|United Nations System-Wide
FOR AGENDA 21 CHAPTER 21
SOLID WASTES AND SEWAGE
Waste disposal and reduction - updated 4 August 1999
As the World economy grows so does its production of wastes. For example, US production of hazardous and toxic waste rose from 9 million tons in 1970 to 238 million tons in 1990 (Gourlay, 1995). Europe produces more than 2.5 billion tons of solid waste a year (Elkington, 1995), and every day the inhabitants of New York throw away approximately 26,000 tons (Gourlay, 1995).
As regulation of international trade in waste has been tightened (see Implementing the Basel Convention), and public opinion has become increasingly environmentally conscious, industrialized countries have had to develop means to deal with the waste they produce. Traditional waste management strategies include reusing materials, recovering materials through recycling, incineration and landfills.
In recent years recycling has become the preferred choice of waste disposal for many industries. The British government set a target of recycling 25% of all household waste by the year 2000. Likewise, the proportion of household rubbish recycled in Germany increased from 12 to 30 percent between 1992 and 1995 (Edwards, 1995b). Around 75% of the average European car is already recycled, largely because the metal can be sold as scrap. However, electrical scrap accounts for merely 2% of waste produced in the European Union, and car scrap even less. On the commercial level, government regulation usually works to the advantage of big firms and to the disadvantage of small ones (The Economist, 1996a). Due to a shortage of research on its possible economic and environmental spillovers, the practice of reusing materials remains as yet a gray area (Boulton, 1995).
Each method of waste disposal has its drawbacks. Reusing glass bottles can require more energy than their initial manufacture as they have to be sterilized. Incineration is a source of greenhouse gases and toxic chemicals like dioxins and lead. Landfill sites are a possible source of toxic chemicals and produce large quantities of methane gas. They must be managed so that pollutants do not seep into groundwater and should therefore be kept dry, but this slows down the rate of decomposition.
Tyres constitute another problem, as their resilience and indestructible nature become distinct disadvantages when it comes to disposal. Tyres are virtually non-degradable and spread noxious fumes when burnt. Western Europe, the US and Japan combined produce around 580 million tyres a year. So far, measures proposed by a committee of experts assembled by the European Commission include placing a ban on landfilling both whole tyres and shredded ones by the year 2000 (Simonian, 1995).
The ocean has long served as a dumping-ground for human beings' waste, such as dredge spoil and sewage sludge. However, direct dumping at sea is one of the fastest ways for toxic compounds to enter the food chain. Increased international concern over this practice led to the 1972 London Convention on the Dumping of Wastes at Sea, which restricted further ocean dumping.
Further research needs to be carried out on the effects of these various waste management options to determine the extent to which they positively benefit the environment. There are complex tradeoffs between costs, energy consumption, transportation, pollution, greenhouse gas production, and toxic by-products, which require careful consideration on a case-specific basis.
One solid waste problem requiring increased efforts at minimization is space junk, the increasing amount of debris from old rockets and satellites orbiting the earth. A collision with even a small fragment can damage a satellite, shuttle or space station. Debris have dented shuttle windows on several occasions and in August 1996, the French military satellite Cerise became the first casualty of space junk (Ward, 1996). The risks to the international space station, with a surface area of some 11 000 square meters when completed, are alarmingly high (Kiernan, 1997a). Chances of penetration by orbiting space junk and meteors were calculated in 1996 to be 1% per year (David, 1996).
Failure to take preventive measures could severely limit future uses of space (National Research Council, 1995). Indeed, NASA has calculated that if the amount of debris exceeds 150 000 fragments 1 centimeter or larger, space flight could become impossible (Ward, 1997). Major efforts are already required to map such materials and to try to avoid dangerous orbits (Iannotta, 1995).
Every time a satellite is put in space, second- and third-stage rockets used to get into orbit are discarded. And our use of space is increasing. International telecommunication companies are currently putting up three times as many satellites in orbit as were launched in the past forty years, with a predicted total in excess of 1000 satellites in space (Ward, 1997). And new technologies involving microscopic rocket thrusters will allow swarms of small satellites of a few kilograms to be built, with telecommunications, military, and astronomical applications, and a dramatic increase in space junk (Iannotta, 1999).
Possible solutions range from better designs to bringing down satellites at the end of their lifetime. However, this just slows down the rate of increase, and more long-term solutions must be devised. Using satellites specifically to sweep up debris (http://rsd.gsfc.nasa.gov/goes/text/pacman.html) seems, although plausible, to have been a scheme proposed on April the first.
Further information can be
obtained from the ESA website on debris: http://www.esoc.esa.de/external/mso/debris.html
|REFERENCES AND SOURCES|
National Research Council (US). 1995. Orbital Debris: A Technical Assessment. National Academy of Sciences, Washington, D.C. Cited in Kiernan, Vincent. "Please dispose of your spacecraft carefully." New Scientist, 24 June 1995, p. 9.