In my previous two columns, I explained that over the past couple of decades we have learned that nitrogen discharges from sewage treatment plants cause serious problems in places like the Long Island Sound.
The nitrogen in the water is like nitrogen on your lawn - it fertilizes green plants, including algae. When the algae die, their decomposition robs the water of the oxygen that marine animals need to live.
The U.S. Environmental Protection Agency and the States of New York and Connecticut agreed that a nitrogen reduction of nearly 60 percent from anthropogenic sources - mostly sewage treatment plants - was necessary to prevent massive "dead zones" from forming every summer in the western part of the Sound. A detailed computer model was used to allocate the needed nitrogen reductions among more than 100 sewage treatment plants throughout the watershed.
It ain't cheap. At the time of the agreement in the late 1990s, it was estimated that the total cost for all the affected plants would be close to $2 billion that would be spread out over the 15-year period from 1999 to 2014.
To increase the economic efficiency of the effort, "trading" among treatment plants is permitted. Some plants will be able to achieve greater reductions than required at an economically favorable cost because, for example, they are newer or have more space to install new equipment. They are allowed to sell their excess nitrogen reduction to plants where it is more costly to fully achieve the required reductions.
The trading scheme also takes into consideration the fact that a pound of nitrogen discharged in the western Sound does more damage than a pound of nitrogen discharged in the eastern Sound. Thus, for trading purposes, one pound of western Sound nitrogen is worth more than one pound of eastern Sound nitrogen.
This finally brings us back to where we started in the first column of this series: the Belgrave Sewage Treatment Plant that serves portions of Great Neck and discharges into Udalls Cove. As with the other treatment plants in the Long Island Sound watershed, Belgrave wasn't originally designed to remove nitrogen. Like the other plants, Belgrave was assigned a reduced nitrogen discharge limit.
Actually, there were three different limits, getting progressively more restrictive over the 15-year period. Interim reductions were to have been achieved by 2004 and 2009. The final discharge limit, which is to be achieved by Aug. 1, 2014, is 165 pounds of nitrogen per day.
The good news is that Belgrave broke ground in the summer of 2010 on a plant designed to reduce its nitrogen loads. The bad news is that after a decade of delays, Belgrave is still not able to meet its 2009 interim target, let alone the 2014 final target. On May 29, the New York State Department of Environmental Conservation issued an administrative consent order to the Great Neck Water Pollution Control District, which operates the Belgrave plant, to correct these violations.
This was the third in a series of consent orders addressing Belgrave's failure to meet the new limits. The first was issued in May 2006, the second in January 2011. The current order established a temporary, but much higher, interim limit of 653 pounds of nitrogen per day - more than four times the 165 pound/day final limit. However, the current order retains the Aug. 1, 2014 deadline for meeting the final limit. The current order also requires Great Neck to contribute $30,000 to other local projects that are environmentally beneficial.
On Oct. 10, an environmental organization known as Save the Sound went to court to challenge the NYSDEC order. The group contends that both the outcome and the process that led to it were inappropriate. The challenge is pending in the courts.
Meanwhile, it is important to point out that the Belgrave plant has a very good record on meeting its other pollution limits - for example, limits on bacteria and toxic chemicals that can get into the sewer system. And while Belgrave has had difficulties meeting its nitrogen reduction limits, other plants in the watershed have been more successful. All the plants are supposed to achieve their final reduction limits by the same 2014 deadline as Belgrave and most are well on their way.
So, is it working? Is the Long Island Sound summertime dead zone becoming smaller and of shorter duration?
The answer is most probably yes, but it is difficult to say for certain. The enormous variation from year-to-year in temperature, wind and water currents overshadows the impact of year-to-year nitrogen reductions. For us to be able to say with confidence that these nitrogen reductions are working, and therefore worth the billions they are costing, will take several more years.
Incidentally, this difficulty is typical when trying to assess environmental improvements or declines. One generally has to wait two or three decades for a true trend to become apparent amidst the "noisy" data produced by annual variation. I'll explore this phenomenon further in my next column.