Emefcy is building a demonstration plant in Israel that will scale up to 16 modules starting next year, and, in the lab, the company is already testing wastewater from factories across the globe. Emefcy hopes the scalable system will be available commercially some time in 2013, with a price tag of $4,000 to $5,000 per module.
Although Emefcy has garnered a lot of attention for its progress, the microbial fuel cell industry as a whole is still trying to prove whether this will really work, says Zhen He, a microbial fuel cell researcher at University of Wisconsin–Milwaukee's Environmental Biotechnology and Bioenergy Lab. He notes that of the nearly 4,000 papers published on microbial fuel cells, less than 2 percent report on processing volumes of water larger than one liter. "I don't think one group can deal with everything." he says. "We need the whole field to move this to a larger scale." But Emefcy is not alone. There are some other groups, including a team at the J. Craig Venter Institute, that are scaling pilots of a microbial fuel cell for wastewater treatment.
While Emefcy tries to cut down on sludge, other researchers look for ways to turn sludge into biofuels, such as BlackGold Biofuels in Philadelphia. Another start-up, Ostara Nutrient Recovery Technologies in Vancouver, is harvesting minerals that would usually end up in sludge and turning them into high-grade fertilizer. Anaerobic digestion is also a growing trend in the industrial wastewater industry, according to the GWI report. Other companies, like FuelCell Energy in Danbury, Conn., are capturing the gas from anaerobic digesters to be used in combined heat and power plants.
About 104 municipal treatment plants use anaerobic digestion gas capture for a combined heat and cycle plant, according to the U.S. Environmental Protection Agency. Municipalities are also taking advantage of the falling price of solar power to offset the energy needs of wastewater plants.
Other companies are looking to harness the flow of wastewater facilities to capture at least some of the hydropower as electricity. Hydrogen is another attractive by-product of wastewater, and some of Logan's research at Penn State involves looking into how to capture hydrogen to run fuel cells.
"I think there's still some uncertainty with whether the benefit is to make electrical power or to have a hydrogen production facility," Logan says. "Right now, it's a toss-up."
Depending on the location and type of wastewater, there will likely be a market opportunity for many different solutions. "We're changing the economics of wastewater," Cohen says. "It's a tremendous source of energy."