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Maryville never wants to put any treated sewage in Little River, but wastewater from heavy rains sometimes surpasses the ability of the pipes to transport it all to Fort Loudoun Lake, officials said Monday.

Maryville operates a regional wastewater treatment plant serving Maryville, Alcoa, South Blount and Knox Chapman Utility Districts, off Wheeler Road just downriver from Rockford,

Maryville is in the middle of a $31 million upgrade of that plant, changes that city officials say are to increase treatment capacity and improve the quality of the wastewater ultimately discharged into Fort Loudoun Lake.

Rockford City Commission got concerned when an engineer was quoted in a recent Daily Times article suggesting Maryville would ask the state for a permit to allow them to deposit all effluent in Little River, saving the expense of pumping the treated wastewater into Fort Loudon Lake near Cox Sky Ranch.

To assure Rockford that the permit will not be requested from the state, Maryville officials met with the Rockford Commission Monday at the plant.

Maryville Mayor Tom Taylor said the misunderstanding resulted from an engineer talking about possibilities out loud, not from a policy of the city. He denied the city will ask the state for such a permit.

Rockford Vice Mayor Chip Koella III said the city would like to see the permit application so the commission would be more able to answer questions from Rockford residents and they were not "asleep at the wheel."

He earlier expressed concerns with the health of the river and obligations to keep it healthy so present and future generations can enjoy recreational opportunities the river offers.

Overflow permit

Maryville City Manager Greg McClain said, "We, like you, are very interested in the water quality of the river. Our goal is to never put any effluent in the river. If we treat more than 20 million gallons per day, we can't do anything else,"

In the event of heavy rains, when the regional wastewater treatment Plant of Maryville has treated wastewater of more than 40 million gallons, it has a permit from the state to allow some discharges in Little River. The discharge is in a curve on Wheeler Road near the plant that is identified by signs.

"That only happens in extraordinary circumstances," Taylor said. "Even then it will be truly treated effluent and the new plant will be even better."

The problem with the heavy rain is that, despite city workers' efforts to keep rainwater out of the sewer lines, sometimes it gets in, said Jeff Rose, Maryville director of Water Quality Control.

This can be from old clay lines that leak, gutters that are illegally connected to the sewer lines or manholes leaking into the sewer line, Rose explained.

This water and sewage mix goes through the treatment plant so fast that it "washes out the microorganisms in the plant after a heavy rain. It takes time to build up the organism population again to treat the wastewater," Rose said.

In times of ordinary flow, water can be held in clarifiers until the plant pipes can discharge them 2.5 miles downstream in Fort Loudoun Lake.

Normally the plant has a capacity to treat 10 million gallons per day (MGD), but in times of peak flow can reach 43 MGD.

The problem is the city has a capacity to pump 20 MGD to a Tennessee Department of Environment and Conservation-permitted discharge point on Fort Loudoun Lake.

In flows in excess of 20 MPG, Maryville also has a TDEC permit to release treated water in the Little River Embayment below the plant.

Occurred six times

This year, due to heavy rains, that has occurred six times, in 2008 four times and in 2007 one time, said Rose.

The new plant is due to come online in October 2010, but hopes are to open the plant in July or August 2010. "We're lucky we got a lot of the work done while it was dry," Rose said.

In 2008, less than 2.5 percent of all treated water was released to the Little River embayment, according to Maryville statistics.

Rockford Vice Mayor Carl Koella III noted "Rockford cooperated during the drought." Alcoa ran a second intake line to Little River at Rockford to provide more water at the Alcoa Water Plant for Alcoa and Maryville.

"We're not obstructive. We just want to be good neighbors," he said.

Commission members stressed they want to be kept up to date on plans and issues that concern their citizens.

Rose said that the upgraded plant will be a big improvement.

75 percent less sludge

"There will be much better screens and grit removal. It will reduce nitrogen and phosphorus and most of the ammonia," he said.

Rose said the existing aeration basins will be replaced by "high temperature aerobic digesters that will reduce the volume of the solids that have to be disposed of at the end of the process. We hope we will have 75 percent less sludge when the new plant is open because of the new process."

"We spent about two years researching the equipment. It's cost us a little more, but should provide longer service down the road," he added.

To keep rainwater out of the sewer lines, Rose said, "the main focus is on rehabbing sewer lines to keep stormwater runoff out."

"You don't design for rainfall. You design your pipes so rainwater doesn't get in there in the first place," McClain added.

The new plant will take the capacity from 10 to 17 MGD, Rose said.

When asked what the city would do then, Taylor replied, "Once we get to that capacity, we'd have to expand the wastewater treatment plant."

Rose added that the way to increase capacity would be to increase motors and propellers.