Modular Algae Photo Reactor V.2
This project is the second version of the basic photo bio reactor array that I started with. While it may look similar to the previous version is dramatically different overall. This design has many improvements that make it far more sustainable and practical for long-term use. I really focused on making it highly modular and insuring it was rugged for prolonged outdoor use that is easier to fill and harvest from. While the array is smaller for this project it can be scaled to any size or requirement.
The Frame :
So we will be starting this project by killing a tree for our project. Basically we will be building a fairly simple frame to hold our reactor cells and pumps. Could you use reclaimed or recycled wood products? Sure! if you have them locally or on hand… if not don’t burn off that gallon or more of gasoline driving 20 miles and back from a recycler…. just go to the home center around the block. However, if you go the home center route make sure to get some good stain to protect the wood from the weather and make it last as long as possible.
For this project we will be using some acrylic sheet that is 1/2 inch thick. This will be cut using a hole saw to make the plugs for the tube ends as well as making the holes for the plumbing. Now I realize that everything can be measured in carbon and energy required in making a product… and I realize that I will get email saying how plastics will kill the earth. Well… your likely right.
These are 3 3/4 OD 3 1/4 ID Cast acrylic tubes. There are two types of acrylic, cast and extruded. It’s important that you use a cast acrylic tube for this project. If you use extruded acrylic it will eventually crack under the pressure of the water in the tubes and you will kill an entire plankton colony. However if you use extruded lengths of 2 foot or less it will last a very long time I found.
We found these WISA air pumps on eBay for 8.00 each. The cool thing about them is that they have a input and output on them so you can easily capture the air and pass it along. These are surprisingly high volume and 6 of them in parallel ran great on our 45 watt solar panel kit.
This simple component while not necessary for an algae reactor to run is really crucial in my mind. Aerating algae both agitates it so it gets uniform light exposure as well as introduces more CO2 to the mix. This air hose we picked up from a local aquarium supply store for 2.00USD and is far more than we need for this project (so we have more for future projects). It’s worth noting that this hose doesn’t react well to long term direct sunlight exposure, a simple UV resistant clear coat though makes it last much longer.
The Hose Fittings:
We found these barbed hose fittings at our local home improvement center. I really have fallen in love with these little guys. They provide a simple connection that is secure yet removable. This makes it easy to vacuumed fill the tubes from the bottom with a siphon hose. Use a plastic zip tie to secure the hose to the barbed end for long term unattended use just in case.
This stuff was one of the major advancements for my reactors. The tubes are dipped into this stuff and allowed time to totally cure. This provides us with 2 great features; it’s totally waterproof and has tremendous shock dampening ability. So the weather and wind and even hail can blast your array and you can rest assured its safe.
Step one; just like in our version one system we install acrylic plugs into the ends of the tubes with acrylic bonding agents. But we then double dip the tubes into the plastic dip to seal them and make them shock resistant. We waited about 10 minutes between dips as per the instructions. One thing I found that was a disappointment and I sure hope your reading this; plastic dip off gasses a lot! If you do not cover the holes at the ends of the tubes with masking tape it will leak into the tubes. As it cures it will actually rupture your tubes. My array here was originally an 8 tube array… I salvaged 3 from this mistake that I masked “just in case”.