Principal Process Engineer

Ayesa is a global engineering consultancy with over 13,000 employees, where our UK & Ireland business combines international strength with the agility and autonomy of an SME. With a presence in 40 countries, Ayesa has built a strong international reputation across a diverse range of engineering disciplines. Our expertise includes water and flood infrastructure, transportation, marine and coastal engineering, geoscience, environmental services, energy, and building structures. Our UK & Ireland teams deliver technically challenging, varied projects that develop broad expertise without confining people to narrow roles — offering the opportunity to make a meaningful local impact while benefiting from the stability, knowledge, and career opportunities of a well-established global organisation.

As a Principal Process Engineer within the Water Infrastructure Team, you will play a senior technical and leadership role, primarily responsible for the design, coordination, and delivery of process engineering solutions within water, wastewater, sewage treatment and utilities sectors, with the potential to expand into energy, transport, and environmental infrastructure sectors.

• Lead the process design for treatment plants, pumping stations, pipelines, and utility systems.
• Define treatment process schemes, undertake mass balance and hydraulic calculations, and specify equipment (e.g. aeration systems, chemical dosing, sludge handling).
• Ensure designs meet UK regulations, standards, and client specifications, such as DWI, EA, or Ofwat requirements.
• Carry out design reviews, challenge assumptions, and sign off key deliverables to ensure technical robustness.
• Oversee multidisciplinary coordination — integrating process design with civil, mechanical, electrical, and control system disciplines.
• Develop and manage process flow diagrams (PFDs), P&IDs, design reports, and technical specifications.
• Ensure all work aligns with BIM and digital design workflows where applicable.
• Present designs and/or scribe HAZOP, HAZID, and SIL studies.
• Lead or support design and build (D&B) projects, working closely with contractors, utilities and delivery partners.
• Manage project scope, schedules, and budgets while maintaining high technical standards.
• Oversee process commissioning, testing, and performance verification on site when projects move into delivery phases.
• Guide and mentor junior process engineers and graduates.
• Lead internal design reviews and promote best practices in process design, sustainability, and digital delivery.
• Engage directly with clients at a senior level — helping shape project briefs, proposals, and process solutions.
• Contribute to business development, proposal writing, and framework management with key UK utilities.

Key Accountabilities

• Integrate within our multi-disciplinary design team to deliver robust design solutions to clients.
• Interface with other engineering disciplines including civil, M&E and structural.
• Ability to communicate effectively with clients and senior staff.
• Ability to manage a challenging workload.
• A team player with a mature approach including first-class inter-personal skills.
• Adheres to all Codes of Practice, Design Standards and Health & Safety Regulations.
• Represent and promote Ayesa in a professional manner and develop effective working relationships with clients and potential clients.
• Management of projects in compliance with Ayesa's Integrated Management System (IMS).

What You Bring Experience & Qualifications:

• Minimum of 10 years’ experience in water treatment and/or wastewater & industrial effluent treatment.
• Has achieved Chartered status.
• A degree and ideally a master’s in chemical/process/environmental Engineering.

Skills & Knowledge

• Deep understanding of the principles of water treatment and/or wastewater & industrial effluent treatment.
• Proven track record in the development of process solutions in industrial and municipal settings, and in accordance with specifications used in Ireland and United Kingdom.
• Proven track record in process selection, process design, application engineering, proposal support and operational support.
• Proven track record in the development of the whole cycle of the treatment process from the concept to the detailed design stage.
• Has undertaken preliminary and detailed design of water/wastewater treatment plants based on data provided and achieved the desired treatment criteria.
• Demonstrate an ability to develop drawings of equipment and plant layouts as required.
• Developing PFDs (Process Flow Diagrams) and P&IDs (Process & Instrumentation Drawings).
• Demonstrate an ability to develop process mass balance, hydraulic, energy, mechanical calculations as part of the detailed design.

What We Offer:

• Competitive Salary: We offer a competitive salary package to attract and retain top talent in the industry.
• Flexible Working: Enjoy flexible working hours and hybrid working, allowing you to achieve a better work-life balance.
• Employer Pension Match Scheme: We offer a pension match scheme to help you secure your financial future.
• Income Protection: Receive support in safeguarding your income in the event of illness or injury.
• Life Assurance: Gain peace of mind with life assurance coverage.
• Training and Development Programme: Access a range of training and development opportunities to enhance your skills and advance your career.
• Family & Well-Being Support: Benefit from our Enhanced Maternity & Paternity Benefits and our confidential support services to address personal or professional challenges, included in our Employee Assistance Programme.
• Sports and Social: Engage in our vibrant sports and social activities to foster a sense of community and well-being among our team members.
• Increased Annual Leave: 25 days’ annual leave plus statutory bank holidays, enjoy increased annual leave entitlements based on years of service.
• Recognition Awards: Receive recognition for your contributions through our awards program, celebrating achievements and excellence.

We’re Inclusive by Design

Ayesa is proud to be an equal opportunity employer. We value and celebrate diversity in all its forms, including but not limited to age, disability, gender identity, race, religion or belief, sex, sexual orientation, and socio-economic background or neurodiversity. We believe that a diverse workforce fosters innovation and stronger outcomes. We are committed to inclusive hiring practices, providing reasonable adjustments for applicants and employees with disabilities, and ensuring equal access to opportunities for learning, development, and progression across our organisation.