POST FALLS - Bruce Noble wants to put wastewater to work.

The former Post Falls city engineer is proposing a demonstration plant to his ex-employer in which effluent from the city's wastewater reclamation plant would run through a turbine to produce electricity.

"The plant could save the city between $200,000 and $700,000 over the next 20 years depending on which growth and revenue projections are used," Noble said.

Noble said the size of Post Falls' plant won't make the project as lucrative as it would with larger facilities, but he's offering to build the $360,000 demo plant for free.

Noble's company, Post Falls Hydro, would recoup the cost through the city's energy savings, then the city would reap all of the savings thereafter.

Noble has met with Post Falls officials on the proposal, which needs approval from the City Council. It was tentatively expected to be heard in December before being postponed indefinitely.

Noble said the facility in Post Falls would generate about 15 kilowatts per hour and produce revenues of about $1,000 per month.

City Administrator Eric Keck said the city supports the concept, but there are logistical hurdles to overcome.

"Our consultant engineers have concern with the siting of the hydroelectric turbine and are concerned that it will cause problems with the future installation of an additional outfall to the Spokane River," Keck said. "We need to have JUB Engineers design the second outfall and then have Bruce work with them to see if both can be installed within the existing easement without any problems.

"Everyone loves the concept, but we cannot move forward in haste without having all of the details worked out."

Another thing to consider is that Post Falls has a pending lawsuit against the U.S. Environmental Protection Agency alleging the Spokane River cleanup plan developed by Washington Ecology violates the Clean Water Act.

Post Falls, Coeur d'Alene and the Hayden Area Regional Sewer Board discharge treated wastewater into the river.

Noble said he hopes Post Falls will soon consider a proposed agreement between the city and his company.

"Our request to is not for approval of the project, but consideration of the agreement for adoption so that we have some level of comfort before expending funds to resolve the design concerns," he said.

Noble said other cities from outside Idaho have expressed interest in the hydro proposal, but he declined to specify. He knows of only two other cities using effluent to produce electricity - Deer Island, Mass., and Muskegon, Minn.

The Deer Island plant, he said, saves the utility about $560,000 per year in electrical costs.

With projects after the demo plant is built, Post Falls Hydro would own the plants and split the energy revenues with municipalities. Noble said he has investors for the first full project lined up, but declined to say who or how much money. After a plant is built, a federal tax credit through the Department of Treasury that pays for 30 percent of the cost is available.

While most alternative companies look to wind, solar and geothermal sources for their energy production, hydroelectric power is a somewhat unique approach to renewable energy, Noble said.

"If we capture even 10 percent, it is a significant use of a resource that is currently going to waste," he said.

Post Falls Hydro plans to focus on micro hydroelectric projects in the Northwest to make use of "net-metering," Noble said.

"Net-metering is basically running the electric meter backward when you are producing electricity," Noble said. "It simplifies the permitting process and brings plants online quicker than working through power purchase agreements and the Public Utilities Regulatory Policies Act."

Noble said the company will eventually expand to larger projects and focus on states that have renewable energy portfolios and higher energy rates than the Northwest.

"We're starting out small," Noble said.

An advantage of power generation from effluent is that it's not climate dependent, Noble said.

"A population uses the same amount of potable water on a daily basis independent of the weather," he said. "Unlike wind and solar, we can accurately predict what and when our generation capacity will be."

Noble said there's also a positive environmental aspect, in addition to using a reclaimed and renewable resource.

"Treated wastewater is often oxygen-deprived and running the wastewater through the turbine and spillway will aerate the effluent and make it less toxic to aquatic life," he said.