1. . Integrated Science C Mrs. Brostrom

2.  Objective: Explain short term and long term impacts of landfills and incineration of waste materials on the quality of the environment.

3.   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?

4. 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; to reduce smell, litter, insects, and rodents; and reduces the spread of disease.

5.  Problems With Landfills Leachate Methane gas

6.   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  However, 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. Leachate

7.   When organic waste decomposes away from oxygen methane is produced.  highly flammable gas.  “greenhouse gas”.  if not monitored, 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. Methane

8.  Incinerators Solid –waste incinerators reduce the amount of trash that goes to landfills and can be used to generate electricity Pros:  Reduce the weight of solid waste by 75%  Generate electricity Cons:  Materials that are created by the incinerator can be toxic  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.

9.  Trash to Energy Plants

10.   Scrubbers process the smoke produced by incinerators  Scrubbers 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, lead, and cadmium  By removing plastics from the garbage before incineration much of the dioxin release is prevented  Batteries release mercury Hazards of Incinerators