Chattanooga's $250 million city sewer revamp on schedule

The Moccasin Bend Wastewater Treatment Plant is seen in this aerial photo.
The Moccasin Bend Wastewater Treatment Plant is seen in this aerial photo.

When Nashville and Knoxville got in trouble with the U.S. Environmental Protection Agency, their sewer fixes were expected to be expensive. But the costs spiraled well beyond initial estimates as the work was tackled.

Chattanooga is 32 months into the 88 months allotted by the EPA for completing the first phase of a 2012 EPA agreement over massive sewage system overflows here. Meeting the consent decree requirements is expected to cost $250 million over more than a decade.

City officials say everything is on track here. Still, city auditor Stan Sewell is planning an early 2016 audit of the monumental revamp of Chattanooga's sewer system, which will be one of the most costly infrastructure overhauls in city history.

The EPA hit the city with the consent decree in 2012 because its aging sewer system is ill-equipped to handle the 26 billion gallons of sewage that flow into it each year. Overflows send hundred of thousands of gallons of raw waste into the Tennessee River each year. The consent decree is a negotiated agreement that puts the city on a strict timetable of upgrades that will get the sewer system up to federal standards.

It's a tedious process - that first phase alone features about 100 projects - and it has the potential to be financially volatile.

A similar 2008 consent decree in Nashville rose from an estimated cost of $300 million-400 million to more than $1 billion.

In Knoxville, the estimated cost of complying with a 2005 consent decree has risen from $530 million to $650 million, according to the Knoxville News Sentinel. Chattanooga has 1,263 miles of sewer lines, while Knoxville has about 1,300 miles, said Michael Patrick, Chattanooga's director of waste resources.

"Knoxville is probably the best comparison," Patrick said.

Taxpayers in Knoxville were saddled with the cost as the average residential sewer rate rose from $15.51 per month before the consent decree to a current monthly average of $53.50, according to the Knoxville Utilities Board.

Rates have increased in Chattanooga at a rate of 9.84 percent annually in the four years since the consent decree was issued. The residential monthly average now is $38.43, compared to $25.40 before the decree.

"We knew that rates would have to incrementally increase over time, so every time we adjust the rate - which is once a year - people see it in their sewer bills and they ask more questions," Public Works Director Lee Norris said. "But when they find out it's the consent decree, most of the time questions stop."

Some Chattanooga sewer lines date back to the 1890s. Heavy rain or mechanical problems can overwhelm the infrastructure, which features combined sewer and stormwater lines in some places.

Those issues result in overflows that spill into city streets or the Tennessee River. That happened Aug. 19 when a main line on Rowland Gap Road could not handle the more than 44 million gallons of flow sent its way because of wet weather.

While under the consent decree, the city must document every instance of sanitary sewer overflow to the EPA. That information is accessible at the city's website, where other reports to the EPA also are posted for public inspection.

Twenty-seven projects are under construction, in the design phase, in the planning phase or out to bid as the first phase continues.

Five projects have been completed so far. They have come in on budget, said Daisy Madison, the city's chief financial officer.

"Of course, it worried me when I first saw the figure," Madison said, referring to the total $250 million price tag. "However, because of the way it's been rolled out, it's been very maintainable."

The city got three long-term loans from the state with interest rates of 2 percent or less, and the increased sewer rates have helped it cope with the bills coming in from contractors.

The most expensive price tag on a single project related to the consent decree to date is a $13 million overhaul of the main pump section entering the Moccasin Bend Wastewater Treatment Plant.

Patrick said the sewer system overhaul is being completed with the region's expected growth in mind.

"It plays into almost every project, because we are the regional wastewater treatment facility," he said. "We project into 2030 and 2040."

Sewell's audit, planned for early next year, will focus largely on the many contracts between the city and third-party companies that bid for the various projects that are part of the consent decree.

"There have been things in the past that can raise eyebrows about how well we manage these types of things," Sewell said, citing problems with contractors who have worked on the 21st Century Waterfront.

"It's kind of scary," he added. "I would identify it as high risk. Just because it's risky doesn't mean we won't have great engineers and get a good bang for our buck. It just means it's high risk."

Contact staff writer David Cobb at or 423-757-6249.

Completed projects

Altamont Pump Station Improvements and Sewer RehabilitationThis project included the upgrade of the existing pump station with electrical controls and instrumentation, valves and piping, a new back-up power generator, lighting and other related equipment. Additionally, approximately 15,207 feet of sewer and service pipelines were repaired utilizing trenchless rehabilitation techniques as the main process. Manhole rehabilitation was also part of this project with 58 manholes repaired.Citico Creek Interceptor RehabilitationThis project included the rehabilitation of approximately 4,200 linear feet of sanitary sewer pipe using trenchless rehabilitation techniques as the main process. Manhole rehabilitation was also part of this project with 23 manholes repaired or replaced.Pineville Pump Station and Sewer Basin ImprovementsThis project involved the replacement of the existing Pineville Road Pump Station. Additionally, approximately 3,198 feet of sewer and service pipelines and 21 manholes in the area were repaired using trenchless rehabilitation techniques. The upgrades will allow the station to increase its capacity, performance and reliability and help to reduce sanitary sewer overflows in the area.East Brainerd Collection System RehabilitationThis project involved performing a Sanitary Sewer Evaluation Study on approximately 255,000 feet of pipe to identify areas where unwanted groundwater or stormwater could infiltrate the sanitary sewer system. From the SSES, approximately 43,169 feet of sewer and service pipelines and 87 manholes were repaired or replaced. These repairs will help reduce sanitary sewer overflows in the area.South Chickamauga Creek Pump Station and Force Main UpgradeThis project involved the replacement of large diameter valves, the upgrade of the heating, ventilation, and air conditioning system and other upgrades to the South Chickamauga Creek pump station. The upgrades will allow the station to improve performance and reliability and help to reduce sanitary sewer overflows in the area.Source:

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