Landfills

Question 1

____, most of the MSW in the US was put in a town dump (attracting rodents).

Answer 1

Until the 1970s

Question 2

Biggest environmental impact of dumps were..

Answer 2

contamination of groundwater

Question 3

Dangers associated with older landfills;

Answer 3

• Groundwater & air pollution
• Leaking of toxic heavy metals & solvents/cleaning agents
• Air Pollutants: gaseous emissions
• Methane vented from landfills (fire hazard & greenhouse gas)
  VOC emissions: potentially carcinogenic, cause odors and/or respiratory irritation.

Question 4

What did the EPA do / what year to increase the safety of land fills?

Answer 4

In 1988, the EPA adopted federal standards for their construction to increase safety of land fills.

Question 5

What makes a well-designed landfill?

Answer 5

-When properly sited, well designed, & efficiently operated, a sanitary landfill can be a perfectly adequate means of urban refuse disposal, free from:
-Offensive odors
-Vermin
-Pollution problems

Question 6

Modern Landfills
(4) Major Parts

Answer 6

1. Bottom Liner
2. System for collecting leachates.
3. Cover
4. Appropriate location that minimizes contamination of groundwater by materials released from the site.

[ All items that can not be recycled or composted are deposited in landfills]

Question 7

Modern Landfills : How a landfill works

Answer 7

• Begins as a decompression dug into the Earth’s surface.
• The bottom is lined with a dense layer of clay & sealed with thick plastic sheeting to contain leaks of hazardous materials.
• Note: This flexible membrane liner holds in toxic chemicals that might contaminate groundwater.

Question 8

What does the leachate sump do/collect in modern landfills?

Answer 8

• A leachate sump collects leachates, which is pumped to the surface then is subjected to further treatment.

Question 9

Important things to remember that happen in modern landfills:

Answer 9

Garbage is piled up in rows where bulldozers & rollers compact the garbage. (Covered with soil & other materials).

After covered, the garbage is decomposed with the aid of anaerobic bacteria, eating the organic material. This produces methane gas, which is then collected and used as an energy source.

The surface area can be used in construction that does NOT involve housing development but a recreational area.

Question 10

Incineration is used to;

Answer 10

The incineration of garbage is used to generate energy & reducing its volume & weight.

Question 11

Is there an attempt to separate the trash into its appropriate components?

Answer 11

No

Question 12

High temeperatures;

Answer 12

Make glass & aluminum melt.

Residual metals of combustion can be recycled into scrap metal.

The remaining ash is deposited into landfills.

Question 13

Some of the incineration plants have the capacity to burn ~2,250 tons of solid waste/per day at temperatures of 2,500 degrees F.

TRUE or FALSE?

Answer 13

TRUE

[ In 2014, 33 million metric tons were burned for energy generation ]

Question 14

Disadvantages of Incineration;
(3)

Answer 14

1. Emissions
   may be potentially hazardous to human health & the environment.
2. Toxic materials
   when emitted can cause air pollution or be deposited on land.
3. Substances
   that are contained in the incineration plant emissions are hazardous to human health & the environment. (i.e., lead, cadmium, mercury, polychlorinated biphenyls).