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Paul T, Aggarwal A, Behera SK, Meher SK, Gupta S, Baskaran D, Rene ER, Pakshirajan K, Pugazhenthi G. Neuro-fuzzy modelling of a continuous stirred tank bioreactor with ceramic membrane technology for treating petroleum refinery effluent: a case study from Assam, India. Bioprocess Biosyst Eng 2024; 47:91-103. [PMID: 38085351 DOI: 10.1007/s00449-023-02948-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 11/12/2023] [Indexed: 01/10/2024]
Abstract
A continuous stirred tank bioreactor (CSTB) with cell recycling combined with ceramic membrane technology and inoculated with Rhodococcus opacus PD630 was employed to treat petroleum refinery wastewater for simultaneous chemical oxygen demand (COD) removal and lipid production from the retentate obtained during wastewater treatment. In the present study, the COD removal efficiency (CODRE) (%) and lipid concentration (g/L) were predicted using two artificial intelligence models, i.e., an artificial neural network (ANN) and a neuro-fuzzy neural network (NF-NN) with a network topology of 6-25-2 being the best for NF-NN. The results revealed the superiority of NF-NN over ANN in terms of determination coefficient (R2), root mean square error (RMSE), and mean absolute percentage error (MAPE). Three learning algorithms were tested with NF-NN; among them, the Bayesian regularization backpropagation (BR-BP) outperformed others. The sensitivity analysis revealed that, if solid retention time and biomass concentrations were maintained between 35 and 75 h and 3.0 g/L and 3.5 g/L, respectively, high CODRE (93%) and lipid concentration (2.8 g/L) could be obtained consistently.
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Affiliation(s)
- Tanushree Paul
- Center for the Environment, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Ayushi Aggarwal
- Process Simulation Research Group, School of Chemical Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu, 632 014, India
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Shishir Kumar Behera
- Process Simulation Research Group, School of Chemical Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu, 632 014, India.
- Industrial Ecology Research Group, School of Chemical Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu, 632 014, India.
| | - Saroj Kumar Meher
- Systems Science and Informatics Unit, Indian Statistical Institute, Bangalore, Karnataka, 560 059, India
| | - Shradha Gupta
- Process Simulation Research Group, School of Chemical Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu, 632 014, India
| | - Divya Baskaran
- Center for the Environment, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
- Department of Chemical Engineering, Sri Venkateswara College of Engineering, Sriperumbudur, Tamil Nadu, 608 002, India
| | - Eldon R Rene
- Department of Water Supply, Sanitation, and Environmental Engineering, IHE Delft Institute for Water Education, Westvest 7, 2611AX, Delft, The Netherlands
| | - Kannan Pakshirajan
- Center for the Environment, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781 039, India
| | - G Pugazhenthi
- Center for the Environment, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781 039, India
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Liu X, Liu Q, Sheng Y. Nutrients in overlying water affect the environmental behavior of heavy metals in coastal sediments. ENVIRONMENTAL RESEARCH 2023; 238:117135. [PMID: 37714367 DOI: 10.1016/j.envres.2023.117135] [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: 05/14/2023] [Revised: 07/18/2023] [Accepted: 09/12/2023] [Indexed: 09/17/2023]
Abstract
Excessive nutrients in aquatic ecosystems are the main driving factors for eutrophication and water quality deterioration. However, the influence of nutrients in overlying water on sediment heavy metals is not well understood. In this study, the effects of nitrate nitrogen (NO3-N) addition and phosphate addition in the overlying water on the environmental behaviors of chromium (Cr), copper (Cu), and cadmium (Cd) in coastal river sediments were investigated. Fresh estuary sediments and synthetic saltwater were used in microcosm studies conducted for 13 d. To determine the biological effect, unsterilized and sterilized treatments were considered. The results showed that the diffusion of Cr and Cu was inhibited in the unsterilized treatments with increased NO3-N. However, under the NO3-N sterilized treatments, Cr and Cu concentrations in the overlying water increased. This was mostly related to changes in the microbial regulation of dissolved organic carbon and pH in the unsterilized treatments. Further, in the unsterilized treatments, NO3-N addition considerably increased the concentrations of the acid-soluble (Cr, Cu, and Cd increased by 5%-8%, 29%-41%, and 31%-42%, respectively) and oxidizable (Cr, Cu, and Cd increased by 10%, 5%, and 14%, respectively) fractions. Additionally, compared with that in the unsterilized treatments, Cu and Cd concentrations in P-3 treatments decreased by 7% and 63%, respectively. By producing stable metal ions, microorganisms reduced the amount of unstable heavy metals in the sediment and heavy metal concentration in the overlying water, by considerably enhancing the binding ability of phosphate and heavy metal ions. This study provides a theoretical basis for investigating the coupling mechanisms between heavy metals and nutrients.
