Thames Water has gone out to tender with a wide-ranging AMP8 framework contract for digester inspection and refurbishment works with an indicative total estimated value of £70 million including VAT.

The water company intends to establish a single-lot, multi-supplier framework agreement to deliver inspection, repair, refurbishment and upgrade works to anaerobic digester assets and associated infrastructure across its operational estate. No supplier is guaranteed any minimum volume or value of work under the framework.

The framework will support the ongoing maintenance, regulatory compliance and enhancement of Thames Water's digester portfolio, which forms a critical part of sludge treatment operations. Works will be required across multiple sites and will be delivered as discrete packages or programmes of work called off over the duration of the framework.

Scope of services to be delivered under the framework includes:

• Decommissioning, isolation and preparation of digesters for inspection and refurbishment
• Removal, treatment and disposal of sludge, grit and associated waste materials in accordance with all applicable regulations
• Internal and external inspection of digester structures and associated assets, including provision of inspection reports, defect identification and recommended remedial actions
• Cleaning and enabling works required to facilitate inspection and subsequent refurbishment activities
• Structural repair and refurbishment of digester assets, including roofs, walls, bases and associated civil infrastructure
• Repair, replacement and upgrade of mechanical, electrical, control and instrumentation (MECI/MEICA) systems, including mixing equipment, pipework, valves, heating systems, and control/automation systems
• Upgrade works to meet current regulatory, environmental and operational standards, including those relating to emissions control, gas management and asset performance
• Temporary works, access solutions, cranage, site establishment and all associated enabling activities required to safely deliver the works
• Testing, commissioning, performance validation and handover of refurbished assets
• Provision of as-built documentation, asset data, operation and maintenance manuals, and training for operational personnel

The water company says the nature, scope and value of individual call-off contracts will vary and in many cases, the full extent of refurbishment and upgrade works will only be confirmed following completion of initial decommissioning, cleaning, and detailed inspection activities.

Works packages may therefore comprise a combination of defined and developing scopes, with suppliers required to work collaboratively with Thames Water to refine and deliver solutions based on inspection findings.

The framework is expected to operate across multiple sites within the Thames Water region. Works will need to be carefully planned and executed to ensure continued operational performance of the wider network, including constraints on the number of digesters that can be taken offline at any one time.

Suppliers appointed to the framework will be expected to demonstrate capability in delivering complex, safety-critical works within live operational environments, and to work collaboratively with Thames Water to achieve programme objectives, regulatory compliance and value for money.

Further detail regarding the scope, technical requirements and contractual arrangements will be set out in the procurement documentation issued at the Invitation to Negotiate (ITN) stage.

Current estimated start and end contract dates are 1 February 2027 to 1 February 2031 with further possible extension options up to 1 February 2035.

General operation of the framework

Call-off contracts will be awarded either:

• through further competition between all appointed Framework suppliers; or
• via award directly to a supplier on an objective basis

For each call-off, Thames Water will issue a call-off tender pack ( tenderers will be required to submit both a technical and commercial proposal) setting out:

• the initial scope of works
• project-specific requirements and constraints
•  pricing approach and assumptions
• evaluation criteria

At the framework award stage (ITN), tenderers will be required to submit a Framework Schedule of Rates, setting out their proposed:

• labour rates
• plant and equipment rates
• daywork rates, and
• rates for defined inspection, repair and refurbishment activities

Deadline for submission of enquiries about the tender is 5:00pm on 25 June 2026, and deadline for requests to participate is 12:00pm on 9 July 2026.

Thames Water is asking suppliers who are interested in participating to register by completing an online form - click here to access the form