UNS: A Novel Algal-Bacterial Shortcut Nitrogen Removal Process for Wastewater Treatment

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1511439ErgasManagement of the nitrogen cycle was identified by the National Academy of Engineering (NAE) as one of the grand challenges of the 21st century. High ammonia strength wastewaters, such as anaerobic digestion effluents, are difficult and costly to treat in conventional biological nitrogen removal systems due to their toxicity and high oxygen requirements. The PIs overall goal is to investigate nitrogen metabolism in algal-bacterial shortcut nitrogen removal and identify the optimum conditions needed to sustain this novel process. The proposed research is significant because it has the potential to reduce the costs, energy requirements and greenhouse gas emissions associated with nitrogen removal from wastewaters. The guiding hypothesis is that the close association of algae and bacteria and light/dark cycles results in conditions within biological particles that favor shortcut nitrogen removal.Through interdisciplinary and international collaboration, the PIs propose to: 1) investigate the effects of varying operating conditions and substrates on system kinetics and performance, 2) investigate the microbial consortium, which includes algae, ammonia oxidizing bacteria, nitrite oxidizing bacteria, and denitrifying bacteria using molecular tools, 3) optimize the system design through coupled process-optimization modeling, and, 4) develop global competency in US students though an international collaboration. The interrelationships between nitrogen loading, light penetration and oxygen production will be studied using bench-scale SBPRs operated at varying illumination, temperature and loading rates. The presence and activities of algae nitrogen metabolizing microorganisms will be tracked via measurements of key chemical constituents and by using molecular biological tools to target functional genes encoding steps in the N cycle relevant to nitrification/ denitrification. Additional experiments will investigate the use of volatile fatty acids harvested from livestock waste fermentation as an electron donor for denitrification and coupling of partial algal-bacterial ammonia oxidation with anammox technology to improve system economics. A framework that couples an algal-bacterial shortcut nitrogen process models and an optimization models will be used to minimize system footprint with target total nitrogen removal as a constraint. The optimization model will allow the PIs to find the optimal operating conditions to minimize reactor footprint for different geographic regions. The PIs have assembled a team of researchers in the US and Netherlands with expertise in biological nitrogen removal and algae production, autotrophic bacterial physiology, and wastewater process and optimization modeling. Graduate and undergraduate students, secondary science teachers and HS students will receive training in interdisciplinary, globalized science and engineering research in developed and developing world contexts. We will build on student exchanges between University of South Florida and UNESCO-IHE in Delft, the Netherlands and University of South Florida's Peace Corps Masters International Program to gain additional resources (students, facilities, and research expertise), build developing world sustainable water treatment capacity and continue co-development of the shortcut algal-bacterial nitrogen removal process.