When the City of Glen Cove, N.Y.
contracted
operation of its wastewater treatment facility in 1992, they did so as a means of
obtaining technical and operational excellence beyond the scope of their internal
capability. Plagued by odor complaints from a local open-air restaurant, the City and
its private partner invested more than US $3 million in capital improvements to upgrade
the facility over the first two years of the then-unprecedented 20-year contract.
Environmental compliance is a key driver in municipalities deciding to enter
public-private partnerships. Proof positive: In a little over a decade after
the start of its partnership, the City of Glen Cove is at the forefront of
environmental leadership.
At the Forefront
In early December 2005, the
New York State Department of Environmental
Conservation (DEC) announced the winners of its second annual New York State Environmental
Excellence Awards. Glen Cove’s wastewater treatment plant was one of six winners cited
for their contribution to “environmental innovation, sustainability, and creative
partnerships.” The only treatment facility to receive the award, Glen Cove was
honored for its “unprecedented nitrogen discharge reductions.” According
to N.Y. State DEC Commissioner Denise M. Sheehan, “Glen Cove provided leadership
well beyond their compliance requirements for the protection of the Long Island Sound,
and the nitrogen reductions will contribute to improved water quality and habitat.”
Total Maximum Daily Load
Nitrogen is the primary pollutant that causes hypoxia (low dissolved oxygen). During
the summer months, dissolved oxygen levels in the Long Island Sound fall below both New
York and Connecticut standards (5.0 mg/l and 6.0 mg/l, respectively). Also fueled by
nitrogen, algae in the Sound eventually decays, resulting in additional oxygen consumption.
Human activity during the summer months also contributes nitrogen to the Sound, causing
oxygen levels to dip below 1 or 2 mg/l. In 1987, anoxia, the absence of oxygen, was
reported in a portion of the Sound.
Under the federal
Clean Water Act, bodies of water not meeting state water quality standards must
undergo a Total Maximum Daily Load (TMDL) analysis. Working together, New York and
Connecticut have developed a TMDL for nitrogen to ensure the sustained health of the
Sound. The U.S. Environmental Protection Agency approved the Long Island Sound TMDL
for implementation on April 3, 2001.
Defining sewage treatment plants as the largest contributors of nitrogen, the TMDL
specifies a nitrogen reduction target of 58.5 percent by 2014.
Forward Thinking
In 1999, plans were made to implement nitrogen reduction measures, making the Glen
Cove facility the first Long Island community to do so. Its private partner provided
a US $900,000 capital contribution to cover engineering and construction costs for plant
modifications related to the facility’s biological nitrogen reduction (BNR)
process. In 2002, the City procured a US $3.5 million grant from the DEC to fund the
facility upgrade, as well as modifying their State Pollutant Discharge Elimination
System (SPDES) permit to reduce the effluent flow to 5.5 MGD. Construction to upgrade
the facility began that same year.
Looking Ahead
Glen Cove’s BNR process, operated by the City’s long-time private
partner, is helping the City meet the 2014 permit requirements established in
the newly issued SPDES permit.
According to Nick DeSantis, Glen Cove’s director of public works, “The BNR uses fine air diffusion and process flow modification that maximized our
nitrogen removal. Our next goal is to eliminate the need for liquid chlorine to be
added to the final effluent that leaves the plant.”
To date, the City of Glen Cove has reduced its effluent nitrogen levels 74 percent,
well ahead of the 2014 permit limits.
For more information, email
info@severntrentservices.com