Lesson Plan Outline for Science Saturdays
Title of Lesson: Waste to Energy
Target Grades: 11th and 12th grade; most appropriate for AP Biology or AP Chemistry
Time Required: 90 minutes
Materials Needed: candle, glass, lighter, list of amounts of wastewater produced by each state
(in millions of gallons per day), calculators, dimensional analysis worksheet, access to internet
and GoogleDocs
Background Information
Needed by Teachers
Fuel cells
Types of energy and energy conversion
Cellular Respiration including ATP production
Oxidation/Reeducation reactions
Electrogen bacteria
Dimensional analysis and conversions
Greenhouse effect
Use of GoogleDocs to make spreadsheets
Needed by Students
Relationship of greenhouse gases to climate
change
Basics of cellular respiration; more in depth
knowledge will make this lesson easier
Basics of redox reactions
Use of calculator to do math involving
exponents
Lesson Objectives
 Students will be able to describe how bacteria can use cellular respiration to produce
energy that can be harvested by a fuel cell.
 Students will be able to use dimensional analysis to calculate the MWh/day that can be
produced by a certain amount of wastewater (MGD).
 Students will be able to analyze data using a chart generated by GoogleDocs.
Instructional Process
Hook
Student Actions
Enter, read prompt, and begin brainstorming a
list of alternative energy options.
Teacher Actions
Display a prepared prompt asking students to
develop a list of alternative energy options.
Share alternative energies with class. Add to
class list to develop as inclusive a list as
possible.
After a few minutes of brainstorming, have
students share answers. Develop a large class
list of all alternative energy options.
Think about similarities between these sources.
Share them with the class. Participate in class
discussion.
Discuss similarities of these alternative
energies. Focus on the fact that they are
renewable. Transition into new material
discussion of microbial fuel cells, which is
likely not on the brainstorming list.
Introduction of New Material
Student Actions
Listen attentively. Take notes. Ask
questions as necessary.
Connect to prior knowledge by
recognizing that bacteria can produce
electrons during cellular respiration.
Teacher Actions
Describe the general structure of a fuel cell. Introduce
microbial fuel cells, which use bacteria as a catalyst.
Describe the general method by which bacteria break
down sugar to release electrons which can be used to
generate electricity. This is bio-electricity. Ask
students to recall a process by which bacteria could
generate electrons.
View the demo. Answer questions asked
by teacher.
Light a candle. Talk to students about combustion
and the fuel and oxygen needed. Place a glass over
the candle to limit the amount of oxygen that the
candle has. Describe cellular respiration as the
“burning” of carbs, requiring oxygen.
Answer teacher questions about cellular
respiration. Offer elaboration on other
students’ answers.
Review cellular respiration; focus on electron
transport and ATP synthase. Stress the movement of
electrons. Allow the class to lead this review, if you
have already taught cellular respiration.
Explain that unlike the burning candle, some
organisms can use molecules other than oxygen for
cellular respiration, but there will be less energy
produced. The electrogen bacteria in the fuel cells are
anaerobic.
Explain that the electrogen bacteria can pass their
electrons from cellular respiration through an electron
transport chain and to a biological nanowire that can
be used to harvest electricity. This is how a microbial
fuel cell works.
After being used to generate electricity, the electrons
are finally accepted by oxygen on the cathode side of
the microbial fuel cell to create water, like in human
cellular respiration.
Practice
Student Actions
Listen attentively. Ask questions to
clarify. Recall prior knowledge about
dimensional analysis (if applicable).
Teacher Actions
Now that students understand how a fuel cell works,
they can calculate the potential energy production
from a microbial fuel cell using wastewater.
Show/review dimensional analysis with students. Be
sure students understand that they must cancel unit on
top and bottom to obtain the desired end units.
Show students a sample calculation using
dimensional analysis.
Beginning with wastewater in MGD, use
a calculator, equalities, and dimensional
analysis to determine the number of
MWh/day that can be produced in the
assigned state using microbial fuel cells
which break down organic matter in
wastewater.
Pass out dimensional analysis worksheets and give
each student a slip of paper with one state’s
wastewater production in millions of gallons/day.
**NOTE: numbers on info sheet are in millions of
gallons/day, but the dimensional analysis worksheet
begins with gallons/day, so students will need to be
sure to account for that.**
Rotate, checking on student progress.
