The Tahoe-Truckee Sanitation Agency is moving forward on a new wastewater treatment facility. The decision is a big pivot from the 2022 Master Sewer Plan, intended to guide the agency in addressing its aging infrastructure over
25 years.
The variable leading to this pivot? Covid-19 and its impacts on constructions costs and materials and labor shortages. When TTSA began receiving bids for various projects under the sewer plan, there were significant inconsistencies compared to the preliminary November 2021 estimates. That difference led to staff in early 2024 shifting from the rehabilitation strategy to implementation of a more modern replacement.
Which brings us to the Clean Water Revitalization Project, set to replace TTSA’s existing nutrient removal (or wastewater treatment) facility to the tune of $310 million. The rehabilitation plan in today’s numbers would cost, according to project consultant numbers, $393.3 million.
General Manager Jason Hays walks us through some key questions about the project, what it means, and how ratepayers — amid a significant rate increase — will be affected.
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In general terms, what is the Clean Water Revitalization Project?
Jason Hays, TTSA General Manager: Tahoe-Truckee Sanitation Agency (TTSA) is embarking on a multi-year initiative to modernize the existing wastewater treatment infrastructure that has been in existence for over 50 years. The Clean Water Revitalization Project is focused on modern treatment methods that will more reliably protect public health, the Truckee River, Lake Tahoe, and the surrounding watershed, while also improving system stability and ease of operation.
Did the following factors lead the agency to move forward with building a new wastewater treatment facility?
- Aging TTSA nutrient-removal facilities, which require increasing maintenance to maintain operations
- Significant cost increases from rehabilitation costs stated in a 2022 Master Sewer Plan
- A desire to shift to less energy- and chemical-intensive processes for cleaning wastewater
- The possibility of more stringent limits, monitoring, and reporting (TTSA could be regulated under the Federal NDPES permitting program in the future based on the U.S. Supreme Court’s “County of Maui v. Hawaii Wildlife Fund” case.)
These assumptions are accurate with a few minor caveats; while TTSA is seeking to establish a reduced dependence on chemicals and move toward a more biologically focused process, the new Membrane Bioreactor (MBR) facility is not likely to reduce energy usage. Throughout the design process, we will continue to remain open to opportunities for energy efficiency, but pumping water is an inherently energy intensive process. We are also closely watching opportunities for green energy offsets like solar and using biogas generated onsite for energy production.
Regarding potential future regulatory pressures, it’s important to note that TTSA is already subject to some of the most stringent discharge requirements in the country. At this time, there is no immediate reason to believe that the regulatory monitoring program under which we are regulated will change. Leadership within TTSA recognized during initial evaluations and continues to maintain the position that it is our responsibility to be prepared for any potential regulatory scenario. MBR technology offers both the most secure assurance to continue to meet existing limits and the strongest potential to expand capabilities if the discharge requirements become more stringent at some point in the future.
TTSA currently utilizes a Biological Nitrogen Removal (BNR) system but is looking to shift to an MBR system. Could you explain what this means?
Biological Nutrient Removal or Biological Nitrogen Removal (BNR) is the process of using a variety of microorganisms cultured specifically to consume nitrogen and phosphorus. TTSA is currently using a hybridized approach that requires a chemically intensive process to remove phosphorus in combination with BNR. Membrane Bioreactor (MBR) is a variation of BNR that uses very fine filter membranes to dramatically reduce the dependence on chemical processes. MBR also allows us to intensify the BNR process and use a much smaller footprint with improved automation and operational simplicity to accomplish the same or better levels of nutrient removal.
Where is the water coming out of this nutrient removal facility going to go?
Currently, we are planning to maintain the same discharge and disposal system for the new MBR facility that we currently have in place. TTSA currently injects the treated water from the facility into the ground in Martis Valley. The water migrates from the injection point through the ground toward the confluence of the Truckee River and Martis Creek where it comingles and joins the waterways. TTSA rigorously monitors several wells along the groundwater flow path and also monitors the Truckee River and Martis Creek above and below TTSA influence.
Does TTSA currently have any trouble meeting discharge requirements from the Lahontan Regional Water Quality Control Board?
TTSA consistently meets all discharge limits under its existing Waste Discharge Requirement (WDR) permit. While some of the processes used at TTSA are chemically intensive and require substantial operational and maintenance staffing, we have proudly protected Lake Tahoe and the Truckee River for over 50 years. A major driver for initiating the Clean Water Revitalization Project is to ensure future generations of community members and visitors can continue to rely on a high standard of public health and environmental protection for the next 50 years and beyond.
What is the total project cost?
In order to make the most fiscally responsible long-term decisions for the future of TTSA, staff engaged in a 50-year life cycle cost assessment comparing the cost of the Clean Water Revitalization Project to a progressive rehabilitation of the existing facility. While it is important to note that cost estimates used in this assessment are very high level and actual costs can vary significantly as the scope of the project becomes clearer, we believe the assessment strongly supported moving forward with the project. Currently estimated costs for the entire project are approximately $310 million. As design milestones are met, a clearer picture of actual final costs will become more focused. TTSA is committed to providing the rate-paying public with revised cost information as it becomes available.
In 2023, after no rate increases for the previous 12 years, TTSA approved a significant hike in customer bills (96.72% increase) over the course of four years (2024 to 2028) in order “to ensure proper funding for upcoming major capital projects and increasing costs due to hyper-inflation.” That increase happened before any final decisions on the new nutrient removal facility were made.
How will the new facility impact customer costs? What other funding sources is the agency considering for this project?
We at TTSA recognize that large increases to rates in a short timeframe are undesirable. This abrupt increase in rates was proceeded by 12 years of 0% rate increases, primarily due to a relatively minimal capital replacement plan. After the 2022 Master Plan established a more substantial capital plan with baseline cost assumptions and timing, TTSA staff recognized that current rates could not fully support the plan. In 2023 the TTSA Board approved Prop 218-compliant annual adjustments for fiscal years ’24 through ’28 to address long-term inflation and to fund the capital plan. The rate increases were as follows:
FY24: 30.1%
FY25: 18.6%
FY26: 13.6%
FY27: 8.6%
FY28: 3.4%
TTSA is currently seeking to perform a new rate study that includes timing and costs associated with the Clean Water Revitalization Project. Many projects identified in the master plan will be made unnecessary by the decision to move forward with MBR technology. Project and capital spending timing will also change substantially. Staff has engaged in a process of identifying strategic cost saving measures to ensure a continued focus on operational efficiency. As part of our funding strategy, we are exploring opportunities to fund portions of the project with grants and subsidized lending programs. Efforts are already underway to position the agency and the project as an attractive opportunity for potential alternative funding mechanisms.
What is the most critical information TTSA wants the public to know about this project and process?
We live and work in one of the most environmentally pristine and beautiful locations in the world. We owe the clarity of Lake Tahoe and the natural beauty of the Truckee River to those men and women 50 years ago that had the foresight and drive to do what was needed to rehabilitate and ensure the protection of these amazing water bodies. We believe that we have a generational responsibility to the people enjoying this area 50 years from now to guarantee protection of our water resources. In the 1970s the U.S. Congress enacted the Clean Water Act to reverse the damage done to our environment. We are welcoming in the next 50 years of environmental responsibility and public health with the Clean Water Revitalization Project.
For more information, visit cleanwater.ttsa.ca.gov
