Principal Mechanical Engineer - Wastewater

Start here. Grow here.

At AECOM, we boast an impressive and expansive Water Team operating across the globe. With approximately 600 experts sitting in our UK and Ireland Offices, we are constantly evolving to remain at the forefront of innovation, and we’re on the lookout for talented, dedicated and passionate individuals to join us.

Our dynamic and multidisciplinary Water Team are looking for a Principal Mechanical Engineer to join our Belfast office – whilst also taking advantage of work from home days through our hybrid approach. As part of our thriving business, you’ll take on rewarding multi-disciplinary projects from inception to delivery, creating innovative solutions that enhance the environment and improve communities.

Projects will range from small rural sites to multi-million-pound schemes, covering both water and wastewater (Infrastructure and Non-Infrastructure), being delivered under the CRU’s fourth regulatory control (RC4) period 2025-2029. You’ll have the opportunity to contribute major frameworks, programmes, and projects as part of this investment including: 

• Uisce Éireann Growth & Development Programme: Supporting our Tier 1 Contractor on a national programme of targeted investment to increase the capacity of water and wastewater infrastructure to enable social and economic growth and development, including the delivery of essential housing. 

• Uisce Éireann Engineering Services Provider Framework: Delivering on Uisce Éireann’s 19-062 framework objectives by providing comprehensive engineering design services spanning project planning and appraisal, network and process modelling, and the detailed design of water and wastewater treatment plants, networks, and associated infrastructure to support the successful delivery of capital investment programmes. 

Here's what you'll do:

• Undertake the design and review of mechanical elements in wastewater and water infrastructure treatment projects, such as chemical dosing, pumping stations and sludge treatment units, from conception to handover.
• Prepare feasibility studies, outline design, detailed design and construction support.
• Produce P&IDs using Plant 3D, including Valve schedules, Equipment Schedules and Instrument Schedules.
• Produce and co-ordinate mechanical 3D models using Revit.
• Oversee mechanical plant selection including preparation of specifications, production of pump calculations, preparation of WIMES Data Sheets and lifting strategies, piping and plant layouts etc.
• Liaise and collaborate with our other discipline teams including process, electrical, structural and civils nationwide.
• Visit site to carry surveys and support of liaisons with clients, contractors & suppliers.
• Lead and contribute design review meeting such as HAZOPs, ALMs and Workshops.
• Act as Mechanical Lead on projects including WwTW, WTW and Infrastructure. Supporting the Project Manager and Design Leads to successfully deliver the Mechanical Scope to programme and budget.
• Assist the Project Manager to set realistic programmes and budgets for Mechanical projects.
• Be a Line manager for Mechanical Graduates, Engineers and Senior Engineers.

AECOM’s digital strategy is driving the adoption of global digital solutions internally in our design process, to improve quality and consistency and streamline activities. You will help shape these digital offerings and use them on projects, including ACC, intelligent P&ID’s and AECOM’s own tools developed in-house, such as our pumping station generator.

Let's not forget the perks! You'll enjoy a range of core and personalised benefits designed to support your future and well-being, customised to fit your lifestyle. Take advantage of career development opportunities, technical practice networks, AECOM University, volunteering days and our flexible hybrid working model to ensure a work-life balance that suits your lifestyle.

Join our team. If you're passionate about innovation and turning bold ideas into reality, we want to hear from you. We don't just deliver projects; we uplift communities and enhance lives. Why not give our AECOM Water page on LinkedIn a follow to stay updated on the impactful projects we're working on and see firsthand the difference we're making in the industry! 

• A degree (or equivalent) in Mechanical Engineering.
• Chartered (or near Chartered) Member of a relevant Professional Institution.
• Hands-on experience in delivering innovative solutions for water and wastewater engineering projects.
• A proven ability to deliver engineering designs, reports, drawings, technical specifications, and calculations with confidence and precision.

At AECOM, we value everyone's unique contributions and perspectives. We celebrate diversity, including neurodiversity, and believe it enriches our teams. We welcome applications from all backgrounds and abilities so, if you're an applicant with a disability that requires reasonable adjustment to complete the application process, please contact us at [email protected]

At AECOM, we are committed to maintaining a secure and trustworthy recruitment process and take any fraudulent hiring activity seriously. To support this commitment, all newly hired employees are required to attend an in-person Day 1 onboarding at an AECOM office location as a condition of employment.

About AECOM

AECOM is the world’s trusted infrastructure consulting firm, delivering professional services throughout the project lifecycle – from advisory, planning, design and engineering to program and construction management. On projects spanning transportation, buildings, water, new energy and the environment, our public- and private-sector clients trust us to solve their most complex challenges. Our teams are driven by a common purpose to deliver a better world through our unrivaled technical and digital expertise, a culture of equity, diversity and inclusion, and a commitment to environmental, social and governance priorities. AECOM is a Fortune 500 firm and its Professional Services business had revenue of $16.1 billion in fiscal year 2025. See how we are delivering sustainable legacies for generations to come at aecom.com and @AECOM.

Freedom to Grow in a World of Opportunity 

You will have the flexibility you need to do your best work with hybrid work options. Whether you’re working from an AECOM office, remote location or at a client site, you will be working in a dynamic environment where your integrity, entrepreneurial spirit and pioneering mindset are championed.

You will help us foster a safe and respectful workplace, where we invite everyone to bring their whole selves to work using their unique talents, backgrounds and expertise to create transformational outcomes for our clients.

AECOM provides a wide array of compensation, benefits and well-being programs to meet the diverse needs of our employees and their families. We’re the world’s trusted global infrastructure firm, and we’re in this together – your growth and success are ours too.

Join us, and you’ll get all the benefits of being a part of a global, publicly traded firm – access to industry-leading technology and thinking and transformational work with big impact and work flexibility. As an Equal Opportunity Employer, we believe in each person’s potential, and we’ll help you reach yours.

We are a Disability Confident Employer and will offer an interview to applicants who have a disability or long-term condition, who meet the minimum/essential criteria for the role. Please let us know using this email address [email protected]  if you would like to apply through the Disability Confident Interview Scheme.

All your information will be kept confidential according to EEO guidelines.