Description Costain is working closely with Severn Trent Water on their Capital Delivery Framework, as part of it's capital programme for AMP8. As part of the Design and Build Framework lot, Costain brings together its design, construction, and consultancy expertise to undertake renewal and refurbishment projects and will assist Severn Trent in its target to make continuous improvements to its safety performance, whilst ensuring continuity of supply and consequently lowering costs for its customers. The Mechanical Project Engineer is responsible for the delivery of mechanical packages across our water and wastewater projects, ensuring they are completed safely, on time, within budget, and to the required quality standards. This role involves leading early-stage mechanical design integration with the supply chain and delivery team, translate designs into procurement packages and serve as the mechanical package lead for subcontractors as projects move from design phase into manufacturing and site delivery, installation and commissioning. Responsibilities Early-Stage Design & Integration Lead the integration of internal mechanical design with specialist third-party supplier designs (e.g., aeration systems, pumps, various mechanical package plant, chemical dosing, inlet screening, valves, and Washwater systems) Critically review P&IDs, 3D models (BIM), and general arrangement drawings and feedback comments to the 3rd party designers through the design management function, as well as managing collaborative design between 3rd party designers and supplier design functions Ensure all designs meet UK water industry standards (WIMES), and specific client (STW) specifications Design-to-Procurement Management Translate design/datasheets into robust technical tender documents. You will ensure that mechanical specifications are precise, correct, and work closely with the commercial teams to initiate subcontract engagement and delivery Assist in the technical evaluation of subcontractor bids, identifying potential technical risks or "scope gaps" in vendor proposals before they are onboarded Identify and specify critical mechanical assets early to secure manufacturing slots and protect the project programme, working closely with the PM function to manage the procurement schedule proactively Subcontractor & Package Management Act as the primary point of contact for mechanical subcontractors. You will manage their design finalisation post-award, ensuring their "as-manufactured" drawings align with the requirements of the design team Manage mechanical packages proactively, you will ensure Subcontractors work to programme and implement robust planning of works alongside the site teams, as well as monitoring the scope of works, ensuring any change from the original design are technically assured, and commercially justified under NEC3/4 contract terms Work with the MEICA team, where required to attend Factory Acceptance Testing (FAT) and quality inspections to verify that the physical mechanical assets match the approved design prior to delivery to site Qualifications Essential Degree/HND/HNC in Mechanical Engineering or related discipline Chartered Engineer status (or working towards) preferred Proven experience in mechanical package management within the water or wastewater sector, with a deep understanding of hydraulics, pumping systems, package plant and pipework Strong understanding of treatment processes and mechanical systems Experience managing suppliers and subcontractors Strong project management and organisational skills Excellent communication and stakeholder management abilities Commercial awareness and contract understanding Problem-solving mindset with attention to detail Proficiency in reviewing 3D/BIM environments and AutoCAD Valid CSCS / EUSR water hygiene card Desirable Experience with major infrastructure or utility projects Knowledge of relevant standards (e.g., BS, ISO, water industry specifications) Familiarity with NEC or similar contract forms LI-JA1