In a little more than four years, an upgrade to the treatment plant will allow it to process more of the wastewater coming into the plant, Director Darren Gore said, or from 16 million gallons per day to 24 million gallons per day.
Once the project is complete, it will have cost $36 million, he said. To fund it, ratepayers are being charged $3 per month per customer over the next five years.
“We just got it approved for design Nov. 8,” Gore said. “We’re looking at 15 to 18 months for the design phase and two and a half to three years for construction.”
Population growth is the most urgent reason for having to upgrade, Gore said.
The Tennessee Department of Environment and Conservation rules limit the amount of wastewater that can be processed to 80 percent of the plant’s capacity, which is 16 million gallons a day.
“We’re just reacting to the growth we’ve had and planning for the future growth,” Gore said.
Unlike the high-technology membrane filtration system installed in the latest upgrade at the city’s water treatment plant off Sam Jared Drive in northern Murfreesboro, construction will primarily duplicate existing processes that have proven successful over time, said Assistant Superintendent Stan Wallace, a veteran of 37 years with the city of Murfreesboro.
“While we always look at new technology, it isn’t always a good idea to change from a proven process in this business,” Wallace said.
As elaborate as the multimillion dollar add-on will be, Gore said the upgrade is likely to only address a 10- to 15-year event horizon, and to a large extent, even that will depend on the rate of population growth.
That creates another hitch – how to get rid of the near-potable water the treatment plant produces.
Gore said a large portion goes back into the West Fork of the Stones River at the plant’s discharge point, but the Department of Environment and Conservation has branded this section of Murfreesboro’s waterways as impaired.
That means only so much treated water can be returned to the river, even if it is far better quality than what is there naturally.
One ingenious system of a 500,000 gallon holding tank to supply spraying a portion of it onto two large farms acquired mainly for the purpose takes care of part of it, he said.
Gore said an even more ingenious water-reuse program irrigates nearly every corner of the Gateway District, The Avenue Murfreesboro and other locations, including a few residential properties.
However, if growth continues and unless new ways of ridding the city of its effluent are found, Gore said there will eventually be a point at which new sewer connections may be significantly hindered.
At that point, he said the city will face buying more land or finding another stream or river into which the city can discharge its wastewater.
Gore noted the department is working diligently with state officials to come up with creative and progressive ways to dispose of this highly treated water.
In the meantime, Gore has said it is his goal to keep the city moving forward in the “business as usual” fashion it has grown accustomed to; where there are no concerns about new developments being afforded sanitary sewer services.
For now, though, Gore said the increase in capacity at the wastewater treatment plant on Blanton Drive should serve the needs of Murfreesboro residents for the next 10 to 15 years.