Gardiner treatment plant nearing capacity


Gardiner’s wastewater treatment plant is nearing capacity, impeding future development.
The treatment plant serves approximately 200 residences in the hamlet of Gardiner. Jason Pitingaro, president and principal engineer of Pitingaro and Doetsch, P.C., said if there is to be any new development in the hamlet, Gardiner must either reduce its flow to the treatment plant or expand the capacity of the plant.

Town Supervisor Marybeth Majestic said several developers are considering building multi-unit properties on parcels within the sewer district.

“At this point, I think that if an applicant came in and was asking to connect to the district, the capacity is just not there,” Pitingaro said.

The average monthly flow capacity is 57,000 gallons per day. The average monthly flow for 2018 was 54,000 gallons per day, dangerously close to capacity.

The town can greatly reduce the flow to the treatment plant by reducing its infiltration and inflow (INI), Darren Doetsch, vice president and principal engineer of Pitingaro and Doetsch, concluded during a presentation to the town board at meeting on Feb. 14.

Infiltration is groundwater that infiltrates the system through broken or cracked pipes, defective joints or leaking manholes. Inflow is stormwater that flows into the sewer system through inappropriate connections, such as sump pumps, roof drains or storm drains.

INI taxes the sewer system because it adds water to the system that doesn’t need to be treated.

“What INI does is it actually steals the capacity from your plant,” Doetsch said. “You’re treating stormwater unnecessarily.”

Doetsch estimated the base sanitary flow—or only sewage—to the treatment plant is an average of 30,000 gallons per day.

He estimated the treatment plant receives an average of 20,000 gallons per day in infiltration and 21,000 gallons in inflow. The treatment plant treated on average 24,000 gallons per day of storm water in 2018.

“This is not a good thing, obviously,” Doetsch said.

Doetsch also said the town needs to rehabilitate the Dusinberre pump station, which is corroded and in dire need of repairs. With unnecessary INI, these pumps stations are in danger of overflowing.

“The plant operator told me he gets very nervous when you have large storms because these pump stations fill right up because so much INI is getting into the system that these pump stations can’t keep up,” Doetsch said.

The next steps for the town board are to launch an investigation into the sources of INI, Darren said. That includes analyzing sewer maps, conducting nighttime flow studies, installing flow meters in manholes, inspecting septic tanks, and conducting smoke and dye testing.

Next, the town must implement corrective actions to reduce INI and increase capacity. The town might also consider expanding its treatment plant.

Doestch said if the town board moves quickly, it could put pipe-lining (which reduces infiltration) out to bid as early as this fall.

Gardiner has a unique design in that there are 200 connections to the system through septic tanks, reducing the amount of waste to the plant. Typically, sewer is connected directly to the sewer main which flows into the treatment plant.

Pitingaro said the treatment plant is simple and efficient. Dosing syphons distribute the flow to reed beds. Flow then undergoes seasonal chlorine disinfection before being discharged into the Wallkill.


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