View Full Version : Fuel from algae
2009-Feb-14, 11:13 PM
~The following was in response to a suggestion by a reader of an Australian Newspaper.~ Let me see if I understand the donut in a big dry salt lake concept. We dig around the parameter to a few meters below sea level, using the salty soil to construct a mountain size donut in the center of the dry salt lake. We fill the deep part with a meter or two of ocean water and grow algae on the surface of this salty lake. Now we fill the center with toxic water from the mines to a water level perhaps 100 meters higher than the algae growing lake. The toxins are removed from the water as it ozzes though the salty dirt donut shaped dam. This provides non toxic (to the algae) make up water for the algae lake, as evaporation will other wise concentrate the salt until it is too salty for any kind of algae. The only living thing in Utah's Great Salt Lake is a type of brine shrimp. To keep the carbon dioxide content high we bubble the exhaust gas from cement kilns into the algae lake. The flue gases from coal fired electric plants would likely poison the algae, but perhaps we can bubble it into the toxic water at the center of the donut. Insoluble carbonates would precipitate out in the toxic lake, but perhaps enough carbon dioxide would make it though the donut shaped earth dam to nourish the algae. How much sodium and potassium carbonate can algae tolerate, as these are soluble in water? Please correct if I have this wrong and suggest improvements. ~Neil~
2009-Feb-15, 02:05 AM
Although I support the idea of using mine effluent water to nourish fuel producing algae I do see several practicality issues.
1. The cost of transporting the effluent to the salt site.
2. The lack of cement plants operating close to salt lakes.
You may end up burning more fuel than you make.
Could blue green algae be used? It wouldnt need the salt, so could be built on the mine site.
2009-Feb-15, 02:40 AM
You're discussing ecological sanitation (http://en.wikipedia.org/wiki/Ecological_sanitation), which involve many different technologies (http://en.wikipedia.org/wiki/Ecological_sanitation#Technologies_of_ecosan_syste ms).
I believe a more efficient proposal involves the use of meandering canals and artificial wetlands through which polluted water flows. The length is seeded with varying flora and fauna (bacteria), each of which is best suited to break down the pollutants throughout their various stages. Sediments precipitate, toxins are broken down, and a couple of miles later, good, clean water (mostly) comes out on the other side.
It's already in use.
Similar uses include it's use for closed systems. My local community's pool uses both the meandering stream and an artificial wetland. The pool water is about as natural as it gets, and is cool, clean, clear, and quite healthy. They save boatloads on chlorine and other supplies.
If you just want to produce algae, the stabilization pond (http://en.wikipedia.org/wiki/Stabilization_pond)approach would work, but I believe there are far more efficient ways.
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