At Tetra Tech, successful outcomes start with people—specialists who bring diverse skills together to solve the industry’s toughest challenges.
In this article we introduce two new senior technical directors, Rob Grant and Mariana Gonzalez, whose deep experience in process engineering, multidisciplinary design, and project leadership is already enhancing our engineering toolkit.
What does your job entail?
Mariana: In my role, I am responsible for leading and overseeing the Process Engineering side of Design. Process engineering focuses on the design, operation, control, optimisation, and intensification of chemical, physical, or biological processes. A process engineer will look at the transformation of a material into a product of added value.
The solutions available for any project is determined by the root cause analysis, which is performed by process engineers. Once the root cause has been established, the process team optimises the current processes and selects the required solutions that need to be implemented following the optimisation. Following that, the engineering design team, Rob, looks at adding value by streamlining the design.
Rob: This means that when clients have got a problem, for example they need a bigger pumping station, or their water treatment works or sewage treatment works is failing for whatever reason, we can go in and examine their assets, define the problem, and develop a holistic and fully engineered solution.
I must determine what the client’s need is, determine what solutions are available to fix that need, be that a simple replacement of a pump or a whole new treatment works and determine the best value, most effective solution that leaves the client with a quality product and a reliable asset.
What’s your experience? How have you built your expertise?
Mariana: I started my career in Chemical Engineering. Shortly after, I obtained a master’s degree in water and environmental engineering and a PhD in anaerobic digestion. My roles working in water utilities, consultancy and construction have given me the wholistic view of the sector, where the application of the correct procedures for project delivery include different points of view and innovative solutions.
I spearheaded the creation and leadership of a new business vertical dedicated to asset optimisation, driving a focus on integrating advanced digital technologies within water and wastewater treatment systems. But also, I had led initiatives that improved process reliability, reduced operational costs, and enhanced client deliverables through strategic process engineering solutions.
With over 20 years of experience, I have demonstrated success in leading innovative process engineering projects across water, wastewater treatment, and environmental sectors
Rob: My background is in multidisciplinary project engineering. I qualified as a mechanical engineer, but very quickly started gathering a lot of knowledge about electrical, ICA civil, structural, and geotechnical engineering as well. I started by working on a wide range of capital projects with water companies around the UK and beyond, and built myself up from being a designer, an engineer on jobs, to being a client-facing technical leader and project manager.
From there I’ve become a project director, technical specialist and business leader, utilising my knowledge and experience of the whole suite of skills that are used in the project lifecycle and in design and engineering.
Why did you join Tetra Tech?
Mariana: The water industry offers a tremendous amount of opportunity in terms of innovation and being able to change things and improve things. Tetra Tech is the epitome of this with a commitment to technical excellence and an emphasis on improvement and a collaborative work environment.
In addition to this, with the upcoming challenges of AMP8, there are a variety of diverse project opportunities. These opportunities have an incredible potential, and I can see endless possibilities to apply our skills and create an impact.
Rob: I saw Tetra Tech and this role as an opportunity to return to senior business leadership, having spent the last few years focusing on enhancing my technical skills and enhancing my reputation as a technical specialist. I enjoyed the technical focus but really missed the people- and project-management roles I had previously held.
I was also attracted to the global impact that Tetra Tech has. With Tetra Tech, they’ve continued extending their reach and conceptualising projects on an even larger scale. Complementing this, during my interview and research, I was given the impression that Tetra Tech was still an intimate, friendly, and personable organisation. I felt that they were still as people oriented as they have ever been, and that feeling has been borne out since joining just a few weeks ago.
How are you utilising your experience at Tetra Tech?
Mariana: I have been leveraging my experience to lead a range of complex, multidisciplinary projects from concept through to delivery. One of my core contributions is building technical capability within the team and fostering a collaborative and solutions-driven culture. I actively share knowledge and best practices, encouraging professional development and continuous improvement. I look for opportunities to implement new technologies, sustainable design strategies, and more efficient processes. I assess project workflows and design methodologies to identify areas where we can optimise performance, reduce waste, or improve overall delivery.
Ultimately, I am doing my best to bring proactive mindset to identify areas for improvement and ensuring our results not only meet technical requirements but also exceed expectations in terms of innovation, functionality, and sustainability.
Rob: When the project lifecycle has been optimised and solutions are being implemented from Mariana’s side, I work on improving efficiency, reducing costs, and increasing value. I analyse the project to identify cost reduction opportunities while maintaining or enhancing performance by specifically streamlining design.
