The issue of domestic waste management has always been controversial; yet we don’t give much thought to the garbage we throw away. Most of us have at least a baseline idea of what happens to it afterwards but very few people actually care. Landfills are by far the most popular and the cheapest supposed solution. Dumping garbage into its own reserved area where many will never have to see it again is a very appealing idea. There are of course a number of more environmentally friendly options, but not every country can afford them. This is a common dilemma, balancing environmental impacts with the costs of the overall process of disposing of waste. A study done in January 2009 by the Institute of Chemical and Engineering Sciences analyzed Singapore’s methods of dealing with municipal solid waste.
Singapore is a small country, lacking the land for extensive landfills. Its one main landfill is predicted to last until 2030 . They have turned to a number of processes to handle their waste problems, most of which revolve around incinerating MSW (Municipal Solid Waste). They have also begun trying to harness some of the product gas produced as usable electrical energy. Of Singapore’s eight main waste managing methods it was determined that the steam gasification of wood and pyrolysis gasification of waste was the most effective. Gasification consists of shredding waste wood to produce a product gas, then combusting the gas to create electrical energy, making it the most environmentally friendly yet at the same time the most costly. Pyrolysis gasification of waste created the least amount of waste. However all methods of incineration cost a considerable deal, first to heat the waste and second to pretreat and deal with the product.
The study determined that the costs of these methods in comparison to land filling were almost double. For example the gasification of shredded wood was roughly 95 USD/ton feedstock, while land filling was 55 USD/ton feedstock. A number them had high global warming potential, thermal cracking gasification scored highest, with the addition of pretreatment for the waste amounted to almost 2700 kg_Co2 – eq. The study tested a number of different impacts including eutrophication levels and photochemical ozone formation levels. Gasification and pyrolysis was the second most expensive, yet it’s estimated that the trade off of energy produced by the product waste could make it more affordable and beneficial for the environment. Hopefully more alternative methods of waste management will be considered more internationally, improvements in technology should make the transition simpler. However there is a long way to go before we can manage waste in an environmentally sustainable way that is also cost effective, thought the near future holds many possibilities.
Resources:
Life cycle impact assessment of carious waste conversion technologies. Khoo H. Hsien. January 20, 2009. Waste Management V. 29 I. 6. Accessed October 9, 2009. From: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VFR-4VDSCVJ-8&_user=1067211&_coverDate=06%2F30%2F2009&_alid=1046587035&_rdoc=1&_fmt=high&_orig=search&_cdi=6017&_sort=r&_st=4&_docanchor=&_ct=48&_acct=C000051237&_version=1&_urlVersion=0&_userid=1067211&md5=cee5e4a2470c102220e1cd856bc564be.
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I really enjoyed reading your blog because it was concise and to the point. Your introduction clearly explained the topic that your study was dealing with. I also think that you did a good job of identifying the main conclusions from the primary source. I found it interesting because my previous 2 blogs have been about exporting waste to foreign countries but yours was about how these countries actually deal with their own. My advice would be to proofread more carefully because I noticed a few typos.
ReplyDeleteI think this article meets the assignment's objectives. It was structured such that it identified a problem, outlined the study and its results, and discussed how these results could be applied to the problem.
ReplyDeleteSome of the results discussed remain vague, though. For example, you describe the addition of pretreatment for waste amounting to 2700 kg_Co2 – eq. I think most readers would not understand data presented this way, and would benefit from a brief explanation of what these data mean.
I believe when writing articles like the ones we’ve been writing this week, one should be cautious as to not make generalized, unsupported statements. In the first paragraph, you write “Most of us have at least a baseline idea of what happens to it (waste) afterwards but very few people actually care". How do you know very few people actually care? Is there quantitative evidence to supports this? If so, I think it should be provided when making such a statement.
I found this blog very interesting because I think that it's important that we see the different ways that people dispose of waste. I really found it interesting how you said that in Singapore they do not have very much land to put landfills because I have never really thought about the space implications when building landfills, but only how expensive it is and how environmentally friendly it is.
ReplyDeleteI think that you maybe should have defined a few of the terms you used and explained some of them in a bit more detail because I found some of the blog to be confusing since I didn't really know what you were talking about. For example, you talked about eutrophication levels, but did not really explain what they mean and why they are relevent to what your blog is about. Overall though I think that this blog was very well done.