Chesterfield County Gains Sewer Flow Monitoring Freedom
Recently ranked one of the fastest growing counties in the nation, Chesterfield County, Va., is bound by the James and Appomattox Rivers and is known for its miles of historic picturesque landscapes. Residents and governmental agencies alike realize the importance of their natural resources and have set forth plans to keep it that way for future generations.
Their dedication has garnered them multiple awards and esteemed recognition amongst both governmental agencies as well as major industry associations, including the Environmental Protection Agency (EPA) and the Association of Metropolitan Sewerage Agencies (AMSA).
An AMSA spokesperson stated, “they are among the best-operated, most efficient water systems in the nation and are a credit to their communities.” Additionally, the county is one of two water and wastewater utilities in the nation to earn a AAA bond rating for their well-managed financial operations.
A major force within the county’s Utilities Department is their steadfast commitment to utilize only innovative technology to maintain their water and wastewater systems. Providing outstanding wastewater services to over 75,800 customers in their service area, they are also responsible for the maintenance and operation of 23 pump stations, 1,690 miles of sewer line and two wastewater treatment plants including the Proctors Creek Wastewater Treatment Plant and the Falling Creek Wastewater Treatment Plant. Together, the two plants treat 21.87 million gallons of wastewater per day (mgd) with a total combined capacity of 37.10 mgd.
For over 20 years, the county has utilized Marsh-McBirney Flo-Tote Open Channel Flowmeters to capture flow data for their continual Inflow and Infiltration (I&I) studies as well as long-term monitoring projects.
Wayne Riggins, utilities supervisor, stated, “when I joined the county 19 years ago they were already using the Flo-Tote meters. We have 15 Flo-Totes today and we are still using the meters in various locations. The person who had my position prior to me, Kenny Swann, had budgeted for five flowmeters from Marsh-McBirney. The meters used a new technology and he thought they would be a good fit.”
Kenny Swann added, “I was looking for new flowmeters for our I&I monitoring work. We saw that Marsh-McBirney’s new meter, the Flo-Dar, had a non-contact sensor. The non-contact nature would cut down on the number of times we actually have to go out and clean submerged sensors due to fouling or sedimentation.”
Since its introduction in 1996, Flo-Dar Radar Velocity/Area meters have been installed worldwide to accurately monitor open channel flows. Marsh-McBirney’s new generation of flowmeters utilizes highly accurate radar technology to remotely monitor open channel flows. Sensor fouling is totally eliminated, saving thousands of dollars at each monitoring site usually required for sensor maintenance and confined space entry when using submerged style sensors.
The Flo-Dar sensor can easily be removed or re-installed from street level. Additional benefits include field-replaceable/interchangeable sensors and monitors ensuring no lost data in the field, especially during critical monitoring periods. Sensors can be installed with either a permanent mount (affixed to wall) or a portable mount (jack-bar tension rod) dependent upon the specific application.
Flo-Dar applications that challenge traditional flowmeters include shallow flows, high velocities, surcharge flows, caustic flows, high temperature flows and flows with high solids content.
Five Flo-Dar flowmeters were ordered by the county and have been installed for just over a year now. While they will be used in various applications throughout the county, the meters are currently being used on 36-in. wastewater lines for a long-term monitoring project.
Riggins added, “the meters have cut down on the number of times we actually have to go out and clean sensors due to fouling or sedimentation…That’s the one thing that stands out.”
Regarding the use of confined space entry in their flow monitoring programs, Riggins added, “it has cut down on that quite a bit as well. Once Flo-Dar is installed and set up you don’t have to go back in. You also don’t have to worry about cleaning the sensors or worry about anything like paper hanging on it because there is nothing there in the flow to foul. It has some real benefits to it. The accuracy is good and the readings from all of the meters we have are very consistent.”
Both portable and temporary mounts were purchased for use in the Chesterfield County monitoring program. Currently, a manhole located nearby a railroad track was being monitored with one of the Flo-Dar meters. Due to the vibration from passing trains the permanent mount was installed and has been working flawlessly.
Two county field crews responsible for data collection are using Marsh-McBirney’s Flo-Ware FX software installed on their Pocket PC’s to retrieve data from the meters.
Flo-Ware FX is a flowmeter data management tool that operates on the Pocket PC operating system. The convenient hand-held Pocket PC features a touch screen, zero boot-up time and extended battery life, making this system ideal for field use versus cumbersome laptop computers. In the office, the Pocket PC automatically synchronizes with a desktop PC allowing the seamless transfer of files to and from a Pocket PC to desktop PC for data analysis and reporting.
The importance of top-notch, award winning water and wastewater practices displayed by Chesterfield County’s Utilities Department will serve their social and economic future well. Their continued use of state-of-the-art technologies, like those used in their flowmeters, may ensure that their commitment thrives while providing safe, efficient and cost-effective flow monitoring practices.