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This instructable provides detailed directions for building your own microbial fuel cell using Jello, Saltwater and Septic Tank treatment. It's based on the information provided in Make a Microbial Fuel Cell (MFC) - Part 1
This is a true fuel cell in that both the anaerobic and electrolyte media are replaceable and the salt bridge may be serviced as needed. The fuel cell consumes organic material and produces electricity and methane ( or more properly biogas include CO2 and other gasses ). These are captured in a methane store for further processing....Okay, it's a balloon and I have no idea what you should do with the biogas except be careful and experiment with it.
We'll be using a traditional two cell design with a gelatin/salt bridge. Most commonly agar is used but we'll be trying both traditional unflavored gelatin as well as hide glue. Yes, you can actually use Jello brand flavored gelatin and I would be very interested in your results.
I also intend to experiment with gelatinous nutrient medium in the anode chamber. It seems to me a gel based replaceable anode would be a significant enhancement to the utility of this technology.
The device has two relatively small chambers (approximately 100 mL). In theory microbe population densities are primarily a function of nutrients and not space and we should be able to obtain (more or less) the same charge out of a 100 mL cell as we would from a 1L cell with the same population.
Now let's take a look at the materials we'll be using.
This is a true fuel cell in that both the anaerobic and electrolyte media are replaceable and the salt bridge may be serviced as needed. The fuel cell consumes organic material and produces electricity and methane ( or more properly biogas include CO2 and other gasses ). These are captured in a methane store for further processing....Okay, it's a balloon and I have no idea what you should do with the biogas except be careful and experiment with it.
We'll be using a traditional two cell design with a gelatin/salt bridge. Most commonly agar is used but we'll be trying both traditional unflavored gelatin as well as hide glue. Yes, you can actually use Jello brand flavored gelatin and I would be very interested in your results.
I also intend to experiment with gelatinous nutrient medium in the anode chamber. It seems to me a gel based replaceable anode would be a significant enhancement to the utility of this technology.
The device has two relatively small chambers (approximately 100 mL). In theory microbe population densities are primarily a function of nutrients and not space and we should be able to obtain (more or less) the same charge out of a 100 mL cell as we would from a 1L cell with the same population.
Now let's take a look at the materials we'll be using.
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Signing UpStep 1Bill of Materials
Tools:
Drill Press or Drill with bits
Soldering iron with solder
Measuring cups
Skewer ( wood or metal )
2 power tool replacement brushes
I got these from the specialty hardware department at ACE
2 1x1x1 PVC Schedule 40 Tee
3 1" PVC Schedule 40 Connector
1 1" PVC Schedule 40 Slip Cap
2 1" PVC Schedule 40 Plug
1 1x1/2 Slip vs FPT threaded adapter
Titanium fishing lead
Clear plastic wrap
Rubber bands
Salt Bridge Medium
Anaerobic Innoculent
Rid-X which are not specifically anaerobic. I have not tested these and have no idea what results
their microbes may produce
Drill Press or Drill with bits
Soldering iron with solder
Measuring cups
Skewer ( wood or metal )
2 power tool replacement brushes
I got these from the specialty hardware department at ACE
2 1x1x1 PVC Schedule 40 Tee
3 1" PVC Schedule 40 Connector
1 1" PVC Schedule 40 Slip Cap
2 1" PVC Schedule 40 Plug
1 1x1/2 Slip vs FPT threaded adapter
Titanium fishing lead
Clear plastic wrap
Rubber bands
Salt Bridge Medium
- Knox Unflavored Gelatin
- Hide Glue (powdered not liquid)
- Agar
Anaerobic Innoculent
- Microbe-Lift Septic Tank Treatment - Ace Hardware
Rid-X which are not specifically anaerobic. I have not tested these and have no idea what results
their microbes may produce
- Wastewater primary effluent
- Fish bearing river, creek, lake or stream sediment
- Prepared culture such as E. Coli
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http://www.instructables.com/id/Make-a-Microbial-Fuel-Cell-MFC-Part-III/
Which is also one of mine.
