brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Tue Jan 05, 2021 10:53 pm

My plan is to add the compost into the anode, which has the mud, and mix it around. This is so that the anaerobic bacteria contained in the mud can use the nitrate from the compost and, from my understanding, generate more amino acids to grow. The more amino acids there are, the more proteins will be created, and the more proteins are present, the more bacteria are present. An increase in bacteria also means more anaerobic respiration and electrons given off. Therefore, more power will be generated.

This is simply my understanding, but I wanted to confirm before I began my testing.

Thank you!
Brindha

koneill18
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby koneill18 » Wed Jan 06, 2021 1:31 pm

Hi Brindha,

It's really great that you're taking the time to understand the rationale behind your project before you get started! I think you've pretty much got it. Nitrogen is one of the basic building blocks that make up microbial cells. It's a crucial component of the amino acids, proteins, and nucleic acids that are necessary for normal cell growth and function. Supplying the bacteria with nitrogen will increase the growth of the bacterial population, which will increase overall energy output. Additionally, nitrate is an electron acceptor in the electron transport chain that's used by bacteria during anaerobic respiration. The cells use anaerobic respiration to produce ATP, which the cell uses as a source of energy. So by exposing the bacteria to nitrate, you're enhancing their ability to carry out anaerobic respiration.

I hope this answers your questions. It sounds like you're well prepared to start your experiment!

brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Thu Jan 07, 2021 4:26 pm

Thank you!

Yes, I wanted to fully understand the background behind my experiment before beginning, and thanks to your and Dr. Payne's help, I am!

One last question before I begin...

If I have the bacteria out of the water and in the containers for more than 24 hours wouldn't they die? In this case, would the fuel cell still run for 30 days?

Thank you!
Brindha

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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby koneill18 » Fri Jan 08, 2021 10:20 am

Hi Brindha,

I think the reason they tell you to use the mud within 24 hours is because once you remove the mud from the stream, it gets exposed to oxygen. Obligate anaerobic bacteria live in the absence of oxygen, so exposing them to the air can be toxic for them. The anode chamber of the fuel cell is an oxygen-free environment, so it should keep the bacteria alive for an extended period of time.

I hope this helps!

brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Fri Jan 08, 2021 7:12 pm

Hi,

Today I assembled my fuel cell, but unfortunately, I did not get any readings. I only assembled one fuel cell to start with in case there were any problems. Do you know what could have gone wrong?

Thank you,
Brindha

brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Fri Jan 08, 2021 7:36 pm

Also, are the results expected to increase throughout the 30 days I test the fuel cell? I am a bit confused about what to look out for.

Thanks,
Brindha

brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Fri Jan 08, 2021 9:41 pm

brindhaaa wrote:Hi,

Today I assembled my fuel cell, but unfortunately, I did not get any readings. I only assembled one fuel cell to start with in case there were any problems. Do you know what could have gone wrong?

Thank you,
Brindha


Regarding this, with the multimeter, I also tested the circuit connectivity and it was 100%, so that means there is no problem with the circuit, I suppose. So my only guess is that the bacteria may have died, but I am not sure.

Thanks again!
Brindha

koneill18
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby koneill18 » Fri Jan 08, 2021 10:34 pm

Hi Brindha,

Have you checked to make sure there are no air bubbles trapped in the mud? That air could prevent the bacteria from growing properly. If there are any small rocks or twigs trapped in the mud, you should remove those since they can cause air bubbles too. Also, check to make sure that the room you have the fuel cell in isn't too cold. The ideal growth temperature for the bacteria is 66–77° F. Once you set up the fuel cell somewhere, you should avoid moving it since that can disrupt bacterial growth.

brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Sat Jan 09, 2021 11:51 am

Yes, I will be sure to try all of those. The period that I used the mud in was very close to 24 hours, so I was worried that the bacteria may have died. If those tips do not work, I think I will just go back to the park and get some more mud.

Regarding the type of mud, I just collected a sample of mud from the bottom of a lake, but I am not sure if that is benthic mud. Would it still work?

Thank you so much,
Brindha

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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby koneill18 » Sat Jan 09, 2021 3:45 pm

Hi Brindha,

I think that should work. The term benthic means that the mud is taken from the benthic zone, which is the bottom sediment surface of a body of water. So as long as you're getting the mud from the floor of the lake, it should work fine!

brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Sun Jan 10, 2021 11:41 am

Ok, great!

Yesterday I visited a marsh/wetland and dug up some rich mud. It smelled a little but I think that is good because it means the mud has lots of bacteria. The marsh did not really have much water I could take so I bought 2 gallons of distilled water to put in my cathode chambers. The SciBuddies procedures say to miz 6 tbs of salt into 1 gallon of stream water for the cathode chamber, but since I am using distilled water should I still mix in salt?

