Solid, Toxic, & Hazardous Waste

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ObjectivesExplain short term and long term impacts of landfills and

incineration of waste materials on the quality of the environment.

Explain how consumption of resources may effect the environment.

Describe human efforts to reduce the consumption of raw materials and improve air & water quality.

Solid waste is produced by nearly everything we do.

Can you name some examples of solid waste and where it comes from?

Main types of Solid Waste

Agricultural waste

(crop residues, manure, & plastic)

Mining waste

(tailings, overburden from strip mines,

smelter slag)Road & Construction

DebrisIndustrial

waste(400 million metric

tons/year)

Municipal waste

(Household & commercial refuse)

250.4 million metric tons per year! (EPA 2011) Twice as much per capita as Europe or Japan, and five to

ten times as much as most developing countries. Between 1960-2000 the per capita waste generated rose

steadily from 2.68 lbs/person/day to more than 4.74. Since 2000 the per capita generation decreased to 4.40

lbs/person/day. Recycling rates are also rising. (1960- 6.4 %, 2011 34.7%) On average, we recycled and composted 1.53 pounds out

of our individual waste generation of 4.40 pounds per person per day. (EPA 2011)

The U.S. generates the most municipal waste.

Organic materials (yard and garden waste, food

waste, sewage sludge) Paper: Newspapers, magazine, advertisements,

office refuse, cardboard. Metal, glass, and plastic food and beverage

containers. Construction materials (wood, concrete, bricks, glass) Bags (plastic and paper) Junk cars Worn out furniture

What do we discard?

The steady flow of varied wastes that get mixed and

deposited in landfills or burned in incinerators. Problems with the waste stream:

Mixing and crushing waste makes accessing valuable resources to recycle difficult and expensive.

Hazardous materials get dispersed throughout the waste making disposal or burning difficult, expensive, and risky.

Spray paint cans, pesticides, batteries (zinc, lead, or mercury) cleaning solvents, plastics that produce dioxins and PCBs when burned are mixed with nontoxic materials.

What is the waste stream?

Modern waste management stresses the “three R’s”.

s

Reduce

Reduce- cut down on generation of waste.

How?...

Reuse: Use again (without

industrial processing) Examples:

Reuse

Recycle: reprocessing of discarded

materials into new, useful product Popular recyclables: metal, glass,

paper, cardboard, some plastics (#1 PETE, #2 HDPE, #4 LDPE, and #5 PP)

Recycle

• A type of limited recycling usually with one step• The process of converting waste material into a

product of lesser quality and reduced functionality.

• Reduces consumption of fresh raw materials, energy demands, and emission of greenhouse gases.

• Examples: • plastic bottle to canvas bag or carpeting, food

containers into railroad ties or fencing • white office paper into cardboard

Downcycle

In 2011, Americans recovered over 66 million tons of MSW

(excluding composting) through recycling. Composting

recovered over 20 million tons of waste. We combusted about 29 million tons for energy recovery

(about 12 percent). Subtracting out what we recycled and composted, we

combusted (with energy recovery) or discarded 2.9 pounds per

person per day.

The EPA is seeking to reduce materials use and associated environmental impacts over their entire life cycle, in a process called sustainable materials management (SMM).

1. Begins with extraction of natural resources 2. Material processing through product design and

manufacturing3. the product use stage 4. collection/processing and5. final end of life (disposal).

By examining how materials are used throughout their life cycle, an SMM approach seeks to use materials in the most productive way with an emphasis on using less; reducing toxic chemicals and environmental impacts throughout the material life cycle; and assuring we have sufficient resources to meet today’s needs and those of the future. (EPA 2011)

80% of our electronic waste (e-waste) is

shipped illegally to developing countries. (China, Asia, & Africa)

Workers there strip wire and break the equipment apart to retrieve valuable metals.

Unprotected from hazardous materials that get into soil, groundwater, and surface water contamination.

Electronics tend to contain: lead, mercury, gallium, germanium, nickel, etc…

Export waste to other countries

Landfills receive most of our waste.A landfill is 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 is covered with dirt daily to reduce smell, litter, insects, and rodents. Also reduces the spread of disease.

leachate water that has percolated through

a solid and leached out some of the constituents.

• The fluids that move through a landfill and pick up chemicals

• Coffee and tea

Water percolating through dumps or landfills

dissolves the waste and rusts containers allowing toxins to mix with the water and create leachate.

Some leachate contaminants include: paint, cleansers, pesticides, batteries, heavy metals…

Modern landfills are lined with clay or plastic to prevent the leachate from getting into soil and the groundwater.

Leachate is gathered in pipes that pump it to storage tanks for treatment.

Problems with landfills:

When organic waste decomposes away from oxygen

methane is produced. Methane is a highly flammable gas. Methane is a “greenhouse gas”. If not monitored it can build up and explode. Since 1984 all new landfills must be lined and have

vents to release the methane or combust it as a fuel.

Many landfills have been closed due to reaching capacity. 1988 8,000 landfills/ 1999 decrease to 2,300.

Methane is a second problem associated with landfills.

Solid –waste incinerators reduce the amount of trash that

goes to landfills and can be used to generate electricity. Materials that are created by the incinerator can be toxic.

Positive: reduce the weight of solid waste by 75%. Positive: generate electricity. Negative: Because waste isn’t sorted hazardous

materials that shouldn’t be burned are incinerated releasing polluting gases and ash.

Ash from incinerators can be more toxic than the waste it originally was.

Incinerators

Trash to Energy

Plants

Scrubbers process the smoke produced by

incinerators. The special pollution control devices release small

amounts of poisonous gases and particles of toxic heavy metals into the air.

Ash from incinerators has been found to contain high levels of toxins: dioxins, furans, lead, and cadmium..

By removing plastics from the garbage before incineration much of the dioxin release is prevented.

Batteries (button & cylinder) release mercury.

Hazards of incinerators

http://www.youtube.com/watch?v=lmtOuAed5nM