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Affiliation(s)
- Xiaozhu Liu
- CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China; University of Chinese Academy of Sciences, Beijing, China
| | - Qunqun Liu
- CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
| | - Yanqing Sheng
- CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.
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Elizabeth George S, Wan Y. Microbial functionalities and immobilization of environmental lead: Biogeochemical and molecular mechanisms and implications for bioremediation. JOURNAL OF HAZARDOUS MATERIALS 2023; 457:131738. [PMID: 37285788 PMCID: PMC11249206 DOI: 10.1016/j.jhazmat.2023.131738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 05/26/2023] [Accepted: 05/28/2023] [Indexed: 06/09/2023]
Abstract
The increasing environmental and human health concerns about lead in the environment have stimulated scientists to search for microbial processes as innovative bioremediation strategies for a suite of different contaminated media. In this paper, we provide a compressive synthesis of existing research on microbial mediated biogeochemical processes that transform lead into recalcitrant precipitates of phosphate, sulfide, and carbonate, in a genetic, metabolic, and systematics context as they relate to application in both laboratory and field immobilization of environmental lead. Specifically, we focus on microbial functionalities of phosphate solubilization, sulfate reduction, and carbonate synthesis related to their respective mechanisms that immobilize lead through biomineralization and biosorption. The contributions of specific microbes, both single isolates or consortia, to actual or potential applications in environmental remediation are discussed. While many of the approaches are successful under carefully controlled laboratory conditions, field application requires optimization for a host of variables, including microbial competitiveness, soil physical and chemical parameters, metal concentrations, and co-contaminants. This review challenges the reader to consider bioremediation approaches that maximize microbial competitiveness, metabolism, and the associated molecular mechanisms for future engineering applications. Ultimately, we outline important research directions to bridge future scientific research activities with practical applications for bioremediation of lead and other toxic metals in environmental systems.
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Affiliation(s)
- S Elizabeth George
- US EPA Office of Research and Development, Center for Environmental Measurement and Modeling, Gulf Ecosystem Measurement and Modeling Division, One Sabine Island Drive, Gulf Breeze, FL 32561, USA
| | - Yongshan Wan
- US EPA Office of Research and Development, Center for Environmental Measurement and Modeling, Gulf Ecosystem Measurement and Modeling Division, One Sabine Island Drive, Gulf Breeze, FL 32561, USA.
