Protecting Water Quality With the Best Treatment Process on Puget Sound
The Budd Inlet Treatment Plant is one of the only plants along Puget Sound to remove nitrogen as part of the treatment process. Treatment performance is among the best in the country, and routinely better than that required by permit. In this way, LOTT helps to protect water quality in Budd Inlet and ensures wastewater treatment capacity for our communities in the future. One way that we achieve this high level of treatment is through continued investment to maintain and upgrade treatment facilities.
Why nitrogen removal?
Too many nutrients, mainly nitrogen, are a problem in Puget Sound. They result in excessive algal growth because nutrients act like fertilizer for algae and aquatic plants. When these algae and plants die, their decomposition uses up oxygen that fish and other marine life need to survive. This can especially be a problem in narrow inlets like Budd Inlet. LOTT is required to meet stringent discharge permit limits for nutrient reduction by removing nitrogen from the treated water before releasing it to the inlet.
How does it work?
In very general terms, biological nutrient removal (BNR) is a process of keeping microorganisms (bacteria) thriving so they will do the work of transforming nitrogen compounds in water from one form into another, and ultimately into nitrogen gas, which dissipates into the atmosphere. Carefully managing conditions in the BNR tanks involves adding oxygen, withholding oxygen, and adding a food source for the bacteria to trigger complex biochemical interactions.
What makes it possible?
LOTT’s highly trained plant staff take a team-based approach to manage nutrient removal. Treatment plant Operators understand how to manage conditions to keep billions of microscopic “workers” at their best. Lab Analysts keep an eye on the microbes and the chemical reactions, letting Operators know if conditions are changing. Having the right equipment in proper working order to monitor the process and manage conditions is critical, and is not possible without help from Maintenance and Control Systems staff.
Biological Process Improvements Project
In 2020, LOTT began construction on the Biological Process Improvements project – a major upgrade to our nutrient removal processes. The project was completed in 2023. The key to this project was reconfiguring the original aeration basins to allow for adjustable aeration and anoxic conditions to optimize the biological process. In addition, this project replaced aging equipment, enhanced operational control and flexibility, increased process reliability, freed up valuable plant space for alternate uses, and greatly improved the energy efficiency of the wastewater treatment process.
Procurement
Construction Complexity
Team-Based Design
Funding Assistance
Investment
The Right Contractor for the Job
The importance and complexity of this large-scale project led to the decision to utilize a relatively new alternative procurement process under RCW 70.150.040, the Water Quality Joint Development Act. This process allows for the selection of a contractor based on criteria that extend beyond the lowest cost. While cost was still the highest consideration, the selection process also considered experience with similarly complex wastewater-related projects. Prospect Construction of Puyallup, Washington, was selected as the construction contractor.
Procurement
The Right Contractor for the Job
The importance and complexity of this large-scale project led to the decision to utilize a relatively new alternative procurement process under RCW 70.150.040, the Water Quality Joint Development Act. This process allows for the selection of a contractor based on criteria that extend beyond the lowest cost. While cost was still the highest consideration, the selection process also considered experience with similarly complex wastewater-related projects. Prospect Construction of Puyallup, Washington, was selected as the construction contractor.
Construction Complexity
Open Heart Surgery on the Plant
Project construction was designed to occur in stages over several years to avoid disruption of essential plant operations. Throughout construction, the treatment plant had to continuously meet permit limits for nutrient removal. That meant the biological process had to remain operational at the same time that major construction was occurring on the system. Construction of the improvements was carefully phased to ensure no downtime in treatment. LOTT’s Executive Director told the Board, “It is a lot like completing open heart surgery on a patient while ensuring the blood keeps pumping through their system.”
Team-Based Design
Early Staff Input Contributes to Project Success
During the multi-year design process, Parametrix engineering firm worked closely with LOTT staff for LOTT’s team delivery approach. Through team meetings and interim design reviews, staff members from all work groups provided important input, identifying potential operational and maintenance issues from their perspectives. This iterative approach cut down on unforeseen problems likely to be experienced during construction, which kept the project on schedule and on budget.
Funding Assistance
Low Interest Loans and Grants
The construction cost is approximately $29 million. LOTT was successful in securing two highly competitive low interest loans for the project. The Department of Ecology Water Quality Program State Revolving Loan Fund provided a loan of $11.5 million and a Department of Commerce Public Works Board Construction Loan provided a loan of $10 million. These low interest loans reduced the interest costs associated with the long-term debt. The energy efficiency realized as a result of the project also provides an opportunity to apply for grant funding from Puget Sound Energy (PSE).
Investment
A History of Protecting Water Quality
LOTT has been providing nutrient removal for nearly 30 years at the Budd Inlet Treatment Plant, beginning in 1994. At that time, the upgrade to nutrient removal cost about $30 million. With this second generation upgrade of the biological nutrient removal process, LOTT ratepayers will have invested nearly $60 million to minimize water quality impacts to Budd Inlet and Puget Sound, maximize performance, and address capacity needs. This means that LOTT is doing its part to protect these shared resources.
Project Results
This upgrade eliminates much of the recycle pumping required for biological treatment and includes state-of-the-art energy saving equipment. The project resulted in an estimated energy savings of 2,458,000 kilowatt-hours per year. This is equivalent to a carbon offset of 1,143 tons and results in an annual energy cost savings of $180,899. It will take time operating the new system to truly understand what level of treatment performance can be maintained consistently, but the initial results are very promising.
Next Steps
Project construction was completed in April 2023. Over the next several years, staff will test the boundaries of the new system to optimize operations and redefine treatment performance capabilities.