Dye testing to be done at the Wastewater Treatment Plant

DEC plans to track flow and dispersion


The New York State Department of Environmental Conservation (DEC), in partnership with the U.S. Food and Drug Administration (FDA), will be conducting the first hydrographic dye study of wastewater from the Village of Patchogue Wastewater Treatment Plant.

“I think it’s what they do and it’s an important test that they do,” said Village of Patchogue mayor Paul Pontieri, noting that the village is looking to upgrade the facility again in the next year or two. “We need to take the results and suggestions into account when we upgrade. [The test] has a lot of benefits.”

The study, according to the DEC, will track the flow and dispersion of treated wastewater from March 24 to 30. The FDA provides technical assistance to states to conduct hydrographic dye studies of wastewater treatment plants to evaluate and implement required shellfish closures around outfalls. This study, according to the DEC, will track the dilution and time of travel of the treated effluent from the outfall to help determine and evaluate whether DEC’s current shellfish closure is sufficient to protect public health by prohibiting the harvest of shellfish in the potentially impacted area.

“The data generated from the study will be used to assess the required shellfish closure surrounding the treatment plant outfall,” a DEC spokesperson said.

According the NYSDEC, shellfish can become contaminated if they live in polluted water. Shellfish pump water around their bodies to obtain oxygen and filter out tiny plants and animals for food. This filtering may also pick up disease-causing microorganisms (bacteria, viruses and certain dinoflagellates) that can be eaten with the shellfish. 

“The DEC maintains closure areas around sewage treatment plant (STP) outfalls to prohibit the harvest of shellfish from areas deemed unsafe for the harvest and consumption of shellfish,” explained a representative of NYSDEC in a statement.

The National Shellfish Sanitation Program (NSSP) Model Ordinance (MO) requires states to implement closed areas (prohibited zones) around STP outfalls to ensure the safety of shellfish harvested for human consumption.

There is a year-round closure currently in place for the Patchogue River and a portion of Patchogue Bay that does not meet approved water quality criteria and may be impacted by untreated effluent from the STP outfall in the event of a sewage treatment plant malfunction.

The dye used for this study, according to the DEC, will include Rhodamine WT, which is a is a water-tracing dye approved for use by the U.S. Environmental Protection Agency (EPA), and will not cause environmental harm.

Starting on March 25, for just over 12 hours, the dye will be introduced to the wastewater treatment plant in low concentrations. The dye will only be introduced on this day during the scheduled study period.

However, the public is being warned that due to the dye injection, portions of the Patchogue River and Patchogue Bay may appear discolored and turn red or pink for a small period of time and may be visible from the shoreline.

Additionally, this study will enhance emergency readiness and the ability to respond to events related to any potential spills or untreated discharges at the wastewater treatment plant.  

For more information on this study, please contact the Division of Marine Resources Shellfisheries Bureau at 631-444-0492 or visit the DEC website at Shellfishing - NYS Dept. of Environmental Conservation. 


In 2021, the Village of Patchogue has been awarded a total of $7.7 million from a Department of Environmental Conservation Water Quality Improvement Project grant to upgrade the wastewater treatment plant and increase capacity and reduce the amount of nitrogen entering Patchogue Bay.

This grant allowed the village to expand the wastewater treatment plant by 400,000 gallons per day to 1.2 gpd. 200 for village expansion and 200 for outside connections such as East Patchogue, Blue Point and Bellport.


No comments on this item Please log in to comment by clicking here