Using Science to Gain Community Confidence

BY LOTT CLEAN WATER ALLIANCE | OLYMPIA, WA

LOTT Clean Water Alliance treats wastewater for the communities of Lacey, Olympia and Tumwater in Thurston County, Washington. LOTT also produces Class A reclaimed water that is reused for irrigation, water features, and groundwater replenishment.

While reclaimed water has been used safely for groundwater recharge elsewhere in the US, the local community had questions about the safety of the practice, in part because our climate differs from areas where related research has been conducted.

In response to community questions, LOTT recently completed a multi-year scientific study to investigate residual chemicals that may remain in reclaimed water, and what happens to them when reclaimed water is used to replenish groundwater. Residual chemicals refer to compounds from pharmaceuticals, personal care and household products, and commercial/industrial sources.

The key study question was:

What are the risks from infiltrating reclaimed water into groundwater because of chemicals that may remain in the water from products people use every day, and what can be done to reduce those risks?

To ensure a scientifically credible study that engendered community trust, there were multiple layers of review and input, involving both scientific experts and community representatives.

The Reclaimed Water Infiltration Study began with a scoping process that included active public engagement. Community input, gathered through stakeholder interviews, a phone survey, focus groups, and public workshops provided the framework of the study. A Community Advisory Group, formed in 2012, consisted of local residents with diverse backgrounds and interests. This group was heavily involved in scoping and provided feedback throughout the study effort; most members participated through study completion in 2022.

The study team consisted of LOTT staff and a primary consultant, HDR Engineering, Inc. Expertise from sub-consultants in risk assessment and other specialties rounded out the team, who developed work plans for each element of the study based on accepted scientific practices. Work plans and findings were reviewed and refined based on input from two groups: the Science Task Force of technical staff from LOTT’s partner jurisdictions, the Squaxin Island Tribe, and the State Departments of Health and Ecology; and the Peer Review Panel, a group of national experts in health, toxicology, hydrogeology, and wastewater treatment. The LOTT Board of Directors fully supported the work, investing $6 million and significant staff resources in the effort.

The study entailed extensive field work and analysis, including testing for 134 residual chemicals in wastewater, reclaimed water, surface water, and groundwater. Toxicologists predicted possible risk for humans and wildlife, based on field data, computer modeling, and toxicology information for each chemical. Alternative treatment options to reduce residual chemicals in reclaimed water were also evaluated, comparing costs to risk reduction.

The study involved numerous stakeholders, and outreach was designed to keep all of these audiences informed of progress. Key audiences included jurisdictional partners, water and wastewater professionals, reclaimed water users, state agencies, local tribes, scientists, and community and environmental groups.

To ensure transparency and trust, LOTT made information available throughout the ten-year study period, including:

• Posting technical memos, fact sheets, and Peer Review findings on the website.

• Opening meetings of the Peer Review Panel and Community Advisory Group to the public.

• Providing updates on the study at publicly open Board meetings and to an email distribution list.

• Presenting and receiving feedback at professional conferences.

As the study progressed, information was also available as an exhibit in LOTT’s WET Science Center, and routinely provided as part of public presentations and tours. As the study concluded, communication and public involvement efforts were ramped up to present results to key audiences and stakeholders. These efforts included a community forum, an online open house with survey, media releases, completing a series of fact sheets, and presentations to partner jurisdictions, professional and community groups. LOTT also worked with a video company to produce a 10-minute video to explain study results.

This extensive research effort resulted in over 2,500 pages of scientific reports, available on LOTT’s website. Key findings include:

• Residual chemicals are found in our environment, in areas where reclaimed water is used for infiltration, and in areas where reclaimed water is not used for that purpose.

• Residual chemicals from infiltration decrease with time and distance as water moves underground away from the recharge site.

• Risk assessment experts found a very low risk to human health and no risk to ecological health.

Study findings indicate that LOTT’s long-range wastewater management strategy of using reclaimed water for groundwater replenishment is safe and responsible. This study provides a solid foundation to monitor changing conditions and further explore treatment options if warranted in the future. LOTT plans to monitor key residual chemicals and keep tabs on industry research, new regulations, and the changing chemical landscape to update the study in the future based on new information.

For more information about LOTT’s study, visit lottcleanwater.org/projects/reclaimed-waterinfiltration-study/