Enter data into computer as instructed.
View instructor created graph OR create
down graphs, depending on goals of
instructor.
Closing
Student Actions
Answer questions in writing or through
class discussion as directed by
instructor. Analyze and think critically
about the graph produced. Recall
knowledge of cellular respiration and
relate it to MFCs.
Instruct students to input data into an excel
spreadsheet or googledocs for display.
If desired, students could generate their own graphs
by hand or using a program for additional
mathematics practice. If this is not the goal of the
lesson, displaying a class graph for discussion will
allow the students to accomplish the lesson
objectives.
Teacher Actions
Provide analysis questions for students to interpret
the graph. Examples:
1. Which state could produce the most energy from
wastewater? Why do you think this state has more
wastewater than others?
2. Given that 24MWh/day could power 750 homes,
how many homes could be powered by microbial fuel
cells using the wastewater in all of TN? The US?
3. Do you feel that microbial fuel cells are a viable
alternative energy source? Justify your response using
information you have learned today.
Provide content review questions to ensure student
understanding of cellular respiration and the
connection between it and the electricity production
by electrogen bacteria. Example:
1. Describe how the electrons that are transferred
from the anode to the cathode in a microbial fuel cell
are generated by bacteria. Where did these electrons
originate?
2. Why do living things produce these electrons? In
other words, what important process do these
electrons naturally power?
Assessment/Follow-up
Student knowledge of dimensional analysis can be assessed by having them calculate the
MWh/day from a different state’s wastewater (WGD). Knowledge of cellular respiration driving
MFCs can be assessed using an essay or multiple choice exam.
Key Vocabulary
Bio-electricity
Anode
Cellular Respiration
Anaerobic
Fuel Cell
Cathode
ATP Synthase
Electrogen bacteria
Microbial fuel cell
Catalyst
Aerobic
Wastewater
Safety and Cleanup Required
This lesson has no special safety or cleanup concerns.
Alignment with TN Science and Math Standards
Algebra I
CLE 3102.1.5 Recognize and use mathematical ideas and processes that arise in different settings, with
an emphasis on formulating a problem in mathematical terms, interpreting the solutions, mathematical
ideas, and communication of solution strategies.
CLE 3102.1.7 Use technologies appropriately to develop understanding of abstract mathematical ideas,
to facilitate problem solving, and to produce accurate and reliable models.
CLE 3102.5.1 Describe and interpret quantitative information.
Algebra II
CLE 3103.1.2 Apply and adapt a variety of appropriate strategies to problem solving, including testing
cases, estimation, and then checking induced errors and the reasonableness of the solution.
CLE 3103.1.4 Move flexibly between multiple representations (contextual, physical, written, verbal,
iconic/pictorial, graphical, tabular, and symbolic), to solve problems, to model mathematical ideas, and to
communicate solution strategies
CLE 3103.1.5 Recognize and use mathematical ideas and processes that arise in different settings, with
an emphasis on formulating a problem in mathematical terms, interpreting the solutions, mathematical
ideas, and communication of solution strategies.
CLE 3103.1.7 Use technologies appropriately to develop understanding of abstract mathematical ideas,
to facilitate problem solving, and to produce accurate and reliable models.
CLE 3103.2.3 Use appropriate technology (including graphing calculators and computer spreadsheets)
to solve problems, recognize patterns and collect and analyze data.
CLE 3103.2.4 Understand the capabilities and limitations of technology when performing operations,
graphing, and solving equations involving complex numbers.
CLE 3103.5.1 Describe, interpret, and apply quantitative data.
Biology
CLE 3210.Inq.3 Use appropriate tools and technology to collect precise and accurate data.
CLE 3210.Inq.4 Apply qualitative and quantitative measures to analyze data and draw conclusions that
are free of bias.
CLE 3210.Inq.6 Communicate and defend scientific findings.
CLE 3210.3.2 Distinguish between aerobic and anaerobic respiration.
Chemistry
CLE 3221.Inq.3 Use appropriate tools and technology to collect precise and accurate data.
CLE 3221.Inq.4 Apply qualitative and quantitative measures to analyze data and draw conclusions that
are free of bias.
CLE 3221.Inq.6 Communicate and defend scientific findings.
