State of Washington Pioneers Reclaimed Water Use with State Rule

In California, recycled/reclaimed water is denoted with purple signs and purple pipes to signify that it is not potable. (Credit: By Grendelkhan (Own work) [CC BY-SA 3.0])

With an effective date of February 23, 2018, the State of Washington just became the first in the nation to promulgate a reclaimed water rule. The rule, created by the Washington Department of Ecology and other stakeholders, will streamline the reclamation process and ensure that reclamation projects protect water quality and public health in the process.

The reclaimed water rule in focus

Now, reclaimed water in Washington can be used for a host of beneficial uses, including flushing toilets, irrigation, improving wetlands or stream flows, landscaping, and recharging groundwater. The rule also includes a permit process for generating and distributing reclaimed water as well as using it.

A team from the Washington Department of Ecology responded to questions from EM, explaining how the rule was created, and sharing some of the technical research the scientific team used as a basis for the rule. Jessica Payne, the communications manager for the Water Quality Program, was our contact for the team.

“The rule is in response to a legislative directive established with the adoption of Revised Code of Washington (RCW) 90.48 – Reclaimed Water Use,” Payne explains. “Language in the RCW required Ecology, in consultation with the Washington State Department of Health, to adopt rule language for reclaimed water implementation consistent with the RCW.”

Toward the beginning of the rulemaking process, the Ecology department established a Rule Advisory Committee (RAC), and several subtask forces.

“These subgroups were designed to address specific issues of particular importance to reclaimed water use—things like water rights, technical requirements, and barriers to reclaimed water use,” details Payne. “Although it had been several years since the work of early RAC, our most recent effort to adopt the rule began by reinvigorating this same stakeholder group. Despite the many intervening years, several original members continued to participate and they made a big contribution to the rule you see today.”

In many ways, the monitoring and testing the reclaimed water will undergo is the same as that which is currently defined in the wastewater discharge permits issued by the state. At a minimum, reclaimed water permits will require monitoring for compliance with performance standards set forth in the rule. These include the Minimum Biological Oxidation Performance Standards, Class A and B Performance Standards, and Use-Based Performance Standards, set for in Tables 1 and 2 below.

(Courtesy of: Washington Department of Ecology)

Class A and B performance standards. (Courtesy of: Washington Department of Ecology)

“Additional monitoring will be necessary on a facility specific basis depending on the beneficial use identified for the reclaimed water produced,” adds Payne.

What sorts of destinations await the reclaimed water? A whole range of uses, depending on treatment and approval.

“Ecology currently permits about 30 reclaimed water facilities in Washington State,” details Payne. “Primarily it is used for irrigation and groundwater recharge. Some other interesting uses include constructed treatment wetlands, a fire training academy, and a demonstration wetland and a wading stream which runs in front of the Hands on Children’s Museum in Olympia, Washington. The latter is a project by LOTT Alliance and their facilities include the WET Science Center and is an excellent example of a community partnership. It includes educational features and is a great example of education and outreach to communities to improve the public perception and acceptance of reclaimed water use.”

The wading stream and WET Science Center signal a growing force of public buy-in for the rule. The Ecology team credits the heavy involvement of both internal and external stakeholders throughout the rule development process with much of this success.

Furthermore, the structure of the approval process for individual projects motivates project proponents to stay transparent and advocate for their projects in the affected communities.

“All draft reclaimed water permits will go through a 30-day public comment period,” Payne describes. “During the individual permit comment period, we expect local stakeholders and the public to be more directly engaged. Prior to permitting and as part of the development of a feasibility analysis we look to see that a project proponent is planning on or actively working in their communities to involve and inform the public throughout the process of bringing reclaimed water into the communities water portfolio.”

Technical aspects of reclaimed water

Through the reclamation process, the water is processed to meet the standards for dissolved oxygen, BOD5, CBOD5 , TSS, and pH set forth in the rule. Depending on its intended use, it then needs to meet standards for either Class A or Class B water; these classes have to do with turbidity, disinfection for coliform bacteria and viruses, denitrification. The additional treatment processes needed to meet these standards are actually available already at the majority of secondary wastewater treatment plants.

“Three classes of reclaimed water are identified in the rule: Class A+, Class A, and Class B,” elaborates Payne. “However, the rule only specifies treatment requirements for Classes A and B as Class A+ is reserved for potential direct potable use. While the rule creates a pathway for Class A+, requirements must be worked out on a case-by-case basis and the State Board of Health must approve any direct potable reuse. At this time, there are no plans for any beneficial uses related to Class A+ reclaimed water generation.”

In general, secondary treatment plants use biological oxidation and a lower level of disinfection that meets the State’s recreational use criteria, but not the criteria set forth for both Class A and B reclaimed water, which require more advanced levels of treatment.

“These additional processes include combinations of treatment that may involve coagulation and/or filtration,” remarks Payne. “There are also specific disinfection requirements for both Class A and B reclaimed water. The disinfection standard for Class A reclaimed water is much more stringent than Class B as there may be public contact (which does not include consumption) with the final product. We’ve built in options for existing facilities to come into compliance with the new rule. Ecology and/or Health will work with facilities interested in generating reclaimed water so that site specific requirements are known prior to the permitting process.”

Reclaimed water shown at various stages of treatment, Department of Ecology, State of Washington. (Credit: By Wateralex (Own work) [CC BY-SA 4.0])

“Proposals for direct potable reuse will be handled on a case-by-case basis,” Payne states. “Class A+ treatment requirements for a potable use will be much more stringent than the Class A treatment processes detailed in the rule. Ecology and Health staff will be following developments in California, Arizona, and other states who are actively working on standards for potable reuse.”

The Ecology team is excited about the progress the rule represents, and so are the facilities who are already making use of it. In a time of increasing scarcity of usable water, that’s no surprise.

“Reclaimed water is part of a wise water management strategy,” asserts Payne. “Using reclaimed water where potable water isn’t needed preserves drinking water allowing for better planning and preparation for adapting to climate change and growing populations. Even in rainy Washington using the right water for the right use just make sense.”