OBJECTIVES
:
1. Calculate/estimate the solid waste that you or your household
produces on a yearly basis.
2. Appreciate the fairly large amounts of wastes produced by your
life-style.
3. Recognize methods for decreasing your production of wastes.
INTRODUCTION :
In this exercise, you will be introduced to
various solid wastes which are produced to support the lifestyles
that we are accustomed in the United States. You will calculate
the amount of solid wastes that you personally produce, as well
as, the amounts calculated on a per capita basis. The per capita
amounts are produced indirectly by you because of the manufacturing,
industrial, mining, and agricultural activity needed to support
society in general. For the per capita calculations, assume that
the population of the United States is 250 million. Take whatever
figure is given for the entire U. S. and divide by 250 million
to get the per capita amount.
Large amounts of waste products are produced by agriculture and
logging. Much of this waste is left in place and is eventually
biodegraded. However, agricultural (animal and crop) wastes can
cause serious water pollution problems if concentrated by very
large farms. Mining activities result in huge piles of tailings,
overburden from strip mines, smelter slag, and other residues.
Depending on what is done with them they can have large impacts
on the environment. A rule of thumb is that it takes 20 pounds
of raw material to produce 1 pound of useful product. In this
survey, we will concentrate on household or municipal wastes.
QUES. 1: a. Calculate the total tons of waste
per person per year if 6.67 billion tons are generated nation
wide. Assume a population of 250 million.
(Approx. ans. = 10-50 tons)
b. Convert the tons of waste per person per year to pounds. 1
ton = 2000 pounds.
(Approx. ans. = 25,000-100,000 pounds)
Composition of Municipal Waste: 159 Million tons municipal
waste (excluding commercial) per year
Graphic # 2:
QUES. 2: Calculate how many total tons and then
pounds of municipal or household garbage is produced per person
per year.
(Approx. ans. = 500-2000 pounds)
QUES. 3: Calculate how many pounds of paper per
person are thrown away per year.
(Approx. ans. = 100-1000 pounds)
INVENTORY # 1: Weekly Garbage Survey
Devise a method to calculate the pounds of garbage thrown away
for one/two weeks. Since most of you probably have a bathroom
scale, use this to weigh the garbage. First find your weight,
then hold a bag of garbage and reweigh yourself. The difference
is the weight of the garbage. Note: If you do not have a bathroom
scale, an alternative is to do some type of volume measurement
for the inventories.
QUES. 4: Weight of garbage week # 1: _______ Weight of
garbage week # 2: ________
Weight of garbage per household / year: _______
INVENTORY # 2: Recycling
Another way to dispose of waste products is through recycling.
An increased public and municipal awareness has resulted in a
variety of recycling efforts.
Measure the pounds of recycled materials collected in a one/two
week period. Then pro rate them to a yearly number. Choose any
TWO of the following four categories.
QUES. 5a: DATA
| Material | Pounds/ week | Pounds/year |
| Paper | ||
| Aluminum | ||
| Glass | ||
| Plastic | ||
| Total lbs. recycling |
QUES. 5b: How much do you currently
recycle and what specific methods could you use to increase the
amount that you recycle?
HAZARDOUS AND TOXIC WASTE IN HOMES
Toxic commonly refers to a narrow
group of substances that are poisonous which cause death or serious
injury to humans and animals. Hazardous , a broader
term, includes all wastes that are dangerous, including those
that are toxic. They present immediate or long term health risks
or pose a threat to the environment.
Legally, a hazardous waste is any discarded material,
liquid or solid that contains substances in the following four
categories:
1. Fatal to humans or laboratory animals in low doses.
2. Toxic, carcinogenic, mutagenic, or teratogenic to humans or
other life forms.
3. Ignitable with flash points less then 60 degrees Celsius.
4. Corrosive - Strong acid, bases, or oxidizing or reducing agents.
5. Explosive or highly reactive (undergoes violent chemical reactions).
Although most households do not accumulate large quantities of
hazardous wastes, we all have materials in our homes that are
both toxic and hazardous. Many solvents, paint thinners, old cans
of paint, car batteries, flashlight batteries, cleaners, pesticides,
fuels, used motor oil, and other materials are just as dangerous
as their industrial counterparts. When we discard them in the
sewers, garbage, or on the soil, they combine with those of our
neighbors to make a significant quantity.
Develop a plan of action to safely use, store, and dispose of
the hazardous wastes in your house. Should you put them in the
normal garbage for pick-up?
INTRODUCTION TO LABORATORY:
Within the last 15-30 years, a large variety of plastics have
found many uses in the consumer market including bottles and containers,
wrappings, and packaging. What happens to the millions of plastics
items that are discarded each day? There are a variety of methods
to deal with this solid waste including: source reduction, reuse,
recycling, landfill, and incineration.
The purpose of this laboratory is to use both physical and chemical
properties, to identify and classify various plastic items, and
finally to devise a method to separate and recycle the plastic.
