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Rahway Valley Sewerage Association (RVSA)

Rahway Valley Sewerage Association (RVSA) A uniting of local New Jersey municipalities with a desire to provide cost effective wastewater operations, maintenance and facility improvements, led to the formation of what is known as the Rahway Valley Sewerage Authority (RVSA).

Today, with a staff of 60, the RVSA provides services for more than 200,000 residents and 3,500 industrial and commercial customers in Central New Jersey. RVSA includes the Member Municipalities of Clark, Cranford, Garwood, Kenilworth, Mountainside, Rahway, Roselle Park, Scotch Plains, Springfield, Westfield, and Woodbridge and User Municipalities of Winfield Park, portions of Fanwood and Linden. A long-time user of Hach’s Sigma Model 930 and 950 open channel flow meters in their collection system, Rahway utilizes the meters in billing and regulatory compliance applications.

Tony Gencarelli, Manager of Regulatory Compliance with RVSA adds, “We currently have the majority of our flow monitoring services provided for us through a contract with CSL.” CSL is a flow service provider located in Pennsauken, NJ that provides both temporary and long-term flow monitoring services and other offerings. Gencarelli adds, “We wanted to use the most current state of the art technology since some of our meters are used for billing purposes. Years ago we owned our own flow meters that were from another meter manufacturer and it got in to some proprietary issues with regard to repair parts and software. Going forward we thought it just seemed cleaner to lease the meters from CSL.” According to Gencarelli, CSL is contractually responsible for maintaining the meters and certifying that they meet original factory performance specifications.

RVSA currently has 27 Sigma units consisting of Model 930 and 950 meters deployed throughout their system. According to local Hach flow meter rep Jim Hampson with North East Technical Sales, “The Sigma 950’s gave the RVSA the flexibility to use the same meter for area velocity and ultrasonic applications as well as taking in a signal from a mag meter. This allowed them to use one software package for all of their reporting.” Meters are tied into RVSA’s SCADA system to optimize efficiency and provide ease of data accessibility. The 930 flow meters utilize two area velocity flow sensors for redundant monitoring. The meters support three interchangeable sensors, have an exceptionally long battery life, increased data storage, and offer optional interfaces with samplers.

The Hach Sigma 950 Flow Meter is ideal for portable and/or permanent singlechannel monitoring plus water quality testing, process control interface, and digital display. This meter is ideal for applications including surcharge or reversed flow conditions, weirs and flumes, and small-to-large channels. Up to three different level sensor technologies and a velocity sensor can be utilized by the Sigma meters.

When a difficult to instrument flow monitoring application arose at Rahway’s advanced secondary treatment plant, RVSA staff began investigating an applicable solution. Gencarelli adds, “We have a 66" outfall pipe at our advanced secondary treatment plant. The metering chamber has a 66" diameter inlet and going out it’s 72". There’s a taper in the channel and the pipe is almost always surcharged. It flows anywhere from a half a foot below the crown of the pipe to a foot or two surcharged so it’s difficult hydraulic conditions. It’s really a bad application for any meter.”

Flo-Dar DDS Sensor installed in RVSA 72" line in / 66" line out with a right turn in the chamber.

Originally for flow metering, RVSA had planned to purchase what they called a ‘super-duper’ magnetic flow meter from a German manufacturer with a price tag of $750,000 for this problematic application. They were told that the meter was a one of a kind, if not the only, magnetic flow meter that could measure open channel flow as well as pressurized pipe flow. In addition to the high price tag for the meter, there was also no provision for a bypass around the meter if it ever had to be serviced. Temporary bypassing of the meter would be expensive and would be very challenging from a logistics perspective. Due to these issues, a decision was made to eliminate the high priced meter and seek another solution. When rep Hampson was consulted on the application he recommended Hach’s Data Delivery Services that utilizes the Marsh-McBirney non-contact Flo-Dar sensor. Gencarelli adds, “Jim agreed to come in and demo the meter for free.” Hampson adds, “Rahway demoed the Hach Flo-Dar meter and a ADFM meter by Teledyne ISCO. Our meter worked for the application where the ISCO meter was not able to provide consistent data. A big advantage of the Flo-Dar meter is that it could be installed while the line was flowing versus the ISCO meter that required the line to be shut down.

With Data Delivery Services you pay only for sewer flow data without the need to purchase a meter and you don't have to leave your office to get the flow data. For a low monthly fee, Hach Company furnishes a web-enabled sewer flow meter and all of the following:

• Flo-Dar DDS Sensor installed in RVSA 72" line in / 66" line out with a right turn in the chamber.
• 24/7 access to your unedited sewer flow data via web browser
• 95% data uptime guarantee or it’s FREE
• Secure password protected access
• Unlimited secure data transfer
• Daily data back-ups
• Live customer support

While Gencarelli feels that the Sigma and Marsh meters utilized at RVSA are comparable when it comes to data quality and accessibility he adds, “There’s certainly an advantage with the Flo-Dar. It’s nice that it’s out of flow so you could possibly perform tasks without making confined space entry and if you do, at least you don’t have to stand in the flow.”

According to Gencarelli the DDS Flo-Dar meter is doing quite well and doing the best job yet! He jokingly adds, “But we haven’t compared it to the $750,000 meter!” Future plans may include hard wiring of the DDS Flo-Dar meter into their SCADA system. Currently, their Flo-Dar data resides on a secure server and is available to RVSA personnel 24/7 via any internet browser.

The use of innovative solutions such as Hach’s Data Delivery Services and Open Channel Flow Meters is something that the RVSA is very much accustomed to. In fact, they made history in 1991 when they began a land-based beneficial reuse program for its sludge to be used in agricultural applications. The RVSA prides itself on being in the forefront of initiating programs designed to protect the environment.