The Secret To Savings? Your Utility May Be Letting It Burn Away

In Fort Wayne, IN, the wastewater treatment plant cut its monthly energy consumption from about 1.6 million kilowatt-hours to just over 1 million kilowatt-hours, saving the utility $42,000.

The secret? Methane gas.

After an EPA consent decree in 2013 required the utility to cut down its negative environmental impact, projects were initiated to reduce the amount of methane gas burned off into the atmosphere. It was then that city officials decided that instead of burning off the methane, they would try and utilize it to power certain operations of the WWTP, reports The Journal Gazette. They began utilizing digesters, which heat microscopic organisms and cause them to break down raw sewage, in turn creating energy.

“At our plant, we have anaerobic digestion, which produces methane gas,” said Doug Fasick, a senior program manager for engineering at City Utilities, according to the Gazette. “We’re capturing that methane gas and running it through two generators that are 400 kilowatts each. They’re essentially supplementing our power needs for the water pollution control plant.”

Methane is currently being used to supplements about 32 percent of the plant’s energy needs.

Despite this success, the utility has much bigger plans. Its goal is to get the facility as close to off-the-grid as possible by supplying all its power in-house. On average, electricity costs for the plant run about $1.3 million per year. Together with the Three Rivers Filtration Plant, which processes Fort Wayne’s drinking water, energy costs amount to about $2 million per year, according to the Journal Gazette.

To generate enough methane to power all plant operations, additional waste streams will be brought in and added to the anaerobic digester. The utility is exploring the possibility of utilizing waste grease from commercial kitchens. Currently, that material typically comes in as part of the plant’s normal wastewater treatment process, which causes it to lose some of its energy potential. This can be avoided by bringing grease directly to the digesters, said Matthew Wirtz, deputy director of City Utilities, according to the Journal Gazette.

“Right now they’re required by best practices and by our ordinances to pump that grease out and that gets brought to the plant,” Wirtz said. “We’d like to be more proactive about that and actually bring that directly into the digesters.”

In addition to cost savings for the utility, city officials hope these changes trickle down to savings for the ratepayers. They hope to use alternative energy forms to power the cities two most expensive utilities; the water pollution control plant and the Three Rivers Filtration Plant.