Presentation on theme: "The Chemistry of Garbage. What did you throw away over the weekend? Write a list in your spiral of every item you or your family discarded over the weekend."— Presentation transcript:
The Chemistry of Garbage
What did you throw away over the weekend? Write a list in your spiral of every item you or your family discarded over the weekend Where do all of those items go and what happens to them when they get there? Write down your thoughts in your spiral.
How much garbage? Orange County residents throw away an average of 9 pounds of solid waste per day. Convert that to kilograms. After compacting, solid waste has an average density of about 700 kg/cubic meter. How much compacted waste could our classroom hold, wall to wall, floor to ceiling? Brainstorm with your table partner and those next to you. Figure it out. Check with another group.
How much garbage? If every student from all my classes (135) left their days trash in this room (assume the trash is compacted) how long would it take for the room to fill up?
Orange County Landfill 288-acre landfill : Cells 9, 10, 11, 12 The Magic Kingdom is 107 acres.
What happens to all this garbage after it is hauled to the landfill? Write down in your spiral what you think happens, if anything, to the waste.
Inside a Landfill Landfill Diagram Methane gas recovery system? Leachate collection and treatment systems? Monitor well?
What does a landfill produce? Gases Methane, carbon dioxide, nitrogen, oxygen, hydrogen sulfide, hydrogen, carbon monoxide and organic vapors (benzene, dichloromethane, hexane, toluene,, vinyl chloride, xylenes, others) Leachate Runoff from the landfill containing many substances such as: nitrogen, phenols, pesticides, solvents and heavy metals (Hg, Pb, Cd)
Some of these substances were not on the lists of what you threw away. Where do they come from? Chemical Reactions
Methane (CH 4 ) Production One pathway Biological waste: food, yards waste, diapers, newspaper, etc Anaerobic (bacterial) breakdown to acetic acid then breakdown to methane and carbon dioxide. CH 3 COOH → CH 4 + CO 2 decomposition
Hydrogen Sulfide (H 2 S) Production The anaerobic bacterial breakdown of drywall. CaSO 4 ∙2H 2 O → H 2 S + Ca + + O 2 decomposition FeS + 2 HCl → FeCl 2 + H 2 S What is happening between the iron and hydrogen atoms? double replacement
Dangers of Gas Production Methane is very combustible. If it gets to the surface (oxygen) and is near enough heat, it can explode. CH 4 (g) + O 2 (g) → CO 2 (g) + H 2 0 (g) What type of reaction would this be? combustion
Leachate contaminants Rusting of metals while on the surface of the landfill can be the first step for some other processes. Iron reacts with oxygen to form iron oxide (rust) 2Fe (S) + 3O 2(g) → 2 Fe 2 O 3(s) synthesis
Leachate contaminants cont. If an aluminum can is exposed to acid and rust the following reaction will occur. 2Al (s) + Fe 2 O 3 (aq) → 2Fe + Al 2 O 3 (aq) This reaction also generates a lot of heat and can cause fires in the landfill. How would you describe what is happening in this reaction between the aluminum and iron atoms? single replacement