The Engineering Challenge
The new STW is being constructed on a former sand and gravel pit later used as landfill. Extensive ground improvement, including rapid impact compaction and over 3,000 driven piles, was required before superstructure works could commence. Within this complex environment, the project team required raised access solutions that would:
- Provide safe working platforms
- Perform reliably in a corrosive wastewater environment
- Minimise installation complexity within a tightly sequenced construction programme
- Support long-term operational safety with minimal maintenance burden
The platforms were designed, fabricated and supplied to accommodate a high load requirement of 10kN uniformly distributed load (UDL), safely supporting MCC cabinet and associated electrical equipment.
Traditional steel solutions would introduce weight, corrosion risk and ongoing maintenance requirements. A durable composite alternative was required to align with whole-life performance objectives.
A Durable Access Solution for Critical Infrastructure
The d² Dura Access Structures were selected to deliver robust, corrosion-resistant raised access across multiple treatment stages within the new works.
Manufactured from high-performance glass reinforced polymer (GRP), the system provides inherent resistance to corrosion, moisture and chemical exposure, which are key considerations in wastewater treatment environments. Key advantages of the d² solution included:
- Lightweight components to simplify handling and installation
- High strength-to-weight ratio for elevated access structures including areas designed to accommodate 10kN UDL loading
- Slip-resistant d² Dura Slab walking surfaces to enhance operational safety
- Reduced maintenance compared to traditional metallic systems
- Long design life suited to critical utility infrastructure and fully recyclable should it ever become end of use.
The modular nature of the d² system supported integration with varying foundation levels and adjacent civil works, enabling efficient coordination alongside other enabling works at the site such as piling, tank construction and below-ground pipe installation.
Installation Within a Complex Brownfield Environment
The lightweight characteristics of the d² Dura Access Structures reduced lifting requirements and simplified installation across the former landfill site, where access, sequencing and safety were critical.
Results and Impact
- Safe, elevated access
- Reduced weight and improved installation efficiency
- Corrosion-resistant and capable of performing in harsh, moisture-rich and chemically aggressive conditions.
- Lower anticipated maintenance requirements over asset life
- Modular system enabling coordination within a complex civil engineering programme
- Contribution to long-term, future-ready water infrastructure for Guildford
Looking Ahead
The new Guildford STW is scheduled for full completion and commissioning in 2026. Once operational, it will provide enhanced wastewater treatment capacity, support urban regeneration and leave a lasting infrastructure legacy for the region.
Through the supply of d² Dura Access Structures, Dura Composites has supported the delivery of safe, durable and low-maintenance access solutions within one of Thames Water’s most significant recent capital projects.