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Yan X, Gao B, Wang J, Zhu X, Zhang M. Insights into remediation effects and bacterial diversity of different remediation measures in rare earth mine soil with SO 4 2- and heavy metals. Front Microbiol 2023; 14:1050635. [PMID: 37032866 PMCID: PMC10079077 DOI: 10.3389/fmicb.2023.1050635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 02/15/2023] [Indexed: 04/11/2023] Open
Abstract
The increased demand for rare earth resources has led to an increase in the development of rare earth mines (REMs). However, the production of high-concentration leaching agents (SO4 2-) and heavy metals as a result of rare earth mining has increased, necessitating the removal of contaminants. Here, a series of experiments with different remediation measures, including control (CK), sulfate-reducing bacteria (SRB) alone (M), chemicals (Ca(OH)2, 1.5 g/kg) plus SRB (CM-L), chemicals (Ca(OH)2, 3.0 g/kg) plus SRB (CM-M), and chemicals (Ca(OH)2, 4.5 g/kg) plus SRB (CM-H), were conducted to investigate the removal effect of SO4 2-, Pb, Zn, and Mn from the REM soil. Then, a high-throughput sequencing technology was applied to explore the response of bacterial community diversity and functions with different remediation measures. The results indicated that CM-M treatment had a more efficient removal effect for SO4 2-, Pb, Zn, and Mn than the others, up to 94.6, 88.3, 98.7, and 91%, respectively. Soil bacterial abundance and diversity were significantly affected by treatments with the inoculation of SRB in comparison with CK. The relative abundance of Desulfobacterota with the ability to transform SO4 2- into S2- increased significantly in all treatments, except for CK. There was a strong correlation between environmental factors (pH, Eh, SO4 2-, Pb, and Zn) and bacterial community structure. Furthermore, functional prediction analysis revealed that the SRB inoculation treatments significantly increased the abundance of sulfate respiration, sulfite respiration, and nitrogen fixation, while decreasing the abundance of manganese oxidation, dark hydrogen oxidation, and denitrification. This provides good evidence for us to understand the difference in removal efficiency, bacterial community structure, and function by different remediation measures that help select a more efficient and sustainable method to remediate contaminants in the REM soil.
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Affiliation(s)
- Xiao Yan
- GRINM Resources and Environment Tech. Co., Ltd., Beijing, China
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Co., Ltd., Beijing, China
| | - Bowen Gao
- GRINM Resources and Environment Tech. Co., Ltd., Beijing, China
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Co., Ltd., Beijing, China
| | - Jianlei Wang
- GRINM Resources and Environment Tech. Co., Ltd., Beijing, China
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Co., Ltd., Beijing, China
| | - Xuezhe Zhu
- GRINM Resources and Environment Tech. Co., Ltd., Beijing, China
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Co., Ltd., Beijing, China
- School of Metallurgy, Northeastern University, Shenyang, China
- GRIMAT Engineering Institute Co., Ltd., Beijing, China
| | - Mingjiang Zhang
- GRINM Resources and Environment Tech. Co., Ltd., Beijing, China
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Co., Ltd., Beijing, China
- *Correspondence: Mingjiang Zhang,
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Sinharoy A, Lens PNL. Biological selenate and selenite reduction by waste activated sludge using hydrogen as electron donor. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 319:115745. [PMID: 35853309 DOI: 10.1016/j.jenvman.2022.115745] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/21/2022] [Accepted: 07/10/2022] [Indexed: 06/15/2023]
Abstract
Biological reduction of selenium oxyanions is widely used for selenium removal from wastewater. The process is, however, limited by the availability of a suitable, efficient and low cost electron donor. In this study, selenite and selenate reduction by waste activated sludge using hydrogen as the electron donor was investigated. Both selenite and selenate (80 mg/L) were completely removed using H2 within 8 days of incubation. In the presence of sulfate in the medium, the Se removal efficiency decreased to 77.8-95.4% (for selenite) and 88.2-99.4% (for selenate) at different temperatures and initial sulfate concentrations. Thermophilic conditions (50 °C) were better suited for both selenite and selenate reduction using H2 as electron donor with a 0.8-13.5% increase in overall Se removal. Similarly, sulfate reduction also increased from 69.1- 88% at 30 °C to 72-94.6% at 50 °C. Most of the H2 utilized was diverted towards Se and sulfate reduction with minimal production of byproducts such as methane (<0.32 mM) or volatile fatty acids (<0.92 mg/L). The elemental Se produced from selenite and selenate reduction ranged between 33.9 and 52.1 mg/L. The elemental selenium nanoparticles produced as a result of selenite and selenate reduction were characterized using transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX) and dynamic light scattering (DLS) spectroscopy. Furthermore, characterization of the biomass using Fourier-transform infrared spectroscopy (FTIR) and excitation emission matrix (EEM) spectra of the extracellular polymeric substances (EPS) produced by the waste activated sludge were performed to elucidate the mechanism of selenium oxyanion reduction to elemental selenium nanoparticles.
