Environmental Issues with Construction Plastics
Disposal of plastics presents possibly the greatest dilemma. They don't break down easily, adding significantly to long-term solid waste disposal headaches, with around 17 mln tonnes a year entering the waste stream in the USA alone. Recycling thermoplastics only generally leads to conversion into a lower-grade product, and there are major logistical problems associated with collection, transport and separation of such lightweight, low value materials. Only around 7% of plastics were recycled in the year 2006, with the figure for construction plastics being even lower.
Some plastics produce persistent organic pollutants (POPs) when disposed of. These compounds accumulate in living systems, and become more concentrated at the top of the food chain. This is particularly the case for plastics containing chlorine or bromine, which can become sources for POP dioxins when burned, particularly at low temperature such as on a building site bonfire. PVC is of the greatest concern for dioxin generation, and should not be burnt under any circumstances. Unfortunately, some of the plastics being promoted as PVC alternatives contain brominated fire retardants.
New Developments
There are two broad categories of plastic currently being developed that may offer significant environmental advantages over existing plastics.
The first group is known as metallocene polyolefins. This group has been under development for several decades, but spent around 15 years of this time embroiled in lawsuits, resulting in very little progress until now. The advantage of the polymerisation process involved is that very clean polyolefins, made up of only carbon and hydrogen, can now be precisely engineered to have very specific properties. Polyotefms can now be viable replacements for PVC which, as we have seen, carries a high environmental burden. We should begin to see a wide range of metallocene polyoleftn based building products, from window frames and roofing membranes to wall cladding and cable sheathing in the near future.
The second promising group is bio-plastics. These show multiple environmental benefits as follows:
Because polymerisation is catalysed by enzymes in living organisms, the chemical bonds can also be broken down naturally - they are biodegradable.
Bio-plastics are renewable - fossil fuel may be used for processing but not as a feedstock.
Feedstocks produced agriculturally - supports hard hit farm economies. Less risk of harmful effluent or emissions during manufacture.
There are several types of bio-plastic, some of which are produced from simple plant sugars, particularly from com. A word of caution here about one type of plastic currently under development by our old friends Monsanto. They (and a few other companies) have genetically engineered plants such as mustard nd com to grow a plastic in their leaf tissue.
C) Give a written Russian translation either of the first or second passage. Compare your translations with those made by other students.
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Unit 3
Autonomous Building
I. Translate the following word combinations:
infrastructural support services
sewage treatment system
to apply environmentally responsible building design
to reduce environmental impact
to be energy-efficient in operation
technologically advanced autonomous houses
basement battery system ( )
immediate household use
solar water heaters
II. Read the text:
Autonomous building
An autonomous building is a building designed to be operated independently from infrastructural support services such as the electric power grid, municipal water systems, sewage treatment systems, communication services, and (in some cases) public roads.
Advocates of autonomous building describe advantages that include reduced environmental impacts, increased security, and cost efficiencies. Off-grid buildings often rely very little on civil services, and are therefore safer and more comfortable during civil disaster or military attacks.
British architects Brenda and Robert Vale have said that, as of 2002, "It is quite possible in all parts of Australia to construct a 'house with no bills', which would be comfortable without heating and cooling, which would make its own electricity, collect its own water and deal with its own waste... It is possible to build a "house with no bills" for the same price as a conventional house, but it would be (25%) smaller."
Autonomous buildings can reduce environmental impacts by using on-site resources (such as sunlight and rain) that would otherwise be wasted. Autonomy often dramatically reduces the costs and impacts of networks that serve the building, because autonomy short-circuits the multiplying inefficiencies of collecting and transporting resources. Other impacted resources, such as oil reserves and the retention of the local watershed, can often be cheaply conserved by thoughtful designs.
Autonomous buildings are usually energy-efficient in operation, and therefore cost-efficient, for the obvious reason that smaller energy needs are easier to satisfy off-grid.
An autonomous structure is not always environmentally friendly. However, autonomous buildings also usually include some degree of sustainability through the use of renewable resources.
