Principal Process Engineer – Water & Wastewater Projects

Overview

Principal Process Engineer – Water & Wastewater Projects at Ayesa - UK and Ireland. This senior role is within the Water Infrastructure Team, primarily responsible for the design, coordination, and delivery of process engineering solutions within water, wastewater, sewage treatment and utilities sectors, with 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.

• 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)

• 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

• 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
• Undertaken preliminary and detailed design of water / wastewater treatment plants based on data provided and achieved the desired treatment criteria
• Develop drawings of equipment and plant layouts as required, including Developing PFDs (Process Flow Diagrams) and P&IDs (Process & Instrumentation Drawings)
• Develop process mass balance, hydraulic, energy, mechanical calculations as part of the detailed design

• Competitive Salary Commensurate With Skills And Experience
• Hybrid Work Model (2–3 days from home)
• Flexible Hours 37.5 per week (Core: 10am–4pm Mon–Thu, 10am–3pm Fri)
• Pension Matching & Financial Planning Support
• Income Protection & Life Assurance
• Professional Development and Chartership…