Mud PowerResearch Plan

By

Jonathan Rieco8th grade

Flat Rock Middle School

Abstract Man kind is always trying to look for a more effective way of producing power because we can never seem to find a way that is not only cost effective but is also eco friendly. This is where the microbial fuel cell comes into use. It is a way of producing energy from anaerobic bacteria. The purpose of my science fair project was to find if adding Compost maker or Apple cider vinegar to the mud samples would increase or decrease the voltage output of the fuel cells. I built three fuel cells, one was with no additives, the second was with Compost maker, and the third was with Apple cider vinegar. These were two chamber fuel cells with a PVC pipe glued between them. The connector acted like my proton exchange membrane. Each chamber of the fuel cell has a copper wire with a carbon fiber electrode epoxied to it. I tested each fuel cell every day two times a day for two weeks. All three fuel cells showed a steady state voltage output of between 40 to 70 mV before additives. My data shows that the Compost maker greatly increased the voltage output to 249 mv, but the Apple cider vinegar did nothing to change the voltage output. The fuel cell with the Compost enhancer increased it’s voltage production by four times over is steady state value. My experiment clearly shows that there ways to increase the voltage produced by a Microbial Fuel Cell.

Table of Contents

• Tittle Page

• Abstract

• Table of contents

• Research Question, Variables, and Hypothesis

• Background Research

• Materials List

• Experimental Procedure

• Data analysis

• Conclusions

• Bibliography

Research Question

“Is it possible to change the electrical production of a microbial fuel cell by adding different additives to the mud samples.”

Variables

Question Independent variable

(What I change)

Dependent Variables

(What I observe)

Controlled Variables

(What I keep the same)

If I add Apple cider vinegar or Compost maker to the mud will it increase the voltage production of the fuel cells.

The two different additives that I added to the fuel cells.

The amount of voltage that the fuel cells produce in mV.

All of the fuel cells have been built exactly the same and tested the same.

Hypothesis

I think that it is possible to change the electrical production of a Microbial fuel cell. I predict that the voltage will increase when I add the different additives to the benthic mud samples in the anode side of the fuel cell.

Background Research

My research question was “Will adding Compost maker or Apple cider vinegar to

the mud increase the power output of the Fuel Cell?” Before I found that answer I

had to define a couple of terms first. Like what does benthic mud sample mean.

The bottom of lakes or Oceans were there is very little oxygen, this layer of soil is

usually found below the surface about a foot down. A fuel cell is a device that

converts the chemical energy from a fuel into electricity through a chemical

reaction with oxygen or another oxidizing agent. The most common fuel cell is a

Hydrogen fuel cell since hydrogen is the most abundant gas in the universe. A

Cathode is an electrode through which electric current flows out of a polarized

electrical device. An Anode is a positively charged electrode by which the

electrons leave a device. It is the opposite of a Cathode. Anaerobic means any

organism that requires very little oxygen for growth. Compost maker is food

designed to maximize anaerobic bacteria activity. Apple cider vinegar is apple

cider that has been fermented into an anaerobic product. Voltage output is the

amount of electrons flowing through the wire. A Microbial Fuel Cell (MFC)

converts chemical energy, available in a bio-convertible substrate, directly into

electricity. To achieve this, bacteria are used as a catalyst to convert substrate

into electrons. Bacteria are very small organisms which can convert a huge

variety of organic compounds into CO2, water and energy. The micro-organisms

use the produced energy to grow and to maintain their metabolism. However, by

using an MFC we can harvest a part of this microbial energy in the form of

electricity. A MFC consists of an anode, a cathode, and a proton exchange

membrane and an electrical circuit. The bacteria that live in the anode convert a

substrate such as glucose acetate into CO2. Under aerobic conditions, bacteria

use oxygen or nitrate as a final electron acceptor to produce water. However, in

the anode of a MFC, no oxygen is present and the bacteria need to switch from

their natural electron acceptor to an insoluble acceptor, such as the MFC anode.

Due to the ability of bacteria to transfer electrons to an insoluble electron

acceptor, we can use a MFC to collect the electrons originating from the

microbial metabolism. The electron transfer can occur either through a

membrane-associated component, a soluble electron shuttle or nano-wires. Why

does the cathode side need oxygen? The oxygen is what drives the chemical

reaction to produce electricity. Why is the voltage output erratic? Cause the

bacteria is never consistent. Who invented the microbial fuel cell? M.C. Potter

was the first to perform work on the subject in 1911. How do you measure the

voltage? You connect the volt meter with positive to the Cathode and negative to

the Anode. My results show that adding Compost maker to the Anode side has

greatly improved the power output of that fuel cell. Adding Apple cider vinegar

does nothing to increase the power output. This proves that it is possible to

increase the power of a microbial fuel cell by adding aerobic substances to the

mud. This project has been really fun to do over the course of about a month. It

really has showed me that there are more ways of producing power than just

burning fossil fuels and making the earth even more inhabitable.

