Stony Brook Know-How Helps Protect Long Island’s Water Supply


Would you want to flush your toilet into
your drinking water supply? It may sound absurd, but that’s actually
what’s happening here in Long Island. The septic systems that 70% of the homes in
Suffolk County have are specifically designed to let all the liquid materials
flow directly down into the groundwater — and that’s what we’re drinking. The
Center for Clean Water Technology has been put together in order to clean up
groundwater, surface waters and drinking water here in Long Island. Nitrogen is
virtually everywhere. It’s about 80 percent of the air. But reactive nitrogen,
which is in wastewater, is very detrimental ecologically and has health
risks. So the idea is how to transform that reactive nitrogen that is in human
wastewater back into inert and to gas. And that’s what we do through a process
called coupled nitrification-denitrification. Right now we have seven
nitrogen-removing biofilters installed at residences around Suffolk County. It’s
not a controlled experiment, so we don’t always know when we collect samples how
much a certain homeowner waters their lawn, or whether they did laundry the day before we sampled. Where this trailer comes in, is it allows us to run more controlled
experiments using the same source of wastewater. This facility is built on an
existing Suffolk County VPW pump station. We take raw wastewater and we pump it through a sand filter,
followed by wood chips, a source of carbon. Each of those steps involves
naturally occurring microbes which convert reactive, harmful nitrogen into
inert nitrogen gas. The Center is a collaborative effort between civil
engineering and the School of Marine and Atmospheric Sciences, so one of the great
things about working for this Center is the facilities and graduate students at
Stony Brook University who, in addition to working about 16
hours a day seven days a week, are incredibly inspiring and motivated. There’s two serious concerns when it comes to high nitrogen and groundwater.
One the EPA sets a limit for 10 milligrams per liter of nitrate because
it’s a human health hazard, and frankly some drinking water supplies are over
that limit already. And so that’s a concern, and just as important, excessive
nitrogen is known to degrade wetlands They’re an important marine ecosystem.
They support fisheries and other wildlife, but actually what we learned
during Hurricane Sandy is they actually protect coastal communities. And that is,
the communities that had wetlands still intact were not flooded nearly as badly
as communities that had lost their wetlands. So by removing nitrogen, we’re
actually protecting coastal communities as well.

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