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Primary Flow Signal installs flowmeter at US wastewater treatment plant to improve Potomac River water quality

Primary Flow Signal (PFS), a designer and manufacturer of flow metering solutions, has successfully installed a rectangular Halmi Venturi flowmeter used to measure sewage discharge from the Blue Plains advanced wastewater treatment plant in Washington, DC, US.

According to the District of Columbia Water and Sewer Authority, the Blue Plains 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 two million Washington metro area customers.

PFS 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), PFS performed scale model testing that validated the projected accuracy and head loss of the meter despite the physical, dimensional, and low-pressure challenges of the flow channel.

A full-size rectangular Halmi Venturi flowmeter was manufactured in the company's Rhode Island facility and installed by Ulliman Schutte Construction with assistance from PFS personnel. Once installed, grouting and concrete work ensured a smooth flow through the meter. This was vitally important as the low pressure in the channel made head loss a significant concern for maintaining accuracy.

Halmi Venturi flowmeters are designed to measure full pipe flow of gases or liquids over extreme temperature ranges, as well as contaminated liquids, sludges, slurries, and sewage. The 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 flowmeter is offered cast in place (usually concrete and typically rectangular) depending upon application requirements