A new patent has been awarded to Qingzhi Zhu, Associate Professor at Stony Brook University’s School of Marine and Atmospheric Sciences, for a sensor system that can simultaneously 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 role of Stony Brook University in supporting research efforts. “The university plays a crucial role in advancing solutions for urgent environmental issues,” Zhu said. He noted the value of the university’s research infrastructure, including facilities such as the New York State Center for Clean Water Technology (CCWT), Aller Laboratory, and machine shops. Zhu also pointed out that collaboration with colleagues from different departments was key to developing the sensor. Funding from sources like the State University of New York Technology Accelerator Fund, CCWT (NYSDEC), and the US EPA supported improvements, verification, and pilot testing.
Traditional methods for monitoring nitrogen pollution often involve slow manual sampling and laboratory analysis. This delay can mean that contamination is not detected until after damage has occurred. Zhu explained this challenge: “If something happened in the system, that means it happened a month ago already,” he said about conventional approaches. “But [my] sensor can tell you immediately when that happened.” The new device is described as the first capable of measuring both nitrate and ammonium at once, even under difficult wastewater conditions.
The ability to monitor nutrients in real time helps identify system malfunctions quickly and allows for faster intervention. For example, a spike in nitrogen detected by one of these sensors led to prompt repair of an aeration pump failure at a Southampton home following a holiday weekend.
High levels of nitrogen and ammonium—often from cesspools or septic tanks—can cause health problems if present in drinking water supplies such as those on Long Island. Excess nitrogen also contributes to harmful algal blooms along coastlines, damaging aquatic life. The new sensor’s self-calibration and self-cleaning features are designed to make it reliable for long-term use in challenging environments.
Zhu’s career has focused on chemical sensors for studying elemental cycles and biogeochemical processes in marine settings. His work includes developing optical planar sensors for mapping chemicals like dissolved oxygen and pH in two dimensions within marine sediments. Participation in Phase 2 of the EPA Advanced Septic System Nitrogen Sensor Challenge motivated him to develop this combined nitrate-ammonium sensor, which was not previously available commercially or suited for harsh wastewater conditions. Zhu’s design was reportedly the only one to pass all stages of EPA field testing—including ISO 14034 verification—and earned him an EPA award in 2020.
Pilot testing is underway with installations at homes, schools on Long Island, and municipal wastewater plants. Zhu acknowledged support from Stony Brook’s Office for Research and Innovation as well as Intellectual Property Partners during the patent process.
Looking ahead, Zhu plans to develop sensors capable of detecting per- and polyfluoroalkyl substances (PFAS), known as “forever chemicals,” which are difficult to measure due to very low regulatory limits—such as four parts per trillion—in drinking water standards set by agencies like the Department of Defense’s SERDP program. He described this potential advancement as a “game changer” if successful.