Tender: PFAS Source Investigation and Mitigation Options for Two Surface-Water Catchments Supplying Water Treatment Works – Severn Trent

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Severn Trent is seeking a supplier to investigate sources, controls and future risks of PFAS in two surface-water catchments that feed two water treatment works, and to review mitigation options to reduce PFAS levels and dependence on energy‑intensive removal such as granular activated carbon. The work will assess origins from current and historic activities, drivers of concentration variation, likely future changes, and the feasibility, effectiveness and costs of interventions; it will also support stakeholder engagement and education to meet DWI guidance. The scope covers the catchments upstream of the two WTW, review of water quality data from 2022–2025 plus outputs from catchment risk assessments, shareable stakeholder engagement materials and AMP7 investigations, with one catchment requiring review and possible follow-up of AMP7 recommendations (including further upstream and sediment sampling and collection of flow data). Expected tasks include catchment water‑quality and flow monitoring (building on EA flow monitoring), sampling influent/effluent of large wastewater treatment works and up/downstream of potential discharges, desktop integration of water‑quality, flow and spatial data, forensic compound breakdown analysis and comparison with potential sources, mass-balance and simple modelling of sources, and recommendations on stakeholder engagement and source‑reduction options.