Venturi Flowmeter Helps Improve Water Quality in the Potomac River

Primary Flow Signal installed a rectangular Halmi Venturi Flow Meter to accurately measure sewage discharge at one of the world's largest advanced wastewater treatment plants, which serves more than 2 million customers in the Washingon, D.C. metro area.


Primary Flow Signal, a designer and manufacturer of flowmetering solutions, has successfully installed a rectangular Halmi Venturi Flow Meter used to accurately measure sewage discharge from the Blue Plains Advanced Wastewater Treatment Plant in Washington, DC.

According to the District of Columbia Water and Sewer Authority, the Blue Plains Advanced Wastewater Treatment Plant is the largest of its kind in the world with a capacity of 370 million gallons per day (MGD), a peak capacity of 1.076 billion gallons per day and covering 150 acres. The plant provides wastewater collection and treatment services to more than 2 million Washington metro area customers.

Primary Flow Signal collaborated with Black & Veatch to assess the authority’s flow metering requirements for treatment of sewage that will eventually flow back into the Potomac River and ultimately the Chesapeake Bay. Due to the unique upstream configuration and extremely low-pressure within the channel (5 PSI), Primary Flow Signal performed scale model testing that validated the projected accuracy and head loss of the meter despite the significant physical, dimensional, and low-pressure challenges of the flow channel. The model work shed light on potential pitfalls, but Primary Flow Signal’s experience in hydraulic engineering ensured that the full-size meter’s accuracy would not be impacted.

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Ultimately, a full-size rectangular Halmi Venturi Flow Meter was manufactured in the company’s Rhode Island facility and installed by Ulliman Schutte Construction with assistance from Primary Flow Signal personnel. Once installed, grouting and concrete work ensured a smooth flow through the meter. Primary Flow Signal says this was vitally important as the low pressure in the channel made headloss a significant concern for maintaining accuracy.

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“The Blue Plains project presented an opportunity for us to collaborate with the authority’s internal engineers and Black &Veatch to come up with what is, frankly, the only solution possible for this particular application,” said Gary Gilbert, Senior Principal Engineer at Primary Flow Signal.  “From initial planning, model testing, manufacturing, installation, to final acceptance, this important project validated our approach to ensure the meter will meet and exceed its projected performance.”

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Halmi Venturi Flow Meters are rugged, reliable, differential-pressure measurement devices, designed to measure full pipe flow of gases or liquids over extreme temperature ranges, as well as contaminated liquids, sludges, slurries, and sewage. Halmi Venturi Flow Meters are available in a variety of materials, including a cast iron pressure vessel, fabricated (welded) metal pressure vessel, plastic insert style, welded insert, and welded-in pressure vessel. Additionally, the Halmi Venturi Flow Meter is offered cast in place (usually concrete and typically rectangular) depending upon application requirements.

Source: Primary Flow Signal

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