Subject: Life Science- Advanced Biology 2 Standard: Cellular Processes

Transcription

1 Subject: Life Science- Advanced Biology 2 Standard: Cellular Processes Grade Level: 11 th -12 th Lesson Name: Building Your Own Biodigester Time: 43 minute period Clear Learning Target: By the end of the lesson students will be able to define the basic principles of anaerobic digestion and a biodigester, and determine how this process can generate a renewable energy source. Pre-lab Knowledge for the instructor: This lesson plan ties into a previous lecture on Archaea Bacteria, specifically pertaining to methanogens. In addition to the previous lecture, this lesson covers the principles of Bioenergy and of Biodigesters. Background information on these three concepts has been provided on an additional resource sheet. Instructional Strategies/Learning Activities: Review from previous lecture Prelab discussion Student Collaboration- lab groups of 2-3 students Lab Post lab discussion Post lab application Instructional Map and Timeline: 3 min Review previous knowledge 3 min Prelab Discussion 20 min Lab 5 min clean up 5 min Post lab questions and discussion 7 min Post lab application- project introduction

2 Materials: Computer Projector Smartboard Whiteboard Pen or pencil Lab and lab analysis sheet Lab materials listed below: 1. Water Bottle with sports cap 2. Funnel ml beaker 4. Stirrer 5. Vinegar (Acetic Acid) 6. Baking Soda (NaHCO3) 7. Tap water 8. Lighter 9. Fresh anaerobic digester sludge (Or pond mud if sludge is unavailable) 10. Balance 11. Incubating Oven (if available) 12. Goggles 13. Gloves Estimated Costs: 1. Water Bottle with sports cap- brand: Deja Blue 24 pack $5.00 (Target) 2. Funnel- $1.00 (Target, Walmart, Dollar Tree) 3. Vinegar (Acetate) 128 oz $2.74 (Target, Walmart, Kroger) 4. Baking Soda (NaHCO3) - $.79 (Target, Walmart, Kroger, Dollar Tree) 5. Lighter- brand: Coleman Disposable Lighter 2-pk $5.99 (Target) 6. Fresh anaerobic digester sludge (Or pond mud if sludge is unavailable) Free Assessment: Classroom discussion Informal Observation Lab Analysis Sheet Post lab questions and project

3 Name: Date: Period: Build Your Own Biodigester Lab Handout Prelab Question: Can bacteria create a renewable energy source? How? What prior knowledge did you use to come to this conclusion? Materials ml Water Bottle with sports cap 2. Funnel 3. Vinegar (Acetic Acid) 4. Baking Soda (NaHCO3) 5. Tap water 6. Lighter 7. Fresh anaerobic digester sludge (Or pond mud if sludge is unavailable) * Sludge should be stored at 4 Celsius if it can t be used immediately ml beaker 9. Stirring Utensil 10. Balance 11. Incubation Oven (if available) 12. Goggles 13. Gloves

4 Lab Procedure 1. Put on goggles and gloves for safety. 2. Secure fresh anaerobic digestion sludge as microbial inoculum from a local anaerobic digester. 3. Prepare a water bottle that comes with a sports cap allowing for quick open and shut operation. 4. For a 500 ml water bottle, dilute 24 ml vinegar with 50ml tap water and then add in enough baking soda (2.6 grams for our experiment) to adjust ph to neutral. 5. Mix this ph neutral solution with the 125ml fresh anaerobic digestion sludge. 6. Use tap water to bring the total mixture up to 250ml. 7. Mix thoroughly with stirrer. 8. Add the mixture solution into the water bottle with the help of a funnel. 9. Squeeze all the air out of the bottle until liquid level reaches the bottle top. 10. Lock the bottle cap (Note: steps 9 and 10 ensure an anaerobic condition inside the water bottle, which is absolutely critical) 11. Incubate the bottle in a warm place for anaerobic fermentation to proceed. (Ideal temperature is 35 to 40 Celsius, bottle will fill with biogas for several days. At room temp it will take weeks) 12. Please monitor Biogas production with water displacement method. Mark down water level before and after record difference. Please record this information on the lab analysis sheet provided. To be completed after bottle has filled with gas. 13. Once the bottle is full, the next step is to verify if any methane has been successfully produced. When ready, please report to lab instructor. You will squeeze biogas through a lighter flame upon opening the sport cap to determine if methane was successfully produced. 14. Alternate way: We can also verify biogas production by trapping the biogas in bubbles by blowing it through soapy water. *This lab is courtesy of Dr. Zhiwu (Drew) Wang. The Ohio State University/ ATI.

