products, hence the name.
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Image credit Catherine Weetman, CC BY-SA 4.0
2. End-of -life designators are a way of marking products or materials in such a way as to inform their owners how to dispose of them properly when they are being discarded. Several end-of-life designation standards are currently used, the most common of which are the plastics recycling numbers shown to the right.
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While these symbols are popular and certainly helpful to the informed citizens, they may not be as good as solution as needed. For instance, it is a common misconception that any plastic with a recycling triangle can be put in any recycling bin. This is however not true, this depends on differing recycling facilities from one city or collection district to another and the only sure way to know what is recyclable in your area is to contact your collector.
While laws can be put in place to enforce such labeling, I believe first a better standard should be put in place that makes disposing of recyclable materials a clearer process, and campaigns should be put in place to educate people on the standard. Properly recycling everyday objects should not require extra research and making personal contacts.
3.
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initial weight of Cu = (0.7)(1000) = 700 kg
initial weight of PVC = (0.3)(1000) = 300 kg
Cu lost = 700 - 690 = 10 kg
PVC lost = 300 - 50 = 250 kg
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tailing weight = PVC lost + Cu lost
= 250 + 10
= 260 kg
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composition of Cu = Cu weight / total weight
= 10 / 260
= 3.85%
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composition of PVC = PVC weight / total weight
= 250 / 260
= 96.15%
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grade = Cu processed / total processed weight
= 690 / 740
= 93.24%
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recovered Cu = Cu processed / initial Cu weight
= 690 / 700
= 98.57%
4.
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max recoverable value = (0.20)(0.50) + (0.10)(1.70) + (0.12)(5.30) + (0.70)(1.00) + (0.28)(1.20)
= $1.94
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min recoverable value = (0.20)(0.40) + (0.10)(1.60) + (0.12)(4.80) + (0.70)(0.80) + (0.28)(1.00)
= $1.66
5. Polypropylene has a gross energy requirement of between 85 and 105 MJ/kg, roughly double its 46 MJ/kg heat of combustion. This means that even if the thermal recycling process was able to retrieve all the combusted energy, it would still only be getting back half the energy put into producing the polypropylene.
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Considering efficiency lessons learned from the second law of thermodynamics this may not be as terrible (in the context of "thermal recycling") as it may sound, but unfortunately the assumption of full retrieval is unfounded. Using the 25% efficiency figure, this means only roughly one eighth (12%) of the energy put into the polypropylene in the first place can be "recycled".
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While this may be better than nothing (purely energy speaking), it is certainly not a "good" solution to the issue at hand.