PRACTICEº 2 GRADE:
NAME: Andrea Sosa
: 1 Bach. “C” DATE: 15-05-2011
A landfill is a site that is used for the disposal of waste materials by burial and is the oldest form of waste treatment.
Until a few time ago people disposed of waste in open landfills, holes in the ground that arevery dangerous to the environment, because when rain mixes with the chemicals from the wastes it forms a polluted liquid called leachate. It could run off into a source of groundwater polluting it.
In present days it`s supposed that solid wastes are disposed in well constructed landfills that hold wastes in a safer way, preventing groundwater pollution; these are called sanitary landfills. Thisis how a sanitary landfill must look:
Unfortunately that is not everybody’s reality; in several places there is not enough money to build that kind of landfills therefore open landfills are commonly used because they are cheaper and easier to build. But in long term effects sanitary landfills are way better. Thinking in farmers that use groundwater for their crops and cattle, they will beaffected sooner or later.
* Modeling three different landfill systems
* Observing how each kind of landfill affects groundwater sources.
* Watching how each kind of landfill works and analyzing which one is better.
* Measuring cup
* Metric ruler
* Small pebbles
* Plastic wrap
* 5 rubber bands
* Red food coloring
* Heavy-duty plastic bag
* 12 small sponge cubes
* 3 transparent, wide-mouthed jars
1. Into three identical jars, put about 5 cm of water and equal amounts of small pebbles, just below the surface of water.
2. In system 1 mix the pebbles and water with 2,5 cm of soil.
3. In system 2 hangthe cheesecloth in the jar 5 cm above the waterline, place it with a rubber band and then put some pebbles into the cheesecloth.
4. For system 3, suspend a resistant plastic bag in the jar, 5cm above the waterline, then hold it with a rubber band and finally put some pebbles into the plastic bag.
5. Use red food coloring for coloring 12 sponge cubes that will simulate the leachate and thewastes.
6. Cover the sponge cubes for system 2 and system 3 with a thin layer of soil.
7. Put 150 mL of water over each system, then cover the jars with plastic wrap and hold it with a rubber band.
8. Let the systems stand overnight.
Analyze and Conclude:
1. Which part of the model represents the leachate? How well did each landfill system protect the groundwater from theleachate?
The leachate was represented by the red food coloring that the sponge cubes, that represented the garbage, absorbed before being collocated in the systems.
System 1: This system didn’t protect the groundwater from the leachate at all, because the “wastes” were put directly there with no other material to protect the environment. So, as we were able to see in the jar the water becamecompletely red and dirty, with mud too, very polluted.
System 2: This one fortunately had the cheesecloth, that held the polluting chemicals a little but it wasn’t extremely effective, even though the cheesecloth didn’t allow the dust or the soil to pass to the water. The water became red; a little bit less than system 1, but the huge difference was that unlike system 1 it wasn’t dirty with allthe soil, just red.
System 3: This system was the m0ost effective one, the water in the next day, was as clear as in the beginning. It was all because the material that we used for preventing the pollution was in good conditions and had a very good quality.
2. Identify which of your three models represent each of these three common types of landfills: a well-designed, or sanitary,...