A new sensor system developed by Qingzhi Zhu, an associate professor at Stony Brook University’s School of Marine and Atmospheric Sciences, has been awarded 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 emphasized the importance of Stony Brook University’s research environment in making this achievement possible. “The university plays a crucial role in advancing solutions for urgent environmental issues,” said Zhu. He noted that the institution’s support includes advanced facilities such as the New York State Center for Clean Water Technology (CCWT), Aller Laboratory, and specialized machine shops. Zhu also highlighted the collaborative nature of his work, which involved colleagues from different departments and centers.
Funding for this project came from several sources, including the State University of New York (SUNY) Technology Accelerator Fund (TAF), CCWT (NYSDEC), and the US Environmental Protection Agency (EPA). These funds supported improvements to the sensor, verification processes under ISO 14034 standards, and pilot testing.
Traditional methods for monitoring nitrogen pollution often require manual sample collection and laboratory analysis that can take days or weeks. This delay may allow contamination to go undetected until after it has caused harm. In contrast, Zhu’s patented sensor provides immediate readings and is reportedly the first device able to measure both nitrate and ammonium simultaneously under field conditions.
“If something happened in the system, that means it happened a month ago already,” Zhu explained about conventional methods. “But [my] sensor can tell you immediately when that happened.”
The need for such technology is particularly acute on Long Island, where groundwater serves as a main source of drinking water. High levels of nitrogen compounds from septic tanks can pose health risks to people and contribute to harmful algal blooms that damage aquatic ecosystems. By offering continuous monitoring with features like self-calibration and self-cleaning, Zhu’s sensor aims to help municipalities and households manage water quality more effectively.
Zhu’s background includes developing chemical sensors for studying marine sediments and biogeochemical processes. His participation in Phase 2 of the EPA Advanced Septic System Nitrogen Sensor Challenge led him to create this combined nitrate-ammonium sensor when he saw there was no suitable commercial option available. His design was reportedly the only one to pass all stages of EPA field testing—one week, one month, and six months—and earned him an EPA award in 2020.
Currently, pilot tests are underway using this technology in homes, schools on Long Island, and municipal wastewater plants. Zhu credited support from Stony Brook’s Office for Research and Innovation as well as Intellectual Property Partners during the patent process.
Looking ahead, Zhu plans further development focused on sensors capable of detecting per- and polyfluoroalkyl substances (PFAS), chemicals with very low regulatory limits in drinking water that are difficult to monitor with current methods. He described creating a PFAS-detecting sensor as his next major goal: “Developing a sensor capable of measuring PFAS at such minute levels would be a ‘game changer’.” A proposal has already been submitted to the Department of Defense’s SERDP program toward this aim.
Zhu remains committed to advancing sensing technologies designed to address ongoing environmental challenges.
