Letter from Ron Glisci

I attended the Airmont Village Board meeting Monday night specifically to hear Dianne Phillips, the Executive Director of the Rockland County Sewer District address the sewage overflow problems we have been experiencing in the village. Unfortunately, no one from the sewage district showed up for this scheduled presentation.

As an environmental engineer with extensive sanitary sewer design experience, I was interested to learn why raw sewage is chronically sprayed from a manhole on S. Monsey road during rain events, and eventually makes its way into the Saddle River, a public drinking water supply.

This problem is of interest to us all, since raw sewage contains high numbers of bacteria that cause typhoid fever, dysentery, diarrhea and cholera, and viruses that cause hepatitis. A study showed that from 10,000 to 100,000 infectious doses of hepatitis virus are emitted from each gram of feces of a patient with this disease. It is known that some viruses will live as long as 41 days in water or sewage and for 6 days in a normal river.

The overflow appears to be caused by sewer lines that can no longer handle the flow coming to them. This location is of particular importance, because is the start of the Ramapo Interceptor, a large diameter major sanitary sewer line that runs eastward, downhill through Monsey. The majority of wastewater flow from the village of Airmont, including Hillside Avenue, flows to this point and enters the Interceptor.

Sanitary sewers are designed and sized to transport only wastewater, but a generous allowance is made to handle a certain amount of infiltration from rainwater.

For these overflows to occur, therefore, there must either be a massive amount of infiltration, much greater than planned for, OR the sewers must already be flowing NEAR OR AT MAXIMUM CAPACITY when there is no rain.

How does so much rainwater get into the sanitary sewer? There has been much speculation regarding illegal hookups of basement sump pumps overloading the sewer. It is not clear if these potential violations are ever investigated, but it has come to the point now where they should be. The entire Ramapo Interceptor may be backing up, all the way to Airmont.

Alternatively, the problem may be due to too much wastewater flow from over development. Sewers that were originally sized to handle flow from single family homes are now expected to carry flow from multi-family structures now built at those same locations.

This begs the question, how can we allow uncontrolled development in the Village, which will add additional wastewater flow to this S. Monsey Road location, when the Ramapo interceptor is backing up already at that location? The overflows will occur more frequently.

The sewer district is said to be developing a hydraulic model of the Ramapo Interceptor, to assist in planning future upgrades. This study will determine exactly what is required to prevent these overflows.

The only sensible recourse is to put a hold on future development until we determine the results of the hydraulic study and how much it will cost the taxpayers to solve these problems, to protect the health, welfare, and safety of our residents.

Ronald A. Glisci, P.E.