TNPOP Case Studies

Carthage Wastewater Treatment Plant 

Empowered by Local Leadership, Driven by Efficiency

In 2017, with strong backing from the Mayor and Town Council, the Carthage Wastewater Treatment Plant joined the Energy Efficiency Partnership. The assessment, conducted by experts from the University of Memphis and the University of Tennessee's Municipal Technical Advisory Service, identified actionable strategies for improvement.

• 19% reduction in total energy usage
• 19% cut in energy-related operating costs
• 85,000+ kWh saved annually through low- and no-cost upgrades

These improvements not only reduced environmental impact but also delivered lasting financial savings for the town.

 [Read the Full Case Study]

Wastewater Plant Savings in Carthage, TN

Norris Water Commission

Proving That Low-Cost Changes Can Deliver High-Impact Results

Since 2016, the Norris Water Commission has actively embraced innovative, low-cost strategies to improve water quality and energy efficiency by voluntarily participating in TDEC’s Wastewater Nutrient Plant Optimization Project. Using the techniques learned through the program, Norris has achieved remarkable environmental and operational outcomes:

• 17.6% reduction in average monthly electricity use
• 84% decrease in total nitrogen discharged
• 25% reduction in total phosphorus levels
• Lower energy costs
• Less sludge produced
• Improved effluent quality before discharge to surface waters

These ongoing results highlight Norris’s commitment to sustainable practices and the long-term value of optimization, without the need for major capital investment.

[Read the Full Case Study]

City of Columbia

Leadership, Smart Adjustments, and Impressive Results

In 2011, Mayor Dean Dickey accepted an invitation for the City of Columbia Wastewater Treatment Plant to join the Energy Efficiency Partnership. Following an in-depth assessment, the Partnership team recommended operational improvements, including reduced aeration and modified UV control.

• 24% reduction in total energy use
• $160,000 in annual energy cost savings
• $0 in capital expenditures

Through strategic operational changes alone, Columbia achieved measurable improvements—demonstrating that strong leadership and smart optimization can drive significant results without major infrastructure upgrades.

[Read the Full Case Study]

Church Hill, TN

Partnering for Progress on the Holston River

In 2016, the Church Hill Wastewater Treatment Plant accepted an invitation to join the Tennessee Water and Wastewater Energy Efficiency Partnership. Over the following five years, city and plant staff committed to reducing environmental impact and boosting operational efficiency.

• 35,800 tons/year reduction in nitrogen loading to the Holston River
• 310,000 kWh/year in energy savings
• $26,000/year in reduced energy costs

Church Hill’s results highlight how consistent effort and strategic optimization can deliver measurable environmental benefits and long-term savings—without requiring major capital investment.

[Read the Full Case Study] 

Plateau Utility District: Wartburg STP

A detailed case study is on its way for the 2024 Nutrient and Energy Optimization Study at the Wartburg Sewage Treatment Plant (STP), operated by the Plateau Utility District. This forthcoming report will highlight key strategies, performance data, and outcomes in improving nutrient removal and energy efficiency.

City of Dyer WWTP

We are excited to soon share the 2024 Nutrient and Energy Optimization Study for the City of Dyer Wastewater Treatment Plant (WWTP). This upcoming case study will showcase the innovative solutions and impressive outcomes achieved in optimizing nutrient management and enhancing energy efficiency at the plant.

Fayetteville Public Utilities

Cutting Energy, Costs, and Nitrogen – All at Once

In 2011, the Fayetteville Public Utilities Wastewater Plant joined the Energy Efficiency Partnership to explore opportunities for improved performance and sustainability. The results exceeded expectations.

• Significant energy and cost savings
• Substantial CO₂ emissions reduction
• 50% decrease in Total Nitrogen discharge

Through targeted low- and no-cost strategies, the plant demonstrated how operational optimization can drive both environmental and financial impact.

[Read the Full Case Study]

Lawrenceburg Utility Systems

Boosting Efficiency While Handling More Demand

In 2017, the Lawrenceburg Utility Systems Wastewater Treatment Plant partnered with the Energy Efficiency Partnership to explore ways to improve performance without major investment. After a site assessment in March 2017, the facility began implementing operational changes—and the results speak for themselves.

• 22% reduction in electricity costs
• 26% drop in electricity use
• $21,000+ in annual energy savings

Despite a 13% rise in plant loading, energy costs dropped—proving that smart optimization can offset rising operational pressures.

[Read the Full Case Study]

Harriman Wastewater Treatment Plant

Smart Solutions for Cleaner Water and Lower Costs

Starting in 2016, the Harriman Wastewater Treatment Plant took a proactive approach to improving performance at its aging facility by voluntarily joining TDEC’s Wastewater Nutrient Plant Optimization Project. Through this initiative, Harriman adopted innovative, low-cost strategies to enhance water quality and energy efficiency.

• Reduced electricity consumption
• Improved biological treatment performance
• Significant nitrogen and phosphorus removal before discharge
• Ongoing cost savings and environmental benefits

Using data collected between August 2017 and July 2019 as a performance baseline, Harriman has continued to build on these early improvements, demonstrating that even older facilities can achieve modern efficiency without major capital investment.

[Read the Full Case Study]

City of Franklin

A Leader in Energy Efficiency from Day One

The City of Franklin’s Water Reclamation Facility (WRF) joined the Energy Efficiency Partnership in its inaugural year, 2011—becoming one of the program’s earliest adopters. While many participants focused on traditional wastewater treatment facilities, Franklin took a different approach by targeting its Water Reclamation Facility for optimization.

Partnership assessments revealed key opportunities, and Franklin acted—implementing energy and process improvements that delivered major returns:

• $200,000+ in annual energy cost savings
• 13% reduction in annual energy use
• 1,835 tons of CO2 emissions eliminated per year

Franklin’s forward-thinking approach and commitment to resource recovery positioned its WRF as a model for sustainable facility operations across the state.

[Read the Full Case Study]

Cookeville Wastewater Treatment Plant

Reducing Costs, Improving Water Quality, and Lowering Energy Use

In 2015, the Cookeville Wastewater Treatment Plant joined TDEC's Wastewater Nutrient Plant Optimization Project, setting the stage for impactful changes in both environmental performance and operational efficiency.

• Nutrient Reduction: Successful removal of nitrogen and phosphorus before discharge to surface waters
• Energy Efficiency: By optimizing aeration processes, the plant reduced electricity consumption by 40.1%
• Cost Savings: A 36% reduction in energy costs, despite a 7.7% increase in electricity prices
• Sustainability: Reduced energy use and less sludge production, benefiting both the facility and the environment

Cookeville's journey began in January 2014, when staff were trained in techniques that reduced nutrient levels and energy consumption. By using less aeration equipment, the plant dramatically improved its operational efficiency, saving both energy and costs—proving that with the right approach, sustainability can also be cost-effective.

[Read the Full Case Study]