Sylvester Manor consulting engineer files report on town’s wastewater treatment plan

“Sylvester Manor cannot support the introduction of contaminants redirected from the Town Center into a relatively pristine watershed.”

That is the take by Sylvester Manor’s consulting engineer Drew B. Bennett, principal of D.B. Bennett Engineering, on the latest engineering reports presented to the Town Board at a work session March 21.

Bennett sent his conclusions in a letter dated March 30 to the Town Board,

Another environmental report — this one from P.W. Grosser, an environmental consulting firm hired by the Town Board, is due to be discussed at Tuesday’s work session.

In advance of that, Mr. Bennett is calling on the Town Board to give the Center wastewater project proposal a positive declaration — meaning it would need a full environmental impact statement before it could move forward.

That could likely preclude Shelter Island School from continuing to be a part of a central system serving several municipal buildings along with the Library in the Center.

The school has aged and unreliable septic systems in place and probably can’t be postponed much longer to start a project to upgrade. School officials had originally set the end of January for a decision and have extended that, but if a full environmental study is needed, that could take months to complete.

Mr. Bennett isn’t buying reports to date showing installation of a Nitrex wastewater treatment system would have no detrimental effect on Sylvester Manor’s wells.

“We do not agree with key conclusions by the engineer authors,” Mr. Bennett said, referring to town consultant Pio Lombardo’s presentation of a two-part report to the Town Board March 21 that included his own conclusions and those of professional hydrologist Thomas Cambareri.

“The reports and presentations omit objective consideration of the potential downsides of the project siting on Manwaring Road and fail to acknowledge or respond to stated concerns of Suffolk County,” Mr. Bennett said in his letter. The information provided “reinforces our concerns regarding the proposed project and the likely unintended negative environmental impacts to Shelter Island and the Sylvester Manor operation and mission,” he said.

“Sylvester Manor cannot support the introduction of contaminants redirected from the Town Center into a relatively pristine watershed,” Mr. Bennett said.

He has served as consulting engineer for Sylvester Manor since 2020 and the East Hampton-based company has been a long-time environmental consulting engineering firm serving Long Island and other New York communities since 2004.

Mr. Bennett cited several general comments in his letter.

• The groundwater modeling requested by Mr. Bennett confirms the effluent will travel through Sylvester Manor and through or in close proximity to a number of its water supply wells, including its public water supply well number.

• There’s no provision in the Lombardo design for treatment of emerging contaminants, only studies and suggested possibilities. The Town needs to commit, Mr. Bennett says, to covenants and restrictions limiting the future expansion of flow and the required monitoring of effluent, with requirements to augment treatment to manage future contaminants.

• The Suffolk County Department of Health Services said in its letter to the Town that their Manwaring Road site discharge location fails to comply with its standards.

• The use of local treatment units in the Center within its own watershed was discounted because of “regulatory variances required.” But the Health Department has emphasized its best-fit policy that would likely permit such an approach administratively, Mr. Bennett said. “Hence it is feasible” and would cost less and be easier to manage, he said.

Mr. Bennett challenged Mr. Lombardo’s estimate of the Nitrex system being able to reduce the nitrogen level to 3 mg per liter “We feel this is an overly optimistic projection that is not supported by peer review of the technology,” Mr. Bennett said.

He questioned why the land behind the Center Firehouse couldn’t be used, even though it isn’t owned by the Town, or why Fiske Field couldn’t accommodate the treatment system. That’s something Town Engineer Joe Finora said would make the field unusable for recreational purposes.

The Sylvester Manor area has been cited as a venue for a public water well if it’s needed in that area, Mr. Bennett said. Locating a wastewater treatment system across from the educational farm would threaten that possibility.

He further cited several technical comments and requested that his full letter be made part of the record of the project.