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TEAM: Image


Confluence is comprised of civil engineers, chemical engineers, licensed treatment and distribution operators, and field services professionals. We are located in the Pacific Northwest and work throughout North America.

TEAM: Team Members
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Melinda is President of Confluence Engineering Group. She has been working to solve complex water quality problems for 30+ years and has helped to prepare many prominent industry Guidance Manuals and research papers. She was the recipient of the AWWA George Warren Fuller Award for engineering leadership in 2017, and is the 2022 recipient of the A.P. Black Research Award.

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Michael Hallett co-founded Confluence with Melinda Friedman in 2008. He serves as both Chief Operating Officer and Lead Field Scientist. He specializes in development and implementation of main cleaning programs, pilot studies, bench-scale studies, and implementation of monitoring plans while working closely with utility crews and providing field training.

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Andrew Hill is a Senior Project Manager at Confluence with 22 years of expertise in process engineering, reaction chemistry, source integration and mitigation of legacy pipe deposits. Andrew leads our Main Cleaning Optimization program and has published numerous reports and peer-reviewed manuscripts on water quality and asset management, distribution system best practices for water quality control, and distribution main cleaning.

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Chris Senior Project Manager and engineer at Confluence. Prior to joining Confluence, Chris spent 30 years serving as a leader in both private and public organizations, including serving as Deputy Superintendent at Tacoma Water. Chris manages projects of all sizes, and works across utility management to find successful solutions to water quality challenges. He leads our PFAS monitoring and assessment program.

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Alex Mofidi is a Senior Project Manager at Confluence with 29 years of experience in water planning and process engineering for treatment and distribution system improvement projects. He has had a prominent role in many corrosion control studies. Alex leads Confluence's Legionella risk assessment program, and has helped to develop the most recent industry guidance for Legionella management best practices.

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Virpi Salo-Zieman serves as Senior Project Engineer on regulatory assessments, corrosion control, supply integration, assessing distribution system water quality projects. Prior to joining to Confluence, Virpi worked at the Washington State Department of Health (DOH) as a regional engineer for 11 years where she was the Lead and Copper Rule (LCR) specialist.

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Danbi is a Project Engineer at Confluence specializing in water quality data analysis and modeling. Danbi routinely conducts complex metal (i.e. Mn, Pb, Cu) speciation modeling to predict water quality outcomes and to select optimal water quality treatment using Geochemist’s Workbench (GWB), WaterPro, and spreadsheet models.

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Al has 30 years of experience supporting municipal drinking water related engineering projects providing pilot system logistics, construction, innovation, and maintenance services along with laboratory and field-testing expertise. Al oversees manufacturing of pilot and bench-scale equipment and supports all aspects of field implementation and research.

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