DEEP: Nitrogen Control Program for Long Island Sound

Nitrogen Control Program for Long Island Sound

Each summer, the bottom waters in the western half of Long Island Sound experience hypoxia, or very low levels of dissolved oxygen. Extensive monitoring and modeling of Long Island Sound have identified the excessive discharge of nitrogen from human activities as the primary pollutant causing hypoxia. Nitrogen fuels the growth of algae in the Sound, which eventually decays, consuming oxygen in the process. There is enough nitrogen added by human activity to cause a hypoxia problem each summer. 

In 2001, Connecticut DEEP and New York DEC, in concert with US EPA, completed plans for nitrogen control that identifies the maximum amount, or the Total Maximum Daily Load (TMDL), of nitrogen that can be discharged to Long Island Sound without significantly impairing the health of the Sound.  One of DEEPís management strategies to reduce nitrogen loading was to develop an innovative nitrogen-trading program among 79 sewage treatment plants located throughout the state. Through the Nitrogen Credit Exchange, established in 2002, Connecticut has reduced the nitrogen load from that source by nearly 65% by 2014.

On January 2, 2002, pursuant to Public Act 01-180, the Department issued the General Permit for Nitrogen Discharges for Publically Owned Treatment Works (also known as the Nitrogen General Permit). The Nitrogen General Permit was reissued with revised discharge limits consistent with the Long Island Sound TMDL on December 21, 2005; again in 2010; and recently renewed effective January 1, 2016. The Nitrogen General Permit will expire on December 31, 2018.

The current Nitrogen General Permit continues with the same permit limits as listed in the General Permit for the year 2014. These facilities, in aggregate, must continue to achieve a reduction in the annual loading of total nitrogen to Long Island Sound by approximately 64% from the original baseline TMDL in order to continue to meet the target 2014 waste load allocation.

On June 5, 2015, Public Act 15-38, an act concerning the sustainability of the Nitrogen Credit Exchange Program was signed by the Governor.   DEEP and the Nitrogen Credit Advisory Board (NCAB) proposed the legislation to move the nitrogen trading program to self-sufficiency ("state subsidy neutral") for the 2015 trading year credit exchange transactions to be completed by August 2016. The Nitrogen Trading Program has been a successful approach for cost-effectively meeting the 2014 Total Maximum Daily Load for reducing nitrogen in Long Island Sound. Over $450 million in grants and loans from the Clean Water Fund for municipal sewage treatment plant nitrogen removal upgrade projects is expected through 2018. It is estimated that $300 - 400 million have been saved by not forcing municipalities to upgrade all at once.

The Nitrogen General Permit is being reissued, and will cover the 5-year period from January 1, 2019 to December 31, 2023.  A Public Notice of Intent to Reissue the General Permit was published in local newspapers on June 12 and 13, 2018.  The public notice provides instructions on how to view the draft Nitrogen General Permit and submit comments.  The draft Nitrogen General Permit and a copy of the public notice were transmitted electronically via the Municipal Wastewater Listserv on June 20, 2018, and may also be viewed below.  The public comment period for the Draft Nitrogen General Permit has been extended until July 16, 2018.  

General Permit for Nitrogen Discharges

General Information on the Nitrogen Trading Program

Total Maximum Daily Load (TMDL) for Nitrogen

Reports of the Nitrogen Credit Advisory Board to the Joint Standing Environment Committee of the General Assembly by Calendar Year 
For more information on:
Nitrogen Credit Exchange Program, please contact Iliana Raffa at (860) 424-3758.
Baseline nitrogen loads, waste load allocation and permitting, please contact CT DEEP at (860) 424-3704.


Content last updated: June 25, 2018