A team of scientists at Stony Brook University (SBU) is working to develop new technology that prevents nitrogen from entering groundwater.
The project, called “10/10/30,” aims to lower nitrate levels in the water to 10 milligrams per liter. The system should cost no more than $10,000 and last at least 30 years.
The initiative is being conducted by the New York State Center for Clean Water Technology, located at Stony Brook University. It was founded in 2015 through a grant awarded by the state to research and develop an affordable wastewater treatment system to help address Long Island’s ongoing problem of water pollution.
“What we’re studying is meta systems that can remove nitrogen in septic tank effluent. One of the technologies we’re investigating is called a Nitrogen Removing Biofilter (NRB),” Frank Russo, associate director for wastewater initiatives at the Center for Clean Water Technology, said. “This is a system that uses a fanbed followed by wood chips. What that does is convert nitrogen through the process of nitritation and denitritation into gas so therefore nitrogen doesn’t get received into the groundwater.”
Most of the Long Island region does not have sewage systems, which causes water pollution. According to documents from the Center for Clean Water Technology, 74% of homes across Suffolk County have septic tank and cesspool systems that do not remove nitrogen from wastewater. The concentration of nitrogen in groundwater across the county has increased by 50% since 1985, according to the same documents.
Nitrogen is contaminating the groundwater by reducing the water’s oxygen levels. This has led to toxic algal blooms throughout the region that affects wetlands and depletes fish populations, including shellfish.
Long Island’s source for drinking water comes entirely from groundwater aquifers.
“Here we are, dumping wastewater and other household stuff into a septic tank or cesspool that eventually just perks into the groundwater and that’s not a good thing,” Russo said.
Nitrogen contamination in the water has been ending up in places like the Long Island Sound and the Great South Bay, where nitrates are creating algal bloom. Due to the harmful nitrates, oxygen levels in the region’s surface waters have lowered.
The Center for Clean Water Technology is also developing Permeable Reactive Barriers, or PRBs, which intercept groundwater flow and absorb or transform contaminants. The Center for Clean Water Technology is developing this technology in hopes to remove nitrogen from groundwater across the county.
“They are vertical versions of NRBs, so they just act to intercept the flow of groundwater before it reaches a vulnerable shoreline and it can convert nitrogen into gas as well,” Samantha Nyer, a graduate student at SBU’s School of Marine and Atmospheric Sciences who is working on the project, said.
PRBs are used to treat many different contaminants, including pesticides and chlorinated compounds.
“We’ve also been working with the county to write a guidance document so that installers in the county can put these systems in real easily,” Nyer said.
The Center for Clean Water Technology has no clear timeline on the completion of the project.
Xinwei Mao, an assistant professor of civil engineering who is also involved with the project, said this is a complicated issue that other parts of the country are battling too.
“In 2018, there was a paper published that showed where studies found a lot of deoxygenated areas in coastal zones on both the east and west coasts of the United States,” Mao said. “It has been overlooked for decades.”
Mao explained that the issue on Long Island is that people are still using old septic systems, which are difficult to monitor.
“There’s no regulation or law telling people you cannot use those cesspools and we have to abandon them,” Mao said.