CLE 3221.3.3 Explore the mathematics of chemical formulas and equations.
Alignment with AP College Board Enduring Understandings
AP Biology
EU 2A: Growth, reproduction and maintaining the organization of living systems require energy and
matter.
EU 2B: Growth, reproduction and homeostasis require that cells create and maintain internal
environments that are different from their external environments.
EU 2D: Growth and homeostasis of a biological system are influenced by changes in the system’s
environment.
AP Chemistry
EU 3A: Chemical changes are represented by a balanced chemical reaction that identifies the ratios with
which reactants react and products form.
EU 3C: Chemical and physical transformations may be observed in several ways and typically involve a
change in energy.
EU 4C: Many reactions proceed via a series of elementary reactions
EU 4D: Reaction rates may be increased by the presence of a catalyst.
EU 5B: Energy is neither created nor destroyed but only transformed from one form to another
Resources
STATE
AL
AZ
AK
CA
CO
CT
DE
DC
FL
GA
HI
ID
IL
IN
IA
KS
KY
# waste
treatment
plants
286
121
362
570
235
91
18
1
359
306
22
168
675
418
763
628
243
MGD
629.2
266.2
796.4
1254
517
200.2
39.6
2.2
789.8
673.2
48.4
369.6
1485
919.6
1678.6
1381.6
534.6
MWh/day
340
144
431
678
280
108
21
1
427
364
26
200
803
498
908
747
289
LA
MN
MD
MA
MI
MN
MS
MO
MT
NE
NV
NH
NJ
NM
NY
NC
OH
OK
OR
PA
SC
SD
TN
TX
UT
VT
VA
WA
WV
WI
WY
166
136
167
124
391
139
315
746
114
468
48
88
156
27
582
330
723
490
215
830
165
25
244
1326
106
73
228
92
257
591
97
365.2
299.2
367.4
272.8
860.2
305.8
693
1641.2
250.8
1029.6
105.6
193.6
343.2
59.4
1280.4
726
1590.6
1078
473
1826
363
55
536.8
2917.2
233.2
160.6
501.6
202.4
565.4
1300.2
213.4
198
162
199
148
465
165
375
888
136
557
57
105
186
32
693
393
861
583
256
988
196
30
290
1578
126
87
271
110
306
703
115
Purpose: You will use dimensional analysis to determine the amount of energy in MWh/day (Megawatt hours/day) produced by a particular
amount of waste water in MGD (million gallons per day).
Instructions
• Start with a known value and your desired end value
units.
• Fill in the chart with “equalities” from the list to the right
that cause your units to cancel. A unit on the bottom can
cancel out the same unit on top.
• Continue to cancel units using equalities until you are
only left with your desired end value units on the top and
bottom.
• Multiply numbers across the top and bottom to get your
end value in the correct units.
Equalities
1 day = 24 hours
3.785L = 1 gal
1 hour = 3600 sec
0.2g organic matter = 1 L
1 mole organic matter = 30g organic matter
4 moles e- = 1 mole organic matter
Beginning
value
End Value
=
gal
moles e-
day
Reduce your number from above to moles
e-/ 1 second by dividing the numerator by
the denominator.
sec
___________moles e1 sec
*This conversion factor will cancel all units, leaving you with MWh/day.
x
0.46313*
=
___________MWh
1 day
Instructions for Creating Map Display of Data in GoogleDocs
1. Sign into Google Account. Click on “drive.”
2. Click “create” and then “spreadsheet.”
3. In cell 1A, type State as a column title. In cell 1B, type Power (MWh/day) as a column
title.
4. Type (or have students type) the state abbreviations in column A.
5. Type (or have students type) the calculated amount of power generated by wastewater in
each state in column B.
6. Click “insert” and “chart.”
7. Next to “recommended charts” click “more.”
8. Click “map” and then choose the map that displays large circles.
9. Look at the tabs at the top of the Chart Editor box. Click “Customize.”
10. Select “United States” for the region. Change the colors as you’d like. Click “Insert.”
11. Click the chart that has been inserted into your spreadsheet. A small arrow will appear in
the upper right hand corner. Click it. Click “move to own sheet.”
12. You can now switch back and forth between the spreadsheet and your graph using the
tabs at the bottom of the webpage. The circles on your map will change as data is entered
into the spreadsheet.