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LOTT officials found chemicals are present in its reclaimed water. Are they safe?

Olympian - 8/9/2022

Aug. 9—Over the last 10 years, officials with Thurston County's wastewater treatment department have been trying to answer a question posed to them by the public.

People were becoming increasingly concerned about chemicals that were passing through treatment processes to create reclaimed water — wastewater that is treated to bring water to the quality needed to ensure public health, environmental protection, or specific user needs.

For example, reclaimed water for crop irrigation would need to be of sufficient quality to prevent harm to plants and soils, maintain food safety, and protect the health of farm workers. In uses where there is a greater human exposure, reclaimed water receives more treatment, according to the U.S. Environmental Protection Agency.

In some cases, Thurston County converts its reclaimed water to groundwater through infiltration. But it also uses reclaimed water for irrigation of the Tumwater Valley golf course and public parks and in public water features such as the East Bay Public Plaza.

In other words, people come in contact with the water quite often. Representatives with LOTT Clean Water Alliance — the nonprofit that provides wastewater management services for Thurston County's urban — gave a presentation to Olympia City Council in July regarding whether chemicals were found in these water sources. The short answer: They are, but they've been deemed harmless, for now.

Matt Kennelly, assistant executive director at LOTT, said LOTT started cleaning and reusing water in the late 1990s after the county's Comprehensive Plan was developed. At the time, the nonprofit treatment plant was discharging wastewater into Budd Inlet, but the state Department of Ecology stepped in to put a cap on the amount as the county population continued to grow.

Now the facility discharges 13 million gallons of treated wastewater a day, on average, and the rest is cleaned through coarse sand and gravel at the Hawks Prairie Reclaimed Water Ponds off Hogum Bay Road and 31st Avenue Northeast in Lacey.

Kennelly said the county has some of the best treatment plants and strategies in the country.

There are benefits of using recycled wastewater, including offsetting how much is dumped into Puget Sound. It also improves stream flows through groundwater replenishment, which helps fish and other aquatic life, and it helps offset municipal water withdrawals.

But the public started raising concerns about contaminants that might not be tested for regularly, such as byproducts from medicines, cleaning products, foods, soap, industry — residual chemicals that could be harmful to humans in the long run.

"These are part of our everyday lives, some of which are made to not break down in our bodies, some of which get rinsed off," Kennelly said.

So LOTT studied 134 chemicals found in Thurston County's reclaimed water.

Lisa Dennis-Perez, director of environmental planning and communications for LOTT, said staff worked for about 10 years with a contractor, HDR engineering, to narrow down a list of thousands of chemicals to the 134 to be searched for in reclaimed water in Thurston County.

"There's thousands of chemicals out there that are on the market right now and in use," Dennis-Perez said. "We needed a subset of chemicals that would be representative of chemicals often found in reclaimed water that are of particular interest that could impact environmental and human health."

Part of the research and planning process involved creating a computer model to estimate conditions of the water and presence of chemicals 100 years into the future.

The model assesses the risk for humans and wildlife over time, and it found no threat to human or ecological health, but two chemicals were flagged for possible concern down the road.

Potential hazards

In an interview with The Olympian, Dennis-Perez said two chemicals were identified as potential hazards in the future.

Coming in at just above their minimum risk thresholds are Perfluoropentanoic acid, a byproduct of the breakdown of other PFAS. The Environmental Protection Agency defines PFAS as "widely used, long lasting chemicals, components which break down very slowly over time."

Dennis-Perez said this byproduct is found in clothing, furniture, carpets, food packaging, takeout containers and more.

According to LOTT, under a maximum exposure scenario, a child who drinks one liter of water daily, 350 days a year, for at least six years from the same house has a non-cancer risk of 1.3, above the 1.0 threshold. But it found no adverse health effects from this scenario.

The other chemical, called NDMA, is formed in the human body from consuming food and products such as cured meats, cheeses, fish, beer, shampoo, detergents and more.

Under a maximum exposure scenario for NDMA, a person who has lived and breathed in their home for 32 years or more could be more likely to develop cancer at 2.9 in 1 million, compared to the threshold for negligible risk of 1 in 1 million. It's considered acceptable by the U.S. EPA, according to LOTT.

NDMA is a byproduct of the chlorination of wastewater and drinking water at treatment plants that use chloramines for disinfection, according to the EPA.

To produce reclaimed water, Dennis-Perez said they use membrane bioreactor technology to filter the water at the Martin Way Reclaimed Water Plant. At the Budd Inlet Reclaimed Water Plant, they use sand filtration technology.

According to LOTT, NDMA wasn't consistently found in samples of reclaimed water or groundwater. But to err on the side of caution, they're treating it as if it's present throughout the system they studied.

Public invited to weigh in

This information is what LOTT wants public feedback on in an upcoming community forum at 5:30 p.m.Aug. 15. To sign up, email

The nonprofit is planning to host a series of community forums to inform the public about the study's findings and to receive feedback before beginning a broader master planning effort to determine how to keep these chemicals at low levels — and if the 1990s plan of reclaimed water is still the best option for long-term health.

From here, Dennis-Perez said they plan to continue the use of reclaimed water for infiltration and to conduct additional targeted monitoring of some of these problem chemicals. They'll also decide if advanced treatment is needed to keep the water clean and safe.

"Conditions are likely to change over time," she said. "We expect new regulations around PFAS chemicals, products may be phased out and new ones will come in. It'll be important to update the study over time and keep tabs on new information."

After the first community forum, LOTT will take public feedback and the study findings to help build a master plan. A second forum will take place to garner feedback on the master planning process, then a third forum will share the plan.

For more information about the study, visit LOTT's website.


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