Solid waste is any garbage discarded in solid form. The United States generates more solid waste than any other country. We produce 267.8 million tons per year,

Solid waste is any garbage discarded in solid form. The United States generates more solid waste than
any other country. We produce 267.8 million tons per year, or 4.51 pounds per person per day.
Municipal solid waste is waste generated by homes, office buildings, retail stores, restaurants, schools,
hospitals, prisons, libraries and other commercial or institutional facilities. The composition of municipal
solid waste is roughly 28.2% paper, 13.7% yard waste, 14.1% food waste, 12.3% plastics, 8.6% metals,
8.3% rubber, leather and textiles, 6.5% wood, 4.8% glass, and 3.5% other. The five ways to get rid of
solid waste are sanitary landfills, incineration, composting, reuse, and recycling. What should also be
considered is not producing the waste in the first place.

About 54% of our solid waste is discarded in sanitary landfills. In sanitary landfills, the waste is placed in
a hole, compacted, and covered with a thin layer of soil each day. In today’s landfills, there are layers of
compacted clay and plastic sheets at the bottom, which prevent liquid waste from seeping into
groundwater. Sanitary landfills are not without problems. One problem is that sanitary landfills require
land, which tends to be in short supply near urban areas, sometimes requiring the waste to be trucked
long distances to get it to the landfill. Also, existing landfills are filling up. Another problem is the
production of methane gas by the microorganisms that break down the waste. Methane is a
greenhouse gas, contributing to climate change, and is potentially explosive. However, some landfills
are now piping the methane off and burning it to generate electricity. Once a landfill is full, closing it is
expensive. The EPA (Environmental Protection Agency) requires that landfills be monitored for 30 years
after they are closed, for groundwater pollution and gas explosions. Buildings cannot be built on old
landfills, because as the waste decomposes the ground sinks. They can be used for parks or wildlife
areas.

About 12% of our solid waste is incinerated, or burned. Incineration has the advantage of reducing the
volume of solid waste by 90%. In addition, incineration produces heat that may be used to warm
buildings or produce electricity. There are problems with incineration. Incineration causes air pollution.
Because of this, backyard incinerators were banned in the L.A. area back in 1957. Incinerators also
produce large quantities of ash that must be disposed of properly in licensed hazardous waste landfills.
(Burning trash tends to concentrated toxins.). Site selection for incinerators is also highly controversial.
In the past, incinerators were often located in low income areas inhabited by people of color. When
incinerators have been disproportionately located in these areas, it has been referred to as
environmental racism. Environmental racism has been described as environmental injustice that
occurs within a racialized context.
Only about 34% of U.S. municipal solid waste is composted or recycled. The EPA lumps recycling and
composting together. Composting was discussed in an earlier lab and is a very effective way to reduce
the amount of solid waste that goes into sanitary landfills. A big advantage of composting is that it
produces soil that can be used in many different ways. Recycling is the process of collecting and
processing materials that would otherwise be thrown away and turning them into new products.

Recycling reduces the amount of solid waste that goes into landfills and creates jobs. Unfortunately, we
as a country do not do a very good job at recycling. In comparison, Germany recycles 68% of its solid
waste!
The EPA does not calculate the percentage of municipal solid waste that is reused. It is lumped in with
recycling and composting, and is probably fairly small. Reuse is the return of discarded goods to be used
over. Examples are garage sales and thrift stores. Reuse saves money, and reduces the amount of solid
waste that goes into landfills.

Lab Questions:
1. What is solid waste?

2. How much municipal solid waste does the U.S. generate?

3. What is the composition of municipal solid waste?

4. What are the problems with sanitary landfills?

5. What are the advantages and disadvantages of incineration?

6. Does the U.S. do a good job of recycling solid waste? Explain. How do you think this could be
remedied?

To do the lab, you will need two days worth of solid waste from your household.

Observation/Question: Make initial observations and come up with a question.
Hypothesis: Come up with a testable hypothesis about the composition of your household’s solid
waste. Here is an example: My household’s solid waste will consist mostly of glass. Remember, your
hypothesis is a simple statement made in a single sentence. You do not say why.
Experiment: You will need to separate the trash and weigh out each of the categories: paper, yard
waste, food waste, plastics, metals, rubber, leather and textiles, wood, glass, and other. Alternatively,
you may weigh out recyclables versus non-recyclables. Get the percent weight of each category. If you
have a relatively small amount you may use your food scale. If you have a large amount you might want

to use your bathroom scale. You must weigh in grams or kilograms. If you use a scale that weighs in
pounds, you may convert pounds to kilograms by dividing the number of pounds by 2.2046. The percent
weight is the weight of the category divided by the total weight of the entire sample of trash.
Results: Here, in simple sentences, you will explain what the different percent weights of the different
categories of trash in your sample were. After explaining your results, show your calculation. You may
wish to include a graph. You do not explain why you think it happened the way it did. Save that for the
conclusion.
Conclusion: In this section, restate your original hypothesis first. Then you may accept or reject your
hypothesis. Remember not to use the words prove or disprove, or correct or incorrect. You may only
accept or reject. At the end of your conclusion, explain why.

What to turn in: Turn in the answers to the lab questions, and a lab writeup with five labeled
sections: Observation/Question, Hypothesis, Experiment (describe what you did), Results, and
Conclusion