LEWISTON — It is a problem that has been around since man first started gathering in cities: How to get rid of human waste in a way that is safe and efficient.

A group in Lewiston-Auburn tweaked the cities’ existing solution to that problem and, as a result, the U.S. Environmental Protection Agency has recognized it for creating a waste disposal system that reduces the amount of waste and produces energy to cut costs at the same time.

The Lewiston-Auburn Water Pollution Control Authority was given an honorable mention for excellence and innovation for the project. The kudos are impressive, if not a little hard for a layman to understand. Technically, the project was lauded for its “anaerobic digestion and co-generation units,” a method of disposing of “biosolids.”

According to a news release, the LAWPCA needed new options to dispose of waste processed by the Twin Cities’ treatment plant because of the rising costs of applying it to farm fields.

The authority received a loan to construct an anaerobic digestion facility and that is when the magic happened. The project reduced the amount of final waste product while producing significant amounts of electricity, which is used to power the water reclamation facility.

According to the EPA, the project’s two 230-kilowatt biogas cogeneration engines produce an average of 200,000 kilowatt hours per month and have gone as high as 380,000 kilowatt hours some months. This self-generated power significantly reduces the facility’s energy costs.

The local project was one of four in New England to be recognized and among 30 honored nationwide

“The scale and complexity of the projects that are being recognized show the determination and creativity of EPA’s partners in achieving water quality goals,” EPA New England Regional Administrator Alexandra Dunn said in the release.

Details about the project can be found at the LAWPCA website.

The Lewiston-Auburn Water Pollution Control Authority facility in Lewiston. (Courtesy of LAWPCA)

What is Anaerobic digestion?

Anaerobic digestion is a series of biological processes in which microorganisms break down biodegradable material in the absence of oxygen. One of the end products is biogas, which is combusted to generate electricity and heat, or can be processed into renewable natural gas and transportation fuels.

A range of anaerobic digestion technologies are converting livestock manure, municipal wastewater solids, food waste, high strength industrial wastewater and residuals, fats, oils and grease and various other organic waste streams into biogas, 24 hours a day, seven days a week. Separated digested solids can be composted, utilized for dairy bedding, directly applied to cropland or converted into other products. Nutrients in the liquid stream are used in agriculture as fertilizer.

Source: Lewiston-Auburn Water Pollution Control Authority

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