First and fundamentally, independence is a matter of degree. Complete independence is very hard or impossible to attain. For example, eliminating dependence on the electrical grid is one thing, and growing all of your own food is a more demanding and time-consuming proposition.
Living in an autonomous shelter can require one to make sacrifices in one's lifestyle choices, personal behavior, and social expectations. Even the most comfortable and technologically advanced autonomous houses may require some differences in behavior. Some persons adjust easily. Others describe the experience as inconvenient, irritating, isolating. A well-designed building can reduce this issue, but usually at the expense of reduced autonomy.
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Greywater systems reuse wash water to flush toilets, and water lawns and gardens. Greywater systems can halve the water use of most residential buildings. Some builders are installing waterless urinals and even composting toilets that completely eliminate water usage in
sewage disposal.
Most desert and temperate climates get at least 250 mm of rain per year. This means that a typical one storey house with a greywater system can supply its year-round water needs from its roof alone. In the most extremely dry areas, it will require a cistern of 30 m3. Many areas average 13 mm of rain per week, and these can use a cistern as small as 10 m3. It can be convenient to use the cistern as heating system or air conditioning system; however this can make cold drinking water warm, and in drier years the efficiency of the Heating, Ventilation and Air-Conditioning system may decrease.
Cistern design can reduce costs and inconvenience. Gravity tanks on short towers are reliable, so pump repairs are less urgent. The least expensive bulk cistern is a fenced pond or pool at ground level.
Since electricity is an expensive utility, the first step towards conservation is to design a house and lifestyle to reduce demand.
Using a solar roof, solar cells can currently provide electric power. Solar roofs are far more cost-effective than retrofitted solar power, because buildings need roofs anyway. Modern solar cells last about 40 years, which makes them a reasonable investment in some areas.
There are a number of areas that lack sun, but have wind. To generate power, the average autonomous house needs only one small wind turbine, 5 m or less in diameter. On a 30 m tower, this turbine can provide enough power to supplement solar power on cloudy days.
The largest advantage of wind power is that larger wind turbines have a lower per-watt cost than solar cells. However, location is critical. Just as some locations lack sun for solar cells, some locations lack sufficient wind for an economical turbine installation. Paul Gipe says that in the Great Plains of the United States a 10 m turbine can supply enough energy to heat and cool a well-built all-electric house. Economic use in other areas requires research, and possibly a site-survey.
During times of low demand, excess power can be stored in batteries for future use. However, batteries need to be replaced every few years.
III. Answer the questions to the text:
1. What kind of buildings are usually autonomous?
2. What is an autonomous building?
3. What are the advantages of an autonomous building?
4. What are the disadvantages of living in a "house with no bills?"
5. Is an autonomous structure always environmentally friendly?
6. How does autonomy reduce the costs?
7. How is the problem of water supply solved?
8. Why does an autonomous building rely on renewable resources much?
IV. Fill in the prepositions and translate the phrases:
rely.........civil services
.........the expense of
have an effect.........psychology
be concerned.........
.........least
.........ground level
deal.........
depend.........
.........instance
V. Pick out the pairs of synonyms:
Conventional, involve, clear, shelter, basic, reach, independent, decrease, benefit, normal, fundamental, absolute, impact, security, advantage, reduce, autonomous, obvious, complete, construction, safety, include, attain, effect.
VI. Change the word given in brackets into the necessary form:
1. (History), architects searched for a magic ratio which represents the ideal of perfect proportion.
2. All (combustion) materials should be kept at a safe distance from a steel fire door.
3. The draught in the staircase tends to increase the (probable) of a small fire becoming a large one.
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4. As both buildings have the same floor area and (high), they both have the same volume.
5. The system is to protect the client's interests by exercising (independence) control over the (contract).
6. Different types of fuel are used in different geographical (locate) and (situate).
7. The (strong) of a column is directly proportional to its (high) and inversely - to its (thick).
VII. Are you in favour or against living in an autonomous building?
Write a paragraph, listing your arguments. Make use of the words:
Opinion
In my opinion/ view, Personally, As far as I'm concerned
Addition
Besides
Moreover
Furthermore
Contrast
However
Nevertheless
On the other hand
