A Japanese research group announced Dec 2, 2014, that it has succeeded in recovering phosphorus with microbial fuel cells while generating electricity from animal husbandry wastewater including porcine excreta.
The group is led by Kayako Hirooka and Osamu Ichihashi, associate and specially-appointed assistant professors, respectively, at River Basin Research Center, Gifu University.
A microbial fuel cell uses electrons generated when microbes called "power-generating bacteria" decompose organic substances. When it is used for wastewater treatment, it not only removes organic substances from the wastewater but also recovers electric energy. In addition, the research group found for the first time in the world that it is also possible to recover phosphorus by attaching it to electrodes, the university said.
Phosphorus is used not only as the main component of chemical fertilizers but in various fields such as metalworking and food additives. However, until a few years ago, there was a concern that economically minable phosphate ores would be depleted within decades.
Though new phosphate ores were found in recent researches and there is currently no immediate concern about depletion, the issue has not been completely solved, the group said. Especially, Japan imports almost all of the phosphate used in the country. Therefore, the recycling of phosphate is needed to stably secure a necessary amount of phosphate and price bargaining power, it said.
Furthermore, many kinds of wastewaters contain a large amount of phosphorus. And if phosphorus is discharged without processing it, it causes eutrophication in the water area. Therefore, it has been a requirement that phosphorus be removed from wastewater.
The research group plans to increase the size of the microbial fuel cell and reduce its cost in the aim of commercializing it after 10 to 20 years.