MWH Treatment logo

Coppermills Water Treatment Works, Thames Water

Coppermills Water Treatment Works has a critical role in supplying water to 3.5million customers across the City of London and the borough of Tower Hamlets. It treats reservoir stored water, producing around 680Ml/d of treated water. Construction of the first phase of works were completed in 1969. The works was uprated to its current design maximum of 680 Ml/d in the 1980s with links to the London ring main added later that decade. In the 1990s interstage ozonation was incorporated prior to the slow sand filters and a layer of GAC added to enable the treatment of pesticides. A transfer pumping station to allow movement of treated water to / from the London ring main was added in 2012.



DfMA (design for manufacture and assembly) construction techniques were maximised at the £44m Coppermills project. This approach further enabled by the full utilisation of MWH Treatment’s digital toolbox, collaborative planning process and early strategic supply chain engagement produced an accelerated programme for this critical asset. The new delivery method reduced the original 36 programme by 18 months, reduced onsite labour by 75%, saved approximately £4m on site preliminaries and overall project cost resulting in a 10% saving. In addition the approach realised further indirect benefits reduced waste, minimal temporary works, improved quality from controlled manufacturing environment, reduced interruption to daily plant operation, minimised working-at-height, zero accidents and reduced risk. As an MWH Treatment Conversion project, the safe and successful delivery of Coppermills has achieved another step forward in MWH Treatment’s objective of redefining construction.


Historically, the works operators have managed the quality of the raw water supply by careful selection of the raw water reservoir feed source. Over recent years however, environmental changes have led to increased algal activity which meant the operators have found it difficult to manage raw water abstraction effectively. Consequently, the output of the works has been significantly reduced due to the poor quality of water entering the site during algal bloom periods, particularly during spring and in the early Autumn, reducing the amount of water supplied into the London zone. Following exploration of various solutions, it was concluded the lowest whole life cost option was to increase the primary filtration capacity by constructing a new RGF block to operate in parallel with the existing RGFs and capable of treating up to 200Ml/d.

The scope

The scope for the new works included:

  • New pumped connections to 3 of the raw water sources
  • 12 no. 90m2 twin cell, dual media units.
  • Clean backwash water system.

As part of SMB, MWH Treatment were awarded the Coppermills RGF project in April 2015.The initial project had a 36 month construction programme promoted by Thames Water.

Innovative approaches

Conversion Project

Coppermills WTW was identified early in its life cycle as a Conversion project. MWH Treatment use Conversion projects as vehicles to drive improvement in the way we, our clients and our supply chain deliver innovative change. As this project was delivered through our SMB JV, we worked collaboratively with our partners to share our innovations thus redefining construction in the sector as a whole.


Digital Toolbox

Our delivery strategy for Coppermills involved the full range of MWH Treatment’s digital toolbox, from visual project initiation, digital scanning, digital collaborative planning, digital construction rehearsal and digital commissioning rehearsal. The power of our digital toolbox is in the visualisation of complex activities in a way that breaks down language and knowledge barriers allowing all members of project teams to contribute. Coupling the visualisation with collaborative commercial relationships we unlock the power of collaborative innovation.


Design for Manufacture and Assembly (DfMA)

DfMA was an identified efficiency driver to reduce time on site. The project team set the vision to deliver as much of the project as possible using DfMA principles. An early team objective was to target 50% reduction in time on site. The project team actively sought out partners that utilised DfMA. This also involved working collaboratively to manage the parallel manufacture of products and coordinating across multiple interfaces. ­At Coppermills over 40% of the value of the project was manufactured off-site. The resulting benefit, in terms of outperforming the programme, reduced the Health and Safety risk and improved “right first time” quality were key factors in the successful delivery of Coppermills. The DfMA approach also significantly reduced the impact of the project on Thames Water’s neighbours and customers by reducing the number of vehicle movements and the length of time those movements occurred by 65%.

Planning & engagement

Collaborative Planning / Integrated Working / Early Supply Chain Partners Engagement

A critical factor in all successful MWHT projects, is the early identification and meaningful engagement of our supply chain partners. On Coppermills, 80% of our critical supply chain were on board within the first quarter of the design activity. When this was aligned with integrated working and collaborative planning with MWH Treatment and the client we saw significant early value add created and the construction programme substantially reduced.


Asset Optimisation and Integration Management

A significant portion of the new project would rely on interfaces with existing assets. Integration had to have been achieved without disruption to water production and supply to London. A joint team developed virtual rehearsals of detailed construction and commissioning sequences. This involved a risk-based review of existing asset conditions and critical interface activity. The resulting schedules and Synchro simulations gave the client increased confidence and ownership regarding the operationally critical elements of the project.


Health and Safety

Coppermills delivery has currently had 500,000 man hours without injury or significant near miss.


Ahead of Schedule

Coppermills RGF was commissioned 18 months ahead of schedule realising a £6m benefit



The project is forecast to deliver for c£40M, £4M ahead of the earlier project estimates following value engineering.



Through utilising DfMA we achieved an overall embodied carbon saving of 45%