Instructables

An Algae Bioreactor from Recycled Water Bottles

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Picture of An Algae Bioreactor from Recycled Water Bottles
In this instructable, we describe how to build a photo-bioreactor that uses algae to convert carbon dioxide and sunlight into energy. The energy that is produced is in the form of algae biomass. The photo-bioreactor is built from plastic recycled water bottles. By designing the apparatus to be compartmentalized, we are able to do many experiments in parallel.

Michael Fischer
mfischer @t stanford.edu



By using algae as a biofuel, we can increase the world's supply of oil while at the same time we decrease the amount of atmospheric carbon dioxide used during its production. The resulting product is a sustainable biofuel whose carbon footprint is neutral inasmuch as the CO2 produced on consumption is essentially balanced by the CO2 used in its production. In this instructable, we first make the carbon dioxide delivery system, then mount the water bottles on a rack, and then inoculate the bottles with algae. After letting the algae grow for a week, we extract the biomass.
 
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Step 1: Make Carbon Dioxide Delivery System

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To make the carbon dioxide delivery system, connect an eight port sprinkler system manifold to a one inch long PVC pipe. To get good seals, use Teflon tape to tape the threads before attaching the pieces together. Next, attach the one inch pipe to a T-connector. Block off one end of the T-connector and attach the other end to a foot long PVC pipe.

Step 2: Attach Tubing to Manifold

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For each manifold, cut eight-pieces of flexible tubing and connect each piece to a port of the manifold. The manifold that I am using has a dial on each port to control the rate of flow. Make sure all the ports that you use are open and allow approximately the same amount of carbon dioxide to flow through the port.

Step 3: Mount Carbon Dioxide System

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Mount the air system to a metal rack using zip ties. Attach the air system to a tank of carbon dioxide.

Step 4: Mount Water Bottles

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Hot glue the water bottles to the metal rack.

Step 5: Make Algae Media

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We next make the medium to grow the algae. Although there are many possible mediums, a standard garden store fertilizer contains all the nitrogen and nutrients that the algae need.
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Calladus5 years ago
A tree could sequester biomass if you turned it into furniture or a house. Burning it is carbon neutral, as long as you're farming trees. Burning the algae would be carbon neutral. Turning it into plastic or something might sequester the captured carbon - if you were careful about the energy you used in the process.
Burning anything is not carbon NEUTRAL....Burning releases the carbon into our atmosphere...back to chem. class.......
tsk tsk - perhaps you should re-read what I've said?
Jux Calladus5 years ago
More food for thought than anything else, but has anybody ever considered the idea that just possibly burning oil is also carbon neutral? Hear me out before you rant and rave, this is just me thinking 'out loud'. For example: burning algae is only carbon neutral as long as you look at the complete cycle from beginning to end; the length of time it takes to remove CO2 from the air, process it, and return it to the air. Is it possible we are only looking at a portion of the cycle of oil? After all a lot of it once walked around this planet on 2 or more legs before being contained in the ground. If we were able to see the entire cycle what would it look like? Don't get me wrong I fully support alternative fuels, I have just never heard anybody talk about a possible cycle of oil or coal. -Jux
AngelaG2 Jux1 month ago

just a little reminder jux...natural gas and pertro derive fro plankton and coal from plant matter ?

