Chelsea Green Publishing

Chelsea Green Blog

Holy $#!*! Our Next Fuel Source May Come from Our Own Waste

Diesel fuel from human poo? It’s true! University of Minnesota professor Roger Ruan has been having a lot of success with small-scale experiments converting human waste into feed for algae, which produce a diesel-like biofuel, and help clean the wastewater in the process. He’s just one of several researchers around the world looking into this promising technology. From <a href=”Alternet:
In his quest for a fuel of the future, Roger Ruan has found a valuable resource in something nobody else wants — the wastewater from Minneapolis’ largest sewage treatment plant.
The University of Minnesota professor is tapping into this rather unlikely source to grow single-celled algae and produce a diesel-like biofuel. He is one of many researchers around the world working to make biofuel from algae at a price that is competitive with gasoline and diesel fuel. But Ruan’s project — along with several other sewage-to-fuel experiments — has a distinct advantage over competing algae-to-fuel efforts: His nutrient-rich feedstock is free and available at a nearly constant rate all year long. And perhaps most importantly, Ruan’s algae can not only be used to produce fuel, but can also clean up the wastewater, potentially saving millions of dollars. “That’s what we’re after,” says Jason Willet, finance director for Metropolitan Council Environmental Services, which operates the wastewater plant and has helped fund Ruan’s research. A single acre of algae, even in an inefficient open pond, can produce 5,000 gallons of biodiesel per year, says Ruan–100 times as much as soybeans. And unlike many other algal biofuel experiments, Ruan’s work does not rely on food-based crops, such as sugar cane, as a feedstock to produce the algae. “This (sewage-based biofuel) potentially is a very, very good energy crop,” says Ruan, a professor of biosystems and agricultural engineering. “Potentially its yield can be much, much higher than starch from corn or oil from soybeans. The main reason is that it can grow at a much, much faster rate.” Growing fuel-producing algae in waste is not Ruan’s idea alone. The concept drew international attention in 2006 when a startup in New Zealand called Aquaflow successfully harvested biofuel from open-air ponds at wastewater treatment plants. The company expects to be able to produce the biofuel on a large scale, and recently attracted the attention of major players in the airline industry by announcing it had distilled a special blend that meets the technical specifications for jet fuel. Aquaflow’s advances, combined with the Pentagon’s interest in biofuels as an alternative to conventional jetfuels, has sparked a flurry of academic and industrial research in the United States. A team at the University of Virginia has been working to maximize the efficiency of the algae-growing process, and the chemistry department at Old Dominion University in Norfolk, Va., has built a small-scale bioreactor at a local wastewater treatment plant that may eventually be able to produce $600,000 worth of fuel per year. Even NASA has thrown its hat in the ring, with researchers working on the development of floating greenhouses for algae cultivation. The bags are stocked with human waste and sown with species of freshwater algae, and then deployed into the ocean. The semi-porous plastic membrane allows the exchange of CO2 and oxygen to continue uninhibited, but prevents the salty seawater from disturbing the fecund growing conditions inside. Soaking up the sun and feasting on the nutrients in the sewage, the algae produce fat-laden cells that can be harvested and refined into fuels. U.S. entrepreneurs have also entered the market. In June, Indianapolis-based Algaewheel contracted with the city of Reynolds, Ind., to construct a module at a wastewater treatment facility that uses a wheel-like rotating contraption to filter incoming sewage through a series of algae cultures. The fuel generated from the process will be used to power the facility. Read the whole article here.   Related Articles:


Ready, Set, Forage: Pick Pawpaws, Win a Book!

It’s pawpaw picking time! As we cruise into fall, the change in season often evokes images of apple picking and pie-eating. But apples aren’t the only fruit reaching their prime this time of year. Lesser known but equally delicious is the pawpaw. Described as a cross between a banana and a mango, this exotic-looking fruit […] Read More..

5 Common Invasive Species and How to Manage Them

Last week, we asked authors Tao Orion and Katrina Blair to share alternative approaches to managing five different plant species commonly held to be “invasive.” St. John’s Wort, Garlic Mustard, Thistle, Oxeye Daisy, and Kudzu are often dismissed as annoyances at best and the target of aggressive eradication with harmful chemicals at worst. Orion and […] Read More..

What in the World is a Pawpaw?

Have you heard of the pawpaw? A few generations ago, most would say “yes!” You could ask just about anyone and they could tell you what this fruit looked and tasted like, and more importantly, where to find it. But today, the pawpaw remains a mystery to some and entirely unknown to others. In Pawpaw: […] Read More..

Uncovering the Many Uses for Abundant Kudzu

As Invasive Species Week comes to a close, Tao Orion, author of Beyond the War on Invasive Species, and Katrina Blair, author of The Wild Wisdom of Weeds,  share alternative approaches to understanding and managing Kudzu. Take a look through our final profile and check out any you might have missed along the way: Oxeye […] Read More..

Oxeye Daisy: A Plant for the Pollinators

As Invasive Species Week continues, Tao Orion, author of Beyond the War on Invasive Species, and Katrina Blair, author of The Wild Wisdom of Weeds, are sharing alternative approaches to managing and using plants considered to be “invasive.” Take a look through today’s profile on Oxeye Daisy and check out tips for working with Garlic […] Read More..