Remote Robotic UHP Water Jetting for Complex Digester Cleaning

Introduction

During a gas digester asset refurbishment project, a persistent gas leak occurred due to voids behind a Glass Reinforced Plastic (GRP) roof system. The structure's complex design, featuring steel-reinforced GRP formwork encased in concrete, combined with low scaffolding access and severe confined space constraints, rendered conventional mechanical removal methods impractical and unsafe for manual workers.

Our Solution

To safely clear the obstruction, UCL engineered a bespoke technical solution utilising Ultra High-Pressure (UHP) water jetting operating between 30,000 and 40,000 psi. Because manual jetting in the restricted space posed unacceptable safety risks, the team adapted a remote-operated robotic system, originally built for pipe cleaning. This robot was mounted onto a custom-designed framework assembled directly inside the tank. The automated system allowed operators to precisely target and jet out the embedded steel rods and GRP formwork. This innovative engineering approach effectively eliminated confined space risks for personnel, protected the structural integrity of the surrounding concrete, and delivered precise, efficient removal within tight project time constraints.

Key Benefits

• Eliminates manual high-pressure jetting risks in dangerous confined spaces through remote automation
• Utilises precise 30,000–40,000 psi UHP water jetting to clear stubborn steel rods and GRP structures
• Fully uncovers embedded rebar without structural damage, ensuring clean steel exposure for compliant concrete remediation
• Prevents collateral impact or structural damage to the primary concrete asset
• Overcomes severe physical site constraints, including low scaffolding decks and restricted access
• Demonstrates UCL's capability to design and adapt bespoke robotic machinery for complex civil engineering challenges

Conclusion

UCL's adaptation of robotic UHP water jetting successfully overcame complex structural and safety challenges. This project highlights our ability to deploy tailored engineering solutions for high-hazard environments, preserving asset integrity while maintaining absolute safety. The custom-built framework remains an active, reusable asset for future technical cleaning challenges.