英赛特名师陈孝宗写作阅读口语素材－环保话题14

Waste Disposal



--------------------------------------------------------------------------------

The more waste we generate, the more we have to dispose of. Some methods of waste disposal release air pollutants and greenhouse gases into the atmosphere. Waste recycling offers one means of reducing the impacts of waste disposal on the atmosphere, but there are other methods of waste disposal which are more environmentally friendly. (定语从句)



The most common disposal methods, particularly in the UK, are landfill and to a lesser extent incineration. Each year approximately 111 million tonnes of controlled waste (household, commercial and industrial waste) are disposed of in landfill sites in the UK. Some waste from sewage sludge is also placed in landfill sites, along with waste from mining and quarrying. There are over 4000 landfill sites in the UK. As landfill waste decomposes, methane is released in considerable quantities. (时间状语从句，被动句) Currently it is estimated that over 1.5 million tonnes of methane are released by landfill sites in the UK each year. Methane is a strong greenhouse gas and contributes to global warming. Furthermore, the leachate fluids formed from decomposing waste can permeate through the underlying and surrounding geological strata, polluting groundwater which may be used for drinking water supplies. (定语从句，被动句，宾语从句，时间状语从句，同位语从句，主语从句，祈使句，表语从句，让步状语从句，条件状语从句，原因状语从句) Containment landfills however, can limit the spread of this waste leachate.



Incineration is the second largest waste disposal method in most countries. In the UK, approximately 5% of household waste, 7.5% of commercial waste, and 2% of industrial waste is disposed of by incineration. (被动句) When burning waste, a large amount of energy, carbon dioxide and other potentially hazardous air pollutants is given off. Modern incinerators however, can use this waste energy to generate electricity and hence prevent the energy from being wasted. Incineration plants range from large scale, mass-burn, and municipal waste incinerators to smaller clinical waste incinerators used in hospitals. During the 1990s many UK hospital incinerators were forced to close owing to tougher emissions legislation introduced by the 1990 Environmental Protection Act. Today, hospitals tend to share one large incinerator to dispose of the wastes for a number of hospitals.



A less common but more sustainable method of waste disposal is anaerobic digestion. In this process waste decomposes in an enclosed chamber, unlike in a landfill site. Digestion takes place in an oxygen-free environment. Bacteria thrive in this environment by using the oxygen that is chemically combined within the waste. They decompose waste by breaking down the molecules to form gaseous by-products (methane) and small quantities of solid residue. Anaerobic sewage plants produce significant quantities of methane, which can be burnt to generate electricity. Liquid and solid organic fertilisers are also formed, and can be sold to cover operating costs. (被动句) For several years, sewage sludge and agricultural waste has been treated by anaerobic digestion, and the process is now being used for municipal solid waste. It requires the biodegradable section of the waste to be separated from other material and put into digestion chambers. Currently, the UK has only a small number of plants, and each can handle only a few hundred tonnes of waste each year. However, the usage of anaerobic digestion as a sustainable waste disposal method is forecast to increase. Many other countries already utilise anaerobic digestion to dispose of large amounts of waste. Denmark for example, treats 1.1 million tonnes of waste by anaerobic digestion every year.



As well as recycling waste, individuals can adopt more sustainable ways of disposing it. One way is to compost any organic waste such as food and garden waste. Organic waste breaks down over a few weeks into a mulch which can be used as a soil fertiliser. Individual households have practiced small-scale composting for many years, and the UK Government is now encouraging this on a wider scale. Large-scale composting schemes are also being developed, with the collection of organic waste from parks and civic amenity sites. Garden and food wastes are collected directly from households in separate kerbside collections. Large central facilities can then compost the collected organic waste. These schemes are to help the UK meet its target of recycling and composting 33% of household waste by 2015.



Many cities around the world are beginning to develop and implement "sustainability" projects. These projects typically include strategies for reducing waste, often by using waste as raw material for building homes, generating energy, or nourishing crops, for example. One effective waste-management program can be found in Copenhagen, Denmark.



Copenhagen has developed a comprehensive program for managing urban waste. The goals of the program are ambitious:  

58 percent of the city's household, commercial, and industrial waste is to be recycled

24 percent is to be incinerated

18 percent is to be deposited in a landfill

Danish municipalities have the authority to regulate all waste generated by their local commercial, construction/demolition, and industrial sectors. Throughout the 1980s, they exercised this authority mainly by requiring that waste producers to pay a tax for waste disposal. The waste was shipped to centralized sorting plant; often the wastes would mix during shipment, making the sorting process difficult.



To increase the impact of the waste-management system, the Copenhagen City Council adopted new regulations in 1991 requiring that waste producers separate all waste at the source of generation. Hazardous waste must be separated from waste meant for incinerators or landfills and must be either recycled or treated at specialized facilities. In addition, waste generators are required to reduce the volume of waste sent to incinerators or landfills by introducing new technologies, processes, or recycling measures.



As a result of these regulations, the number of landfills in use has been reduced from 30 to 3. Today more than 50 percent of the city's commercial, industrial, and demolition waste is recycled. Furthermore, about 50,000 tons of combustible waste, previously deposited in landfills, are now incinerated in plants that convert waste to energy.



Sustainability is the intelligent use of our resources--natural and technological--to meet our communities' needs both today and in the future. People worldwide are beginning to recognize that a healthy, functioning community relies on a healthy environment.



Pollution and overuse of resources can affect everything from the health of children to the availability of raw materials. Increasingly, we are realizing the importance of not only meeting environmental regulations but also taking extra steps to reduce waste, prevent pollution, and conserve resources. As more communities choose to pursue sustainability, successful environmental programs will continue to emerge. (时间状语从句) These programs will become models on which to base global efforts to protect and restore the environment.



Each individual has a role in building a sustainable future. Many individuals and communities have already begun. At home, school, and work, we can make changes that will help preserve our resources for future generations.





Key words and useful expressions:

1.         pollutant n.污染物质

2.         environmentally friendly

3.         landfill n.垃圾掩埋法

4.         sewage n.下水道, 污水

5.         decompose v.分解, (使)腐烂

6.         methane n.[化]甲烷, 沼气

7.         leachate n.沥出液，沥出物

8.         containment landfills

9.         incineration n.烧成灰, 焚化

10.     anaerobic digestion



Useful sentences containing grammatical items:

1.         Waste recycling offers one means of reducing the impacts of waste disposal on the atmosphere, but there are other methods of waste disposal which are more environmentally friendly. (定语从句)

2.         As landfill waste decomposes, methane is released in considerable quantities. (时间状语从句，被动句)

3.         Furthermore, the leachate fluids formed from decomposing waste can permeate through the underlying and surrounding geological strata, polluting groundwater which may be used for drinking water supplies. (定语从句，被动句)

4.         In the UK, approximately 5% of household waste, 7.5% of commercial waste, and 2% of industrial waste is disposed of by incineration. (被动句)

5.         Liquid and solid organic fertilisers are also formed, and can be sold to cover operating costs. (被动句)

6.         As more communities choose to pursue sustainability, successful environmental programs will continue to emerge. (时间状语从句)