Thames Water has awarded the major £400 million AMP8 contract for the significant upgrade of its Coppermills Advanced Water Treatment Works to Acciona Agua UK Ltd, part of the Spanish-headquartered ACCIONA Group.

A global header in the development and management of sustainable infrastructure solutions, the ACCIONA Group operates across the entire value chain, from design and construction to operation and maintenance.

The Coppermills upgrade forms part of Thames Water’s Water Supply System and Resilience Programme (WS-SRP). Work is scheduled to begin in spring 2026 and will be completed over seven years.

The major project consists of a series of wide-ranging packages of work, including:

• new circa 700 Ml/d High Lift Pumping Station (HLPS)
• A new circa 260 Ml/d Slow Sand Filter (SSF) Recirculation and Run-to-Waste system
• A new cryptosporidium treatment system to treat SSF filtrate for Cryptosporidium inactivation
• A new circa 50 Ml/d contact tank draindown pumping station and dechlorination system

Specifics of the project are as follows:

High Lift Pumping Station

Design, construction, and commissioning of a new circa 700Ml/d High Lift Pumping Station (HLPS) and decommissioning of the existing HLPS for Coppermills (AWTW). The existing HLPS is the primary means of distributing water to customers in Northeast London and is being replaced to enhance supply resilience and future proof London's water supply system and will be funded via a conditional allowance programme.

At a high level, the package will involve the construction of a modern, energy efficient, and resilient pumping station in the footprint of an existing slow sand filter in the centre of a busy operational site. The new HLPS building will feature a basement and superstructure to house the new VSD controlled high lift pumps, surge suppression equipment, electrical systems, and Heating, Ventilation, and Air Conditioning (HVAC) plant.

Additionally, The package will include logistically and technically complicated connections and modifications to the existing contact tank(s) and the existing HLPS outlet and inlet manifolds, as well as connection to the Thames Water Ring Main. In addition, the works will include the development and implementation of a comprehensive Supervisory Control and Data Acquisition (SCADA) upgrade along with a new instrumentation and control system to optimise the overall operational efficiency of the new HLPS and to protect customers.

Many of the ancillary works associated with this package are significant and will include: HV power upgrade, additional standby generator capacity, a new uninterrupted power supply system, asset protection and monitoring, and decommissioning of the existing HLPS and associated assets.

Slow Sand Filter (SSF) Recirculation and Run-to-Waste System

This package entails the design, construction, and commissioning of a new recirculation and run-to-waste system for 32 existing SSFs at Coppermills AWTW to enhance supply resilience and overall efficiency, resilience, and adaptability of Coppermills AWTW.

The package will include the construction of 16 below ground SSF recirculation/runtowaste pumping stations with submersible pumps, associated pipework, valves, instruments, and fittings.

Additionally, a sophisticated flow control and monitoring system will be implemented, featuring 32 flow control valves, flowmeters, and sampling points on each SSF outlet. The electrical infrastructure will include an LV substation, East and West LV switchboards, and MCCs for each pumping station. E Flows from the individual pumping stations will be transferred to a central distribution point. The distribution point will incorporate flowmeters, control valves, sampling points, and instruments to enable flows to be sent to waste and/or recirculated depending on water quality and operational requirements. This package will also include the construction of new connections and a discharge pipework to the head of the works and Walthamstow Reservoir No. 3 via Tunnel C culvert. The forward-looking initiative aims to enhance overall efficiency, resilience, and adaptability to future water treatment demands.

Cryptosporidium Treatment System

Design, construction and commission of a new cryptosporidium treatment system to treat SSF filtrate at Coppermills AWTW. The requirements for the package of work are being developed by Thames Water and ACCIONA will need to work collaboratively with Thames Water to help develop the requirements for this package. Thames Water's key driver for including this package in the contract is to ensure an integrated and systematic approach to delivery of all works at Coppermills AWTW and to support early benefit realisation and cost savings where possible.

Contact Tank Draindown System

Similar to the cryptosporidium treatment system, requirements for the contact tank draindown system are still being developed. However, Thames Water says there are considerable linkages between this future package and the HLPS and SSF recirculation and run-to-waste packagesm, making it essential that requirements and solutions are developed in parallel.

The water company says the Coppermills upgrade project will require a high level of civil, mechanical, electrical, process, operational, and construction planning and management expertise to ensure successful delivery.

Scope of works will include:

Site establishment and enabling works

• Identification, specification, and completion of any de-risking surveys/studies required to support the delivery of the project.
• Decommissioning, diversion, and demolition of existing assets as required to facilitate the project.
• Design and installation of measures to protect and monitor existing assets to ensure safe delivery of the project.

SCADA works

Upgrade the existing telemetry and control systems to integrate new assets and optimise control and operation of the site.

Electrical works

• Full upgrade of the existing power supply and distribution systems for the site to support new and existing plant and apparatus.
• New HV switchboards/switchgears, LV MCCs, LV switchboards, uninterrupted power supply, standby generators, and associated equipment.

Demolish SSF no. 18

To make way for the new HLPS building, including substructures, to accommodate the HLPS and associated apparatus.

Civil building works

• Includes the new HLPS, MCC, electrical and control buildings, as well as slow sand filter pumping stations, SSF recirculation/Run-to- Waste distribution system, and discharge chambers.
• Installation of cable ducts, below and above ground pipework and associated supports.
• Structural modifications to the existing contact tank(s) and an adjacent SSF (SSF no. 19) to facilitate the construction of the new HLPS inlet manifolds.
• Construction of new outlet manifold connections from the new HLPS to the four distribution zones and a new tunnelled connection to the Thames Water Ring Main.
• Implement measures and asset protection controls to support construction activities.

MEICA works

Mechanical, electrical and ICA fit for the project including but not limited to, all valves, instruments, pumps, motors, VSDs, control panels, surge suppression systems, chemical dosing systems and mixers, as well as water quality shutdown and control systems.

Commissioning and handover

• Testing, commissioning, and handover of all installed assets in a manner that supports Thames Water's operational needs.
• Decommissioning and reinstatement
• Decommission the existing high lift pumping station and assets made redundant by the works especially those that could pose a risk to water quality and/or health and safety.
• Reinstate and recommission SSF no. 19.
• Reinstate all areas affected by the project to pre-works condition or better.