5 Name: Date: Period: Lab Analysis Sheet Calculation of Biogas production Day Water Level (ml) Before Water Level (ml) After Bottle Volume (ml) Biogas Volume (ml) Record the water levels before and after submerging the water bottle for each day on the table above. 2. Calculate the difference in the bottle volume between Day 1 and another day as the accumulated biogas volume for each day. 3. Create your own graph on graph paper by plotting the biogas volume against the corresponding day. Be sure to label your graph appropriately and attach it to this lab sheet. We will be comparing our results with other groups.

6 Post Lab Assessment and Project 1. Did your biodigester produce methane gas? 2. If yes, how much gas did your biodigester yield? 2a. How could we have increased this amount? 3. If no, what are some possible reasons your biodigester failed to produce methane gas? 4. Many water sewage treatment facilities use biodigestors. However, these facilities often fail to utilize the bioenergy they are producing. Our local community s water sewage treatment facility is outdated and failing. Our city council is currently researching and taking bids on new designs for this facility. After learning about the wonders of anaerobic digestion and methane production, your lab group decides to present a proposal to the city council for this facility. Your proposal must include: 1. A design for a water sewage treatment facility that is appropriate for our community s size. 2. An estimated cost and time frame of this new design. 3. And finally, how the city can utilize or generate income from this untapped resource of methane gas. (Hint- there is many possibilities! Get creative!) The city council has many proposals to consider. Your lab group will only have 2-5 minutes to present your idea by PowerPoint. The city council will select the best project and will use this score sheet to rank the projects.

7 Score Sheet Rubric for Biodigester Proposal 4- Excellent 3-Good 2-Fair 1- Poor Delivery -Holds audiences attention, and uses direct eye contact with minimal note checking -Uses fluctuation and inflection to emphasize key points -Consistent eye contact, glances at notes -Speaks with satisfactory volume and inflection -Minimal eye contact, reads mostly from notes -Speaks in uneven volume with little or no inflection -no eye contact, reads entire presentation from notes -speaks in low volume and monotonous tone. Content/ Organization -Demonstrates full knowledge by answering questions -Provides pertinent examples, facts, and statistics that support the conclusion of evidence. -At ease with answering questions, but without elaboration. Gives some examples, facts, and statistics that support the conclusion of evidence. -Uncomfortable with information, can only answer basic questions. -Attempts to define purpose of subject, but provides weak examples, facts, and statistics that support the conclusion of evidence. -Does not grasp information and cannot answer questions about subject -Does not clearly define subject and purpose, provide weak or no support of subject. Enthusiasm/ Audience Awareness -Demonstrates strong enthusiasm about topic. -Significantly increases audiences knowledge and convinces audience -Shows some enthusiasm and feelings -Raises audience understanding and awareness on most points -Shows little or mixed feelings about topic -Minimally raises audience understanding and knowledge -Fails to increase audience understanding of topic -Shows no interest in topic presented

8 Build Your Own Biodigester Lab Teacher Resource Sheet Methanogens are named for their unique way of getting energy: they convert hydrogen gas and carbon dioxide into methane gas. Oxygen is poisonous to them, so methanogens can live only in anaerobic environments such as in deep fresh water, marine mud, swamp mud, and sewage. The methane that bubbles out of sites such as swamps is called marsh gas. Methanogens also thrive in the intestinal tracts of organisms such as cows and termites. A cow can belch between 200 and 400 liters of methane per day. (Holt, Rineheart, and Winston, Modern Biology 2012) New information for this lesson plan: Definition of Bioenergy- Bioenergy is a kind of renewable energy made available from materials derived from biological sources, also known as biomass. Typical biomass includes agricultural and food waste, municipal sewage and solid waste, as well as industrial and forestry wastes, animal manure and crop residues. The energy harvested from these resources could be biogas, biodiesel, bioethanol, and so on. (The Ohio State University ATI Bioenergy Workshop. Biogas is the most common kind of gaseous bioenergy. Biogas is composed mostly of methane and carbon dioxide and is produced from the anaerobic digestion of biomass. Biogas can be burned to produce heat and electricity, or purified to be used as a vehicle fuel. When scrubbed (i.e. stripped) of other gases and contaminants in the form of biomethane, it can be safely mixed with pipeline natural gas. (The Ohio State University ATI Bioenergy Workshop. Anaerobic digestion- a series of processes in which microorganisms break down biodegradable material in the absence of oxygen. Biodigester- A biodigester uses bacteria to break down organic matter and capture methane released by the bacteria in a process called anaerobic fermentation. Anaerobic means the micro-organisms digest the food in the absence of oxygen. There are several kinds of microbes at work. Some break the food into simpler molecules of sugars and acids. Other microbes, which find oxygen toxic, are able to break down the simple organic matter to form gases, including the burnable gas methane. Methane, the main chemical in natural gas, is trapped and can then be burned for heating and electricity. The leftover organic solid waste can be used as fertilizer, a soil supplement or further composted. (The University of Wisconsin.