All you need to know about butterfly valves for wastewater
Wastewater applications employ a wide range of different valves across the board. Any one system might be reliant on a variety of check valves, shut-off valves and air valves to maintain the efficiency of their processes. In this article, PIF outlines the typical uses of butterfly valves for wastewater applications.
Butterfly valves for wastewater secondary treatment
Whilst swing check and resilient hinge swing check valves are the star attractions in wastewater plants, in terms of preventing reverse flow and slamming, butterfly valves come into their own further down the line within wastewater treatment facilities.
They typically come to the fore in secondary and tertiary treatment processes, whereby organic matter is removed using a suspended growth process and chemical treatment respectively. “Aeration systems frequently use high-power centrifugal air blowers and power-actuated control valves, typically wafer butterfly valves,” says John V. Ballun, writing in Valve Magazine.
“The control valves for air service are designed for dry fluid service and high temperatures approaching 300°F (150°C). Additionally, blowers should be fitted with check valves that have low opening or cracking pressure and are sized so they will not chatter during low-flow operation.”
Wastewater butterfly valves for tertiary treatment
Tertiary treatment processes variously include biological or chemical treatment, tertiary filtration, disinfection of the effluent and dechlorination of the final output water for it to either be pumped for reuse or released into a waterway.
Ballun continues: “Since the sediment has been removed from the wastewater, other types of waterworks valves may now be used. For example, butterfly valves supplied in accordance with AWWA C504 are often used here because of their compact size and low cost, especially in large pipe sizes.
“When pumping effluent for reuse, waterworks pumps, check valves and shut off valves can be used. Both butterfly and ball valves are quarter-turn valves that are reliable and simple to automate for this service,” he concludes.
Bray is the global leader in butterfly valve and actuator manufacture for water filtration. Their valves feature three disc-to-stem connections: Double ‘D’, Splined, and Double Key. These internal non-wetted connections eliminate typically exposed external disc-to-stem connections, such as screws or taper pins. Disassembly of Bray’s internal connection is performed by simply pulling the stem out of the disc.
Bray Controls provides resilient seated valves for many applications in water, wastewater, filtration and desalination applications. For instance, their Bray/McCannalok line of high-performance butterfly valves features a simple and innovative design that offers rugged reliability and extremely easy maintenance in the field. They promise superior service life and bubble-tight shutoff – even after hundreds of thousands of cycles.
If you enjoyed this article, why not carry on reading with this article all about the functions of butterfly valves and their typical applications.
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