title: Advanced treatment of residual nitrogen from biologically treated coke effluent by a microalga-mediated process using volatile fatty acids (VFAs) under stepwise mixotrophic conditions.
abstract: This work describes the development of a microalga-mediated process for simultaneous removal of residual ammonium nitrogen (NH4(+)-N) and production of lipids from biologically treated coke effluent. Four species of green algae were tested using a sequential mixotrophic process. In the first phase-CO2-supplied mixotrophic condition-all microalgae assimilated NH4(+)-N with no evident inhibition. In second phase-volatile fatty acids (VFAs)-supplied mixotrophic condition-removal rates of NH4(+)-N and biomass significantly increased. Among the microalgae used, Arctic Chlorella sp. ArM0029B had the highest rate of NH4(+)-N removal (0.97 mg/L/h) and fatty acid production (24.9 mg/L/d) which were 3.6- and 2.1-fold higher than those observed under the CO2-supplied mixotrophic condition. Redundancy analysis (RDA) indicated that acetate and butyrate were decisive factors for increasing NH4(+)-N removal and fatty acid production. These results demonstrate that microalgae can be used in a sequential process for treatment of residual nitrogen after initial treatment of activated sludge.
authors.affiliation: Environmental and Energy Program, KAIST, 291 Daehakno, Yuseong-gu, Daejeon 305-701, Republic of Korea; Decontamination and Decommissioning Research Division, Korea Atomic Energy Research Institute (KAERI), 989-111 Daedukdaero Yuseong, Daejeon 305-353, Republic of Korea.
authors.forename: Byung-Gon
authors.initials: BG
authors.lastname: Ryu
authors.affiliation: Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehakno, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Woong
authors.initials: W
authors.lastname: Kim
authors.affiliation: Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehakno, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Sung-Woon
authors.initials: SW
authors.lastname: Heo
authors.affiliation: Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehakno, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Donghyun
authors.initials: D
authors.lastname: Kim
authors.affiliation: Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehakno, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Gang-Guk
authors.initials: GG
authors.lastname: Choi
authors.affiliation: Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehakno, Yuseong-gu, Daejeon 305-701, Republic of Korea; Advanced Biomass R&D Center, KAIST, 291 Daehakno, Yuseong-gu, Daejeon 305-701, Republic of Korea. Electronic address: jwyang@kaist.ac.kr.
authors.forename: Ji-Won
authors.initials: JW
authors.lastname: Yang
mesh_terms: D003077:Coke; D005227:Fatty Acids / Q000378:metabolism*; D058086:Microalgae / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D014835:Volatilization
chemical_list: D003077:Coke; D005227:Fatty Acids; D009584:Nitrogen
keywords: Coke wastewater; Microalgae; Mixotrophic conditions; Nitrogen removal; Volatile fatty acid (VFA)