Tapping wastewater: Probing hidden depths for energy
A Brainerd research partnership may have far-reaching implications regarding energy and the economy — and it comes from a steady source that’s largely untapped.
The source could be surprising. It flows throughout the city and has the ability to heat 450 homes in Brainerd per year or part of it could heat the Brainerd High School.
Wastewater decomposes as it flows, which creates energy and it picks up heat from the ground. Geothermal energy, which is stored in the Earth, is well established.
Extracting the energy from wastewater has unique challenges in dealing with the solid matter. The energy collection system wouldn’t move the wastewater but would use a clean glycol process to extract it in a closed system, therefore potential for odor should not be a concern, Hidden Fuels reported.
Energy from the wastewater has been used for 14 years to heat the Brainerd Public Utilities building and keep its sidewalks free of snow and ice during the winter.
Todd Wicklund, Brainerd Public Utilities finance director, said when the system was upgraded in February and was down for a time the heating cost went from $35 to $3,500 in one month, showing the savings.
If it is feasible to extract the energy, the technology developed here could have applications across the nation and potentially beyond.
Last year, a research partnership was formed between the city of Brainerd, the Brainerd Public Utilities, the Brainerd School District and an area firm called Hidden Fuels.
The partnership is looking at the potential to heat and cool school and public buildings by extracting energy from the wastewater stream.
For years, Al Cibuzar, A.W. Research president and Hidden Fuels principal, said he’s been watching as money has been flushed down the drain.
Using geographic information systems — smart maps — and monitoring at lift stations, the research is looking at flow and temperature of the wastewater stream.
Drawing just 10 degrees of heat from wastewater or 3,439,000 Btu an hour would provide enough energy to heat 143 homes.
There are still questions out there, such as who owns the energy and how will consumers use it or how will it affect their energy consumption costs have yet to be fully explored.
But an update Tuesday brought the partners together in a session at the Brainerd Public Utilities. The technology has the potential to be used for municipal wastewater systems and individual septic systems. The group has researched the idea and doesn’t think this type of analysis has ever been done for a community.
“If the final results of this study show that the application of heat extraction technology is feasible and cost effective, these rewards can be significant for the community,” Hidden Fuels reported. “The city of Brainerd and Brainerd School District could expect to find a significant reduction in both heating and cooling costs for many buildings.”
Other benefits Hidden Fuels listed include reduced fossil fuel use and reduced greenhouse gas emissions and a potential income stream for public works utility.
In a case of first things first, the plan is to continue the study for six more months to accumulate a full year of data. Then the group will look at the cost of extracting the energy.
The 16-month research project was funded with in-kind contributions from the partners and a $45,000 grant from the Minnesota Department of Energy Security.
Cibuzar formed Hidden Fuels, which is based at the Brainerd Lakes Regional Airport, with Pete Nelson, an engineer, and Jeff Aga, chief financial officer.
Cibuzar, said the genesis of Hidden Fuels came in the 1990s as he considered the options of capturing heat energy from wastewater. Cibuzar has two conceptual patents regarding the capture of electrical energy from a wastewater treatment system.
After the meeting, Cibuzar said looking at energy emissions from the average home of four people, if homes were even 20 percent more energy efficient that would make a huge impact on their natural gas and electricity costs. A lot of energy is being shipped out the door, Cibuzar said.
He equated the wastewater system to having an energy bank with daily deposits and said no one is collecting the deposits or the available interest.
At least for now.
RENEE RICHARDSON may be reached at firstname.lastname@example.org or 855-5852.