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Li D, Yan S, Yong X, Zhang X, Zhou J. Ball-milled magnetic sludge biochar enables fast aerobic granulation in anoxic/oxic process for the treatment of coal chemical wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 880:163241. [PMID: 37011673 DOI: 10.1016/j.scitotenv.2023.163241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/27/2023] [Accepted: 03/30/2023] [Indexed: 05/27/2023]
Abstract
Coal chemical wastewater (CCW) containing toxic and hazardous matters requires to be treated prior to discharge. Promoting the in-situ formation of magnetic aerobic granular sludge (mAGS) in continuous flow reactor process has a great potential for CCW remediation. However, long granulation time and low stability limit the application of AGS technology. In this study, Fe3O4/sludge biochar (Fe3O4/SC) with biochar matrix derived from coal chemical sludge were applied to facilitate the aerobic granulation in two-stage continuous flow reactors, containing separated anoxic and oxic reaction units (abbreviated as A/O process). The performance of A/O process was evaluated at various hydraulic retention times (HRTs) (42 h, 27 h, and 15 h). Magnetic Fe3O4/SC with porous structures, high specific surface area (BET = 96.69 m2/g), and abundant functional groups was successfully prepared by ball-milled method. Adding magnetic Fe3O4/SC to A/O process could promote aerobic granulation (85 days) and the removal of chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), and total nitrogen (TN) from CCW at all tested HRTs. Since the formed mAGS had high biomass, good settling ability, and high electrochemical activities, mAGS-based A/O process had high tolerance to the decrease of HRT from 42 h to 15 h for CCW treatment. The optimized HRT for A/O process was 27 h, at which Fe3O4/SC addition can result in the increase of COD, NH4+-N and TN removal efficiencies by 2.5 %, 4.7 % and 10.5 %, respectively. Based on 16S rRNA genes sequencing, the relative abundances of genus Nitrosomonas, Hyphomicrobium/Hydrogenophaga and Gaiella in mAGS accounting for nitrification, denitrification as well as COD removal were increased during aerobic granulation. Overall, this study proved that adding Fe3O4/SC to A/O process was effective for facilitating aerobic granulation and CCW treatment.
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Affiliation(s)
- Dan Li
- College of Environmental Science and Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China; Bioenergy Research Institute, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China
| | - Su Yan
- College of Environmental Science and Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China; Bioenergy Research Institute, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China
| | - Xiaoyu Yong
- Bioenergy Research Institute, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China
| | - Xueying Zhang
- College of Environmental Science and Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China.
| | - Jun Zhou
- College of Environmental Science and Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China; Bioenergy Research Institute, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China.
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Shi J, Liang Z, Dai X. Enhanced biological phosphorus and nitrogen removal by high-concentration powder carriers: extracellular polymeric substance, microbial communities, and metabolic pathways. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:4010-4022. [PMID: 35963965 DOI: 10.1007/s11356-022-22363-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 07/29/2022] [Indexed: 06/15/2023]
Abstract
In this study, diatomite, activated carbon, and iron-carbon (Fe-C) were used as biological carriers for the integrated fixed-film activated sludge process. Biomass, pollutant removal efficiency, and extracellular polymer were tested, and the effect of nitrogen and phosphorus removal, enzyme activity, and microbial diversity were studied after the sludge retention time was changed. The mechanism of carrier enriching microorganism and promoting pollutant degradation was studied. The results showed that the addition of these three carriers contributed to the enrichment of nitrifying bacteria in the system, and the NH4+-N removal efficiency was above 98%. Diatomite and Fe-C could improve pollutant removal by increasing the activity of the electron transfer system. The abundance of denitrogenation-related reductases and the enzymes synthesizing poly-β-hydroxybutyrate was increased in activated carbon. The addition of Fe-C increased the abundance of denitrifying phosphate-accumulating organisms by approximately 25% and the removal efficiency of total phosphorus by 12.61-14.88% at the end of the long-term operation.