EXPERIMENTAL PROCEDURES: At home collection
of lab data (Ques 6-10 - 4
points)
Characteristics of Polymers Chains:
1. Cold Drawing of Plastic
Films:
When polymer films are stretched (cold-drawn), the chains orient
themselves. This is similar to the molecular changes that occur
in a rubber band when it is stretched. However, polymer films
such as plastic wrap, generally are not cross linked and thus
do not have a restoring force that is observed in rubber bands.
Orientation (alignment ) of macromolecule chains also occurs during
the processing that occurs prior to use by consumers. As a result,
plastic films tend to have more of the chains lined up in one
direction than the other. If polymer chains are all aligned in
the same direction, then they should stretch longer, and more
easily. In this part of the experiment, we will try to determine
the orientation of the chains in a plastic film.
a. Cut several strips about 1 in wide and about 10 in long from
one edge of a large plastic trash bag. (Carefully keep track of
the direction of the cut.) Grasp the strip firmly between the
thumb and fore finger of each hand so that your hands are about
three inches apart.
b. Pull the film by moving the hands apart slowly. Notice how
the sample narrows (necks) as the molecules align within the sample.
Notice any changes in the amount of pressure required to pull
the strip - initially and as the strip necks. Continue to stretch
the film until it breaks. Place the two broken ends next to each
other and use a ruler to estimate the total length that the film
stretched before breaking. Repeat the procedure one or two times
to see if the observed lengths are reproducible. length ___________
c. Cut several similar strips from the plastic bag, but along
an edge that is perpendicular to the first strips that were cut.
(Carefully keep track of the direction of the cut.) Repeat the
procedure in (#b) on these strips. length ______
QUES. 6: Lengthwise stretch ________; Crosswise stretch
___________
Which strip direction in the bag were the polymer molecule chains more closely aligned i.e. are the polymers running lengthwise or cross wise?
2. Ripping a Newspaper: A newspaper is made of
cellulose polymer chains of glucose units.
QUES. 7: Are the cellulose polymer chains in
a newspaper randomly distributed or are they aligned in a particular
direction? Which direction does a newspaper rip more easily with
less jagged edges? If so which direction? Rip the newspaper in
various ways until you can answer the question. Definitions: The
vertical direction is the up/down direction as you read the newspaper.
The horizontal direction is when you rip it crossways left to
right as you hold it to read the paper.
Give the name of the newspaper you are using such as Tribune,
Sun Times, etc.
Pre-Laboratory Collection of Representative Plastic Samples:
Most plastic items have a recycle code stamped or printed on them
in the form of a triangle and number. Try to find at least one
sample of each of the six types of plastics that have recycle
codes. Cut the samples into smaller pieces about 1 inch square.
QUES. 8: Use the textbook to look up the abbreviation, such as PVC, and the chemical name of the plastic that corresponds to each recycle number.
| Recycle Code | Abbreviation and Chemical Name of Plastic |
|
|
| 1 | Clear, 2 liter beverage bottles | ||
| 2 | Milk jugs, detergent bottles, some water bottles | ||
| 3 | Saran wrap, plastic drain pipe, shower curtains, some water bottles | ||
| 4 | Plastic bags, garment bags, coffee can lids | ||
| 5 | Aerosol can tops, rigid bottle
caps, candy wrappers, bottoms of bottles |
||
| 6 | Hard clear plastic cups, foam
cups, eating utensils, deli food containers, some packing popcorn |
||
| - | Biodegradable, Some packing popcorn | ||
3. Density of Plastics:
Set up one cup and put about 1/2 to 3/4 cup of water in it. Test
the density of each of the samples in the water as described below.
****At home collection of lab data
****
a. Density in Water: Drop the plastic sample into water.
Try various ways of putting the piece into the water, including
pushing it below the surface if it appears to float; so that surface
effects and air bubbles are minimized. If the sample floats, it
has a density of less than 1.0 g/ml. If the sample sinks, it has
a density of greater than 1.0 g/ml. List/describe.
****All Data for Part 3 b and c are
given online****
****You do not actually have to
complete these procedures. Dr. Ophardt did them for you and took
pictures of the results. You should read the procedures to see
what was done, record the data, and answer the questions.*****
b. Density in Saturated Salt Solution: Test the density of the plastic in saturated salt solution that has a density of 1.20 g/ml. List/describe.
c. Density in Rubbing Alcohol: Test
the density of the plastic in rubbing alcohol (70% isopropanol/water),
with a density of 0.94 g/ml.
List/describe.
QUES. 9: RECORD
the density behavior in the DATA TABLE. Such as floats on
water, sinks in alcohol, etc.
****Click on the number to get the online computer data
on the behavior of the plastics in alcohol and salt water.****
Add your own data on the density behavior in water.
| Recyle Number | Abbreviation | Alcohol | Water | Salt Water | Density Range |
|
|
|||||
|
|
|||||
|
|
|||||
|
|
|||||
|
|
|||||
|
|
DENSITY RANGES: From the density behavior tests,
develop a range of densities for each example of plastic.
