As the importance of recycling becomes more apparent, questions about it lin

游客2024-01-02  8

问题     As the importance of recycling becomes more apparent, questions about it linger. Is it worth the effort? How does it work? Is recycling waste just going into a landfill in China? Here are some answers.
    It is an awful lot of rubbish. Since 1960 the amount of municipal waste being collected in America has nearly tripled, reaching 245m tonnes in 2005. According to European Union statistics, the amount of municipal waste produced in western Europe increased by 23% between 1995 and 2003, to reach 577kg per person.(So much for the plan to reduce waste per person to 300kg by 2000.)As the volume of waste has increased, so have recycling efforts. In 1980 America recycled only 9. 6% of its municipal rubbish; today the rate stands at 32%. A similar trend can be seen in Europe, where some countries, such as Austria and the Netherlands, now recycle 60% or more of their municipal waste. Britain’ s recycling rate, at 27% , is low, but it is improving fast, having nearly doubled in the past three years.
    Even so, when a city introduces a kerbside recycling programme, the sight of all those recycling lorries trundling around can raise doubts about whether the collection and transportation of waste materials requires more energy than it saves. "We are constantly being asked; Is recycling worth doing on environmental grounds?" says Julian Parfitt, principal analyst at Waste & Resources Action Programme(WRAP), a non-profit British company that encourages recycling and develops markets for recycled materials.     Studies that look at the entire life cycle of a particular material can shed light on this question in a particular case, but WRAP decided to take a broader look. It asked the Technical University of Denmark and the Danish Topic Centre on Waste to conduct a review of 55 life-cycle analyses, all of which were selected because of their rigorous methodology. The researchers then looked at more than 200 scenarios, comparing the impact of recycling with that of burying or burning particular types of waste material. They found that in 83% of all scenarios that included recycling, it was indeed better for the environment.
    Based on this study, WRAP calculated that Britain’ s recycling efforts reduce its carbon-dioxide emissions by 10m-15m tonnes per year. That is equivalent to a 10% reduction in Britain’ s annual carbon-dioxide emissions from transport, or roughly equivalent to taking 3. 5m cars off the roads. Similarly, America’ s Environmental Protection Agency estimates that recycling reduced the country’ s carbon emissions by 49 m tonnes in 2005.
    Recycling has many other benefits, too. It conserves natural resources. It also reduces the amount of waste that is buried or burnt, hardly ideal ways to get rid of the stuff.(Landfills take up valuable space and emit methane, a potent greenhouse gas; and although incinerators are not as polluting as they once were, they still produce noxious emissions, so people dislike having them around.)But perhaps the most valuable benefit of recycling is the saving in energy and the reduction in greenhouse gases and pollution that result when scrap materials are substituted for virgin feedstock. "If you can use recycled materials, you don’t have to mine ores, cut trees and drill for oil as much," says Jeffrey Morris of Sound Resource Management, a consulting firm based in Olympia, Washington.
    Extracting metals from ore, in particular, is extremely energy-intensive. Recycling aluminium, for example, can reduce energy consumption by as much as 95%. Savings for other materials are lower but still substantial: about 70% for plastics, 60% for steel, 40% for paper and 30% for glass. Recycling also reduces emissions of pollutants that can cause smog, acid rain and the contamination of waterways.

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答案                             回收利用之真相
    随着回收利用的重要性日渐凸显,关于这方面的问题也日益叠加:值得这么做吗?如何进行操作?在中国,回收的垃圾都涌向垃圾场吗?以下是一些相关答案。
    垃圾的数量真是惊人之多。自从1960年以来,美国市区收集到的垃圾总量几乎翻了三倍,到2005年达到了245万吨之多。根据欧盟数据显示,西欧国家市区产生的垃圾数量在1995年至2003年之间增长了23%。人均产生垃圾量高达577公斤(远远超过了当时到2000年人均垃圾量为300公斤的计划量)。随着垃圾总量的增加,垃圾回收利用所做的努力也显得日益重要。1980年,美国市区垃圾的回收率仅为9.6%,但今天垃圾的回收率已达32%。欧洲国家也呈现出相应趋势,例如奥地利和荷兰,他们现在的垃圾回收率已达60%或以上。英国的垃圾回收率目前只有27%,但其回收率快速增长,在过去三年里几乎翻了两番。
    尽管如此,当城市启动路边垃圾回收项目后,满大街垃圾车竞相奔走的情景不禁引起人们的怀疑:垃圾回收后可利用的能源是否远不抵收集和运输这些垃圾所消耗的能源?英国废物及资源行动计划组织的首席分析员朱迪-帕菲说道:“常常有人问我们:回收真的有益于环境保护吗?”该组织是英国一家非盈利性组织,提倡回收理念并努力开拓回收市场。
    关于特定事物生命周期的研究,以一特定事例便可以阐明这一问题。但是,英国废物及资源行动计划组织决定一探究竟,它委托丹麦技术大学和丹麦废物主题中心对55篇相关生命周期分析报告进行再次研究。这55篇报告均因其精确分析的特点而被选出重新研究。接着,研究人员研读了200多个研究方案,并将回收垃圾与掩埋或焚烧特殊种类的废弃物两者各自所产生的影响进行比较。结果他们发现83%关于回收的方案中确实证明回收有益于环境。
    在这项研究的基础上,英国废物及资源行动计划组织得出以下结论:英国对废弃物的回收每年减少了1000~1500万吨二氧化碳的排放量。相当于英国每年汽车的二氧化碳排放量减少了10%,或者大致相当于英国公路上少了350万辆汽车。无独有偶,据美国环境保护局估计,到2005年,回收将使美国碳氧化物排放量减少4900万吨。
    回收还有其他诸多益处:保护自然资源;减少掩埋和焚烧废弃物总量。掩埋和焚烧废弃物根本算不上是理想的垃圾处理方式。(垃圾场占据了宝贵的土地资源,并产生甲烷——一种破坏力极强的温室气体;尽管现在垃圾堆污染严重程度有所改善,但它们依然产生有毒气体,因此,人们讨厌周围有垃圾场的存在),但回收的最大益处也许就在于能源的节约,温室气体和废品转换成原料过程中所产生的污染物的减少。来自华盛顿-奥林匹亚一家咨询公司优化能源管理部门的杰弗里-莫里斯如是说道:如果都能使用回收利用的材料,我们大可不必大肆挖掘矿物、砍伐树木和开采石油钻井。
    尤其,从矿中冶炼金属是一个极其消耗能量的过程。就拿铝金属的回收来说,它能节约高达95%的能源消耗。其他物质回收的能源节约比例相对较小一些,但其总量也很可观:塑料回收能源节约达70%,钢铁回收能源节约约达60%,纸质回收节能约达40%,而玻璃回收节能则约达30%。回收利用同时还减少那些能造成大雾、酸雨和排水沟污染的污染物排放量。

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