Materials List

General Items• Lab Notebook• Digital Multimeter (Auto Ranging) & Alligator Clips • Utility Knife, Wire Cutters, Dremel Tool • Alligator clips

Fuel Cell Containers Items• (6) Clear Plastic Containers with Lids (4 Cup Capacity Each)• (3) PVC Compression Connector (3/4 inch diameter) • Plastic Bonding Epoxy (LocTite) • Aquarium Air Pump and 3 feet of tubing

Copper Electrodes Items • Carbon Cloth sheet (20cm x 20 cm) cut into 5 cm square pieces

• (6) Pieces of 12-gauge copper wire, with one end striped back 6 inches

• Quick Steel Epoxy (Conductive)

Salt Bridge Items• (3) Plastic Petri Dish Containers with Lids• 1Qt of Distilled Water • Agar Gelatin Substitute, 30 grams per Salt Bridge• Potassium Chloride Salt, 6 grams per Salt Bridge• Digital Kitchen Scale (measures down to 1 gram)• Aluminum Foil to cover the ends of the PVC tubes

Benthic Mud Sample Items• 1 Qt plastic container with Lid• Backyard stream to collect Benthic Mud Samples from• Trenching shovel to dig up samples

Fuel Cell Additives Items• Compost Accelerator Food• Apple Cider Vinegar, raw and unfiltered

Experimental Procedure

Building the Anode and Cathode Containers1. First you will open holes in one side of each plastic container

using a utility knife and the Dremel tool. Make sure the holes are even and are the same diameter as the interior of the PVC end cap that will go on them.

2. Roughen the end of the end cap and container with sand paper.

3. Bond the end cap to the outside of the plastic containers on one wall with a plastic welding epoxy. After the epoxy is dry, verify the PVC tubes will screw inside the end cap.

4. Drill one hole in the corner of the container lid on the cathode side for the Aquarium pump.

5. Drill another hole in the middle of each container lid to allow the copper wire to come out for taking electrical readings.

6. Tightly screw in the PVC tube in the end cap with teflon tape.

7. Test the connection with water and wait for 10min and check that it is watertight remove the PVC tube for later use.

8. Make three of the assembled pairs of plastic containers joined with the PVC couplings.

Building the Electrodes9. Use scissors to cut the carbon cloth into six equal squares

5cmx5cm each.

10.Strip 6in of the copper wire on one end and glue it to the carbon cloth with quick silver in a square pattern with carbon cloth on both sides of the copper wire.

11. After the Epoxy is dry perform a continuity test with the volt meter to verify there is a good electrical contact between the carbon cloth and copper wire for each electrode.

Making the Salt Bridges

12.Place some plastic wrap along the bottom of a petri dish so that the ends of the plastic wrap are overlapping the edges of the petri dish. Set the covered dish aside.

13.Cover one end of the PVC tube section from the compression fitting securely with aluminum foil. Repeat with the tubes from all of the compression fittings. Place all tubes, open end up, vertically on the petri dish.

14.Measure 300 milliliters (mL) of distilled water and pour it into the pot.

15.Using the scale, measure out 30 g of agar per salt bridge. Set the measured agar aside. Now measure out 6 g of salt per salt bridge.

16.Place the pot of water on the stove and bring it to a boil. When the water is boiling, add the agar and stir it until it is dissolved.

17.Once the agar is dissolved, take the pot off of the heat and add 6 g of salt. Stir until the salt is dissolved.

18.While the solution is still warm, carefully pour the solution into the tubes in the petri dish. If the tubes leak, tighten the foil and refill them. Once the tubes are filled and stable for 10 minutes, carefully move the petri dish to the refrigerator. Let the tubes sit in the refrigerator overnight. These tubes are the salt bridges.

19.The next day, come back and place the salt bridges into a 1qt. plastic baggie and seal it. This prevents the salt bridges from drying out. Take the bridges out when you are ready to use them for your experiments.

Obtaining the Benthic Mud20.Go to a local creek or stream with a shovel and dig down

about one foot until you find the dark smelly mud. This is the mud you will collect into a sealed plastic container for the experiment.

21.You will need about 1 qt for three fuel cell units.

22. Make sure you also collect 3 cups of creek water to use with the fuel cell units.

Assembling the Fuel Cells23. Remove the aluminum foil from the salt bridges. Connect a

pair of containers with a salt bridge. Repeat two more times. You now have the anode-cathode pair for three microbial fuel cells.

24. Make a conductive salt solution using distilled water. Measure out 3 cups of distilled water into a stove top pot. Bring the water to a boil and then add 6 Tbsp. of salt to the pot and stir until the salt has been dissolved. Fill the cathodes of the three fuel cells with the salt solution.

25. Take an electrode and thread it through the center small hole of one of the lids with two holes. Place the lid with the two holes and the connected electrode back onto the cathode. Make sure the electrode is submerged. Repeat this step with another electrode and the other lids with the two holes. Seal each cathode with a lid.

