WASTEWATER
applications . The pinch valve ’ s operating principle is straightforward : 1 . A flexible , elastomeric sleeve is housed within a robust designed body .
2 . When open , the sleeve provides an unobstructed flow path .
3 . During closing , two pinch bars squeeze the valve sleeve shut on the centre line with various types ( e . g . mechanical , pneumatic or hydraulic ) of actuators . This design offers several advantages in wastewater treatment :
• Unobstructed flow : This minimises pressure drop and reduces the risk of blockages with suspended solids .
• Effective closure : Achieves reliable shut-off even with abrasive or scaling media present .
• Wear resistance : Suitable for handling corrosive chemicals and abrasive slurries .
• Simplified maintenance : The sleeve is typically the primary wear component , which can simplify maintenance procedures .
Some pinch valve designs , such as those offered by Valmet , incorporate additional features :
• Sleeve materials optimised for specific chemical compatibilities
• Positioners for flow control applications
• Diagnostic capabilities for maintenance planning
These valves have demonstrated long service lives in demanding applications , with some installations operating for extended periods without sleeve replacement .
Case Studies
Camden Wastewater Treatment Plant , USA
Challenge : The plant needed to transition from gas chlorine to liquid sodium hypochlorite for disinfection and use sodium bisulfite for dechlorination , requiring a reliable dosing system with a small footprint . Solution : Valmet supplied wall-mounted packaged Flowrox metering pump systems . Key features included :
• Space-efficient design
• Integrated containment for enhanced safety
• Capability to handle off-gassing in sodium hypochlorite service Outcome : The installation addressed the plant ’ s chemical dosing needs
In the wastewater industry there are over 18,000 Flowrox valves and pumps installed in over hundreds of municipal / industrial wastewater treatment plants across the globe . Each valve is designed to reduce clogging , ensure purity and increase reliability .
whilst improving safety and reliability . The system ’ s effectiveness led to its specification for a second site .
Czajka Wastewater Treatment Plant , Warsaw , Poland
Challenge : This large-scale plant required precise sludge flow control across its treatment process . Solution : Twenty electrically actuated Flowrox pinch valves were installed for sludge flow control . The solution offered :
• Gentle handling of bacteria-rich sludge , important for maintaining biological treatment efficacy
• Wide flow control range , adapting to varying process conditions
• Extended maintenance intervals , reducing operational disruptions
Outcome : The valves have operated without sleeve changes for over a decade , demonstrating durability in a demanding application . This longevity has reduced maintenance costs and improved overall plant reliability .
Future developments in wastewater treatment
Several trends are shaping the future of flow control technology in wastewater treatment : 1 . Increased use of sensors and connectivity : This is enabling realtime monitoring and informed maintenance planning .
2 . Focus on energy efficiency : Pump and valve designs are being optimised to reduce power consumption without compromising performance .
3 . Emphasis on chemical reduction : Control systems are being developed to optimise dosing and minimise chemical usage whilst maintaining treatment efficacy .
4 . Resource recovery : Flow control solutions are being adapted to support the extraction of valuable resources from wastewater streams . Industry suppliers , including Valmet , are working to develop solutions that address current challenges and anticipate future needs .
Conclusion
The wastewater treatment industry continues to face challenges in managing complex processes , ensuring environmental compliance and optimising operational efficiency . Advanced flow control solutions , such as those offered by various manufacturers including Valmet , play a crucial role in addressing these challenges . By offering improved accuracy , reliability and efficiency , these technologies enable wastewater treatment plants to meet regulatory requirements while minimising costs and environmental impact .
22 Valve World November 2024 www . valve-world . net