Ecology Department seeks public comment on draft permit to control nutrients discharged by wastewater treatment plants

The City of Lynnwood wastewater treatment plant. (Photo courtesy City of Lynnwood)

The Washington State Department of Ecology is asking for public review and comment on a draft permit aimed at better controlling nutrients that wastewater treatment plants — including the City of Lynnwood plant — discharge directly into Puget Sound. Virtual information sessions are also scheduled this Tuesday and Wednesday, Feb. 9-10. (More details below.)

The Puget Sound Nutrient General Permit applies to nearly 60 treatment plants that discharge directly to Puget Sound and its estuaries. All of the facilities already have individual National Pollutant Discharge Elimination System (NPDES) water quality permits that include a wide range of requirements to protect water quality. However, only a few of these NPDES permits currently require nutrient controls. The new general permit will focus only on controlling nutrients and work in conjunction with the broader individual permits for each facility, the Ecology Department says.

“The informal draft is conceptual and does not have as much detail as the formal draft and final permits will include,” Ecology says in a post on its Ecology Blog. “Given the complexities of this permit and the critical services sewage treatment plants provide, we are offering multiple opportunities for stakeholder input as we develop the permit.”

The informal draft was prepared, Ecology says, after working with an advisory committee comprised of regional wastewater treatment plant representatives, state agencies (including Ecology and the Department of Commerce), the U.S. Environmental Protection Agency, and the environmental community.

City of Lynnwood Public Works Manager Jared Bond said the city has received a copy of the draft permit and is reviewing it. “We will be checking to see how the requirements match up with our future planning efforts, and also how the proposed TIN (Total Inorganic Nitrogen) action levels compare to the historical loads,”  Bond said. “At this time, we are uncertain how this will affect our treatment processes.”

Graphic courtesy Department of Ecology

The Ecology Department notes that nutrients are an important part of a healthy marine ecosystem, but excess nutrients cause too much algal growth, which ultimately depletes dissolved oxygen (DO) in the water. This algal growth occurs because nutrients are fertilizer for algae and aquatic plants. When these algae and plants die, their decomposition uses up oxygen. Many parts of Puget Sound and the Salish Sea have dissolved oxygen levels that fall below the concentrations needed for marine life to thrive. In addition to low levels of oxygen, effects of excess nutrients include:

  • Increasing the acidity of the water
  • Shifts in the food web
  • Increases in harmful algal blooms and nuisance species like jellyfish

These issues are directly related to supporting a healthy ecosystem for salmon and orca recovery, Ecology says. “Science tells us that excess nutrients from sewage treatment plants are contributing to low oxygen levels in Puget Sound. Because of this, we must require treatment plants to control nutrients consistent with the federal Clean Water Act and Washington’s Water Pollution Control Act.”

Most wastewater treatment plants in Puget Sound were not designed to remove nutrients such as nitrogen and will need upgrades to sufficiently control nutrients, Ecology adds.

The goal of the informal draft permit is to describe Ecology’s proposed requirements for the first permit term and provide context and explanation for how we used the conceptual approaches identified in the Advisory Committee’s recommendation document.

While some algae/jellyfish blooms and macroalgae littering the beaches happens naturally, Ecology scientists are seeing increased number of events and more severe blooms than before. (Image courtesy Department of Ecology)

The approaches include:

  • Optimization of current treatment processes to enhance nutrient reduction
  • Monitoring to evaluate nutrient reductions and get a consistent Sound-wide data set that can support a framework for future “water quality trading” among plants
  • Nutrient Action Levels that will trigger additional required actions at some plants
  • Initial planning for future plant upgrades, but not engineering design work unless plants trigger additional requirements
  • Lesser requirements for plants already successfully implementing nutrient control technologies

“We’re not proposing to require major infrastructure investments in the first five-year permit,” Ecology says. “Depending on the current capabilities of each individual WWTP and their community’s plans for growth and development, they will have a reasonable amount of time to plan appropriate upgrades or other improvements, while remaining in compliance with their permits.

“Our proposed adaptive management approach prevents further increases in excess nutrient loading in this first general permit,” Ecology adds. “After additional modeling, we will propose nutrient limits in the second five-year general permit, continuing the path to compliance with water quality standards. Once we have limits, we will continue to work with permittees to develop a multiple year, stepwise process for attaining final limits.”

While the technology to control excess nutrients exists, addressing this type of pollution is a relatively new task for many Western Washington wastewater treatment plants. Many communities will need to make infrastructure investments to reduce excess nutrients, the Ecology Department notes. “Planning these investments will take time and there’s significant cost associated with this work,” the Ecology Blog states. “In some cases, where existing facilities are located on limited land or have other constraints, communities will need to plan for more creative solutions. This is why efforts to reduce nutrients need to start now, before Puget Sound’s health further declines.”

Ecology says it will support this work through its traditional State Revolving Fund grant and loan program and a nutrient-specific grant request during the 2021 state legislative session. As part of Gov. Inslee’s proposed 2021-2023 budget, the $9 million grant program will help provide financial assistance to facilities for nutrient reduction planning and optimization projects.

From now through March 15, the Ecology Department is seeking feedback on these proposed permitting approaches, “especially where there are options available for which direction we should take on a specific permit condition.” Al comments received during the informal comment period will be used to develop the formal draft permit, Ecology says.

Use the online comment form (ecomments) to submit comments. More information on how to comment on the informal draft is on the permit webpage.

As a way to provide additional information and answer questions, Ecology has scheduled the following virtual information sessions:

The formal draft general permit is scheduled to be issued for public comment this spring and there will be public hearings during this time. Ecology expects to make a final permit decision later in 2021, after reviewing public comment.

“Reducing nutrient pollution is an important step in protecting and restoring Puget Sound for all of those who use, need, and enjoy the sound in their daily life,” Ecology concludes. “Puget Sound communities will continue to grow, adding more people and more nutrients into the system. Our proposed permitting approach supports smart growth — ensuring communities invest in wastewater infrastructure that protects Puget Sound and all it provides to people and the environment.”

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