GOALI: Effect of Hydroxylamine on the Structure and Function of Nitrifying Biofilms

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Wastewater treatment is needed for environmental protection, but most treatment processes are very energy intensive. A recently developed biological treatment process, called partial nitritation-anammox (PNA), can save energy. However, it is difficult to use in most treatment processes because it requires the suppression of some bacteria commonly found in wastewater. This research explores a new type of reactor configuration, along with the addition of the chemical hydroylamine, that may allow PNA to be effectively used for wastewater treatment. The research involves a collaboration with SUEZ, an industrial partner. It will train undergraduate and graduate students, as well as a post-doctoral researcher, and will include outreach to a community college with a new program in vertical farms.A collaborative study between the University of Notre Dame and SUEZ, a leader in membrane technologies, is proposed for a novel biofilm-based treatment technology that allows control of the internal physical and chemical environment in the biofilm. This method enables partial nitritation in existing wastewater treatment plants, a critical bottleneck in the energy-efficient PNA process. Furthermore, this biofilm environment control could enable other critical functions not currently possible in wastewater treatment, potentially serving as a disruptive technology. A key part of the new treatment process is the supply of chemicals to biofilms. In particular, this project will investigate how the supply of hydroxylamine, an intermediate of ammonia oxidizing bacteria (AOB) that can stimulate AOB growth and suppress nitrite-oxidizing bacteria (NOB) will alter the effectiveness of the PNA process. Researchers will first characterize the effects of hydroxylamine on the growth kinetics of AOB and NOB. Then the effects of hydroxylamine spikes on the structure and function of nitrifying biofilms will be explored using micro sensors, molecular tools, and imaging. An advanced biofilm model will be used to predict the best strategies for PNA. Finally, pilot-scale studies will be carried out to determine the process effectiveness in the field and to gather data and recommendations for scale-up and potential commercialization. This is the first research to study the effects of hydroxylamine on the microbial community structure of nitrifying biofilms. By determining the kinetics of AOB and NOB during and following exposure to hydroxylamine, this work will provide insights into fundamental inhibition mechanisms. This information will also provide a foundation for predicting the behavior of biofilms intermittently exposed to hydroxylamine. By studying mixed-culture biofilms with microsensors and molecular tools, the research could reveal potential niches for novel bacteria. The modeling and biofilm experiments will help engineer more effective water treatment processes. Workshops, lectures, and seminars at the University of Notre Dame and SUEZ will disseminate knowledge on biofilm research and process development to undergraduate, graduate, and Ivy Tech Community College students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.