capital improvement Projects

The City’s Capital Improvement Projects are developed based on meeting the future needs of the various utilities and street systems and are generally formulated through a comprehensive planning process.

2021 Projects:

Wastewater treatment plant improvements

The City’s 2017 Wastewater System Facilities Plan describes a series of projects that need to be completed at the WWTP to allow the City to reliably and safely convey and treat sewage from the City. These projects add redundancy, enhance reliability, improve worker safety, support environmental requirements and eliminate hydraulic bottlenecks. Phase 1 construction should be complete in early 2021. Phase 2 - currently in design phase - is expected to be complete in 2023-2024. 

Phase 1 Upgrades: 

  • A new 80 foot diameter clarifier, including launder trough covers, weirs and scum baffles, clarifier sludge and scum collection mechanism, scum and waste activated pumping systems and RAS flow control system.
  • Rehabilitation and reconstruction of the existing clarifier.
  • Upgrade of UV disinfection system, including installation of new disinfection equipment.
  • A new mixed liquor pumping and flow splitting system.
  • A new effluent flow metering system.
  • A new automated secondary effluent pipeline flushing system.
  • Relocation and upgrade of the existing plant washwater system.
  • Site stormwater improvements.

Phase 2 Upgrades:

  • Construct new headworks, including influent screening, sampling, and metering.
  • Reroute raw wastewater from the original WWTP operations building to the ULID #6 lift station.
  • Redirect stormwater that currently enters the WWTP to stormwater treatment facilities.
  • Install new, larger motor on ULID #6 Lift Station Pump #2, and install new drives for all pumps.
  • Reroute WWTP recycle flows from the original WWTP operations building to the new headworks.
  • Construct two new oxidation ditches that each contain one aerobic zone, two anoxic zones, and three anoxic selector zones.
  • Provide a cover over the new oxidation ditches and mount solar power arrays on the covers.
  • Install aeration systems in the new oxidation ditches.
  • Extend WWTP washwater system to new areas of the WWTP.
  • Install chemical addition systems for pH and phosphorus control.
  • Convert existing oxidation ditch to two aerobic digesters.
  • Install aeration system in new aerobic digester.
  • Install new, higher capacity sludge dewatering system.
  • Remove existing sludge dewatering and drying systems.
  • Demolish original WWTP operations building, former Youth Activity Center, existing headworks, and upper floor of existing pump house building.
  • Install a digested sludge thickening system.
  • Install new odor control system for dewatered sludge handling systems.
  • Construct a new electrical/blower building to house electrical gear, air blowers, and new, larger backup power generator.
  • Perform site work to support new process areas.
  • Site stormwater improvements.

City Contacts

Tom Mohr, PE
Deputy Public Works Director
425-888-7653

Carrie Smith
Public Works Coordinator
425-888-7651

A detailed list of recently completed, ongoing and future capital projects is available on the 2021 Capital Project Update (PDF).