Client
Ward & Burke Construction Limited
Value
£130k
Sectors & Services
Water Industry Concrete Repair Condition Surveys Coatings Membranes Cleaning & Preparation Projects
Ward and Burke Construction Limited commissioned CRL Surveys to assess the condition of four large circular concrete digesters at a major sewage treatment works operated by a UK water company. In service for approximately 50 years, the digesters are critical assets in the wastewater treatment process and had begun to show signs of deterioration due to prolonged exposure to aggressive chemicals and water ingress.
The commission focused primarily on Digester AD1, including its walls, base slab, and associated Limpit and Inlet Chambers. The inspections were required to identify structural defects, understand deterioration mechanisms, and inform appropriate repair and asset management strategies.
Services undertaken
- Detailed structural inspection of concrete digesters
- Inspection of walls, base slab, Limpit Chamber, and Inlet Chambers
- Identification and assessment of cracking and water ingress
- Resin injection to internal and external wall cracks
- Removal of existing Hypalon and bituminous overbanding
- Application of Masterseal 930/933 overbanding system
- Concrete repairs to digester walls and base
- Condition reporting and maintenance recommendations
The scope of works undertaken by CRL Surveys included a detailed structural inspection of Digester AD1, concentrating on the condition of the concrete walls, base slab, and associated internal chambers. During the inspection, cracking was identified in both the base slab and upper wall sections, occurring in both horizontal and vertical orientations, particularly along construction joints. Evidence of active water ingress was observed, including efflorescence and water staining, confirming that moisture was penetrating through the concrete. The Limpit Chamber was also found to be in a deteriorated condition, with roughened concrete surfaces and visible corrosion staining, indicating ongoing degradation of embedded reinforcement.
In parallel with the inspection works, CRL carried out targeted repair activities to Digester AD4. These works addressed identified cracking and localised damage to the walls and base slab. Resin injection was undertaken to seal both internal and external wall cracks, restoring structural continuity and preventing further water ingress. To enhance durability, a Masterseal 930/933 overbanding system was applied over the treated cracks, providing additional protection against chemical attack and moisture penetration.
As part of the repair strategy, all existing protective materials, including legacy Hypalon and bituminous overbanding systems at construction joints, were removed and replaced with the Masterseal 930/933 system. This upgrade significantly improved the joints' resilience in the demanding wastewater environment. Based on the inspection findings, CRL also provided recommendations for the use of long-lasting repair solutions and protective coatings, alongside the importance of regular maintenance to safeguard the long-term performance of these essential concrete assets.
"CRL did a great job fixing and protecting the digesters with solutions that last. Their know-how and advice on regular upkeep helped keep everything in great shape!"
Nigel Pierce | Survey Manager | CRL Surveys
The inspection and repair works delivered benefits extending well beyond immediate defect remediation. By identifying deterioration mechanisms and addressing active cracking, CRL helped stabilise critical wastewater infrastructure and reduce the risk of unplanned outages. The use of durable resin injection and modern overbanding systems improved resistance to chemical attack and water ingress, supporting extended service life and reduced future maintenance requirements.
CRL’s methodical inspection approach and practical repair recommendations provide a strong foundation for proactive asset management, enabling informed maintenance planning across the broader digester portfolio. The project demonstrates CRL’s expertise in delivering effective structural repairs UK-wide within challenging operational environments, ensuring continued functionality, resilience, and long-term value for the client.