Thank You,
Brindha

brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Sun Jan 10, 2021 2:38 pm

Hello,

I built my constant MFC today and am in the process of testing it. I have connected the multimeter for a while because the reading keeps increasing! My constant MFC is currently generating 205 millivolts and still rising!!

I am planning to test all 3 of my MFCs for 3 weeks, but am curious what the readings should look like going forward. Are they supposed to increase? stay the same? decrease? I want to be ready to know what to look out for.

Thank you so much for all the help!

Brindha

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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby koneill18 » Tue Jan 12, 2021 9:44 am

Hi Brindha,

I'm so happy to hear that things are going well! It's hard to predict what your readings are going to be over the course of the 30 days since your experimental system is unique. Something you can do is do an online search for "microbial fuel cell compost" and look at the research articles that come up. You can look at those researchers' data to get an idea of what your data might look like. Here's one paper that might be helpful to you. Let me know if you're not able to access it and I can attach the PDF for you.

https://www.sciencedirect.com/science/article/pii/S0956053X14005200

If you scroll down to figure 3, there's a graph showing how the voltage in the microbial fuel cells changes over the course of 120 days. Buckets 3 and 4 were the ones that had compost in them, so the readings from those buckets might be more similar to what you're going to see.

Let us know if you need more help finding information!

brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Mon Jan 25, 2021 12:02 am

Hi again!

I have now been testing my fuel cell for a little over 2 weeks, and I have 6 more days left to go! So far, my 5% nitrate addition MFC is producing the most energy out of all fuel cells. In the last reading I took, it was up to 514.3 mV with the pump! I think that's good :lol: . However, a few things happened to my others MFCs. My constant fuel cell's electrode broke. The copper wire detatched from the carbon cloth, but ever since that hapened, it has been producing way more energy! Overall, I think my project is going great!

I do, although, have a few questions I was hoping you could help me with.

1. My original though was that the more carbon cloth there is for the electrode, the more area would be available to collect electrons coming from the anode. However, since the electrode in my constant MFC broke, and the copper wire is not touching the carbon cloth, how is electricity still being produced?

2. I have read that microbial fuel cells can be used as a method of treating wastewater. Other than producing energy from the bacteria living in the wastewater/mud, how would an MFC remove contaminants from the matter?

3. I am currently working on my Data and Results sections for my research paper, and my teacher has made it very explicit to have lots of statistics in my Data section and not just graphs and tables. With my project, since I simply measured voltage readings, do you have any recomendations as to how I would present statistics anywhere else except in my graphs and tables?

Thank you so much for all the help!

Brindha

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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby koneill18 » Tue Jan 26, 2021 12:50 pm

Hi Brindha,

I’m glad to hear your project is going well! I attempted to answer your questions to the best of my ability:

1. I don’t really know enough about physics to answer this question properly. Dr. Payne or another expert on the Physics forum might be able to help explain why you’re still getting readings even though the copper wire isn’t connected to the electrode. However, if you haven’t already, you should definitely try to reattach the copper wire to the carbon cloth! When you’re performing an experiment, you want to make sure that all of your experimental groups are exactly the same except for the independent variable you’re trying to test. If the copper wire is still attached to the carbon cloth in your other two fuel cells, then it should be attached in the control cell as well. If you see a difference between your control fuel cell and your fuel cells that have nitrate, you won’t be able to tell if the difference is due to the nitrate or to the fact that the electrodes are made differently.
2. Waste water is full of organic matter that needs to be removed during waste water treatment. This organic matter is a food source for bacteria, and they’re able to clean up the waste water by digesting the organic matter and leaving clean water behind. An added bonus is that the bacteria release protons and electrons from the organic matter during the digestion process. This generates electricity that can be used as a power source at water treatment plants. Water treatment normally requires a lot of power, so having bacteria that can produce energy while also eating up organic contaminants from the water would save a lot of money and resources.
3. I’m including a link to the Science Buddies guide to data analysis. This document, and the documents linked within it, will help you learn about different types of statistical analyses that you can perform on your data.
https://www.sciencebuddies.org/science- ... e-projects

At the end of your experiment, you will have the voltage readings you collected, and the power output for each fuel cell, which you calculate using the voltage and the resistance. There are a bunch of options for statistical analyses that you can perform on your data that range from simple to more complex. A simple form of analysis would be calculating the mean power output for each of your fuel cells and comparing those values in graphs. You can also calculate the standard deviation for each of your fuel cells and show that on the graphs as well. The Science Buddies guide I linked talks about all of these analyses and explains how to do them. If you want to take things up a notch, you can try performing a T test on your data to test for differences between each of your nitrate treated fuel cells and your control fuel cell. Here’s a good article that explains the basics of the T test.
https://sciencing.com/how-to-interpret- ... 24290.html

Statistics can be a source of confusion even for experienced scientists, so don’t hesitate to let us know if you need more assistance!

I hope this helps answer your questions!


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