The city of Harrogate may soon be using the latest in alternative wastewater treatment systems if the Board of Mayor and Aldermen decide to go with the Tennessee Department of Environment and Conservation approved recommendations detailed recently by John Allen, partner of the engineering firm Hatfield and Allen.
The plan, Allen said, has always been to follow the traditional path in wastewater treatment, which is a conventional plant sitting upon a body of water. However, TDEC has banned any traditional treatment plants on the Powell River, he added.
“Fifteen years ago, we (the city) had sewers running on top of the ground and failed septic tanks everywhere, to the point where there had been a moratorium,” said Allen.
Those conditions, he said, led to the city contracting with the Claiborne Utility District to allow for the treatment of some 200,000 gallons per day via the CUD facility. Right now, the city is using over 50 percent of that capacity.
The Patterson Road Pump Station (the city’s largest sewage station) is at the end of its useful life, he said.
Cluster systems, Allen said, bridge the gap between traditional and alternative sewers and is a combination of the various means of transport and secondary treatment. The cluster system can be as small as an individual septic tank or as large as a massive municipal plant, he said.
“The way TDEC wants us to look at our system is traditional treatment with alternative disposal – which is one of two things, drip or spray irrigation,” said Allen.
The lower costs and the discharge limits will likely be the catalyst to going this route, he said.
“If we discharge to a river, we have to put in a whole bunch of chemicals. It’s less public opposition because we’re not messing with someone’s boat ride or fishing expedition. We’re basically watering the grass,” said Allen, adding there is also less liability for the operator — due to overflow issues that accompany heavy rainfall.
The alternative package plant utilizing spray or drip irrigation can be placed close to growth areas and is virtually “fail-proof” in its functioning.
Spray irrigation can output up to 3,000 gallons of treated wastewater per cleared acre, per day, said Allen.
Currently, the city is treating about 100,000 gallons of waste each day. With just 33 acres of land devoted to this system, the city’s current disposal needs would be easily met or exceeded, he said.
Up to 2,000 gallons of waste can be disposed of per day, per acre, if woodland is used, he added.
This method uses ordinary spray irrigation equipment, but must be used in combination with a package plant.
The drip irrigation method, which Allen says he “likes,” can dispose up to 6,000 gallons of waste per day, per acre. This method can utilize vacant spaces inside parks or sports fields, due to its small package plants and covered drip fields.
Allen estimated the package plant could cost anywhere from just under $500,000 to $3 million, depending on the city’s needs, with similar installation costs. Harrogate could get by with equipment and installation costs less than $4 million, he said.
The plant, he said, is compact enough to be placed behind the city hall building.
“I would not suggest doing away with anything you have. This is not taking the place of anything – this is simply adding onto what you already have built,” said Allen.
The project could take over two years to complete, he said.
“You don’t want to continue to push this issue down the road as a council because one entity could change what you have, overnight, and then you’re in scramble mode. Right now, we’re not in scramble mode, but we need to do something. Otherwise, something will be done for us within, I would say, five years,” said Allen.
Reach Jan Runions at 423-254-5588 or on Twitter @scribeCP.