Tetra Tech

Tetra Tech is a consulting and engineering firm based in Pasadena, California, working across water, environment and sustainable infrastructure. Founded in 1966, it has become one of the larger design firms serving municipal water utilities and federal environmental programs in the United States. PFAS treatment has emerged as a significant practice area as EPA’s maximum contaminant levels take effect, and Tetra Tech is a design consultant on Dayton, Ohio’s $350 million ion exchange PFAS removal facility at the Ottawa Water Treatment Plant, with a scope estimated at roughly $200 million. It also works extensively in environmental remediation and disaster recovery.

Scale, from the company’s own about page: roughly 25,000 employees, 500 offices, work in 125 countries, about $5 billion in revenue and some 110,000 projects.

The firm is organized into two business groups. Government Services Group handles U.S. federal, state, provincial and municipal clients plus development agency work worldwide. Commercial/International Group covers commercial and government clients elsewhere. Regional operations span the United States, Canada, Europe, Africa, Asia Pacific, the Middle East and South America, with separate country sites for Brazil and the Netherlands.

The PFAS practice goes well beyond treatment design. On the investigation side Tetra Tech runs CERCLA and National Priorities List work, source identification and forensics, 2D and 3D fate and transport simulation, and bioaccumulation modeling for fish and human biomarkers. Analysis draws on EPA Methods 537.1, 533 and 1633, total oxidizable precursor assay, and suspect screening by high-resolution mass spectrometry. Treatment systems it designs use granular activated carbon, ion exchange resin, reverse osmosis and nanofiltration, evaporation and concentration, and mobile containerized units. Destruction technologies being deployed or piloted include electron beam, ultrasound, plasma, supercritical water oxidation and electrochemical oxidation, some under SERDP and ESTCP research funding. A separate line, PFAScrub, cleans and validates firefighting systems during the changeover from AFFF to fluorine-free foam.

Away from PFAS, the solution set runs to One Water, data centers, defense services, federal IT, high performance buildings, mining and metals processing, power and energy, solid waste, transportation, and disaster and emergency management. Tetra Tech Delta is the digital arm, packaging analytics and AI tooling; recent published examples include software that detects marine mammals for offshore energy work and modeling of water and power demand for data centers in Texas.

Engineering News-Record ranks Tetra Tech first in water treatment and desalination, environmental management, wind power and hydro plants.