Three Technologies For Slashing Waste Plant Energy Consumption

A suite of technologies is available to help wastewater treatment plants cut carbon emissions, and savvy operators are already taking advantage of the new tools.

“To treat the nation’s water, the wastewater sector consumes 22 terawatt hours of electrical energy each year. That is enough electricity to power the homes and businesses in the states of New Hampshire and Maine,” according to the American Biogas Council.

But as every waste industry stakeholder knows, the organic matter in wastewater is an energy resource. Some plants are already exploiting that.

“Reducing treatment plants’ energy footprints through energy efficiency and using the currently wasted energy could save money and reduce greenhouse gas emissions,” according to Ensia.

Ensia recently examined three technologies that can help wastewater plants cut their energy output.

Merits Of Membrane Aerated Biofilm Reactors

One of the most promising tools for reducing energy costs is known as membrane aerated biofilm reactor (MABR) technology, the report said.

“Instead of forcing air into the bacteria tank, operators insert massive cubes full of porous membrane tubes. A blower moves low-pressure air into the tubes. Bacteria congregate on the outside of the tubes, sucking up the oxygen that passes through them and creating an oxygen concentration differential that helps more oxygen diffuse,” the report explained.

ZeeLung is one example of this technology. The Metropolitan Water Reclamation District of Greater Chicago, which is working to become energy neutral by 2023, has test-driven the technology, which was provided by GE, according to a statement.

“GE estimates that, depending upon existing plant design and operation, ZeeLung is four times more energy efficient than conventional forced draft aeration,” Ensia reported.

Biogas Benefits

Harnessing the power of biogas is another way waste plants cut their energy consumption. But only a third of U.S. waste plants take advantage of this opportunity, Ensia reported.

“In order to be cost effective, you have to be a fairly large facility, at least 5 million gallons a day of wastewater treatment,” says Virginia Lew, manager of the Energy Efficiency Research Office at the California Energy Commission, per the report.

So how can small wastewater plants tap the same potential?

“Plants that do not produce enough gas to bother generating electricity often burn it off instead. Adding battery storage could allow them to store enough energy to make using it worthwhile,” the report said, citing Lew.

Anammox Advantages

Anammox is another way plants can save energy. Neutralizing ammonia during wastewater treatment is energy-intensive for wastewater plants.

“Krüger, a subsidiary of Veolia Water Solutions & Technologies, has trademarked a process called ANITA Mox to better deal with ammonia,” Ensia reported.

The technology introduces surfaces covered in ammonia-oxidizing bacteria.

“If you can break down that ammonia in an anaerobic process, your demand for air significantly decreases,” said MWRD executive director David St. Pierre, per Ensia.