Record on the Data Table - below and above. If
the sample floats, the density is less than the solvent. If the
sample sinks, the density is greater than the solvent. To determine
the density ranges for the plastics the following concepts may
be useful. Think of the behavior and densities of water, a rock,
and a piece of wood. The density of water is 1.0 g/ml, the rock
sinks so its density is greater than 1 g/ml, the wood floats so
its density is less than 1 g/ml.
If the above three solutions are very carefully layered, the salt solution is on the bottom, the water is in the middle, and the alcohol floats on top. To help determine, the density ranges, list the plastics in the proper places on the diagram. The plastics that float on alcohol are less than 0.94 g/ml. Click the online example for help
QUES. 10: Density Column
| Solvent Density | Plastic abbrev. and recycle number |
| Floats on rubbing alcohol | |
| ---0.94 g/ml rubbing alcohol--- | |
| sinks in alcohol, but floats on water | example from
Help: # 2 - HDPE = dens. range 1.0-0.94 |
| ---1.0 g/ml water--- | |
| sinks in water, but floats on salt water | |
| ---1.2 g/ml sat. salt water--- | |
| sinks in salt water |
PHYSICAL AND CHEMICAL PROPERTIES OF PLASTICS
Ques. 11-13 (4points)
****At home collection of lab data
****
First make a descriptive list of the pieces of plastic
including recycle numbers, if known. Try to have an example of
each recycle number or type of plastic. (If you can not find one
recycle number, that will be OK.) Bottom line you need 5 or 6
different plastic plus the two types of "packing peanuts".
Then carry out the classification tests (4-6) below and record the results as follows separated by spaces and commas:
QUES. 11: DATA Property Listing:
Recycle No., Abbreviation, Chemical Name, product name(example - milk jug), transmission of light, flexibility, solubility in water, solubility in acetone.
4. Transmission of Light:
Classify the plastic samples according
to transparent, opaque, or translucent.
5. Flexibility:
How easily does the sample bend? Does it have fine lines after
bending called "crazing" after it is bent? List the
properties as: Rigid, brittle; Stiff but will bend; Flexible or
"crazes"
6. Solubility in Solvents:
Materials may be soluble in a particular solvent depending upon
the nature of the interaction of the molecules in the solid state.
A general rule that is followed is that: "Likes dissolve
Likes". This means that substances which have a similar property
such as polarity will dissolve in each other. Some familiar examples
include salt (ionic) and sugar (polar) which dissolve in water
(polar). On the other hand oil (nonpolar) does not dissolve in
water (polar). Oil based paint (nonpolar) dissolves in turpentine
(nonpolar). Finger nail polish (nonpolar) dissolves in acetone
(nonpolar). Some substances are not soluble in anything due to
the structure of the solid (this will include many of the plastics).
Most plastics are insoluble in water and
insoluble in acetone.
Two types of packing "popcorn" are found in the lab
equipment baggie (S-shape vs. C-shape. Conduct the following solubility
tests ONLY on those.
Set up two porcelain or glass cups. Put about
1/2 cup of water in one and 1/8 to 1/4 cup of acetone or finger
nail polish remover in the second. Test the solubility of each
of the packing "popcorn" samples in acetone and water.
Stir around and wait about 2-3 minutes to see if anything is going
to happen, as these may prove to be the most interesting. These
samples were provided in the "baggie". For some fun
try a styrofoam coffee cup with acetone. One of the packing "popcorns"
is starch based and eventually will dissolve at least partially
in the water but not the acetone.
QUES. 12: Use the textbook to find the monomer
or partial polymer chemical structures for at least three of the
polymers listed above. At least give a word description of the
monomers present in the polymers and some of the more important
atoms.
QUES. 13: Why can plastics not be recycled or reused
as one large group of all plastics such as glass or paper or aluminum
cans? Or stated another way, why must plastics be separated by
recycle numbers before they can be recycled? Be specific and incorporate
something from question 12 in your answer.
SUMMARY ACTIVITY:
QUES. 14: (2 points)
Recycling Scenario: Form a plan to separate
and recycle as many of the plastics as possible. Start with a
mixed batch of household plastic items that might be present in
the recycling bin for garbage pickup. The recyclables are transported
to a large recycling center. How are you going to separate all
of the different types of plastics after they arrive at the recycle
center and are all mixed up?
Remember that you have paper labels, possible metal rings on some
bottles, plastic caps, and aspirator assemblies.
Other items to keep in mind are that you will need to wash or
clean the plastic, probably crush or break it into pieces, some
hand inspection or sorting is also currently used. Although not
previously considered, blowing air might be a way to separate
some items. Can you separate some of the plastics by the solubility
or density properties as found in this lab exercise?
For full credit, your plan must include an application
of some of the concepts and principles of this lab - mostly density.
Be specific about the recycle numbers and/or types of plastic
that float, sink, or dissolve at various stages of the operation.
