Principal Process Engineer - Water & Wastewater Treatment

Principal Process Engineer – Water & Wastewater Treatment

Location: Auckland, New Zealand

At Mott MacDonald, we’re passionate about creating infrastructure that improves lives and strengthens communities. Our New Zealand team has delivered some of the country’s most impactful projects—from Te Kaha Stadium in Christchurch to the Snells Beach Wastewater Treatment Plant. We’re now looking for a Principal Process Engineer to join our Auckland office and help us deliver technically challenging and meaningful water and wastewater treatment solutions.

The Opportunity

As a Principal Process Engineer, you’ll play a key role in shaping our water and wastewater treatment projects across Aotearoa. You’ll lead and mentor junior engineers, guide multidisciplinary teams, and apply your technical expertise to deliver innovative, sustainable solutions.

This is a fantastic opportunity for someone with a strong background in chemical or process engineering who is passionate about design excellence, collaboration, and community impact.

What You Will Do

• Lead the technical design and delivery of complex water and wastewater treatment projects.  That’s all the exciting stuff like mass balances, process flow diagrams, aeration and nutrient removal calcs, chemical dosing requirements, sludge production rates, to name but a few.

• The sort of projects we love doing are new wastewater treatment plants, MBR designs, water and wastewater treatment plant upgrades, biological nutrient removal, biosolids processing and digestion, long terms strategies and feasibility studies for water, wastewater and biosolids treatment.  If you have some or all of these on your CV, consider it a bonus!

• Maintain currency with the latest technologies by liaising with suppliers and our global team of like-minded treatment experts

• Mentor and support junior engineers, fostering a culture of growth and collaboration

• Coordinate multidisciplinary project teams, ensuring high-quality outcomes

• Engage with clients, contractors, and stakeholders throughout the project lifecycle

• Contribute to project planning, technical reviews, and quality assurance

• Promote innovation, sustainability, and continuous improvement in design

About You

• A degree in Chemical or Process Engineering (or a related discipline)

• Proven experience in the design and delivery of water and wastewater treatment projects

• Strong or developing mentoring and leadership skills, with a collaborative mindset

• Experience working in multidisciplinary teams

• Chartered Engineer status or working towards it

• A passion for technical excellence and making a positive impact

Why Mott MacDonald?

• A competitive salary and performance-based bonuses

• Flexible working arrangements and enhanced KiwiSaver contributions

• Access to a global network of experts and ongoing professional development

• Opportunities to work on nation-shaping projects

• A culture that values diversity, integrity, wellbeing, and teamwork

Apply Now

If this role resonates with you—even if you don’t meet every requirement—we encourage you to apply. We’re committed to building a diverse team and welcome people who share our values of inclusion, collaboration, adaptability, and integrity.

Join us and help shape the communities of tomorrow.

Employee ownership

• Our employee ownership model means no external investors, just us, creating a culture of shared success.
• Our employees have a stake and a voice in our business, giving them a direct connection to our success through our personal and group performance bonuses.
• As your career grows, so does your stake, recognising your long-term impact and contribution.
• Your voice matters, with the opportunity to connect directly with senior leadership through formal channels to help shape our future.

Our benefits package:

•    A flexible and agile work atmosphere that caters to your professional journey and life's special moments
•    A competitive salary complemented by Discretionary Group and Personal Performance Bonuses for eligible employees
•    Comprehensive coverage including life, personal accident, and salary continuance insurance, providing peace of mind during uncertain times
•    Opportunities to enhance your work-life balance through the option to purchase extra annual leave
•    Employee resource groups including the Inclusive Network for Women, Corporate Social Responsibility and more

You've got this!
We endorse a diverse and inclusive workplace and look to provide suitable opportunities for employees including the opportunity for part time and job shared roles where possible. If you are interested in this role and looking for a part time permanent opportunity, please apply!