Calladus Jux5 years ago
It's true if you define a long enough cycle it might encompass the cycling of biological material (of which we are a part) back into sequestered carbon. But the rapid conversion of sequestered carbon into free carbon might also cause the extinction of humanity due to a too rapid change in climate and pollution. The length of the cycle doesn't matter if one small part of the cycle is responsible for the death of us all. The questions are, will we survive the rapid change of carbon status? Should we be concerned about climate changing chemicals in our biosphere? How can we figure out if this is a problem? What can we do about this while we figure things out? It would suck for humanity to go extinct in the next few hundred years due to our own incompetence in the way we manage our biosphere. The logical thing to do would be to minimize our impact until we have a better understanding about what is going on.
Look at your time frame. ... You are right, in the short term. ... But 'farming' (algae, trees, etc) is 'harvesting' the carbon from mainly the atmosphere. Farming does a 'temporary sequestration' if you 'burn' the tree or algae, up to the point it is re-gasified by the burning process. The only reason that burning coal or oil is not considered 'carbon neutral' is because the time frame we are viewing is to short. ... Peat that is burned some places as fuel is carbon neutral over a 10 to 200 year period. Most farmed pine trees are typically on a 10 year or more cycle, oak is longer, bamboo is shorter. Again, it just depends on the time frame. Our bio-system is not a nice set of linear equations. We can typically find the reactions for simple systems, just not for the more ones with more complicated connections.
Wrong. If the carbon produced came from the air in the first place, then the burning is carbon-neutral by definition. Burning wood is carbon neutral. Burning coal is not, since the carbon in the coal was removed from the atmospheric cycle millions of years ago. Perhaps you could use a refresher course in chemistry yourself.
Carbon Dioxide + water and light in photosynthesis creates carbohydrate – the major component of Cellulose (plant matter). When Cellulose is burned it creates Carbon Dioxide and water vapor and more heat. The problem with burning fossil fuel is that a LOT of oil and coal has sequestered a LOT of carbon over millions of years. And in less than 200 years we've drastically depleted these reserves and released all of that carbon. The logical thing to do would require humanity being carbon negative for the next fifty to hundred years. But large groups of humans are rarely logical. Being carbon neutral is something we're just now starting to understand and agree with as a species.
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As Calladus said, as long as you are burning plants and algae rather than the oil found in the earth's crust, you are actually carbon neutral. Any CO2 or Methane released by the burning of such materials is only equivalent to the amount that would have been free in the atmosphere had the plant not temporarily sequestered it. Burning oil extracted from the earth is not carbon-neutral because it is releasing carbon into the environment that otherwise would have remained trapped deep underground. So yes, Back to Chem. Class for someone... Environmental Science helps too
static Calladus5 years ago
However this is "farming" algae. Burning any product produced from the algae is carbon neutral as is burning tree's. The same is true for burning biomass. There may be varying degrees of efficiency, I don't know, but it has to be better than releasing prehistoric carbon into the atmosphere.
Unknown4191 month ago

What type of air system did he use to feed the Carbon Dioxide into the system? Is there a place to purchase this?

Unknown4191 month ago

What type of air system did he use to feed the Carbon Dioxide into the system? Is there a place to purchase this?

Unknown4191 month ago

What type of air system did he use to feed the Carbon Dioxide into the system? Is there a place to purchase this?

Unknown4191 month ago

What type of air system did he use to feed the Carbon Dioxide into the system? Is there a place to purchase this?

Unknown4191 month ago

What type of air system did he use to feed the Carbon Dioxide into the system? Is there a place to purchase this?

Unknown4191 month ago

What type of air system did he use to feed the Carbon Dioxide into the system? Is there a place to purchase this?

Unknown4191 month ago

What type of air system did he use to feed the Carbon Dioxide into the system? Is there a place to purchase this?

Unknown4191 month ago

What type of air system did he use to feed the Carbon Dioxide into the system? Is there a place to purchase this?

C I A H9 months ago

does it have to be fed with the co2 or can you use a regular air pump to circulate air into the bottles? might just take longer to grow?

lxlbacon12 months ago
Now do you supply your own source of CO2? As in, a tank.
elevalther1 year ago
Hi Michael
I like your bioreactor, but do you know it is possible to get a cheap algea screew oilpress- eventually bluepeints,

br

Valther
".....hopefully, in the future..."

