1. Oxygen transfer performance of a supersaturated oxygen aeration system (SDOX) evaluated at high biomass concentrations.
- Author
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Kim, Sang Yeob, Garcia, Hector A., Lopez-Vazquez, Carlos M., Milligan, Chris, Herrera, Aridai, Matosic, Marin, Curko, Josip, and Brdjanovic, Damir
- Subjects
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MASS transfer coefficients , *SEWAGE disposal plants , *OXYGEN , *FOOD biotechnology , *MASS transfer , *DISSOLVED air flotation (Water purification) , *ACTIVATED sludge process - Abstract
• The SDOX technology uncapped the limitations imposed by diffused aeration for working at high MLSS concentrations. • The SDOX technology exhibited higher alpha factor compared to bubble diffuser at MLSS concentrations higher than 20 g L−1. • Bubble diffusers showed higher K L a coefficients compared to the SDOX system, but lower SOTRs and SOTEs. Oxygen transfer in wastewater treatment is significantly influenced by the mixed liquor suspended solids (MLSS). The effect is more pronounced at MLSS concentrations higher than 20 g L−1 when supplying air by conventional diffused aeration systems. The oxygen transfer performance of a supersaturated oxygenation technology (i.e., the supersaturated dissolved oxygen (SDOX) system) was evaluated in clean water and in activated sludge with MLSS concentrations from 4 to 40 g L−1 as a promising technology for uncapping such limitation. The evaluation was carried out at the laboratory facilities of the faculty of food technology and biotechnology at the University of Zagreb. The sludge was collected from a full-scale conventional activated sludge (CAS) wastewater treatment plant (WWTP) operated at a solid retention time (SRT) of approximately 5 days. The evaluation was carried out using a laboratory-scale setup consisting of a bench-scale SDOX system (2.75 L) supplying pure oxygen to a 5 L biological reactor. The SDOX exhibited oxygen mass transfer rate coefficient (K L a) values (2.6 h−1) in clean water lower than for fine bubble diffusers (11 h−1). However, higher oxygen transfer rate (OTR) values and alpha factors (mass transfer ratio of process-water to clean-water) as a function of the MLSS concentration were observed. A standard oxygen transfer efficiency (SOTE) of approximately 100 % in clean water was reported. The SDOX technology can be presented as a promising alternative for supplying dissolved oxygen (DO) into mixed liquor solutions; particularly, at the high MLSS concentrations required by high-loaded membrane bioreactor (HL-MBR) systems and aerobic digesters. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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