Brightwater Treatment Plant

LOCATION

Woodinville, Washington

DESCRIPTION 

This project was to build a new wastewater treatment plant for the growing region.  Our team was contracted to perform site preparation, site demolition, site grading cut to fill, early large diameter pipe backfill, temporary erosion sedimentation control, mass excavation and embankment, storm drainage, import and embank fill, site grading for all roadways and landscapes, structural excavation and backfill, dewatering, creek restoration, large diameter yard piping for the treatment plant, fire protection, installation of gas main, sanitary sewer, fire protection lines with cathodic protection, foul air lines, precast chemical trenching, all site grading paving and channelization.

SCOPE OF WORK 

This large, complex project included four different contracts.  The first phase was the site preparation contract, which consisted of site grading, excavation and backfill for King County’s effluent drop structure, and trenching and backfill for large diameter pipe. The second phase for the site was the mass excavation and embankment of all the structures onsite. The scope of work also included temporary erosion control and stormwater treatment, storm drainage, underslab drainage, site grading of all landscaping berms and ponds, dewatering, structural backfill, and a restoration of Howell Creek. The third phase, we teamed up with University Mechanical to install all the various yard piping required for the treatment plant. The utilities included domestic water, fire protection, natural gas, foul air, reclaimed water, sanitary sewer, and others. The fourth phase was to perform all roadway grading, paving, and channelization.

PROJECT HIGHLIGHTS

• Phase 1 – Site Preparation
  • Clearing and grubbing of 10 acres
  • Temporary Erosion Sedimentation Control
  • Utilization of stormwater to irrigate wetland mitigation area
  • 14,000 cubic yards of site stripping and stockpiling contaminated soils onsite
  • 205,000 cubic yard cut to fill
  • 29,000 cubic yard structural excavation for Drop Structure
  • 54,000 cubic yard trenching and backfill for 66” effluent carbon steel pipe
• Phase 2 – Earthwork & Storm Drainage
  • Temporary Erosion Sedimentation Control
  • Interim Haul Roads
  • 310,000 square feet of hard surface demolition
  • 121,000 cubic yards of site cut to fill
  • 550,000 cubic yards of imported site fill
  • 405,000 cubic yards of building excavation for all structures
  • 311,000 cubic yards of structural backfill for all structures
  • 290,000 square feet of imported crushed surfacing base course for roadways and flatwork
  • 7 million square feet of finegrading of landscape areas
  • Dewatering – Eductor well-point system and deep wells
  • Furnish and install new culvert for Howell Creek Restoration
• Phase 3 – Yard Piping
  • 3,800 linear feet of Domestic Watermains with cathodic protection
  • 6,570 linear feet of 12” & 16” restrained joint fire protection lines with cathodic protection
  • 2,890 linear feet of 6” & 8” sanitary sewer
  • 3,050 linear feet of 6” HDPE private gas main
  • 2 each, twin 162 LF of 54” carbon steel Raw Sewage (RS) pipe, approximately 35 feet deep
  • 3,035 linear feet of 16” HDPE pipe
  • 6,715 linear feet of various size yard piping 1,1/4”-4” diameter (pvc, copper, HDPE)
  • 1,200 linear feet of HDPE pumped drainage lines
  • 2,900 linear feet of various sized large diameter piping (24-54” CPEP Foul Air, 48”-72” Carbon Steel with cathodic protection)
  • 2,800 linear feet of precast chemical trench with expansion loop vaults and leak detection vaults
  • All trenching and backfill,
    • 40,000 cubic yards of trench excavation and embankment
    • 61,000 tons of imported pipe bedding
    • 5,000 cubic yards of CDF trench bedding
• Phase 4 – Paving
  • 10,000 tons of ½” HMA Paving
  • 25,000 tons of Crushed Surfacing Base Course
  • 65,000 linear feet of striping & channelization