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Affiliation(s)
- Arindam Sinharoy
- National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland.
| | - Piet N L Lens
- National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland
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6
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Sinharoy A, Lens PNL. Selenite and tellurite reduction by Aspergillus niger fungal pellets using lignocellulosic hydrolysate. JOURNAL OF HAZARDOUS MATERIALS 2022; 437:129333. [PMID: 35728327 DOI: 10.1016/j.jhazmat.2022.129333] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/24/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
The performance of Aspergillus niger pellets to remove selenite and tellurite from wastewater using batch and continuous fungal pelleted bioreactors was investigated. The acid hydrolysate of brewer's spent grain (BSG) was utilized by A. niger as the electron donor for selenite and tellurite reduction. The dilution of BSG hydrolysate using mineral medium had a positive effect on the selenite and tellurite removal efficiency with a 1:3 ratio giving the best efficiency. However, selenite and tellurite inhibited fungal growth with a 40.9% and 27.3% decrease in the A. niger biomass yield in the presence of 50 mg/L selenite and tellurite, respectively. The maximum selenite and tellurite removal efficiency using 25% BSG hydrolysate in batch incubations amounted to 72.8% and 99.5% Two fungal pelleted bioreactors were operated in continuous mode using BSG hydrolysate as the substrate. Both the selenite and tellurite removal efficiencies during steady state operation were > 80% with tellurite showing a maximum removal efficiency of 98.5% at 10 mg/L influent concentration. Elemental Se nanospheres for selenite and both Te nanospheres and nanorods for tellurite were formed within the fungal pellets. This study demonstrates the suitability BSG hydrolysate as a low cost carbon source for removal of selenite and tellurite using fungal pellet bioreactors.
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Affiliation(s)
- Arindam Sinharoy
- National University of Ireland Galway, University Road, H91 TK33 Galway, Ireland.
| | - Piet N L Lens
- National University of Ireland Galway, University Road, H91 TK33 Galway, Ireland
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Barkatt A, Okutsu M. Obtaining elemental sulfur for Martian sulfur concrete. JOURNAL OF CHEMICAL RESEARCH 2022. [DOI: 10.1177/17475198221080729] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A potential candidate material for the construction of Mars habitats is concrete made from the Martian regolith and sulfur extracted from the regolith itself. Sulfur concrete, which has excellent mechanical properties, can be prepared at a low temperature (<150 °) and without water (unlike Portland-cement concrete). The surface of Mars has a much higher concentration of sulfur than those of the Earth, the Moon, or the asteroids. Sulfur on Mars, however, exists not as elemental sulfur—which is needed in concrete production—but as sulfates (usually hydrated) and sulfides. This paper surveys thermochemical and electrochemical methods that might be used to produce elemental sulfur from its compounds contained in the minerals on Mars. Possible methods include chemical or electrochemical oxidation or decomposition of sulfides, which include sulfides that exist naturally on Mars as well as sulfides that are produced via chemical or electrochemical reduction of sulfates. Some of the methods to obtain elemental sulfur—such as chemical or electrochemical oxidation or decomposition of metal sulfides or hydrogen sulfide—have already been demonstrated. The methods of producing elemental sulfur from sulfur-containing minerals on Mars will have the added benefit of generating byproducts (e.g. water, hydrogen, oxygen, and metals) that are useful for explorations of the Red Planet. In the future, chemical processes for the production of elemental sulfur may also have important industrial applications on Earth.