26. Connect the tubing to the outlet of the aquarium pump. Push the tubing into the cathode containers through the larger hole in the lid. Be sure to submerge the end of the tubing.

27.Now, wearing gloves and safety goggles, fill half of the anode chamber of a fuel cell with the benthic mud sample. Make sure that there are no bubbles in the mud. Push the mud sample down or gently tap to remove any bubbles. Take one of the electrodes and bury it in the mud. Then place more of the benthic mud into the anode, covering the electrode. Push the free end of the electrode copper wire into the 2-mm holes in the container lids. Replace the lid onto the container to make sure that the electrode is hanging freely without hitting any of the walls or the bottom. Repeat this with the anodes in the other fuel cells and the benthic mud sample. The fuel cells are complete and you should have three fuel cells.

Testing the Fuel Cells28.Turn on the aquarium pump to oxygenate the salt water.

29. Connect the volt meter to the Fuel Cell using alligator clips, minus with the mud, and positive with the salt water.

30.Test and record your reading in your lab note book.

31.Take the voltage for twice a day for two or three weeks.

32.Repeat steps 1–3 of this section for the other two fuel cells. Always record your data in your lab notebook.

Data and Analysis

My experiment shows that it is possible to change the electrical output of a Microbial Fuel Cell by adding different additives. Fuel Cell 1 had no additives, fuel cell 2 had Compost maker as it’s additive, and fuel cell 3 had Apple cider vinegar as it’s additive.My prediction was that both additives would increase the voltage output of a Microbial Fuel Cell. I thought that because the Compost maker is food for anaerobic bacteria and that the Apple cider vinegar is an acetic acid bacteria. My data shows that the prediction for fuel cell 2 was correct, but my data also proves that my prediction for fuel cell 3 is wrong. I tested each MFC two times a day for two weeks. I would measure the voltage production from the copper wires using a volt meter.

ConclusionI have learned that the microbial fuel cell concept does work. I was able to quadruple the voltage generated by adding compost enhancer to fuel cell #2. The raw Apple Cider Vinegar in Fuel Cell #3 had no effect to the bacteria. The control Fuel Cell #1 functioned well through out the entire experiment. It produced voltages that moved up then down between 80 to 100 mV, but no additives were added to that particular fuel cell.

The generation of electricity in an eco-friendly manner is real and needs to be developed. I have learned that it takes many days for the bacteria to grow in large numbers. I have also learned that you have to change the salt bridges every two weeks or else the two sides will mix and the power production will decrease substantially.

This is a great alternative to the use of fossil fuels in locations where there are large amounts of waste bacteria generated. I would like to see waste management plants powered by this technology in the future. If they were to use this they would get free power and use it to clean the water. This will help the earth restore it’s reservoirs with clean affordable water.

Bibliography1) Source: WebsiteAuthor: Snider, Gene (egbertfitzwilly)Date Published: April 6, 2009Title of Website: instructables (share what you make)Title of Article: Make a Microbial Fuel Cell (MFC) - Part 1. Website URL: http://www.instructables.com/id/Simple-Algae-Home-CO2-Scrubber-Part-III-An-Algae/

2) Source: WebsiteAuthor: Snider, Gene (egbertfitzwilly)Date Published: June 13, 2009Title of Website: instructables (share what you make)Title of Article: Make a Microbial Fuel Cell (MFC) - Part II. Website URL: http://www.instructables.com/id/Make-a-Microbial-Fuel-Cell-MFC-Part-II/

3) Source: WebsiteAuthor: Maranowski, Michelle, PhD. Date Published: November 18, 2011Title of Website: Science BuddiesTitle of Article: Waste Not, Want Not: Use the Microbial Fuel Cell to Create Electricity from Waste. Website URL: http://www.sciencebuddies.org/science-fair-projects/project_ideas/Energy_p026.shtml/

4) Source: WebsiteAuthor: Logan, Bruce, E., PhD.Date Published: currentTitle of Website: Penn State Logan LabTitle of Article: Microbial Fuel Cell ResearchWebsite URL: http://www.engr.psu.edu/cep/env/logan/default.htm/

5) Source: WebsiteAuthor: None ShownDate Published: current blogTitle of Website: Microbial Fuel Cells (From waste to power in one step)Title of Article: Question and Answer section of site. Website URL: http://www.microfuelcell.org/www/index.php/Tutorials/

6) Source: WebsiteAuthor: University of East AngliaDate Published: May 23, 2011Title of Website: Science DailyTitle of Article: Using microbes to generate electricity?Website URL: http://www.sciencedaily.com/releases/2011/05/110523152337.htm

7) Source: WebsiteAuthor: On Line Account Name: “iqbatteryshop”Date Published: December 14, 2009Title of Website: APSense (Business Social Network)Title of Article: Microbial fuel cell research and application of the latest developmentsWebsite URL: http://www.apsense.com/article/134797.html