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Li Q, Xu Y, Chen S, Liang C, Guo W, Ngo HH, Peng L. Inorganic carbon limitation decreases ammonium removal and N 2O production in the algae-nitrifying bacteria symbiosis system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 928:172440. [PMID: 38614328 DOI: 10.1016/j.scitotenv.2024.172440] [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: 02/05/2024] [Revised: 04/08/2024] [Accepted: 04/10/2024] [Indexed: 04/15/2024]
Abstract
Ammonium removal by a symbiosis system of algae (Chlorella vulgaris) and nitrifying bacteria was evaluated in a long-term photo-sequencing batch reactor under varying influent inorganic carbon (IC) concentrations (15, 10, 5 and 2.5 mmol L-1) and different nitrogen loading rate (NLR) conditions (270 and 540 mg-N L-1 d-1). The IC/N ratios provided were 2.33, 1.56, 0.78 and 0.39, respectively, for an influent NH4+-N concentration of 90 mg-N L-1 (6.43 mmol L-1). The results confirmed that both ammonium removal and N2O production were positively related with IC concentration. Satisfactory ammonium removal efficiencies (>98 %) and rates (29-34 mg-N gVSS-1 h-1) were achieved regardless of NLR levels under sufficient IC of 10 and 15 mmol L-1, while insufficient IC at 2.5 mmol L-1 led to the lowest ammonium removal rates of 0 mg-N gVSS-1 h-1. The ammonia oxidation process by ammonia oxidizing bacteria (AOB) played a predominant role over the algae assimilation process in ammonium removal. Long-time IC deficiency also resulted in the decrease in biomass and pigments of algae and nitrifying bacteria. IC limitation led to the decreasing N2O production, probably due to its negative effect on ammonia oxidation by AOB. The optimal IC concentration was determined to be 10 mmol L-1 (i.e., IC/N of 1.56, alkalinity of 500 mg CaCO3 L-1) in the algae-bacteria symbiosis reactor, corresponding to higher ammonia oxidation rate of ∼41 mg-N gVSS-1 h-1 and lower N2O emission factor of 0.13 %. This suggests regulating IC concentrations to achieve high ammonium removal and low carbon emission simultaneously in the algae-bacteria symbiosis wastewater treatment process.
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Affiliation(s)
- Qi Li
- Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan 430070, China; Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Yifeng Xu
- Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan 430070, China; Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China.
| | - Shi Chen
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Chuanzhou Liang
- Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan 430070, China; Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Wenshan Guo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Huu Hao Ngo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Lai Peng
- Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan 430070, China; Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China.
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Tang B, Zhang L, Salam M, Yang B, He Q, Yang Y, Li H. Revealing the environmental hazard posed by biodegradable microplastics in aquatic ecosystems: An investigation of polylactic acid's effects on Microcystis aeruginosa. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 344:123347. [PMID: 38215868 DOI: 10.1016/j.envpol.2024.123347] [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: 10/20/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 01/14/2024]
Abstract
The influence of petroleum-based microplastics (MPs) on phytoplankton has been extensively studied, while research on the impact of biodegradable MPs, derived from alternative plastics to contest the environmental crisis, remains limited. This study performed a 63 days co-incubation experiment to assess the effect of polylactic acid MPs (PLA-MPs) on the growth, physiology, and carbon utilization of M. aeruginosa and the change in PLA-MPs surface properties. The results showed that despite PLA-MPs induced oxidative stress and caused membrane damage in M. aeruginosa, the presence of PLA-MPs (10, 50, and 200 mg/L) triggered significant increases (p < 0.05) in the density of M. aeruginosa after 63 days. Specifically, the algal densities upon 50 and 200 mg/L PLA-MPs exposure were increased by 20.91% and 36.31% relative to the control, respectively. Meanhwhile, the reduced C/O ratio on PLA-MPs surface and change in PLA-MPs morphological characterization, which is responsible for substantially increase in the aquatic dissolved inorganic carbon concentration during the co-incubation, implying the degradation of PLA-MPs; thus, provided sufficient carbon resources that M. aeruginosa could assimilate. This was in line with the declined intracellular carbonic anhydrase content in M. aeruginosa. This study is the first attempt to uncover the interaction between PLA-MPs and M. aeruginosa, and the finding that their interaction promotes the degrading of PLA-MPs meanwhile favoring M. aeruginosa growth will help elucidate the potential risk of biodegradable MPs in aquatic environment.
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Affiliation(s)
- Bingran Tang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China
| | - Lixue Zhang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China
| | - Muhammad Salam
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
| | - Bing Yang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Ecological and Environment Monitoring Center of Chongqing, Chongqing, 401147, China
| | - Qiang He
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China
| | - Yongchuan Yang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China
| | - Hong Li
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China.
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