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This is the feed stock. About 2 gallons of green algae. I'm not sure what strain it is but it's one that occurs naturally here in the Northwest.
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This gives you an idea of the concentration.
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After adding the little initial sample you can immediately see the algae being captured.
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I added the algae water as fast as it would go down the funnel.
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This is the outflow.
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After running about a gallon you can see the results side by side. I'm not sure if I'm recovering 100% but it is recovery a large percentage. I'd need to experiment with the feed rates. Every material separates at a different rate.
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Check out the collected algae. Algae in interesting in that it's a single cell. It will pass through even the finest of filters.
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As the centrifuge slows much of the algae remixes with the water in the bowl.
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Once the bowl stops you can see the algae cake that has formed. This cake would then be dried and pressed for oil.
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This is the pool. It look like it has a lot of algae. After this picture I did sweep the pool walls and bottom to get the algae mixed up.
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This is the basic setup. The submersible pump has been plumbed with an open T fitting and a ball valve. This allows the pump to deliver a 20 to 30 gallon per hour feed to the centrifuge. The open T allows the remaining pump volume to circulate the pool and keep the algae in suspension.
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This is a sample from the pool. It looks drinkable. I can't see that it's full of algae. This has NOT been centrifuged. This is not like the high concentration from the earlier test.
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This is the first flow I tried from the pump.
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I originally set the speed a bit fast and the removal was less than expected. Before centrifuge on the left and after the centrifuge on the right.
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After turning the speed down you can see the results.
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After two hours I stopped the machine to look at the results.
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Even after just two hours you can see the algae cake forming. This algae concentration is very light in the pool water compared to the earlier test.
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Much of the algae that didn't cake was drained off on shutdown. Note how concentrated it is.
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This photos shows the original pool water along side the concentrated solution that drained from the machine.
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After the pool has mixed for a few hours you can no longer see the bottom.
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Removed the centrifuge lid after leaving the machine run for a few days at 20 gallons per hour. The algae ring on the lid indicates we ran too quickly.
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The centrifuge rotor appears dark... I hoped it was full.
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After opening the rotor you can see about 3/8 of an inch of algae cake. Less than expected after running for a few days.
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The lid revealed the problem. It appears that the flow rate at 20 gallons per hour was great enough to break up the algae cake and push it out of the rotor.
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The algae is very dense almost like paste.
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I reinstalled the rotor with a prototype polycarbonate lid. This will allow me to see what's really happening inside the rotor while it's running. This is what it looks like empty with just the algae cake.
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I then quickly added the algae concentrate that drained from the rotor. I wanted to see if it could clarify the water.
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The separation has started this is after about 5 seconds.
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After about 10 or 15 seconds the water is totally clear.
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I then added water at 20 gallons per hour. The same rate I used over the past few days and the water instantly clouded. It is very obvious to me that turbulence caused by the incoming pool water is mixing and breaking up the cake.
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Next I tried half the flow. About 10 gallons per hour. Less turbulence but still too much mixing and cake damage.
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I then added water at about the 4 gallons per hour rate. No noticeable turbulence. Note the clarity of the water despite having just added pool water to the centrifuge.
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Algae cake.
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Algae cake with the feed cone removed.
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I removed the cake from the wall to see how dry it was.
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I installed the fins into the rotor. These fins may allow me to feed more gallons per hour.
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The fins are just a blur while running.
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The machine is being fed pool water. There is a lot of water misting past the camera.
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Kyle sent us these photos and writes: I believe I promised to send some pictures of our use of the centrifuge for separating micro-algae from water. It works pretty well as a batch
process.
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Another photo from Kyle.
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And another photo from Kyle.
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Another customer wrote: Got the centrifuge and we're processing algae! I've attached the
first jug processed so you can see the difference between what goes in and what comes out.
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