A good description for most alternative fuels. I've been hearing that for 35 years.
twighahn2 years ago
how is this used for fuel?
Milke19912 years ago
How much energy you will use for compressing air into bottles?
jbpitcher2 years ago
If I misses this comment from someone else I apologize.
I believe this is the fuel of the future.
- However, my question is: how much net energy is actually gained by the time you run a compresses/pump to circulate the water, press out the oil and other processes needed to gain a usable product.
- How extensive is the processing needed to turn the algae into a user-friendly product.
- How interchangeable is the end product with existing fuel consuming machines/engines.
ilpug3 years ago
awesome, although i noticed that you said that "By using algae as a biofuel, we can increase the world's supply of oil while at the same time we decrease the amount of atmospheric carbon dioxide used during its production"

i understand how this retains carbon dioxide, but how does it increase the world's supply of oil? it only reduces the speed at which we use said oil.

excuse me for being a grammar Nazi (although as you see mine is far from perfect).

I loved the instructable.
Nagarok ilpug3 years ago
This particular video refers to starch as "Oil"

Although it is a particular type of energy source, I personally believe it's incorrect to refer to them in the same manner. Starch is the solid condensed energy source that, with correct technology can be used to replace petroleum, but those systems are far more complex, and the output for mass for pure starch in terms of burning engines is lower.

Thats why fuels higher in ethanol, although much cleaner for the environment, also have a higher consumption per 100km driven. The initial cost of producing a fuel from plant sources is a very large sum of money compared to the petroleum based sources, that is why the world has not shifted across to alternative sources like biofuel. Eventually we will have to, else we will not be able to live anymore.
Live in the manner that we do at this time..
waldosan2 years ago
i think it's a smart idea to be doing this at least as a short term solution to our growing oil crisis. i'm thinking that if i build one of these i can burn the oil in an oil furnace to heat my house, in addition i could find/build a boiler and burner and possibly run a home made steam turbine off it. and grow my tomatoes in the rotting decay of the solids, that'll make them taste good!
WhiteTech2 years ago
I've read most of the comments. But pertaining to biodiesel, as in actually being used in cars, I've haven't found anywhere on how to do this. Just people saying "Oil to be used in making fuel"

I defiantly love the "Algae Pellets", but biodiesel would be much more useful in my position.
the oil is kind of like a replasement for used frier oil
I've seen this asked a few times and I couldn't find an answer yet - how much "fuel" (extracted and dried algae) does this experiment yield? I'm sure it can be estimated from the end photos, but I'm curious what Mr. Fischer gets after all this work? Is it enough to burn for 60 seconds? 5 minutes? Do tell! Thanks! :)

(My apologies if I missed an answer/reply to this question somewhere in the 200+ comments)

Cheers!
I did this and i got about 15 mL of bio oil
I tried this but is the algae bio-oil supposed to rise to the top? I noticed a small film of oil on the top of my bottles after 7 days. Also if it does rise to the top, any idea how to get it out? Thanks
Also, the french press does not obtain any bio oil on the filter...?
maliksudhir3 years ago
Hi ,
Can any one help me out in some calculation work its really very urgent , please help me out ..... i need to consume 1932.3kg/hr of CO2 with the help of Algae in a pond (water) for example Raceway pond , so i need to know the specific area to construct that pond and its sizing and dimension (length,etc) and the quantity of water needed and amount of algae used so that it easily consumes the mentioned amount of CO2 rate per hour..... please help me out soon you can also drop your suggestion and questions if any my email id is : sudhirmalik2011@gmail.com ....i will be waiting for your reply soon and i'll be highly thankful to you, if someone can help please do tell me its very urgent....

Thank you
pashanoid3 years ago
Thank you for this amaizing instructable! I now really want to build one of my own! However, up here in Moscow, Russia we don't get that much sunlight. Should I start with a scaled down model. I have one window in my apt facing west - gets the most sunlight... In any case -- great story, thank you!
jbuk13 years ago
visit the our online site http://www.phycotechinc.com/ for more information regarding photobioreactor
algaemaster3 years ago
do the tubes that the co2 passes through go in the plastic bottle through the top?
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