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Single-Reactor Nitritation-Denitritation for High Strength Digested Biosolid Thickening Lagoon Supernatant Treatment
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- Author / Creator
- Zou, Xin
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Nitrogen is an essential element for living organisms, accounting for 80% of chemical elements in the atmosphere. Nitrogen is also one of the most concerned elements in the environment. The significant sources of nitrogen that released into the Canadian environment is municipal wastewater, as well as the non-point sources. The supernatant of biosolid digestate thickening lagoon contains 25-30% of the total amount of nitrogen but only 1% of the flow in the influent in WWTPs. To meet the stringent discharge standards for nitrogen in water, highly effective and energy saving nitrogen removal technologies should be investigated. The conventional nitrogen removal method, nitrification-denitrification, has been widely used in mainstream treatment. Compared to that, nitritation-denitritation can save 25% aeration cost, and 40% external carbon demand.
The ammonia-rich lagoon supernatant with limited alkalinity is ideal for the single reactor nitritation-denitritation operation. In this work, an integrated fixed film activated sludge (IFAS) system was operated in sequencing batch mode at 21 oC. This thesis evaluates the feasibility and stability of single reactor nitritation-denitritation for treating ammonia rich lagoon supernatant, investigates the distribution of microbial community and predominant microbes that contribute to nitritation and denitritation. With a hydraulic retention time (HRT) of 2 days, the nitritation-denitritation reactor achieved a stable inorganic nitrogen removal rate at 98%. The dominant nitrifying and primary denitrifying genera were Nitrosomonas and Thauera, respectively. The relative abundance of both genera increased in suspension and biofilm after long-term operation. The suspended biomass exhibited higher activity than biofilm and suspended biomass were also proved to contribute more on both nitritation and denitritation process than biofilm.
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- Graduation date
- Spring 2020
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.