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Kong Z, Wang H, Yan G, Yan Q, Kim JR. Limited dissolved oxygen facilitated nitrogen removal at biocathode during the hydrogenotrophic denitrification process using bioelectrochemical system. BIORESOURCE TECHNOLOGY 2023; 372:128662. [PMID: 36693505 DOI: 10.1016/j.biortech.2023.128662] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 01/17/2023] [Accepted: 01/19/2023] [Indexed: 06/17/2023]
Abstract
Effects of limited dissolved oxygen (DO) on hydrogenotrophic denitrification at biocathode was investigated using bioelectrochemical system. It was found that total nitrogen removal increased by 5.9%, as DO reached about 0.24 mg/L with the cathodic chamber unplugged (group R_Exposure). With the presence of limited DO, not only the nitrogen metabolic pathway was influenced, but the composition of microbial communities of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria were enriched accordingly. After metagenomic analysis, enriched genes in R_Exposure were found to be associated with nearly each of nitrogen removal steps as denitrification, nitrification, DNRA, nitrate assimilation and even nitrogen fixation. Moreover, genes encoding both Complexes III and IV constituted the electron transfer chain were significantly enriched, indicating that more electrons would be orientated to the reduction of NO2--N, NO-N and oxygen. Therefore, enhanced nitrogen removal could be attained through the co-respiration of nitrate and oxygen by means of NH4+-N oxidation.
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Affiliation(s)
- Ziang Kong
- School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Han Wang
- School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Guoliang Yan
- College of Food Science and Nutritional Engineering, China Agricultural University, 17 East Tsinghua Rd, Beijing 100083, China
| | - Qun Yan
- School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi 214122, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou 215011, China.
| | - Jung Rae Kim
- School of Chemical Engineering, Pusan National University, 63 Busandeahak-ro, Geumjeong-Gu, Busan 46241, Republic of Korea
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Zhou Y, He Y, Zhou Z, Xiao X, Wang M, Chen B. A newly isolated microalga Chlamydomonas sp. YC to efficiently remove ammonium nitrogen of rare earth elements wastewater. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 316:115284. [PMID: 35584596 DOI: 10.1016/j.jenvman.2022.115284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 04/26/2022] [Accepted: 05/08/2022] [Indexed: 06/15/2023]
Abstract
The aim of this study was to establish a practical approach to remove ammonium nitrogen of rare earth elements (REEs) wastewater by an indigenous photoautotrophic microalga. Firstly, a new microalgal strain was successfully isolated from REEs wastewater and identified as Chlamydomonas sp. (named Chlamydomonas sp. YC). The obtained results showed that microalga could completely remove the NH4+-N of 10% REEs wastewater after 10 days of cultivation; however, the highest NH4+-N removal rate was attained by microalga to treat undiluted REEs wastewater. Then, three cultivation modes including batch, semi-continuous and continuous cultivation methods were developed to evaluate the ability of NH4+-N removal rate by this microalga to treat diluted (10%) and undiluted REEs wastewater. It was found that, Chlamydomonas sp. YC exhibited superior performance towards NH4+-N removal rates (32.75-61.05 mg/(L·d)) by semi-continuous and continuous processes for the treatments of 10% and undiluted REEs wastewater in comparison to the results (19.50-30.38 mg/(L·d) by batch process. Interestingly, under the same treatment conditions, among the three cultivation modes, microalga exhibited the highest removal rates of NH4+-N in undiluted REEs wastewater by semi-continuous (61.05 mg/(L·d)) and continuous (57.10 mg/(L·d) processes. In term of the biochemical analysis, microalgal biomass obtained from the wastewater treatment had 35.40-44.40% carbohydrate and 4.97-6.03% lipid, which could be potential ingredients for sustainable biofuels production. And the highest carbohydrate and lipid productivities attained by Chlamydomonas sp. YC in the continuous mode were 226.36 mg/(L·d) and 32.98 mg/(L·d), respectively. Taken together, the established processes mediated with Chlamydomonas sp. YC via continuous cultivation was the great promising approaches to efficiently remove NH4+-N of REEs wastewater and produce valuable biomass for sustainable and renewable biofuels in a simultaneous manner.
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Affiliation(s)
- Youcai Zhou
- College of Life Science, Fujian Normal University, Fuzhou, 350117, China
| | - Yongjin He
- College of Life Science, Fujian Normal University, Fuzhou, 350117, China; Engineering Research Center of Industrial Microbiology, Ministry of Education, Fujian Normal University, Fuzhou, 350117, China
| | - Zhihua Zhou
- College of Life Science, Fujian Normal University, Fuzhou, 350117, China
| | - Xuehua Xiao
- College of Life Science, Fujian Normal University, Fuzhou, 350117, China
| | - Mingzi Wang
- College of Life Science, Fujian Normal University, Fuzhou, 350117, China; Engineering Research Center of Industrial Microbiology, Ministry of Education, Fujian Normal University, Fuzhou, 350117, China
| | - Bilian Chen
- College of Life Science, Fujian Normal University, Fuzhou, 350117, China; Engineering Research Center of Industrial Microbiology, Ministry of Education, Fujian Normal University, Fuzhou, 350117, China.
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