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Affiliation(s)
- Aaron Barkatt
- The Catholic University of America, Washington, DC, USA
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Mal J, Sinharoy A, Lens PNL. Simultaneous removal of lead and selenium through biomineralization as lead selenide by anaerobic granular sludge. JOURNAL OF HAZARDOUS MATERIALS 2021; 420:126663. [PMID: 34329094 DOI: 10.1016/j.jhazmat.2021.126663] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 07/05/2021] [Accepted: 07/14/2021] [Indexed: 06/13/2023]
Abstract
This study demonstrated the simultaneous removal of lead (Pb) and selenium (Se) as lead selenide biomineralization using anaerobic granular sludge. The microbial community of the granular sludge was first enriched for 140 days in the presence of Pb(II) only, selenate and selenite only, Pb(II)+selenate, and Pb(II)+selenite. In the absence of Se, removal of Pb(II) mainly occurred via biosorption and deposited on the biomass as lead oxide and lead carbonate. The Pb removal efficiency (94% of initial 50 mg L-1) was reduced to 90% and 86% in the presence of selenate and selenite, respectively, due to biosorption. Addition of Pb(II) didn't exert any toxic effect on the Se-reducing microbial community, on the contrary: Pb(II) addition improved the Se removal efficiency for selenate from 85% to 90%, but did not affect selenite removal after 14 d of incubation. The bioreduction of the Se-oxyanions produced elemental Se (Se(0)) and selenide, which later interacted with Pb(II) to produce lead selenide (PbSe). Adsorption of Pb(II) onto the Se(0) nanoparticles and precipitation as the Se(0)-Pb complex might also have contributed to the simultaneous removal of Pb and Se. XPS and XRD analysis further confirmed the immobilization of Pb as PbSe, PbO and PbCO3 in the biomass.
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Affiliation(s)
- Joyabrata Mal
- National University of Ireland Galway, University Road, H91 TK33 Galway, Ireland; Department of Biotechnology, MNNIT Allahabad, Prayagraj 211004, India.
| | - Arindam Sinharoy
- National University of Ireland Galway, University Road, H91 TK33 Galway, Ireland
| | - Piet N L Lens
- National University of Ireland Galway, University Road, H91 TK33 Galway, Ireland
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Yang C, Lu G, Xie Y, Guo L, Chen M, Ge L, Dang Z. Sulfate migration and transformation characteristics in paddy soil profile affected by acid mine drainage. ENVIRONMENTAL RESEARCH 2021; 200:111732. [PMID: 34324849 DOI: 10.1016/j.envres.2021.111732] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 06/09/2021] [Accepted: 07/16/2021] [Indexed: 06/13/2023]
Abstract
SO42-, a major component of acid mine drainage (AMD), plays an important role in study environment of AMD. We investigated the distribution and adsorption-desorption mechanisms of SO42- and the variation of stable isotope of sulfur (δ34S) values in the soil profile polluted by AMD. Results showed that the species and 34S values of SO42- differed significantly among different soil depths. In the surface soil (0-20 cm), native water-soluble SO42- (WSS) in the range ~85 % total SO42- was the dominant species. There was a peak of adsorption, which correlated significantly with amorphous oxide Fe, indicating that iron oxides and pH was fundamentally proportional to SO42- forms. The high concentrations of Cu2+ and Pb2+ also played important roles in form of SO42- in soil profile. Desorption kinetics of explained three SO42--bound forms. The trend mean δ34S values of WSS and AS in soil vertical profile was very similar with increasing from surface to subsurface, and have lower δ34S values than those of total sulfur, indicating that mineralization of organic sulfur should produce SO42- that was more depleted in δ34S. SO42- desorbed and trend δ34S values could provide reasonable explanation for the migration of SO42-. In the AMD irrigation scope, the higher SO42- concentration was reserved by immobilized as organic sulfur, and then main approach of SO42- migration was desorption and organic sulfur mineralize in now stage.
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Affiliation(s)
- Chengfang Yang
- School of Environmental Engineering, Xuzhou University of Technology, Xuzhou, 221000, PR China
| | - Guining Lu
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China; Guangdong Provincial Engineering and Technology Research Center for Environmental Risk Prevention and Emergency Disposal, South China University of Technology, Guangzhou, 510006, PR China.
