Waste management

Waste management is literally the processo fextracting value from garbage.

In southern California, some waste services already separate recyclable wastes from houshold garbage. The separation process produces relatively pure streams of paper, plastics, glass, steel, copper and aluminum. Toxic wastes are usually easy to identify and segregate.

The process starts with the trucks, which collect garbage in cans from streets, and from dumpsters and compacting dumpsters in businesses.

The trash is dumped to a conveyor belt. Workers remove whole bottles to a special conveyor belt. The bottles go through a machine that reads the product bar code, and sorts the bottle by its color of glass. The bottle's return deposit is then recorded (it's being recycled, an acceptable use).

At the same time, suspicious packages, such as bottles of paint or motor oil containers, are separated into toxic waste containers.

The remaining waste is mostly cans, paper, plastic and miscillaneous trash. It goes to a separator. The separator dumps the trash down a wind-tunnel that blows paper into a separate container, to be pulped. In the pulper, plastics and foreign objects are removed, chopped and run through the waste process again.

The non-paper waste goes to a hammer mill, which produces very small pieces of waste. These are run past a powerful magnet. Iron and steel waste is extracted. Aluminum, silver and copper waste are pushed away from the magnet. Plastic and woody waste fall straight down.

The small amount of remaining waste is inert, and not very valuable. In California, because of extremely strict air-pollution control laws, it must go to a land-fill.

A continuiong problem with recycling is that common recyled materials such as paper are often of slight or negative value compared to new materials.

In many areas of Europe, including France, Germany and Switzerland, unrecyclable waste (mostly paper and plastics), is incinerated. This is often used to produce electricity. If toxic materials are removed, and incineration is completed at controlled temperatures, little pollution is produced. Incineration also reduces the waste volume by more than twenty-fold.

However, incinerator ash is toxic. In the middle 1990s successful experiments in France and Germany used plasma torches to melt incinerator waste into rounded glassy pebbles, perfect for inclusion in concrete. The glasses are far more inert than the ashes, because they do not easily dissolve in water.

An alterative use for the ashes is to chemically separate them into lye, and other useful chemicals. This is usually done at a central national chemical plant. The processes produce unsalably small amounts of chemicals when performed at a small scale.