Wastewater treatment plant uses sequencing batch reactor to meet goals & standards
The city of Cle Elum, Washington, completed the construction of a new 3.6 million gallon per day (mgd) sequencing batch reactor (SBR) wastewater treatment plant in 2005.
The plant is known as the Upper Kittitas County Regional Wastewater Treatment Facility (WWTF) and is managed by Veolia North America. The WTTF has replaced the old lagoon treatment system and now provides wastewater treatment for the communities of Cle Elum, South Cle Elum, the city of Roslyn, city of Ronald and the Suncadia Resort.
In 2019, the Cle Elum Wastewater Treatment Plant received the 2019 Outstanding Performance Award by the State of Washington Department of Ecology for its outstanding record of 100% compliance with federal environmental requirements under the EPA National Pollutant Discharge Elimination System.
The plant has achieved this distinction for the past 12 consecutive years. In 2019, Cle Elum WWTP was one of only 125 out of 300 plants in the state of Washington to be fully compliant.
William Lerue, project manager of Veolia North America, contracted with the city to operate their facilities.
The plant filters and processes water from the Yakima river and Cle Elum river, and according to the city, the service area is expecting a period of rapid growth in the next few years.
Challenges & Growth
“We have refined our operations, just tweaking things day to day depending on temperature and weather conditions given to us,” said Lerue. “We are at an elevation of 2,000 feet above sea level so we deal with some pretty extreme temperatures and snowfall.”
Lerue is into his fourth year working with the facility, having been in the business for 37 years. A major challenge for Cle Elum is major snowfall and rainfall, resulting in flooding, which creates issues for the facilities.
There is a staff of four at the plant, operating not only the wastewater plant but the water treatment plant as well.
“We took extra precautions early on,” said Matt Burgard, manager of communications for Veolia, in regards to COVID-19 restrictions. “We have a deep safety culture.”
SBR Treatment Process
SBR is a biological wastewater treatment system in which all the major process steps including flow equalization, aeration and clarification occur sequentially within the same tank. Wastewater first enters the treatment facility at the influent pump station and undergoes primary treatment. The filtered solids materials are collected and transported to the local landfill for permitted disposal.
In the secondary treatment process, the flow is directed into one of two SBRs where the wastewater is naturally broken down further. The remaining sludge is separated and pumped directly to a double-lined treatment lagoon for further aeration, natural dewatering and eventual disposal through permitted land application as fertilizer.
The resulting effluent then flows into an equalization basin where it receives further aeration before it is directed through a final ultraviolet disinfection treatment system. The clean effluent is metered and then discharged directly into the Yakima River over a constructed rock drop outfall for even further aeration and treatment.
“We strive to meet water quality requirements on a daily basis. We work hard to achieve this award every year,” Lerue said.