Process Project Engineer

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Join Tetra Tech’s Water Team in Irvine, CA, and help shape the future of municipal and regional water systems across Southern California. As a Process Engineer – Project Engineer, you’ll be part of a dynamic group designing and delivering advanced treatment solutions, including PFAS treatment systems, large‑scale water treatment facilities, and complex rehabilitation projects. This is an ideal opportunity for a licensed engineer ready to deepen technical expertise, contribute to innovative water projects, and take the next step toward project leadership.

At Tetra Tech, we are Leading with Science® to solve the world’s most complex challenges. Our industry‑leading experts in engineering and consulting are committed to driving positive change in communities around the world. For over 50 years, we have been at the forefront of innovation and sustainability. Today we stand as a market leader, offering cutting‑edge solutions in water, environment, energy, and international development.

Our work has improved more than 625 million lives around the world.

Join Tetra Tech to make a real difference. Our work leverages cutting‑edge technologies, advanced analytics, and the expertise of world‑class scientists and engineers to create meaningful change around the world. Discover your full potential – join us to advance your career while leaving a lasting legacy.

The Process Engineer – Project Engineer will support the planning, design, and implementation of water and wastewater treatment projects. The role requires strong technical and analytical skills, attention to detail, and an enthusiasm for problem‑solving within a collaborative, client‑focused environment. This position offers the opportunity to grow into project management and technical leadership roles within Tetra Tech’s expanding water practice.

• Lead or support process design for advanced water and wastewater treatment systems, including PFAS, GAC, ion exchange (IX), RO, filtration, and disinfection processes.
• Participate in facility planning, alternatives analysis, and conceptual design for public sector treatment and infrastructure projects.
• Develop design calculations, process modeling, equipment sizing, and system layouts.
• Prepare engineering reports, technical memoranda, construction drawings, specifications, and cost estimates.
• Collaborate with project managers and senior engineers to deliver projects on time, within budget, and to the highest technical standards.
• Support construction‑phase activities, including responding to RFIs, reviewing submittals, and conducting field observations.
• Participate in pilot testing, startup assistance, and site inspections as needed.
• Contribute to client meetings, presentations, and progress updates to communicate findings and recommendations.
• Work collaboratively across disciplines to develop innovative, sustainable treatment solutions.
• Mentor junior staff and contribute to internal knowledge‑sharing initiatives.

• Bachelor’s degree in Chemical, Environmental, or Civil Engineering.
• Professional Engineer (PE) license required.
• 5+ years of experience in municipal water and/or wastewater treatment design.
• Demonstrated understanding of treatment processes, hydraulics, and process controls.
• Strong written and verbal communication skills.
• Ability to work both independently and collaboratively within a team‑oriented environment.

• Experience with PFAS, GAC/IX/RO, or other advanced treatment systems.
• Familiarity with process modeling software such as Bio Win, GPS‑X, or similar.
• Knowledge of California water regulations and permitting requirements.
• Experience supporting pilot studies, field testing, or treatment optimization.
• Desire to advance toward project management and client‑facing responsibilities.

• Prolonged periods working at a computer and performing design work in an office environment.
• Occasional walking, standing, bending, or lifting up to 25 pounds may be required.
• Field visits may include exposure to outdoor…