June 1999

Waste Management

The final stage in a product's life cycle - and in the waste management process - is disposal. Waste disposal is the culmination of all previous efforts including source reduction, storage, treatment, recovery and recycling. For even under the most optimistic scenarios, some waste and residue will always need to be disposed of.

Landfills

The primary purpose of solid waste management processes is to remove wastes from living and work areas in ways that protect human health and the environment. Fortunately, new landfill technologies, stabilization techniques and site-monitoring systems are ensuring the protection of our present and future environment. For example, to seal in wastes, well-designed and well-managed landfills often use thick plastic liners to prevent leachate from entering groundwater and also control biodegradation by preserving rather than decomposing waste. Uncontrolled biodegradation could result in production of leachate that, if leaked, could contaminate nearby groundwater supplies, lakes and streams. Many landfills include thick plastic liners, required by the EPA, that help protect groundwater from contamination as well as several foot-thick linings of clay and an imperious synthetic fabric to prevent rain and other liquids from draining into the ground. Pipes collect water that accumulates above the liner and it is pumped into holding tanks for treatment. Systems are also in place that monitor methane gas, a volatile byproduct of rotting garbage.

Degradation

Researchers who dug down into old landfills found 25 to 50 year-old newspapers still perfectly readable and grass clippings that were still green. Unlike compost piles that are constructed to enhance degradation, the whole purpose of modern landfills is to safely entomb waste so that uncontrolled degradation doesn't endanger groundwater and so that the land can, in many cases, be used after the landfill is capped. Parks, golf courses and even airports have been built on top of closed landfills. You could think of it as "land recycling and reuse" made possible by the stability of today's high-tech "nondegradable" landfills.
In some areas of the country, alternate disposal methods such as composting are available as a solid waste disposal option for readily degradable materials. But it is important to remember that compost facilities and landfills are very different things. Modern landfills are designed to limit degradation, so degradable materials of any type are not likely to affect the amount of landfill space available. Most people do not realize that plastics act similarly to other materials in a modern landfill, since the conditions necessary for rapid degradation are not present - or even desirable! Degradation takes place so slowly that nothing breaks down quickly enough to open up new space. In fact, contrary to popular belief, plastics are not even the most prevalent material in landfills - paper accounts for more than 50 percent of a landfill's contents with newspapers alone taking up as much as 13 percent of the space in U.S. landfills. By contrast, all plastics (packaging, durable goods, consumer products, etc.) account for about 11 percent by volume. [source: William Rathje, The Garbage Project, University of Arizona, 1992).

Are We Running Out of Landfills?

In the 1980s, there was a perceived crisis over a lack of landfill space that led to the presumption that America would soon run out of room for its garbage. Images of garbage barges floating up and down our coasts were ingrained into our minds. Even today there are those who believe that America still has a waste "crisis." Yet, the threat of running out of landfill space simply does not - and did not - exist. While it is true that there were some localized landfill shortages in the 1980s, particularly in densely populated areas, a shortage never occurred nationwide. While the total number of landfills is decreasing, total landfill capacity is actually steadily increasing.
In 1991, 28 states reported that they had less than 10 years of disposal capacity remaining. However, in 1996 only 13 reported having less than a decade. Conversely, while less than half of the states reported having more than 10 years of remaining capacity in 1991, 35 states now claim to have more than a decade of disposal capacity.
Additionally, according to a 1998 U.S. EPA report, Characterization of Municipal Solid Waste (MSW) in the United States, waste generation has actually declined since 1994. This can be attributed again to the renewed emphasis placed on curbside recycling, the addition of compost programs into communities and the pursuit of source reduction. In fact between 1990 and 1996, these efforts were responsible for a 17 percent decrease in waste landfilled. National recovery levels reached 27 percent in 1996 and MSW landfilled declined from 83 percent of all MSW in 1986 to 55.4 percent in 1996.
Even the amount of waste going into the landfills is declining. In 1996, 116 million tons went to landfills, compared to 140 million in 1990. It has even been calculated that at the current rate of waste generation, all of America's garbage for the next 1000 years will fit into a single landfill measuring 120 feet deep and 44 miles square; in other words, a patch of land approximately the size of three Oklahoma Cities.
Environmentally compatible long-term landfilling will continue to evolve with scientific research, technology development, and improved construction and operation. With these safeguards in place, the disposal of plastics will continue to be problem-free. Free Website Home 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 preetam free webhosting free articles website health