Riverdale has been faced with a major dilemma with our waste water sewer system for many years. As a result Riverdale Sewer customers may be paying higher prices for our service than we should. In addition, we have “dry pipes”; sewer lines that have been installed but we have not been able to connect to houses because we do not have available waste water allocation. I can assure you that this matter has not been missed by our Mayor and Council; the problem has been known for years but the root cause remains a mystery. I am sure you are wondering how this can happen. At the Town Council Meeting on Monday, August 4th, Councilman Ted Guis was able to provide EOR with a good explanation of the problem and why the solution is so elusive.
Riverdale’s sewer system is tied into the Pequannock River Basin Regional Sewerage Authority’s (PRBRSA) which was started by 3 founding member towns; Bloomingdale, Butler, and Kinnelon). PRBRSA’s main line runs directly through Riverdale and into Pompton Plains where is connects with the Two Bridges Sewerage Authority’s (TBSA) system. There are 2 towns that contract with the PRBRSA to access their system with limited allocation; Riverdale and West Milford. Allocation is the amount of waste water that each town is allowed to put into the system based on their contract with the PRBRSA. Towns are charged, however, based on readings taken from meters placed at various points in the sewer lines. According to these readings, Riverdale has used up its allocation and the only way to obtain more is to acquire it from one of the PRBRSA’s member towns. Here’s where it gets interesting.
According to Mayor Budesheim, the water usage of our sewer customers averages about 250k gallons per day; this includes both indoor and outdoor use. Most outdoor use should not be entering the waste water sewer system. According to the PRBRSA, we have been averaging 488k gallons per day; about double what our water meters tell us it should be. This is where Infiltration and Inflow can come into play.
Infiltration occurs when ground water levels reach damaged or poorly installed sewer pipes. Inflow is occurs when through improper connections, usually drainage systems such as sump pumps, gutters, etc. Experts will tell you that you can expect a certain amount of I/I in every municipal system, however, what Riverdale is seeing far exceeds any reasonable expectation.
The is another complicating factor, our usage is based on meter readings by the PRBRSA; one located just before the main line enters Riverdale and one just after it leaves. However, these meters are not like water meters that measure full pipe flow, they use radar and other devises to measure the rise and fall of waste water levels over time. The margin of error is 10% of total flow which, at 2.6 million gallons per day, equals 260k gallons; more than our total estimated usage. In other words, if the meter at the beginning of our line was low by 5% and the meter at the end of our line was high by 5%, this would account for more than the 238k gallon disparity between our water usage and our expected waste water flow.
Councilman Guis proposed a 3-pronged approach in finding the root cause.
His rationale was simple; validate the data and the methods in which it is processed, before spending additional money looking for infiltration and inflow. It seems like a sound and scientific approach to solving a big problem that has dragged on for years.