King County’s Wastewater Treatment Division picked Kiewit Infrastructure West as general contractor and construction manager for its $400 million Elliott West Wet Weather Treatment Station project in Seattle.
Although the construction contract for the job will be negotiated later, the agency took a step forward by signing a $5.5 million preconstruction contract with Kiewit, agency spokesperson Akiko Oda said in an email.
Elliott West, a combined sewer overflow facility completed in 2005, stores and treats sewage and stormwater during periods of heavy rain, according to the project website. Now the treatment station needs to be upgraded to comply with stricter environmental regulations, meet the demands of a growing population and handle a changing climate.
The total project cost is currently estimated at $400 million to $450 million, while the construction costs are anticipated at approximately $220 million, Oda said.
This is not King County’s only such effort: In the coming decade it is investing $10 billion in wastewater treatment and other resilience measures in order to reduce pollution in waterways and prepare for storms, which are likely to become more frequent and intense due to climate change. The county has 14 water infrastructure projects planned to make its system more reliable and protect Puget Sound.
Seattle joins a slew of other communities across the country that are investing billions to modernize their combined sewer infrastructure, which can release untreated wastewater into bodies of water when the system is overwhelmed. The Elliott West project will reduce untreated combined sewer overflow discharge and improve water quality in Elliott Bay, according to the project website.
Once the project is complete, Elliott West will use screening, ballasted sedimentation, and ultraviolet disinfection, which will allow it to achieve more stringent water quality standards. Construction is slated to begin in 2027 and to wrap by 2032, per the project website.
Dallas-based Jacobs is designing the project, according to Oda.
For the preconstruction phase, Omaha, Nebraska-based Kiewit’s scope of work includes support on risk management, value engineering, constructability reviews, construction planning, scheduling and cost estimating, per Oda. The scope of work for the construction phase is still in development.