The inaugural "algae-oil" conference, sponsored by the Minneapolis law firm of Fredrikson & Byron, last week attracted Midwest scientists, venture capitalists and potential operators who say Minnesota and the Midwest can lead the effort to displace millions of barrels of imported oil annually with green fuel produced at sewage treatment plants, power plants and livestock yards.
For example, the more than 120 paying attendees learned how the Metropolitan Council's looming, expensive pollution problem on the Mississippi River below St. Paul may evolve into an economical, environmental upgrade that also could yield several million bucks worth of "green" diesel fuel annually.
"We were ahead of the curve when we started this research a couple years ago," said Jason Willet, finance director of the Metropolitan Council's Environmental Services. "We think growing energy on wastewater works in the Northland and now there's a lot of interest and money coming to it."
The St. Paul sewage-treatment plant is near capacity and regulators won't allow additional municipalities to come on line until tougher regulations are adapted to cut the amount of phosphorus released into the river. Phosphorus, a byproduct of treating 250 million gallons of sewage daily, results in huge algae blooms downriver at Lake Pepin and elsewhere.
A couple of years ago, bio-systems professor Roger Ruan of the University of Minnesota was pulling five-gallon pails of algae from the wastewater. Today, he's operating a $1 million pilot project at the treatment plant that indicates the St. Paul plant could yield more than 600,000 gallons of algae oil annually, including some strains that markedly reduce the phosphorus and nitrogen contained in a toxic concentrated solution that is spun out of sewage sludge. The sludge is distributed as fertilizer or dried and burned to generate heat and electricity at the plant.
As it turns out, the toxic solution, called centrate, is a good breeding ground for oily algae.
"We want to get rid of this stuff by providing a wastewater starter technology for the algae [oil]," Willet said. "We've found that the algae will absorb as much as 70 percent of the phosphorus and it will take some nitrogen and it absorbs carbon dioxide. ... The value of what the algae would take out is worth [up to] $20 million a year to us in phosphorus and pollution control. We're not sure this works completely yet, but the alternative is very expensive."
Gordon Ommen, a veteran of the ethanol industry, has always maintained that, given the constraints of current plants and the corn crop, ethanol is a pollution-reducing additive to gasoline but not a wholesale replacement.