Principal Process Engineer

Join to apply for the Principal Process Engineer role at Ayesa - UK and Ireland. Ayesa is a globally oriented, forward-thinking company deeply committed to fostering diversity, inclusion, equity, and sustainability. These principles form the bedrock of our dedication to our 13,000 employees and support our spirit of innovation. With a presence in 23 countries worldwide, Ayesa has earned a prominent international reputation in engineering fields, including infrastructure, water conveyance and treatment systems, transportation, marine projects, waste management, aeronautics, and defense.

The Opportunity

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 potential expansion 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.
• Communicate effectively with clients and senior staff.
• Manage a challenging workload and maintain quality standards.
• Demonstrate strong team-playing skills and mature interpersonal approach.
• Adhere to all Codes of Practice, Design Standards, and Health & Safety Regulations.
• Represent and promote Ayesa professionally, developing effective working relationships with clients and prospects.
• Ensure project management aligns 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.
• Achieved Chartered status.
• Degree and ideally a master’s in chemical/process or environmental engineering.

Skills & Knowledge

• Deep understanding of water treatment principles.
• Proven track record in developing process solutions in industrial and municipal settings, complying with Irish and UK specifications.
• Experience in process selection, design, application engineering, proposal support, and operational support.
• Developed entire treatment process cycle from concept to detailed design.
• Designed equipment and plant layouts, including PFDs and P&IDs.
• Performed process mass balance, hydraulic, energy, and mechanical calculations.

What’s In It for You

• Competitive salary commensurate with skills and experience.
• Hybrid work model (2–3 days from home).
• Flexible hours: 37.5 per week (core: 10 am–4 pm Mon–Thu, 10 am–3 pm Fri).
• Professional development and chartership support.
• Employee assistance programme (EAP).
• Sustainability & innovation-focused culture.
• Generous annual leave with additional days based on service.

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 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.