The problem of waste disposal - Методическое пособие по дисциплине "Практический курс иностранного языка" (озо,...
The problem of waste disposal
Every society produces waste, doesn’t it? And that waste has to be disposed of somehow. In fact, societies right throughout history have had the same problem and the same answer. Stone-Age man collected together his broken pots, his animal bones and his stone chippings, and simply left them in a pile. And today, modern societies do very much the same thing: we collect our waste together, transport it, and dump it (or burn some of it). Yet things are beginning to change. We’re slowly getting the message that we can’t go on indefinitely throwing our waste away – for two reasons. One is that 20th century societies now produce so much waste that it simply doesn’t make sense to deal with it in this way. And the other reason is that most waste contains valuable materials that can be extracted and recycled.
Let’s firstly talk about where our waste comes from. Basically, there are four sources of waste: it comes form mines and comprises 39% of the total, and waste from agriculture comprises 53%. Domestic waste accounts for 6%, and industrial waste for 2%. And where does all this waste go? Well, most of it goes to open dumps - 5% in fact; 23% is simply not collected and not disposed of at all, but is left on the spot. 12% is buried in the ground by the landfill method, and 9% is burnt. That leaves 1%, which is dumped at sea.
From now on, let’s just consider domestic waste, shall we? – rubbish, refuse, call it what you like. And let’s discuss in more detail what happens to it, and how we’re improving our methods of dealing with it. Domestic rubbish is usually disposed of in one of three ways, all of which have their pros and cons. Open dumps, for instance, have the advantages of being easy to operate, and of being the cheapest of the three methods. However, their disadvantages are that they are unsightly, they cause air pollution when rubbish is burnt, they smell, materials are wasted - land so is land - and they can contaminate ground water and nearby streams.
What about landfill? Landfill means putting domestic refuse in holes in the ground – such as disused quarries, old mines, marshlands, etc., compacting it, and covering the compacted refuse with earth every 2 m or so. Well, a landfill is cheap, there are no objectionable smells or pests; when the landfill is completed, the site can often be more useful than it was before. (It can become a sports field or a park, for instance.) Nevertheless, a landfill also wastes materials, and it uses a large area of land, which may not be available near urban centres.
The third method of disposing of domestic waste is incineration, that is, burning. On the credit side, incineration can handle about 80% of domestic rubbish, and can reduce its volume by about 90%. Also, it requires very little land, and it produces income from the recovery of waste metal and glass. But on the debit side, it’s expensive to build an incineration plant, and it causes air pollution unless sophisticated pollution controls are installed.
This business of putting household waste in a bin outside the house, and having the bin emptied each week into a lorry – it’s very unscientific for the 20th century, isn’t it! Yes, there are better methods. Let’s look at this one, as an example. This is a method that is becoming common when now apartment blocks are built. Here’s the householder emptying his rubbish down a chute. It goes into this separator, which separates out the glass and metal contents – which are recycled. What’s left – mainly paper and burnable waste – then passes into this heating plant to be burnt. The heat produced in the heating plant is used in two ways. It heats the apartment buildings by circulating hot water through a central heating system. And it produces steam that generates electricity, which in turn provides energy for the apartment block.
Finally, let’s look into the future, and see what a typical recovery centre in each town might look like next century. Here’s the average domestic consumer – you and me – whose rubbish would be dropped direct into a pipeline, and pumped to the recovery centre. At the centre, the refuse would first go through the shredder, where it would be broken up into small pieces. Then the separator would do its job. Powerful electromagnets would extract the ferrous metals, and the non-ferrous metals would be in separate chambers; glass would be extracted by fluid flotation; and grass, leaves and food by centrifugal hurling. All these materials – ferrous and non-ferrous metals, paper, plastic, and glass - would be recycled. The food, grass and leaves would be converted into compost, which would be returned to the earth as fertilizer, and what’s left would be buried by the landfill method.
Of course at present, centres like this are rare. But let’s hope this type of resource centre is set up soon, because – as I said at the beginning – waste contains many valuable materials that should be extracted and recycled.I Speak about the following:
1) The sources of waste.
2) The existing ways of waste disposal. The advantages and disadvantages of each of them.
3) Describe a future recovery center. What economic problems are overlooked here?
Beware Home Pollution
«Health and Fitness» Today 2001
Air pollution affects the entire planet. You can’t escape it anywhere not even inside your home.
In fact, indoor air pollution can be up to five times worse than outdoor air pollution. And much of it is related to products that we use every day.
Here are some common household products that foul our domestic atmospheres, along with suggestions for nontoxic replacements:
Note: to further increase your indoor air quality, open up windows and doors for ventilation whenever safety and weather conditions permit. Also, consider installing a high-efficiently particulate air (HEPA) filter in your favorite room to create a pollution-free zone. This is especially important if you live in a big city, where just isn’t as much fresh air to go around. I Explain the word/words, translate them into Russian.