Principal Process Engineer – Water & Wastewater Projects

AlíaGestiónIntegraldeServicios,S.L.U; Greater London; Hybrid; GBP 60,000 - 80,000; Full time

Job summary

A renowned engineering firm in Greater London seeks a Principal Process Engineer. This role involves leading design and delivery in water, wastewater, and utilities sectors while ensuring compliance with UK regulations. Candidates should have a minimum of 10 years’ experience in the field, a Chartered status, and ideally a master’s degree in chemical, process, or environmental engineering. The company offers a competitive salary, a hybrid work model, and numerous professional development opportunities.

Benefits

Competitive salary

Flexible hours

Professional development support

Employee assistance program

Generous annual leave

Qualifications

• 10 years’ experience in water treatment or wastewater treatment.
• Achieved Chartered status.
• Degree with ideally a master’s in relevant engineering field.

Responsibilities

• Lead process design for treatment plants and utility systems.
• Ensure designs meet UK regulations and client specifications.
• Guide and mentor junior engineers and graduates.

Skills

Water treatment principles

Wastewater treatment

Chartered status

Process design

Interpersonal skills

Education

Master's in chemical/process/environmental engineering

Tools

PFDs

P&IDs

Job description

Principal Process Engineer – Water & Wastewater Projects

Ayesa London, United Kingdom Process Engineering Hybrid

Company Description

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 serve as the driving forces behind our spirit of innovation.

With a presence in 23 countries worldwide, Ayesa has earned a prominent international reputation in various engineering fields, including infrastructure, water conveyance and treatment systems, transportation, marine projects, waste management, aeronautics, and defense. Additionally, Ayesa is a well-established technology consultancy, specializing in facilitating the digital transformation of large corporations, particularly in the utilities sector, and providing technological solutions for public institutions.

As a technology and engineering firm, we complement our technological proficiency with the capacity to design physical infrastructures. This includes crafting distinctive buildings that imbue cities with character, designing iconic bridges that seamlessly blend into their surroundings, creating transportation systems such as high-speed roads, intelligent roadways, stations, and airports that serve as the backbone of regions, and engineering remotely controlled networks for energy and water distribution, driving urban and demographic development.

Position

🚀 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 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)

Requirements

🧠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

Other information

🎁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: 10am–4pm Mon–Thu, 10am–3pm Fri).

📚 Professional Development and Chartership Support.

🤝 Employee Assistance Programme (EAP).

🌱 Sustainability & Innovation-Focused Culture.

🌴 Generous Annual Leave with Additional Days Based on Service.

🤝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.