As part of a continued commercial and retail expansion, developer Vulcan and contractor GLY started construction at this 1.86 acre site at the intersection of Westlake Avenue North and Mercer Street in South Lake Union. The project involves construction of a six-story office building with 246,508 square feet of commercial space above 14,428 square feet of ground-level retail and underground parking for 335 vehicles. Prior to construction, 71,000 cubic yards of grading and demolition of existing structures was completed. WaterTectonics worked with GLY to provide on-site treatment of contaminated groundwater that contained heavy metals, TPH, and PAH’s. During construction of the parking garage, dewatering occurred on a 24/7 basis and involved direct discharge to nearby Lake Union. In total, the WaterTectonics treatment system will process approximately 65,000,000 gallons over the course of the project, with all discharges meeting strict limits for heavy metals, TPH, and PAH’s. A 300gpm WaveIonics electrocoagulation system in addition to carbon polishing filtration was utilized for the project.