Arlington Wastewater Treatment Plant Upgrade & Expansion, Phase 1

Project Summary

The project provided extensive improvements and upgrades to Arlington’s existing treatment facility.  Work included the following: relocation of utilities, new electrical, natural gas, and water services, demolition of existing buildings and structures; placement of 5,000 cubic yards of structural concrete and an overhaul of the plant's treatment equipment.  A crucial element to this project was keeping the existing plant operational while constructing the new plant and changing process equipment.  IMCO maintained a great working relationship with Owner and Engineer, throughout entire project.  The project team was able to critically review the existing construction schedule and make modifications to provide temporary facilities.  These changes allowed IMCO to begin construction on portions of the project a year early saving time and money for IMCO and the City of Arlington.  

IMCO was able to propose providing alternate plant process equipment, which maintained the performance requirements of the contract while saving the owner over $500,000.  After deducting the cost of wetland enhancements added to the project by the City the final contract price came in below the original contract value thanks in part to IMCO’s value engineering efforts. The owner also communicated its top priority for the project to keep its plant operational at all times and to minimize the project duration and impact on the plant.  IMCO preconstruction assessment was able to identify creative ways to keep the plant operational, reschedule the job, and save 4 months on completions of the project.  This was done through recognizing the imitations of the operating wastewater treatment facility and providing temporary facilities to accommodate operating treatment plant and moving construction of the lab building construction one year ahead of previously scheduled.

Keys To Success:

  • Meeting the strict milestone completion dates for the MBR completion, the aeration basin, and the substantial completion
  • Keeping the existing plant operational while constructing the new plan and changing the process equipment
  • Coordination and extensive modification, construction and installation of a $6 Million Treatment Equipment Package



Arlington, WA


City of Arlington

Contract Amount

$27.3 Million


Kennedy Jenks


March 2009 - April 2011

Project Highlights

“The work was completed at an operating plant without any system upsets or violations. IMCO’s expertise spanned from system controls, to pumps and motors, to site safety and environmental protection expertise. Most important to our project was the proactive communication IMCO generated with proper document handling and our weekly construction meetings. I am very pleased with IMCO’s performance.” - James Kelly, City of Arlington, Public Works Director