Long Island Sound Nitrogen Campaign

Newtown Creek Wastewater Treatment Plant

Location: New York City, Long Island and CT River

Status: Active 

Background:

Long Island Sound Dead Zone

When too much nitrogen is discharged into Long Island Sound, it creates low oxygen conditions, known as hypoxia, making it harder for aquatic life to survive. In some instances, excess nitrogen creates zones where oxygen levels reach zero, also known as dead zones. Some other impacts are toxic algal blooms, low dissolved oxygen, poor water clarity, loss of aquatic vegetation and tidal wetlands, and coastal acidification. Sewage treatment plants throughout the Long Island Sound watershed have historically been the primary drivers of low oxygen and dead zones in the Sound. Other sources that contribute are stormwater runoff, fertilizers, and poorly performing septic systems. 

The Total Maximum Daily Load (“TMDL”) plan was issued in 2000 to limit the amount of nitrogen discharged to Long Island Sound to begin to bring it back to health. This took the preliminary step of requiring Connecticut and New York sewage treatment plants to reduce nitrogen by almost 60 percent by 2014. This goal has now been largely achieved, decreasing the dead zone in Western Long Island Sound significantly, but it has not been eliminated. Moreover, new nitrogen-based pollution challenges have emerged in our bays and harbors. 

Save the Sound’s 2015 Nitrogen Petition

In 2015 (the deadline for achieving the targets set out in the 2000 plan), Save the Sound petitioned EPA to create a new plan to further reduce nitrogen discharges and bring Long Island Sound back to full health.  

Pursuant to Save the Sound’s petition, EPA announced a far-ranging “Nitrogen Strategy for Long Island Sound,” which sought to achieve many of the goals we advocated for in the nitrogen petition. It set out three large goals to: 

  1. further reduce the dead zone in Western Long Island Sound by further reducing nitrogen discharges from New York City area sewage plants, 
  2. reduce low oxygen zones and dead zones in our bays and harbors through localized action addressing fertilizer, stormwater, failing septics, and other localized nitrogen sources, and 
  3. reduce nitrogen pollution entering Long Island Sound via major rivers such as the Connecticut and Housatonic. 

Each one of these strategies would involve: 

  1. characterizing how much excess nitrogen is contributing to the problem, 
  2. determining the sources of nitrogen, and
  3. setting reduction targets for specific sources to achieve waterbody health.

While full implementation of the strategy has not happened as fast as we would have liked, significant progress has been made on all three fronts by reducing New York City discharges into the western dead zone, creating plans for harbors and bays, and addressing pollution from the upper Connecticut River. 

New York City: New York City sewage treatment plants must make additional reductions to nitrogen in their next permit. In February 2022, Save the Sound filed formal comments urging DEC and EPA to impose meaningful additional nitrogen limits on the total discharge from six sewage treatment plants on the East River in New York City. The discharges have caused or contributed to parts of the East River and Western Long Island Sound violating water quality standards 90-100% of years between 2014 and 2019. Save the Sound issues a Long Island Sound Report Card that characterizes the chronic poor water quality conditions in western Long Island Sound due to the New York City wastewater treatment facilities and other sources[1]. This portion of Long Island Sound has received an F for water quality every year from 2008-2019. 

The agencies, however, are waiting for New York City to finish refined modeling that will inform long-term planning before taking action. 

Ultimately, the agencies should require reductions by: 

  1. requiring the four upper East River plants (Tallman Island, Bowery Bay, Wards Island, and Hunts Point) to use existing nitrogen technology to achieve further reductions, and 
  2. requiring Newtown Creek to install nitrogen-reducing technology. 

Once new modeling and science is developed, the permit for these plants may be reopened to impose final, more refined long-term nitrogen limits.  

Long Island: Long Island voters will have a chance this November to vote for a plan that will solve Long Island’s nitrogen pollution problems. Following years of advocacy by Save the Sound, our partners on Long Island, New York Assemblymember Fred Thiele, Governor Kathy Hochul, the New York State Legislature, and the Suffolk County Legislature have taken action to address the nitrogen pollution attributable to wastewater from the County’s outdated septic systems that has plagued Long Island Sound for decades. In June 2024, Governor Hochul signed the Suffolk County Water Quality Restoration Act. The legislation granted the Suffolk County Legislature the authority to place a referendum on voters’ ballots to approve funding for sewer expansion projects and the replacement of outdated nitrogen-polluting septic systems with Innovative and Alternative On-Site Wastewater Treatment Systems (I/A Systems). The funding would come from a 0.0125% county sales tax increase. Suffolk County Executive Ed Romaine subsequently signed the Water Protection Bill, placing the measure on the ballot for Suffolk County voters’ approval in November 2024.  

If the measure passes, the overhaul of Suffolk’s outdated, polluting septic systems could be a major turning point for Long Island Sound and Long Island communities and economies. The approximately 380,000 septic systems and cesspools in Suffolk have long been identified as a principal cause of the county’s nitrogen pollution problems. But come November, Suffolk County voters could finally change that by approving a sensible, fact-based, and science-driven plan to restore and protect clean water for their community.  

Save the Sound and our partners on Long Island, including Group for the East End, Peconic Baykeeper, and The Nature Conservancy, applaud the Suffolk County Legislature for moving forward with this historic opportunity which will benefit not only Suffolk County, but the entire Long Island Sound region.  

Connecticut River: We must get additional reductions from Massachusetts sewage treatment plants and Vermont agricultural dischargers. new nitrogen limit imposed in 2022 on the Springfield Water & Sewer Commission (Springfield) and other Massachusetts sewage plants represents a significant victory in Save the Sound’s decades-long campaign to eliminate dead zones in Long Island Sound by reducing nitrogen discharges. In late May, the EPA’s Environmental Appeals Board upheld the agency’s decision to impose a 5 mg/L limit on nitrogen based upon the Springfield plant’s capacity. 


[1] “Long Island Sound Report Card.” Save the Sound, https://www.savethesound.org/report-card.

Next step: Continue to document low oxygen and other polluted conditions in Western Long Island Sound due to New York City sewage treatment plants and advocate for opening and modifying the NYC permit when new modeling is available.  Continue to advocate for Suffolk County voters to approve the Water Quality Restoration Act.    

Further reading:

Action opportunities:

Last Updated: September 24, 2024


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