Waste

Solid Waste• Any discarded solid material• The U.S. produces 10 billion metric tons of solid

waste each year.• The amount of waste generated by each person

has doubled since the 1960’s

Where are we going to put it all?

• As the population grows…we are running out of space for waste

Not all wastes are equal

• Biodegradable – can be broken down by biological processes. Ex. Plant and animal matter.

• Nonbiodegradable – cannot be broken down by biological processes. Synthetic materials made by combining chemicals to form compounds that do not occur naturally. Ex. plastic

Municipal Solid Waste

• 2% of total solid waste.

• Includes the waste produced by households and businesses

• This accounts for 254 million tons per year.

• The fastest growing waste sector.

Manufacturing, mining and agricultural waste

• Manufacturing waste includes scrap metal, plastic, sludge and ash.

• We are indirectly creating this waste by creating demand for products

• Mining waste includes rocks and minerals left over from extraction and processing

• Agricultural waste includes crop wastes and manure. Increasingly it includes chemical and plastic waste

Solid waste management

• 57% of municipal solid waste ends up in landfill

• 28% is recycled (we recycled only 6.6% in 1970)

• 15% is incinerated.

Sanitary Landfill

• A permanent waste disposal facility where wastes are put in the ground and covered each day with a layer of soil, plastic or both.

• It’s role is to contain waste so it doesn’t pollute the environment.

• Without air and water, very little decomposition occurs in a landfill.

Problems with Landfills

• Leachate – a liquid that passes through compacted solid waste.

• Since 1976, new landfills must be lined with clay and plastic and have a system for collecting leachate

• Methane – decomposing organic waste produces methane. A flammable gas

• Vent pipes are required to carry methane out to the air

• The methane is often burned to produce energy

Where to put a landfill

• NIMBY – not in my backyard

• Landfills need to be close to cities, but far from residents!

• In 1988 there were 8000 active landfills, by 2005 there were 1700.

• Our landfills are filling up!

• Active landfills in 20 states will be at capacity within 10 years.

Incinerators

• Another disposal option is to burn waste in an incinerator

• However this poses two problems1. There is still a problem of disposing of the

ash2. We do not have the capability to separate

trash that should not be burned ex. Batteries, paints.

• These produce toxic gases