Page 7 - July-Aug 2021 Vol 39 No 2

facility’s outside power dependance. 12% of the plant usage and 6% of the city’s construction and provides a unique
Jacobs evaluated many scenarios total usage through this one project. design to reduce one of the largest users
including fixed-axis vs single axis When the project began construction of energy in the MBWWTP, Equalization
tracking, electrical connection strategies, in March of 2020, the Covid-19 pandemic Basin Blowers.
and financial arrangements including had just begun. Supply chains for solar The MBWWTP Equalization Basin
leasing and private partnerships. Through arrays were significantly delayed. Jacobs and Blower Improvement Project
this evaluation, Jacobs and the city and the city worked with Inman Solar, the utilizes the existing 70-million-gallon
determined that a fixed-axis solar array contractor, to find an equally advanced equalization basins more effectively by
would provide the most benefit over the and approved solar panel that was repurposing the useable space through
lifetime of the project. available for the same cost. By procuring compartmentalization, allowing more
The city’s schedule for completion had this array in an expedited manner, the efficient use. This allows the city to utilize
strict limits for this project, so due to the project was able to keep the aggressive smaller sections of the basins throughout
significant permitting efforts required, schedule, and the Solar Facility came dry weather and reduce aeration needs in
including being located on a site that has online and has produced energy to the the basins by up to 2/3rds.
been inhabited for more than 10,000 years, MBWWTP since October of 2020. The city procured Jacobs to evaluate
we had to expediently perform these efforts The MBWWTP Renewable Energy the existing blower facility and the
to meet these deadlines. The historical Project provides this energy directly to the equalization basins. Through that
location of the project required a thorough MBWWTP, converting the sun’s energy evaluation and collaboration, we were
archeological study of the area as well as into usable energy to power pumps, able to develop a plan to provide new
significant wetland mitigation. mixers, blowers, and other mechanical blowers replacing the existing end of
Project Design and COVID Challenges components used at the facility to clean life blowers, (while reducing the energy
needs) and also pick up approximately 1
the City of Chattanooga, Hamilton
During the project design, we developed
design and procurement strategies that County, and the surrounding regional million gallons of additional plant storage
customers’ wastewater.
utilizing the existing infrastructure. These
would allow the city to take advantage Through the Clear Chattanooga improvements will help better manage wet
of the ever-improving photovoltaic cell Program, Chattanooga also currently has weather flows through the MBWWTP,
technologies. Through a collaborative other ongoing projects that will play a reducing wet weather overflows.
design process and unique procurement major factor in reducing its greenhouse These two projects reduce the
options, we were able to increase the total gases and energy requirements. MBWWTP power usage by up to 25%
project output by approximately 30% to These projects include water reuse annually (and the city’s overall usage by
a 4 MW system in the same area, while improvements, energy efficient facility approximately 13%), providing the city
including the latest technology panels. This updates, and the MBWWTP Equalization resiliency and helping meet its overall
collaboration and Chattanooga’s steadfast Basin and Blower Improvements Project. goals in the Better Buildings Challenge.
desire for green efficient energy usage has This project currently is beginning The projects offer great examples of
led to an approximate annual reduction of
collaboration and creativity to develop
a unique approach and navigate
significant challenges
on the path of reducing Video Link:
energy and the carbon
footprint of one of the
largest Wastewater
Treatment Facilities
in the Southeastern
United States.
Public Works Innovation and Sustainability Award recipient

Graphic Comparison of Fixed-Axis vs. Single-Axis Tracker System Basin Configuration

View online at tnpublicworks.com 7