Algae

Algae are a useful first step in many designed, productive ecosystems. They are easily grown in nearly any body of water. They can be applied to several purposes -

Algae as a food source for humans

Spirulina is an extremely nutritious algae that can be grown on a small scale. I've never met anyone who likes the taste of it, but it can be ground up with avocados or pesto or other things to mask the taste. Spirulina grows in long spiral chains that can be easily harvested in a cloth. It grows in highly alkaline saltwater with a pH around

• Full instructions for how to grow your own spirulina can be found here. 100g/day/4m²
• Other small-scale examples are in Auroville, India, which pioneered spirulina farming. Informative page with details of their operation: [1]
• Then there is another Indian small-scale example in Madurai (video here) - 150g/day/20m²
• Some successful village-scale examples in West Africa. But all of these are rather labor intensive.
• Gunter Pauli and ZERI did an interesting integration project in Namibia: Spirulina and BEER! Beer and Spirulina Basically: Brewery wastewater is highly alkaline, is used for growing spirulina (eliminates cost for chemicals, takes harmful alkaline wastewater out of the waste stream), spent grains from brewery barley are first used to grow mushrooms, then leftovers are put in biogas tank. Biogas powers brewery. It's ingenious.
• There is one patent about growing your own Spirulina at home in a photobioreactor. In terms of contamination, that doesn't seem to be such an issue with Spirulina because of the highly alkaline pH, nothing much else will grow at pH 10.5.
• Intergovernmental Institution for the use of Micro-algae Spirulina against Malnutrition (IIMSAM) [2], which includes an overview of different production systems.
• http://www.spirulinasource.com/earthfoodch9a.html
• http://www.spirulinasource.com/cultivez.html

Algae as a food source for fish

Aquaponics turns algae into edible fish

Algae as a food source for plants

Some species of algae, like maerl, can be used to fertilize plants

Algae as a fuel

The carbon-based compounds produced by some algae can be used as fuel

• http://algaelab.org/ : A community algae lab in Berkley, CA seeking the development of an open-source/DIY-oriented algae technology

• Vinay says this Algal Turf Scrubber is a promising technology -
• http://www.instructables.com/id/An_Algae_Bioreactor_from_Recycled_Water_Bottles/
  • Critique: This is a cute puppy show. Quick calculation shows that you will get about 1 gram of algae from the setup under optimal conditions per day, based on empirical data from the Madurai work above. Therefore, if you did this manually to extract fuel, you would use up more calories in your effort than you get out of the fuel. No one has figured out how to do this with economic feasibility for fuel production. What are the efforts closest to success? This is definitely a proposition that could work, but efficient means of algae collection are one of the technical difficulties that one encounters in practice.