A septic tank requires what is called a single cell design, that is a cell which is deep enough to provide an anaerobic area ( oxygen free) and allows for oxygen to be absorbed from the air near the surface.
A septic tank is perfectly suited to this requirement. First the tank is generally sealed. The liquid media within has a broad surface area which allows more oxygen to be absorbed. Since gas uptake from air only penetrates about 6 cm the lower area provides an anaerobic chamber. There is plenty of food and bacterial activity here which can be trapped.
The challenge of a septic design is in the electrodes. For this I propose two variants on a novel solution. In the commercial world there are many products design to control electro-magnetic radiation in laboratory and development areas. Among these products are various paints which contain carbon. This is used to paint the walls and ceilings to capture stray EMF.
Do not immediately drain your septic tank, try this with a 5 gallon plastic bucket first.
This paint can be used to provide an electrode surface. The tank must be drained and cleaned. Paint the bottom and a foot or so up the side with carbon paint. Use a standard "grounding plate" from the same source to tap the carbon and run a lead out of the tank.
Paint the upper portion of the walls similarly. Make sure to go a foot or so below the low water mark of the tank. Attach a grounding plate to this section and run that lead out of the tank.
Refill the tank and resume use. Once bacterial activity begins in earnest power should begin emitting from the leads. This should provide sufficient energy to continuously trickle charge a series of batteries for use in specific applications.
From the same sources ( I use lessemf.com, I am not affiliated with them but have had good experience with their products ) one can obtain conductive cloth made from vapor deposition silver over nylon. This can be floated on the surface and may increase power output. That's the point of the current experiment cycle.
Also if one can keep a slight air flow over the surface which does not disturb the water power output will increase from the additional oxygen which is made available.
essentially powder coating.
I m making a microbial fuel cell in which i am using a sulfides as a substrate.. and aerobic bacterial cultures. i made a two nylone made chambers with salt bridge. Now i am about to start my work and my guide told me to staderdize a fuel cell,,, so i am not getting how to standerdize a fuel cell with a use of sulfides as a subsrate. i need a help with every type of actions which carry out a good work. it will be a great help of you if you guide me as any......
You might try hide glue ( similar to this http://www.bonanza.com/listings/Dry-Hide-Glue-3-Ounces/21111474 ) which should have a much greater structural integrity and is produced by the same process that makes gelatin.
Yes the material from the bottom of the lagoon can be used although if you have access to a septic tank scheduled to be cleaned that would be very good as well. Carbon cloth can be used but there are other designs better suited to that.
This doesn't use proton exchange, it uses ion exchange with a simple salt bridge with a gelatin medium. The gelatin could readily be replaced by animal hide glue rendered from local sources. Here's a wikipedia link with more information:
http://en.wikipedia.org/wiki/Animal Hide_glue
Using the hide glue as a medium in the salt bridge should provide a significant improvement in stability and life of the cell.
This could be scaled up using two 50 gallon plastic drums and a 6 inch section of PVC pipe to construct the salt bridge between them. I'm not sure metal drums would work well and they would have to be isolated from the ground ( sitting on a table ) and from each other ( except for the salt bridge ).
Some very advanced carbon electrodes could be made using corn or potato plastic. Mix in about 20% carbon ( very finely ground coal ) and you will have some very durable and extremely interesting electrodes.
You could also try steel wool, carbon is not strictly required. Its used in experiments to eliminate false readings from metal creating an electrochemical reaction.
Also it should be possible to aerate the cathode with a small windmill rather than an electric pump. If the windmill pumps water and allows it to fall back down over an inclined plane or slope it should pick up sufficient oxygen to fuel the cell.
