APES – Mrs. Soja – Part 1

A.Solid Waste - any unwanted material that is solid  1.The U.S. produces 11,000,000,000 tons per year (4.3 pounds per day) about 33% of the world’s total  2. Waste Stream : the steady flow of wastes that humans produce from all sources 

A.Mining waste  1.Makes up 75% of all waste, but much of that is used soil or spoil  2. Mining wastes are left in large piles called slag heaps that can contaminate air and water. 

Fig. 21.2, p. 519 Municipal 1.5% Sewage sludge 1% Mining and oil and gas production 75% Industry 9.5% Agriculture 13%

Fig. 21.3, p. 519 Burned in incinerators (16%) Dumped in landfills (54%) Recycled or composted (30%)

B. Industrial Solid Waste: 1. Scrap metal, plastics, paper, fly ash and sludge 2. Most is burned or buried on-site

C. Municipal Solid Waste (MSW) 1. From homes and businesses kg per person per year 3. 60% dumped, 24% recycled, 16% burned

A.Open Dumps - Most common method in developing countries 1.Manila: 10 huge dumps Thousands of people live and work on dumps scavenging for food & materials: Very unsafe 2.Cairo: Traditional garbage collectors live with their trash 3.Outlawed in most developed countries, but still happens a.Dumping of materials like oil and paints: one liter can make 1,000,000 liters undrinkable

1.Stops problems with insects, rodents, cheap, low odor 2.Litter is compacted and covered 6” every day 3.Problems Associated with Sanitary Landfills  a.New landfills (15%) are lined with plastic and clay to prevent leachate from getting into groundwater. Liners are only required in new landfills and only last for 30 years before they leak. Leachate is rainwater that gets contaminated as it moves through the landfill.  b.60% of solid waste ends up in landfills, 50% of U.S. cities have used landfill space  c.Methane gas produced by decomposing microbes d. Cause traffic, noise and dust and deprive us of resources. introduction-video.htm

Fig , p. 537 Topsoil Sand Clay Garbage Sand Synthetic liner Sand Clay Subsoil When landfill is full, layers of soil and clay seal in trash Methane storage and compressor building Electricity generator building Leachate treatment system Methane gas recovery Pipe collect explosive methane gas used as fuel to generate electricity Compacted solid waste Leachate storage tanks Leachate monitoring well Leachate monitoring well Groundwater monitoring well Groundwater monitoring well Leachate pipes Leachate pumped up to storage tanks for safe disposal Leachate pumped up to storage tanks for safe disposal Clay and plastic lining to prevent leaks; pipes collect leachate from bottom of landfill

Fig , p. 538 Advantages No open burning Little odor Low groundwater pollution if sited properly Can be built quickly Low operating costs Can handle large amounts of waste Filled land can be used for other purposes No shortage of landfill space in many areas Disadvantages Noise and traffic Dust Air pollution from toxic gases and volatile organic compounds release greenhouse gases (methane and CO2) Groundwater contamination Slow decomposition of wastes Encourages waste production Eventually leaks and can contaminate groundwater

Fig , p. 538 Advantages Safe method if sites are chosen carefully Wastes can be retrieved if problems develop Low cost Disadvantages Leaks or spills at surface Leaks from corrosion of well casing Existing fractures or earth quakes can allow wastes to escape into groundwater Encourages waste production

4. Energy from Landfills a. Methane gas is produced by anaerobic microbes within the fill; can be harnessed for energy b. Still adds to global warming; risk of explosion from gases

 The Special Problem of Tires in Landfills  a.Tires are made of vulcanized rubber that cannot be melted or reused

 - also called “energy recovery” or “Waste-to- Energy”  1.Trash is burned, and the heat is used to generate electricity  plants word-wide (110 in U.S.)  3.Types of Incinerators

Fig , p. 536 Advantages Reduced trash volume Less need for landfills Low water pollution Disadvantages High cost Air pollution (especially toxic dioxins) Produces a highly toxic ash Encourages waste production

Fig , p. 536 Power plant Steam TurbineGenerator Electricity Crane Furnace Boiler Wet scrubber Electrostatic precipitator Conveyor Water Bottom ash Conven- tional landfill Waste treatment Hazardous Waste landfill Dirty water Waste pit Smokestack Fly ash

a.Mass Burn  1)All trash burned  2)More air pollution: 10-20% of original mass is ash: disposed of as toxic waste  3) In the US- there are few regulations, regulations are not enforced and workers are untrained. b.Refuse-Derived  1)Trash is sorted before burning  2)Less air pollution, higher quality fuel