Inside a greenhouse, algae revolve on belts in and out of the wastewater. Columbus Junction is considering installing this system developed by Iowa State University researchers to treat its wastewater. Credit:

J dropcapulia Mericle reports in The Hawk Eye that Columbus Junction, Iowa, could become a pioneering city in the struggle to treat wastewater if the city council approves new technology that favors algae over bacteria.

Wastewater treatment plants receive permits from the Iowa Department of Natural Resources that regulate what can be legally discharged into waterways. When recent efforts to minimize pollution sparked the Iowa DNR to change standards for the amount of nitrogen and phosphorus that can be put into bodies of water, Columbus Junction found itself on a long list of small communities struggling to meet that demand.

Jeff Carey, wastewater operator in Columbus Junction, and city councilman Mark Huston, considered suggestions and called Gross-Wen Technologies to inquire about an alternative system, which Martin Gross, president and CEO of the company, said is more efficient, sustainable and affordable.

Dr. Gross and co-founder Dr. Zhiyou Wen, developed the wastewater treatment system in 2011 while conducting research together at Iowa State University. If approved by DNR, Columbus Junction could be the first town to receive a commercial installation system.

The patent-pending revolving algal biofilm treatment technology, or RAB, grows micro algae on vertical belts that rotate in and out of the wastewater.

During the rotation, nitrogen and phosphorus are transferred from the wastewater to the algae. The algae also takes out ammonia and other contaminants from the wastewater.

While conventional treatments use bacteria, which becomes a waste product in the process, everything that comes out of the RAB system can be used. The system would recover one ton of nitrogen and a half-ton of phosphorus from waterways each year, or, according to the Gross-Wen Technologies website, enough nutrients to grow 200,000 tomato plants.

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