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Affiliation(s)
- Juan Shi
- College of Environmental Science and Engineering, Shanghai University of Electric Power, Shanghai, 200090, China
| | - Zixuan Liang
- State Key Lab Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Xiaohu Dai
- State Key Lab Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
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Ren Z, Wang Z, Lv L, Ma P, Zhang G, Li Y, Qin Y, Wang P, Liu X, Gao W. Fe-N complex biochar as a superior partner of sodium sulfide for methyl orange decolorization by combination of adsorption and reduction. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 316:115213. [PMID: 35561493 DOI: 10.1016/j.jenvman.2022.115213] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/29/2022] [Accepted: 04/30/2022] [Indexed: 06/15/2023]
Abstract
To enhance the decolorization of methyl orange (MO), Fe-N complex biochar (Fe-N-BC) was developed as an accelerator in the sodium sulfide (Na2S) reduction system. The decolorization effect and mechanism of MO in the Fe-N-BC/Na2S composite system were studied. Surface pore analysis, Raman spectroscopy, FT-IR, XPS, and electrochemical analysis were used to characterize Fe-N-BC and unmodified biochar (BC). These results demonstrated that Fe-N-BC had better adsorption performance (specific surface area 463.46 m2 g-1) and electron transfer capacity than BC. By adding Fe-N-BC to the Na2S reduction system for MO, it was found that the decolorization of MO was greatly improved (increased by 93%). Besides, the effects of critical factors such as the initial concentration of Na2S, the dosage of Fe-N-BC, pH value, and temperature on the decolorization rate of MO were evaluated. Through the analysis of the action mechanism, the cooperation mode of Fe-N-BC and Na2S was to form an infinite cycle of adsorption-reduction-regeneration, so as to realize the rapid decolorization of MO. On the one hand, Fe-N-BC could adsorb MO and Na2S on its surface to increase the contact opportunity; on the other hand, it could act as a redox mediator to accelerate the electron transfer of the reduction reaction. In addition, the degradation of MO by Na2S was also an in-situ regeneration of Fe-N-BC. These findings may provide a feasible method to decolorize azo dyes quickly by cooperating with chemical reducing agents from a new perspective.
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Affiliation(s)
- Zhijun Ren
- Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, PR China.
| | - Zhanxin Wang
- Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, PR China
| | - Longyi Lv
- Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, PR China.
| | - Peiyu Ma
- Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, PR China
| | - Guangming Zhang
- Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, PR China
| | - Yuyou Li
- Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Yu Qin
- Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Pengfei Wang
- Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, PR China
| | - Xiaoyang Liu
- Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, PR China
| | - Wenfang Gao
- Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, PR China
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Liu C, Zhuo Y, Mao Y, Shen Q, Zhang Q, Jiang L, Ji F. Enhancing ammonia oxidation mediated using different crystalline Mn-oxides in an anoxic environment. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 315:115109. [PMID: 35500482 DOI: 10.1016/j.jenvman.2022.115109] [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: 01/19/2022] [Revised: 04/01/2022] [Accepted: 04/16/2022] [Indexed: 06/14/2023]
Abstract
A recent study found that the nitrogen cycle in marine sediments can occur under oxygen-limited conditions, and this is associated with a reduction of Mn (IV). However, the effect of MnO2 mediated anoxic ammonia oxidation in different sediments field test results are controversial. In this study, based on the fact that the crystal form and morphology of MnO2 in marine sediments are affected by geochemistry, α-, β-, γ-MnO2 and amorphous MnO2 were prepared to explore the effect of the different MnO2 crystals on nitrogen removal under oxygen-limited conditions. The experimental results showed that the anoxic ammonia oxidation process was mediated by microorganisms, and the reaction was affected by pH and temperature. The optimal pH was 7 in the range of pH 4-9 and the optimal temperature was 25 °C in the range of 10 °C-40 °C. When the initial concentration of NH4+-N was 50 mg/L, the removal amounts of NH4+-N under an anoxic condition by α-, β-, γ-MnO2 and amorphous MnO2 were 18.97 mg/L/d, 6.12 mg/L/d, 10.68 mg/L/d and 24.89 mg/L/d, respectively. During the anoxic oxidation between MnO2 and NH4+-N, the adsorption process occurred. In addition, the oxidation process produced both NOx--N (nitrification reaction) and gaseous nitrogen (ammonia oxidation reaction). The kinetic study showed that the NH4+-N removal process conformed to the pseudo-second-order rate model, and the removal rates were ranked as amorphous MnO2 > α- > γ- > β-MnO2. Together, these results showed that the amorphous MnO2 crystal structure was conducive to improve anoxic ammonia oxidation and nitrogen removal under oxygen-limited conditions.
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Affiliation(s)
- Caocong Liu
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Yiyuan Zhuo
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Yuanxiang Mao
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Qiushi Shen
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Qian Zhang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Lei Jiang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Fangying Ji
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China.
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