A new sensor system developed by Qingzhi Zhu, an associate professor at Stony Brook University’s School of Marine and Atmospheric Sciences, has received a patent for its ability to detect nitrate/nitrite and ammonium in water in real time. The technology is expected to improve the monitoring of wastewater treatment and septic systems by providing immediate data on water quality.
Zhu highlighted the importance of Stony Brook University’s research environment in supporting this achievement. “The university plays a crucial role in advancing solutions for urgent environmental issues,” said Zhu. He credited the institution’s facilities, such as the New York State Center for Clean Water Technology (CCWT), Aller Laboratory, and various machine shops, as essential resources. Financial support from organizations including the State University of New York (SUNY) Technology Accelerator Fund (TAF), CCWT (NYSDEC), and the US EPA contributed to improvements in the sensor, verification processes, and pilot testing.
Traditional methods for monitoring nitrogen pollution often require manual sampling and laboratory analysis that can take days or weeks. Zhu explained that with these older approaches, contamination might not be detected until after significant damage has occurred: “If something happened in the system, that means it happened a month ago already,” he said. “But [my] sensor can tell you immediately when that happened.” The new device is capable of measuring both nitrate and ammonium simultaneously—something previous technologies could not do reliably under challenging wastewater conditions.
This real-time capability is important for identifying malfunctions quickly and reducing exposure to contaminants. For example, during a pilot test in Southampton, the sensor detected a spike in nitrogen levels after a holiday weekend, which led to prompt repair of an aeration pump failure.
Nitrogen pollution from sources like septic tanks can cause health problems if high nitrate levels enter drinking water supplies—a particular concern on Long Island where groundwater is widely used. Excess nitrogen also contributes to harmful algal blooms that threaten aquatic life. The new sensor allows municipalities and households to monitor water quality continuously, helping protect public health and ecosystems. Its self-calibrating and self-cleaning features are designed for reliability during long-term use in difficult environments.
Zhu’s work builds on his background developing chemical sensors for studying elemental cycles in marine sediments. His participation in Phase 2 of the EPA Advanced Septic System Nitrogen Sensor Challenge prompted him to create this combined nitrate/ammonium sensor because existing commercial options were lacking. His device was reportedly the only one to pass all phases of EPA field testing—including ISO 14034 verification—and earned him an EPA award in 2020.
Pilot testing is underway at homes, schools, and municipal plants on Long Island. Zhu acknowledged support from Stony Brook’s Office for Research and Innovation as well as Intellectual Property Partners during the patent process. He sees strong market potential for this type of nitrogen sensing technology.
Looking ahead, Zhu aims to develop sensors capable of detecting per- and polyfluoroalkyl substances (PFAS) at extremely low concentrations—levels current methods struggle with—which would have broad implications given strict regulatory standards around PFAS contamination.
