1. NOTE: To change the image on this slide, select the picture and delete it. Then click the Pictures icon in the placeholder to insert your own image. CHAPTER 19 WASTE Section 1 – Solid Waste

2. The Generation of Waste  The U.S. generates more than 10 Billion metric tons of solid waste yearly.  Solid Waste  Any discarded solid material  Exs: junk mail, cars, solid trash  The amount of solid waste in the U.S. has tripled since 1960.  33% is recycled  55% goes to landfills

3. Space and Waste  Many towns are running out of space to dispose of waste.  Avg American creates 4.4lbs of solid waste per day.  As populations increase, more land is needed for:  Houses, infrastructure, agriculture  This leads to less land for waste management.

4. Not All Wastes are Equal  Two main types of wastes:  Biodegradable  Nonbiodegradable  Biodegradable can be broken down by biological processes.  Plants and animal matter is biodegradable  Products made of natural materials are usually biodegradable.  Newspapers, paper bags, cotton fibers, leather  Nonbiodegradable can’t be broken down naturally.  Synthetic materials made by combining chemicals that are usually biodegradable.

5. Plastic Problems  Plastics are made from petroleum products.  Even though they are made from natural products, plastics are nonbiodegradable.  Molecular structure of them prevents decay.  Can take 100s-1000s of years to breakdown.  Electronic waste is a growing source of plastic waste.

6. Breaking Down Biodegradable Material  Decomposers (fungi and bacteria) are examples of organisms that break down biodegradable material.  Once broken down, these materials can be reused by other organisms.

7. Solid Waste Management  55% goes to landfills  30% gets recycled (up from 6% in 1970)  15% gets incinerated  Landfill  Permanent waste disposal facility where waste are put in the ground and covered each day with a layer of soil, plastic, or both.  Most important function is to contain waste so that it does not leach toxins into the ground.

8. Problems with Landfills  Leachate  a liquid that forms when water seeps down through a landfill and collects dissolved chemicals from decomposing garbage.  Leachate can contaminate groundwater.  Landfills typically have monitoring wells and storage tanks to measure and store leachate.

9. Problems with Landfills  Decomposing organic material may produce methane gas.  Methane is highly flammable.  It can be harvested by fuel.  Methane can also seep into nearby basements and cause explosions.

10. Safeguarding Landfills  New landfills must be lined with clay and plastic liners.  Must have systems for collecting leachate.  Vents must be installed to carry methane out to be burned off or used for a more energy efficient purpose.

11. Incinerators  Reduces the amount of solid waste by 75%  The remaining ash will go to landfill.  Can’t separate good/bad waste and some things that shouldn’t be burned end up getting burned.  Cleansers, batteries, paints.  The ash waste can be more toxic than before. It can also release air pollution by burning these products.