I'd like to know if you set up actually produces current that can power a light bulb or you'd have to use a mediator. And how can you adjust your set up to one for large scale water treatment. Thanks for the help
I've been experminenting with larger scale designs. There are two that I've focused in on, both use carbon paint as the electrode. In design the bottom of a tank ( say a septic tank ) is painted with carbon paint, a separate band of paint is applied around the top at the surface area of the media. If the tank is filled with waste water I believe that the basic design will produce measurable output.
In a variation on this I use carbon paint on the bottom and a floating piece of conductive cloth on the top.
The big questions is oxygen uptake at the surface and its affect on the output. I suspect the floating conductive cloth will be more effective but there may need to be fresh air circulated across the top the media to get optimal performance.
The tank must be deep enough to ensure that the anaerobic bacteria at work on the the waste remain undisturbed.
I was able to get carbon paint and conductive cloth from a company called lessEMF.
http://www.lessemf.com/specials.html
It may be possible to make carbon paint locally by mixing carbon with a dry acrylic paint before mixing. I have not experimented with that.
I believe you could also use the carbon cloth that is used in making fiberglass as the electrode but again I have not experimented with that.
Contact me privately and we can discuss working together in more detail.
Have you looked at microbialfuelcell.org and Dr. Logan's site at Penn State?
What are you using for electrodes? Probably the best way to increase current flow is to provide more surface area for the electrodes, you might consider one of the Fluval aquarium carbon filters as an electrode.It's not all clear to me that switching to Nafion will impact your performance significantly, but I could be wrong about that.
You could try adding a small amount of hydrogen peroxide, chlorine bleach or sodium hydroxide for increased oxygenation HOWEVER if you are bubbling air through the chamber this probably isn't your problem.
Also it sounds like you are relying on the natural bacteria of milk spoilage, these may not be an effedtive current producer ( I haven't seen anything one way or the other ). You might consider seeding your tank either with Septic tank starter or a small amount of waste effluvient from your local municipal water recycling plant. Yeast is another good choice, as long as the chamber is sealed ( Yeast will switch anaerobic mode in the absence of oxygen ).
As you suggested to use YEAST, I have a doubt that , whether it requires a MEDIATOR or not.If yes, please let me know, which one is the best.
An interesting thing, I observed in my setup is, it produced peak voltage and current with in 5 days of setting it up, and it started reducing.For 30 days it showed the reducing phase, but for the past one week it started rising again and now to my surprise, it gave me a voltage if 0.5 v and 0.8 mA ( on march 11, 2010 ) , which is highest of my reading till now, I hope it is going to increase more.
i'm from from and i want to do project in my college in mfc. as you've done experiment in mfc it will be so kind of u if you tell me what are the thing necessary to create an mfc what is the bacteria you used and where can i get it.please help me sir thank you.........
Make sure you get far enough out to get a good solid mud sample, I'm not sure how well sand will work. You really want a solid base of decaying organic material ( fish crap basically ) providing a nutrient rich, anaerobic environment.
Plus I think you can probably do a single cell design, you might want to check out that design.
One more thing, the salt bridge (jello), you dont quite specify how much salt or how much jello powder?
Depending on where you are ordering the e-coli from you might consider geobacter as an alternative.
Here's the salt bridge construction details from step 3. One package of gelatin and enough salt to top off the coupling...
Take one packet of Knox unflavored gelatin and pour it into the coupling. Fill the rest of the way with salt. Pour this mixture into a dry measuring cup and pour back into the coupling. You'll notice that settling left a little more room. Top off with salt, pour back into the measuring cup and add an extra tablespoon. Mix the dry ingredients thoroughly and pour back into the upright coupler.
i am very interested in the alternative energy, adn therefore created a microbial fuel cell simmilar to this one. My question for you was how high in mv did u reach or did u reach volts?
Unless one has access to significant volumes of black water ( a septic tank at least or a municipal waste water system ) this technology has a limited role, primarily in extremely remote rural areas of the third world.
I've got some other instructables that speak to the aluminum oxide battery which you might more productive as an area of independent research.