Challenge
The primary effluent (PE) pump system, in operation for more than twenty-eight years at the City of Bremerton Wastewater Treatment Plant, was much less efficient than modern technologies, resulting in a loss of energy that was not only costly, but also harmful to the environment. The availability of replacement parts for the outdated system was also limited. The City of Bremerton knew that continuing to use the aging equipment put the wastewater treatment plant at a high risk of catastrophic failure, which would result in the discharge of untreated effluent into Puget Sound.
While the City realized the critical need to replace the equipment, they were also facing fiscal challenges, with capital and operational spending being carefully scrutinized. After jointly conducting a cash flow analysis with Trane Energy Services, the City quickly determined that the energy and maintenance driven financial benefits of replacing the system, plus the reduced risk of a critical system failure, far outweighed other pending capital improvement projects, and that it was essential to reallocate Capital Improvement Plan (CIP) funds. The Bremerton Public Works and Utilities Department outlined its goals for the new project, seeking to replace the aging equipment with new more reliable systems to mitigate risk, while reducing annual energy consumption.
Solution
Optimizing CIP funds, maximizing revenue streams
As the City sought funding for the plant system upgrade, the Public Works Director was alerted about the Department of Enterprise Services Design/Build Energy Savings Performance Contracting Program (ESPC). Through this proven public works acquisition process, the City would be able to optimize capital improvement dollars, select equipment and contractors, maximize grant and incentive opportunities, avoid lengthy contracting processes, reduce energy costs, and expedite construction. The ESPC was used to procure services for the design and installation of the entire PE pump system. The City selected Trane as its ESCO (Energy Services Company) partner to provide an energy efficiency upgrade and replacement of the plant PE pumps and controls.
Aligning goals and outcomes
Trane, Department of Enterprise Services and the City of Bremerton Public Works and Utilities Department met throughout the ESPC process to select the appropriate equipment, subcontractors, design and solutions to ensure alignment of goals and outcomes. Safety plans were outlined, with strict adherence enforced by weekly and periodic inspections. Trane Energy Services provided the City with a guaranteed maximum project cost and minimum energy savings, noting the significant utility and State of Washington Energy Efficiency incentive dollars available due to the magnitude of the projected energy savings.
Working together to overcome the unexpected
Plant and construction personnel coordinated a shutdown of the PE pumps and the holding of flow through the plant, in order to remove a portion of the discharge piping, and install a new in-line flow meter and bypass pumping port. Originally scheduled for five hours, the shutdown was extended to nine hours due to unexpected issues. The ability to hold the flow through the plant for this extended period was facilitated by Trane and plant staff working together to overcome issues, while keeping the treatment plant in compliance with its National Pollutant Discharge Elimination System permit.
Testing to ensure proper performance
Six bypass pumps (four electric and two diesel backups) were installed and tested, and the PE pump demolition was authorized. The bypass pumps were turned off and the flow through the plant was held to drain the well down and install gate valves. Thorough testing of the pumps and variable frequency drives (VFDs) occurred over the following week, allowing each pump to take the lead position and ensuring proper operation of the Programmable Logic Controller.
Results
The City of Bremerton Wastewater Treatment Plant was able to fund the replacement of its entire primary effluent pump system at once, through the ESPC Program utilizing Trane ESCO services, greatly reducing the risk of critical system failure. The innovative process allowed the City to capture additional revenue streams, optimize use of its Capital Improvement Plan dollars, and extend the life of its plant. The project uncovered nearly $110K of annual operational revenue, was awarded a $500,000 Energy Efficiency Grant from the Washington State Department of Commerce, and is receiving utility incentives of $315,000 from Puget Sound Energy. It also produced a positive cash flow return in less than six years, while reducing risk to the City through the guaranteed performance contract.
"We didn’t have to spend our own professional staff time designing, bidding and overseeing the construction of the project. Trane provided that for us, and we are already realizing electricity savings," said Chal Martin, director, Public Works and Utilities Department, City of Bremerton. "Trane has been outstanding to work with."