Using Algae for Wastewater Treatment and Biofuel Production

Warning: Lengthy Backstory

I majored in Cognitive Science in undergrad, but in my last year, took at class on using constructed wetlands to improve water quality, and it changed my life. I finished my BA, took a year off to travel and work, and then made quite the academic shift by starting grad school in Civil and Environmental Engineering where I took even more courses on stream and wetland restoration and the use of plants and other organisms to clean up our messes. My research was about using natural bacteria and UV light to degrade a family of toxic pollutants commonly found at Superfund sites.

Here is the algae and wastewater part!

I then worked for four years and went back to grad school, and this is where the algae part of the story starts. I studied the use of algae to improve the quality of water leaving wastewater treatment plants and then using that algae to generate biofuels. I found the concept of using something we view as a problem (excess nutrients in wastewater) and using it as a solution (free water and fertilizer for biofuel production) to be fascinating. As the human population continues to grow, we will have to follow this example and eliminate the concepts of pollution, trash, and waste. All products will need to be completely recyclable or reuseable (see "circular economy" or "cradle to cradle").

Scientists and engineers are already viewing (and rebranding) wastewater as a resource. It turns out in addition to all the great nitrogen and phosphorus in wastewater, there is also material that makes great compost, stuff that generates methane (which can be burned for heat or electricity), and even actual gold.

Algae can pull nutrients out of water at much lower concentrations than other organisms or methods can. That algae can then be used to generate methane, lipids (think biodiesel), compost, alcohols, fish food, and more. Interestingly enough, some algae go into lipid production overdrive when they encounter scarcity of certain nutrients. This is really convenient in the context of using wastewater. Once they remove most of the remaining nutrients (currently viewed as pollution when in wastewater effluent) they then start getting stressed and storing lipids up in hopes of better times to come. Too bad for them, they might just be harvested for biofuel production!

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