The Mechanics of Modern Incinerators & The Heart of Waste Management

The human race produces a great deal of waste. But how much do you actually know about what happens with it or how it is handled when you throw it away? This article is part four of a series exploring what happens with the tons we throw out.In the U.S. there are basically two methods of disposing garbage: landfilling or incineration. This is how American incinerator manufacturer.

Incineration generates the most heated discussion (sorry). It is unfair to blame incineration for being a polluting method of waste disposal. Incineration is sometimes the best option for a community. But it has environmental implications.

According to the latest EPA statistics, in the United States 23.6% (or MSW) of municipal solid waste is recycled. Other 8.5% were composted, while 6.1% of food waste was handled in another way. The remaining 61.8% were disposed in garbage either at a landfill, or in an incinerator. The United States has 72 incinerators. The incinerators only handle 11.8%, and the rest is sent to landfills.

Incineration, too, has changed over time. The technology is so popular that some people don’t call it “incineration” anymore. But more about this later. Branding aside the environmental impact can vary greatly depending on how old the system is. The first incinerators weren’t much more than large inefficient furnaces. Although they reduced the amount, ash and unburned waste still ended up in the dump.

The Clean Air Act (CAA), passed in 1970, banned the uncontrolled combustion of MSWs and placed limits on particulate emission. Existing incinerators must install new technology, or they will cease operation. Many incinerators failed to comply. The CAA has been updated twice, in 1977 and in 1990. This was mainly to establish new deadlines on improving emissions from incinerators.Waste management companies often refer to incineration as “waste to energy” or WTE. They do this in order highlight the energy recovery that allows modern incinerators to be both a means of waste disposal and an electric power generator.

In all incinerators (including those that are newly constructed), the heat produced by burning waste is used for electricity production. This electricity can offset the cost to build and maintain the facility, which is typically more expensive than landfilling. Energy recovery is ranked above disposal on the EPA’s hierarchy of waste management. It is less efficient than recycle and has a higher ranking. Plastic recycling, at least, is more efficient than combustion. It is difficult to recycle plastic, and some communities have been forced into treating it as nonrecyclable.

Even though incinerators manufactured after 1990 are cleaner and safer than older models, some people still feel that emitting toxic substances, such as acids, dioxins, and heavy metallics, is neither acceptable nor safe.Incineration can destroy toxic and pathogenic materials by using high temperatures. Incineration is therefore the preferred method for disposing of biomedical and certain other special wastes even in communities that landfill MSW.

Incineration has some drawbacks. Not all combustion products are as useful as electric power. Fly ash, which can be recycled in concrete as an ingredient, is hazardous and contains heavy metals.Landfilling will always be necessary. Prior to burning, the waste must be sorted. Hazardous and oversized items will go into landfills. There is also waste left after burning. The bottom ash from the MSW burning is between 15-25% by weight.