Costain Group PLC
Graduate Process Engineer - Water

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Job Description
Costain has been improving the lives of people through infrastructure for more than 160 years.
Today we’re involved in solving some of the UK’s most complex infrastructure challenges across our four strategic markets of transport, water, energy and defence. Population growth, regulatory changes and climate change are having a dramatic impact on water supply and usage. The national approach to managing the water sector is changing to meet these challenges.
Costain has been at the forefront of this change delivering multi-million pound AMP programmes covering strategic planning, solution optioneering, design and construction. We currently work with many of the UK’s leading water companies including Southern Water, Thames Water, United Utilities, Severn Trent, Northumbrian Water, Yorkshire Water and Anglian Water.
We are hiring for water graduate process engineers to join and rotate between our Asset Optimisation and Costain Engineering Limited (CEL) teams so candidates can receive experience working across all parts of a project lifecycle from initial concept development through design and into commissioning roles.
The Asset Optimisation team is primarily based at our St Mary’s Axe office in central London, while the CEL Process Team is based on our Aviator Way office in Manchester. These roles offer flexible and dynamic working between home, office and regular travel to wastewater treatment sites.
On application for this role please ensure that you identify which areas of the country you are applying for and if you are open to relocation.
We are looking for Graduate Process Engineers to join our combined Asset Optimisation and CEL Team which is a growing technical team of process engineers working with municipal wastewater treatment clients across the UK.
The Asset Optimisation Team is an agile team working on the front line with operational and construction teams to develop innovative, practical, and efficient process solutions to help safeguard the environment.
We deliver optimisation studies at feasibility, concept, optioneering and preliminary design stages to mitigate risk, return sites to compliance, or enable optimised or no build solutions to meet new permit drivers. We also provide direct operational support to improve site performance using existing assets.
Costain Engineering Limited (CEL) is a design consultancy composed of an interdisciplinary team which develops an outline design through detailed design, construction and commissioning. The team also provides technical and engineering support to our site teams and clients to ensure successful scheme delivery and long-term operation.
Successful candidates will join our IChemE Accredited Company Training Scheme (ACTS) which is designed to equip graduates with the skills and experience required to take them forward in their career. You will also be assigned a mentor to support your professional development and to guide you towards chartership.
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There is also a broader Costain Graduate Development Programme for graduates of all disciplines across our strategic markets to develop your network and understanding of the wider engineering and construction sector. The programme will work to grow your personal and leadership skills to complement the technical skills learned through your engineering role.
Costain Graduate Development Programme
By joining our 2-year Graduate programme, you’ll get the best of both worlds—great technical development and exciting opportunities to grow your personal confidence and leadership skills. You’ll be working alongside your team to deliver standout, best-in-class projects across the infrastructure sector, all while learning and building your career step by step.
The Graduate Development Programme (GDP) is also a fantastic chance to meet and network with other graduates joining us at the same time. You’ll connect with people across different projects and disciplines throughout the UK, creating a supportive community from day one. Throughout the 2 years, you’ll come together both in person and virtually to take part in engaging modules and activities such as “Growing your Career,” “Costain In Action,” and “Group Coaching.” These sessions are designed to inspire you, challenge you in the best way, and help you get the most out of your programme.
Your line manager will be fully on hand to support your learning, and you’ll have plenty of opportunities to talk through how you can put what you’re learning into your everyday work.
We also strongly recommend getting involved with our Graduate and Apprentice network (GRaAPs). It’s a brilliant way to meet other Early Careers members, discover what’s happening across different teams and projects, and explore areas of the business that genuinely interest you—helping you shape your future learning and direction.
And as a graduate, you’ll have the chance to help influence and shape future recruitment programmes and early careers opportunities—making a real difference to what comes next for future intakes.
Responsibilities
The work undertaken by Graduate Process Engineers is varied and assignments can cover all stages of a project’s lifecycle:
- Supporting principal and senior process engineers in undertaking outline or detailed process engineering design including modelling, mass balances, data analysis and design calculations.
- Visiting sites for data acquisition, on site reviews and meeting site operators to understand a site’s current performance and future potential.
- Site commissioning support during both capital construction planning and delivery.
- Working within a multidisciplinary team including mechanical, civil and electrical engineers to deliver a cohesive integrated design.
- Developing and presenting material for stakeholder workshops to develop solutions and designs.
- Production of presentations, briefing notes, control philosophies, commissioning plans, schedules, DSEAR reports, PFDs and P&IDs.
- Contribution to health and safety assessments including ALMs and HAZOPs.
- Root cause failure analysis, FMECA, other risk analysis and mitigation proposals.


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Essential
Knowledge, Skills, and Experience
- Strong interest in the water sector.
- Delivery driven with a mindset to work to targets and meet team objectives.
- Work accurately to achieve a right first-time approach
- Communicate technical concepts clearly and concisely.
- Excel at building and maintaining positive relationships.
- Understanding of Safety-First work mindset
- Ability to collaborate to achieve shared goals
Qualifications
- A degree or equivalent qualification in a process engineering related discipline
- A full UK driving licence
About Us
Costain helps to improve people’s lives with integrated, leading edge, smart infrastructure solutions across the UK’s energy, water, transportation and defence markets. We help our clients improve their business performance by increasing capacity, improving customer service, safeguarding security, enhancing resilience, decarbonising and delivering increased efficiency. Our vision is to be the UK’s leading smart infrastructure solutions company. We will achieve this by focusing on blue chip clients whose major spending plans are underpinned by strategic national needs, regulatory commitments, legislation or essential performance requirements. We offer our clients leading edge solutions that are digitally optimised through the following five services which cover the whole lifecycle of their assets: future-shaping strategic consultancy; consultancy and advisory; digital technology solutions; asset optimisation and complex programme delivery. Our culture and values underpin everything we do.
Costain appreciate the time and effort taken when applying for one of our positions but, due to the high volume of responses, we are unable to provide individual feedback on candidates at application phase.
We do share individual feedback following an interview.
A Disability Confident employer will generally offer an interview to any applicant that disclose they have a disability and meets the minimum criteria for the job as defined by the employer.
It is important to note that in certain recruitment situations such as high-volume, seasonal and high-peak times, the employer may wish to limit the overall numbers of interviews offered to both disabled people and non-disabled people.
For more details please go to the Disability Confident website:
https://www.gov.uk/government/collections/disability-confident-campaign
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