THE WALKIE-TALKIE,
20 FENCHURCH STREET

Project Overview 

20 Fenchurch Street, internationally recognised as the “Walkie Talkie”, is one of London’s most iconic commercial skyscrapers and a defining feature of the City of London skyline. Designed by Rafael Viñoly Architects, the 160m tall tower comprises 37 storeys of premium office accommodation above retail and public amenities, including the world-famous Sky Garden — London’s highest public landscaped garden. 

Completed in 2014, the development provides approximately 62,000m² of Grade A office space and accommodates a wide range of global financial, insurance and professional services occupiers within one of the capital’s most prestigious commercial addresses. 

As a high-profile landmark building with substantial daily occupancy and complex building services infrastructure, operational resilience and sustainability performance remain critical elements of the building’s long-term facilities strategy. 

Grey Water Recycling Upgrade Scope 

As part of ongoing sustainability improvement works within the building, Indratec was appointed to upgrade the existing grey water recycling infrastructure following operational performance issues associated with the original treatment arrangement. 

The existing multimedia filtration system had become increasingly ineffective in maintaining the required treated water quality and operational reliability expected within a high-demand commercial environment. 

Indratec designed and delivered a complete upgrade solution involving: 

• Removal of the existing multimedia filtration system 
• Installation of a new membrane bioreactor treatment plant 
• Integration of hollow fibre membrane technology 
• Upgrade of controls and operational automation 
• Introduction of a new bespoke mains water backup control system 

The upgraded installation was developed to significantly improve treatment consistency, operational resilience and long-term maintainability. 

Installed System 

• Grey Water Recycling Plant Upgrade 
• Treatment Capacity: 20m³/day 
• Treatment Technology: Hollow Fibre Membrane Bioreactor (MBR) 
• Control System Upgrade: Bespoke Mains Water Backup Controls 

Engineering Solution 

The original grey water treatment arrangement relied on multimedia filtration technology which had become increasingly difficult to maintain effectively under varying operational loads and occupancy conditions. 

Indratec developed a replacement treatment strategy centred around membrane bioreactor technology to deliver substantially improved effluent quality and operational reliability within the existing plant space constraints. 

The new treatment plant combines biological treatment with hollow fibre ultrafiltration membranes, providing: 

• Enhanced suspended solids removal 
• Improved treated water clarity 
• Greater process stability 
• Reduced maintenance burden 
• Improved operational resilience 
• Higher treatment consistency during variable loading conditions 

In addition to the process upgrade, a fully bespoke mains water backup control arrangement was developed and integrated into the system. 

The new control philosophy was specifically engineered to: 

• Maintain uninterrupted non-potable water availability 
• Provide intelligent automatic changeover between recycled and mains supply 
• Improve system monitoring and fault response 
• Reduce unnecessary mains water consumption 
• Enhance operational flexibility for facilities management teams 

The upgraded controls were carefully integrated within the building’s live infrastructure to ensure seamless operation alongside existing building management systems. 

Treatment Process Upgrade 

The new membrane bioreactor treatment process was designed to overcome the limitations associated with the previous multimedia filtration arrangement whilst maximising treatment performance within the available plant footprint. 

Upgraded Process Features 

1. Removal of existing multimedia filtration equipment 
2. Installation of membrane bioreactor treatment system 
3. Secondary biological treatment process 
4. Hollow fibre membrane ultrafiltration 
5. Automated treated water quality management 
6. Intelligent mains water backup control integration 
7. Automated monitoring and operational control systems 

The introduction of membrane technology has enabled significantly improved treated water quality consistency whilst reducing operational intervention requirements. 

Project Engineering Challenges 

The project required extensive coordination and phased implementation within one of London’s busiest operational commercial towers. 

Key engineering considerations included: 

• Removal and replacement of existing live plant infrastructure 
• Installation within constrained central London plant spaces 
• Maintaining continuity of non-potable water services during upgrade works 
• Integration with existing building management systems 
• Coordination within an occupied high-rise commercial environment 
• Development of bespoke control philosophies 
• Minimisation of operational disruption to tenants and facilities teams 
• Long-term operational resilience and maintainability 

Particular attention was given to ensuring that all upgrade works could be delivered safely and efficiently within a fully operational landmark commercial building environment. 

Technical Summary 

20 Fenchurch Street (“The Walkie Talkie”) 

Location City of London 

Building Height ~160m 

Building Use Commercial Headquarters Offices 

Approximate Building Size ~62,000m² 

Grey Water System Capacity 20m³/day 

Original Treatment System Multimedia Filtration 

Upgraded Treatment Technology Hollow Fibre Membrane Bioreactor 

Outcome 

The completed upgrade has transformed the building’s grey water recycling capability through the replacement of an underperforming legacy filtration system with a modern membrane bioreactor treatment solution. 

The introduction of advanced membrane treatment technology and bespoke automated mains backup controls has significantly improved treated water quality, operational reliability and overall system resilience within one of London’s most recognisable commercial developments. 

The project demonstrates how existing commercial buildings can be successfully retrofitted with modern water reuse technologies to support evolving sustainability objectives whilst maintaining the high operational standards expected within premium commercial real estate.