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polluting and demanding more water for all uses from a renewable but finite resource. They are thus suffering from scarcities caused by failure to adapt to the amount of water that is regularly made available by rain and snowfall. Water demands are so high that a number of large rivers decrease in volume as they flow downstream, with the result that downstream users face shortages, and ecosystems suffer, both in the rivers and in adjacent coastal areas.
Many underground water resources, known as groundwater, are being drained faster than nature can replenish them. Intensive and misuse of underground water leads to drainage of water recourses around the city, deserting the big areas beyond the cities boundaries. In some cases, groundwater depletion results in the land above aquifers sinking. Land subsidence caused by high water withdrawals has been recorded in many countries, including Mexico, the United States, Japan, China and Thailand, with the land sinking from 1 to 10 meters.
South and Southeast Asia are facing severe water pollution problems. Rivers such as the Yellow (China), Ganges (India), and Amu and Syr Darya (Central Asia) top the list of the world’s most polluted rivers. In cities in the developing countries of the region, most water bodies are now heavily polluted with domestic sewage, industrial effluents, chemicals and solid wastes. Most rivers in Nepal’s urban areas have been polluted and their waters are now unfit for human use, while drinking water in Katmandu is contaminated with coliform bacteria, iron, ammonia and other contaminants.
There are estimates that in developing countries, which often lack the resources to build and maintain sewage treatment a system, 90 per cent of waste water is discharged without treatment. A UN study found that in Latin America, virtually all domestic sewage and industrial waste is discharged untreated into the nearest streams. In most areas, domestic sewage volumes are far higher than those of industrial discharges. There were similar findings from West Africa, where there were signs of shallow aquifers being contaminated by the seepage of human wastes.
WASTE MANAGEMENT
Some estimates show that New York wastes round 24’000 ton material everyday. It contains metal, glass, plastics, paper, food and etc. It also includes dangerous substances like mercury from battery, phosphate from bulbs and other different type of toxic waste from paintings, detergents, home cleaners and etc.
The sad fact is that wealthy city tends to use more energy and produce more waste than similar developing country’s cities. Developing countries trash about 2-3 times less waste than developed country. To satisfy an average costumer, for example, a company uses more packaging than it needed or more advertisements than it requires, which in other words mean more waste. Among the nations, the US produces the highest waste per person – 520 kg waste per person a year; in comparison Norway, Spain, Nederland – 200-300 kg, African cities – much less.
Depending on the country and its economic stand, there are different approaches to the waste management. Rich and developed countries or countries with scarce land supply use high tech processes to handle the waste. But on opposite side, poor and developing countries are still using the simple methods of waste discharge.
Open Waste Area and Land Filling.
Until recent time, 90% of waste in US is used to bury. Open dumping takes more space and more energy to handle it and usually becomes the shelter of different type of leaving creatures; rats, mosquitoes, bags - the potential carriers of diseases. The process of rotting of organic waste spreads strong smell to surrounding area, and the wind disseminates the loose trashes. In developed countries there are almost no open dumping areas nowadays (except for solid waste), but in third world it is the only way of handling the waste; cheaper and more convenient. The heartbreaking fact is that those open waste areas, in third world, become shelter and the only source of income for many poor people.
Ecological impact of open dumping is wide and significant. The content of waste can be various, starting from usual organic waste and ending with heavy chemical products, which can be dissolved by rain or snow water. It leaks to underground water and can spread many miles away from the original source. In the past, people used open dumping because most of the waste used to be absorbed by the nature; wind, water, ground and sun dissolve the waste. But with the advance of the technology many items just simply don’t dissolve easily. For example, paper takes two to ten years to completely disappear, cans – more than 90 years, filter from cigars – more than 100 years, plastic bags – 200 years, plastic – 500 years, glass – 1000 years.
With the danger of heavy pollution many countries changed open dumping to land filling. Waste problem was solved for a decade, no more headaches for government. But with more pollution of underground water and threat to health, people realized the hidden danger. Nowadays, land filling is a very sophisticated process; just simple burying turned into high technological storage areas. In the US 20 years ago, simply bury of waste cost $2 per kg, now cost round $100 per kg; burying one liter of organic dissolvent costs more than its production and it has an increasing tendency. With production of 160 million tons of waste every year, the US has not only the problem of the expenditure, but also the rapid fill ups of land filling areas.
Waste-to-energy
High-density areas like Europe don’t have much land to landfill so they preferred to burn the waste instead of burying. The first systematic chain furnace was tested in England in 1874. Burning decreases the size of waste about 70 - 90 percent and ashes easily turn into construction materials. This method was adapted on both sides of Atlantic Ocean; in Europe early, in America little bit later. In the developed world waste burning is used for production of electrical and steam energy, construction supplies and crude iron. For example, the leading US’s waste company the “Waste Management Co.” produces about 623 megawatts of energy every year, which is equivalent of supplying 550,000 homes with energy. According company’s report:” … “WM” has processed over 100 million tons of municipal solid waste into energy since 1975, saving more than 150 million barrels of oil while producing 50 billion kilowatt hours of electricity.”
Burning the waste for a production of energy also has its downside. Waste itself is a very difficult burning material. It requires special expensive process to be burnt and not everywhere it repaid the expenditure. For example Moscow had a problem when they tried to establish the new plant. Mayor of Moscow agreed to put in budget to purchase of furnace from western countries but refused to buy the cleaning equipment, because the emission cleaning equipment cost almost the same price as the plant itself. Without the cleaning equipment amount of carbon dioxide it excretes into the air is enormous. Moscow has an air pollution problem without the waste burning plant so the project was canceled.
Most of the third world burning plants work because of subsidies of international organizations. But in many, many developing countries this technology just simply didn’t find the usage. It is much cheaper just burning the waste on open area than trying to turn into energy.
Recycling
So far the most perspective management of waste known to people is recycling. It doesn’t require much government subsidy, doesn’t pollute environment and it is economically efficient. Sweden is one of the highest recyclers of thee aluminum cans, 8 of 10 cans is recycled. Production of cans from recycled material cost only 40% of its original cost. From recycled material produced construction material, furniture, paper towels and all sorts of plastic items. Besides of its economical meaning it has great positive impact on environment; there are less need to cut the tree or explore the new mine. In the US, nowadays, about 20 % of the waste is recycled.
THE ECOLOGICAL FOOTPRINT OF URBANIZATION
Everybody, from a single individual to a whole city or country, has an impact on the Earth, because they consume the products and services of nature. Their ecological impact corresponds to the amount of nature they occupy to keep us going. The definition of footprint is: "The ecological footprint is the corresponding area of productive land and aquatic ecosystems required to produce the resources used, and to assimilate the wastes produced, by a defined population at a specified material standard of living, wherever on Earth that land may be located." If the footprint exceeds the available biologically productive area of the country, it runs an ecological deficit, which in other words the country’s area alone cannot provide sufficient ecological services to satisfy its population’s current patterns of consumption.
London - with 12% of Britain's population covering 170,000 hectares - comes to some 21 million hectares or 125 times the surface area of the city itself, equivalent to the entire productive land in the UK. The city of Vancouver, Canada, indicates that city appropriates the productive output of an land area nearly 174 times larger that its political area to support its present consumer lifestyle. Other researchers found that the aggregate consumption of wood, paper, fiber and food by the inhabitants of 29 cities in the Baltic Sea drainage basin appropriates an area 200 times larger than the cities themselves. Footprint