Within design management and design portfolio development, what I’m intending to do is broaden the business and make sure that we’re offering a diverse range of talents. This is something I’ve done many times with other businesses and clients, and find it is vital for meeting client needs.
My general approach is to want to understand ‘what’s going on’, be that in respect of our clients’ problems or in how we are delivering our services. I like to ask questions and learn every aspect of what we are doing in the whole project sphere, rather than just within my main areas of responsibility.
What makes this work so special for you? What’s your favourite part?
Mariana: This work offers the opportunity to influence the strategic direction of the process engineering department, work on impactful projects and contribute to Tetra Tech’s growth and reputation in the water industry.
My favourite part is working on impactful projects where innovation is a key requirement. Problem solving is a key part of our roles, and together we enhance each aspect of the project lifecycle, to create the most detailed-oriented and effective result.
Rob: I really enjoy everything I do in my job. I enjoyed being challenged and stretched, and I like to see others succeed and grow in suitably challenging environments. I enjoy seeing my teams achieve what they did not think was possible. I enjoy seeing a smaller team growing into a bigger team. But more than anything, I enjoy getting positive feedback from our clients, stating that we’ve done a good job and made a difference.
I also find this role with Tetra Tech special as I can be involved in the full lifecycle of projects, so not only the front end, through modelling and feasibility, but also through the outline and detail design phases, and onto construction and commissioning support. This offers so many opportunities for problem-solving and adding value.
What direction does this create for Tetra Tech? How does it enhance our toolkit?
Mariana: Clients are looking for more efficient solutions with a more strategic use of resources. They are already aware of our technological and innovative digital offering, and now, with expertise in proccess engineering, they can fast-track the innovative solutions needed to optimise the project with the knowledge of our experts. Alongside that, with our design capabilities, clients get another layer of refinement added to the solution.
Rob: The requirements and challenges for AMP8 are huge, and water companies are going to need skilled people from organisations that can deliver effective, efficient, and innovative solutions.
Clients are familiar with Tetra Tech’s rich, varied resource of disciplines from advanced monitoring, detailed modelling, water management, and asset management. Now, as we develop and grow as an organisation, our design capabilities are taking the spotlight, and we have an opportunity to demonstrate our proficiency in this field.
My aim is to make sure that when clients are looking for designers within the water industry that they’re thinking of us. In the same way that they think of our competitors, I want them to be thinking, yes, Tetra Tech can do that.
What difference is our work making? For clients and our communities?
Mariana: By ensuring the delivery of efficient and sustainable engineering solutions, driving innovation, and upholding high standards of safety and quality, we can contribute to the development of infrastructure and processes that have a positive environmental and societal impact.
Rob: The water companies want to make sure that when they are investing their capital, they are doing so in the best way possible for their assets, customers and future. And they all want to achieve the same goal: making the environment a better place for everybody. We, as engineers, have a duty to help them do it as efficiently and effectively as possible.
Utilising our culture of continuous improvement and our team of skilled experts, we can help water companies meet challenging targets with unique solutions.
About our experts
Rob Grant
Rob Grant is a multidisciplinary engineering leader with over two decades of experience delivering capital projects across the water sector.
Trained as a mechanical engineer, Rob has broadened his expertise to include electrical, instrumentation & control, civil, structural and geotechnical disciplines. He has progressed from designer and project engineer to client-facing technical lead, project director and business leader, applying a whole-life view of the project lifecycle—from modelling and feasibility through outline and detailed design to construction and commissioning support. At Tetra Tech, Rob focuses on design portfolio development, streamlining solutions to improve efficiency and reduce cost while preserving performance and reliability. He is driven by mentoring teams, solving complex problems and delivering projects that create measurable value for clients and communities.
Mariana Gonzalez
Mariana Gonzalez is a process engineering specialist with more than 20 years’ experience in water, wastewater and environmental engineering.
She holds a Master’s degree in Water and Environmental Engineering and a PhD in anaerobic digestion, and has worked across utilities, consultancy and construction. Mariana leads the Process Engineering stream, delivering root-cause analysis, process optimisation, and innovative treatment solutions that improve reliability and reduce operational cost. She has established and led business lines focused on asset optimisation and the integration of digital technologies into treatment systems. Mariana is passionate about building technical capability, promoting collaborative problem-solving and applying sustainable, high-impact solutions that advance client outcomes and environmental benefits.