Severn Trent Water is undertaking a comprehensive program to improve air valve performance in high grease and fat conditions across their network. This is part of a wider work program to ensure that all the Sewage Air Valves on the Severn Trent network meet a minimum and maintainable standard. This case study explores the implementation of BERMAD C50 air valves, focusing on their operational efficiency and the challenges faced during the upgrade process.
| Severn Trent operates over 1,400 sewage air valves, many requiring upgrades to meet maintainability and performance standards. The introduction of BERMAD C50 valves was part of a strategic response to overcome challenges posed by high levels of grease and fats in certain locations. To date over 75NO C50 units have been supplied to this program of works. | 
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Specification
The selection of BERMAD C50 valves followed an initial successful trial at Balliol Business Park in Wolverhampton, which demonstrated superior performance in tough conditions. The decision was influenced by the C50’s ease of maintenance and its innovative design, which simplified installation even in constrained spaces.
Technical Specifications and Performance
| BERMAD C50 valves include a Surge Protection device critical for high-fat environments, provided at no extra cost unlike competitors. These valves have shown exceptional performance in handling grease and fats, with significantly reduced maintenance requirements due to their design which keeps internal components relatively clean and easily meets the requirements of a service interval of 3 months, specified by Severn Trent. Competitor products constrained by the same service intervals in these high-risk locations, have been found to be clogged, increasing the risk of bursts and free venting. | 
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Installation Challenges
Installation challenges were minimal due to the valve's design allowing for separate flange installation, with the unit being placed after the flange is installed. Severn Trent noted the ease of installation as a key benefit, particularly in tight chamber spaces where competitor equivalent valves posed significant challenges. As the C50 is manufactured from composite materials it is lighter than traditional ductile iron products. A C50 DN80 flanged unit is 6.7kg, which makes it easier to install and maintain.
Maintenance and Durability
Maintenance has been straightforward, with a standard three-month service interval. The C50’s design allows for top access servicing, which is quicker and less cumbersome compared to competitor equivalent valves.
Cost-Effectiveness
The introduction of C50 valves is considered cost-effective due to lower initial costs and reduced maintenance expenses. Severn Trent anticipates long-term savings from decreased operational costs, including less downtime, increased mitigation of free venting effluent from the valves and fewer burst risks due to clogging.
Environmental and Regulatory Compliance
The C50 valves meet all UK regulatory requirements for sewage systems and are part of Severn Trent’s broader environmental compliance efforts. BERMAD is also undertaking an evaluation of the valves’ carbon emissions, reflecting a commitment to sustainability.
Overall Satisfaction
Severn Trent expresses high satisfaction with the C50 valves, citing their robustness and engineering as beneficial for widespread use in sewage rising mains. They recommend these valves to other water companies for their reliability, favourable pricing, and shorter lead times compared to competitors, in addition to their performance in tough applications.
Conclusion
The implementation of BERMAD C50 air valves by Severn Trent represents a successful adaptation to the challenges of managing sewage systems in conditions prone to high levels of fats and grease.
BERMAD is keen to support any Water Companies and their framework partners in understanding the importance of selecting appropriate technology to meet specific operational challenges while enhancing overall efficiency and sustainability.
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