Solid WasteEnvironmental ScienceChapter 19 Section 1

The Generation of Waste• Solid waste• Any discarded solid material.• Includes everything from junk mail to coffee ground to cars.• The amount of solid waste each American produces every year

has more than doubled since the 1960s.

The Generation of Waste• Space and Waste• Many towns are running out of space to dispose of the amounts

of waste that people create.• Example: Islip, NY filled a barge with 3,200 tons of garbage and

sailed off. Noone would accept the waste, so it returned and burned it down to 430 tons of ash and was buried.

The Generation of Waste• Population and Waste• The amount of waste we produce grows larger.• The amount of land available per person grows smaller.• Average person in the United States produces 4.4 pounds of solid

waste per day.• Therefore, it is becoming more difficult to dispose of it all.

Not All Wastes Are Equal• Two main types of waste:• Biodegradable

• Can be broken down by biological processes.• Examples: newspapers, paper bags, cotton fibers, leather.

• Nonbiodegradable• Cannot be broken down by biological processes.• Examples: polyester and plastic.

Not All Wastes Are Equal• Plastic Problems• Plastics are made from petroleum or natural gas.• Consist mostly of carbon and hydrogen put together in molecular

chains that are not found in nature.• Cannot be broken down by organisms yet, so may accumulate

and last for hundreds of years.

Types of Solid Waste• Municipal Solid Waste• The waste produced by households and businesses.• About 2% of the total solid waste.• More than 236 million tons each year.• Enough to fill a convoy of garbage trucks that would stretch

around the Earth about six times.

Types of Solid Waste• Solid Waste from Manufacturing, Mining, and Agriculture• Make up most of the total solid waste produced in the United

States.• Produced indirectly by consumers – we buy the products that

have been mined or created.• Manufacturing waste – scrap metal, plastics, paper, sludge, and

ash.• Mining waste – rocks and minerals that are left over.• Agricultural waste – crop waste and manure.

Solid Waste Management• Landfills• Permanent waste-disposal facility where wastes are put in the

ground and covered each day with a layer of soil, plastic, or both.• More than 50% of municipal and manufacturing waste ends up

here.

Solid Waste Management• Problems with Landfills• Leachate

• A liquid that has passed through compacted waste in a landfill.• Forms when water seeps down through a landfill and collects

dissolved chemicals from decomposing garbage.• Landfills usually have monitoring wells and storage tanks to store and

measure leachate, which can then be treated as waste water.• Methane

• Highly flammable gas produced by decomposing organic waste.• If not monitored, can seep through the ground and into basements

of homes up to 300 m from the landfill.

Solid Waste Management• Safeguarding Landfills• Resource Conservation and Recovery Act

• Passed in 1976 and updated in 1984.• Requires that new landfills be built with safeguards to reduce

pollution problems.• Must be lined with clay and a plastic liner.• Must have systems for collecting and treating leachate.• Must have vent pipes for methane.

Solid Waste Management• Building More Landfills• Running out of space to build more landfills.• The materials are not decomposing as fast we are filling the

landfills.

Solid Waste Management• Incinerators• Burn solid waste.• In 1999, the U.S. had 102 incinerators capable of burning up to 94,000

metric tons of municipal solid waste each day.• Incinerated materials take up less space, but may be more toxic.• Burning paints and chemicals can pollute the air.