By Rich Pollack
If and when Ocean Ridge’s Septic to Sewer Citizens Advisory Committee recommends the town convert to a centralize sewage treatment system, it is likely to suggest using vacuum technology rather than a traditional gravity and force-main system.
During a meeting last month, members of the committee agreed to recommend in concept using a vacuum system, which pulls sewage to a central collection station before sending it to a regional plant, rather than a gravity and force-main system, which uses pumps and pushes sewage through the lines.
After learning more about vacuum systems during a January presentation from a company that installs them, committee members agreed that the system would be less disruptive and less costly than the more commonly used gravity and force-main systems.
“I don’t think there’s any choice other than a vacuum system,” said Committee Chair Neil Hennigan.
With the traditional gravity and force-main system, sewage from homes flows into a main line where it is brought to a lift station by gravity. At the lift station it is then pumped under pressure to a central treatment facility.
Because the system is dependent on gravity, lines need to be continually deeper in the ground as they get closer to the lift station.
With a vacuum system, sewage from the home flows by gravity into a collection pit that is shared by two or three homes. Once the sewage in the tank reaches a certain level, a valve opens and the sewage is pulled by a vacuum into a main line and taken to a collection station.
From the collection station, the sewage is pushed by pumps into the central sewage treatment facility.
Because the vacuum system is less dependent on gravity than the traditional systems, lines do not have to be as deep in the ground and in many cases could possibly be placed in rights of way rather than under a roadway.
The vacuum system also does not require manholes.
“The intent is to minimize the impact on the roadway,” said town engineer Lisa Tropepe.
If Ocean Ridge went to a traditional gravity and force-main system, several lift stations that depend on electricity would need to be located around town.
The vacuum system requires electricity only at the main collection centers.
If there is a downside, however, it is that those main collection centers — one or possibly two — would need to be large, about the size of a single-family home, and would need to be built.
An additional advantage to the vacuum system, Tropepe and others say, is that lines would be easier to access should repairs be necessary. It would also be easier than with gravity lines to determine if a line has a leak.
“Systems under pressure can be monitored,” Tropepe said.
In addition to agreeing that a vacuum system seems to make more sense, the committee agreed to team Tropepe with committee member Ron Kirn to try to quantify the environmental benefits that would result from a conversion from septic systems to a centralized sewer system. That information would be useful should the town begin the process of applying for state and federal funds to help cover the cost of converting to a sewer system.
How to pay for the project, should the Town Commission decide to go forward, was also discussed during the February committee meeting, with members agreeing that it is important to get the funding process started as soon as possible.
At the town’s March 2 meeting, commissioners approved a $4,500 contract hiring Jupiter-based RMPK Funding consultants to seek state and federal grants to help pay for the town’s septic conversion.