| | - Yingying Xie
- School of Chemistry and Environmental Engineering, Hanshan Normal University, Chaozhou, 521041, China
| | - Li Guo
- School of Environmental Engineering, Xuzhou University of Technology, Xuzhou, 221000, PR China
| | - Meiqin Chen
- Guangdong Provincial Key Laboratory of Petrochemicial Pollution Processes and Control, School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming, 525000, China
| | - Lingya Ge
- School of Environmental Engineering, Xuzhou University of Technology, Xuzhou, 221000, PR China
| | - Zhi Dang
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China; Guangdong Provincial Engineering and Technology Research Center for Environmental Risk Prevention and Emergency Disposal, South China University of Technology, Guangzhou, 510006, PR China
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Negi BB, Sinharoy A, Pakshirajan K. Selenite removal from wastewater using fungal pelleted airlift bioreactor. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:992-1003. [PMID: 31820239 DOI: 10.1007/s11356-019-06946-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 11/01/2019] [Indexed: 06/10/2023]
Abstract
This study investigated the removal of selenite from wastewater using the fungus Asergillus niger KP isolated from a laboratory scale inverse fluidized bed bioreactor. The effect of different carbon sources and initial selenite concentration on fungal growth, pellet formation and selenite removal was first examined in a batch system. The fungal strain showed a maximum selenite removal efficiency of 86% in the batch system. Analysis of the fungal pellets by field-emission scanning electron microscopy, field-emission transmission electron microscopy and energy-dispersive X-ray spectroscopy revealed the formation of spherical-shaped elemental selenium nanoparticles of size 65-100 nm. An increase in the initial selenite concentration in the media resulted in compact pellets with smooth hyphae structure, whereas the fungal pellets contained hair like hyphae structure when grown in the absence of selenite. Besides, a high initial selenite concentration reduced biomass growth and selenite removal from solution. Using an airlift reactor with fungal pellets, operated under continuous mode, a maximum selenite removal of 94.3% was achieved at 10 mg L-1 of influent selenite concentration and 72 h HRT (hydraulic retention time). Overall, this study demonstrated very good potential of the fungal-pelleted airlift bioreactor system for removal of selenite from wastewater. Graphical abstract.
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Affiliation(s)
- Bharat Bhushan Negi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Arindam Sinharoy
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Kannan Pakshirajan
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India.
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Liang DH, Hu Y. Simultaneous sulfamethoxazole biodegradation and nitrogen conversion by Achromobacter sp. JL9 using with different carbon and nitrogen sources. BIORESOURCE TECHNOLOGY 2019; 293:122061. [PMID: 31520862 DOI: 10.1016/j.biortech.2019.122061] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/22/2019] [Accepted: 08/23/2019] [Indexed: 06/10/2023]
Abstract
This study investigated sulfamethoxazole (SMX) biodegradation and nitrogen conversion by Achromobacter sp. JL9 using different carbon and nitrogen sources. Results showed that SMX and sodium acetate could be co-metabolized as carbon sources for bacterial growth and nitrogen conversion with highest removal efficiencies of 82.44%, 80.2%, and 79.45% for NH4+-N, NO3--N, and SMX, respectively. Strain JL9 was able to utilize SMX as its sole nitrogen source for growth, with an SMX biodegradation efficiency of 63.10%. In addition, carbon and nitrogen balance analyses showed that approximately 35.31% and 63.22% of carbon and nitrogen, respectively, were lost as gaseous products. Finally, medium toxicity gradually decreased during the carbon and nitrogen dependence experiments. This study, thus, suggests that carbon and nitrogen play vital roles in SMX biodegradation and biotoxicity reduction.
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Affiliation(s)
- Dong Hui Liang
- School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China
| | - Yongyou Hu
- School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China.
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12
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Sinharoy A, Baskaran D, Pakshirajan K. A novel carbon monoxide fed moving bed biofilm reactor for sulfate rich wastewater treatment. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 249:109402. [PMID: 31450202 DOI: 10.1016/j.jenvman.2019.109402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 08/06/2019] [Accepted: 08/12/2019] [Indexed: 06/10/2023]
Abstract
In this study, a moving bed biofilm reactor was used for biodesulfuruization using CO as the sole carbon substrate. The effect of hydraulic retention time (HRT), sulfate loading rate and CO loading rate on sulfate and CO removal was examined. At 72, 48 and 24 h HRT, the sulfate removal was 93.5%, 91.9% and 80.1%, respectively. An increase in the sulfate loading reduced the sulfate reduction efficiency, which, however, was improved by increasing the CO flow rate into the MBBR. Best results in terms of sulfate reduction (>80%) were obtained for low inlet sulfate and high CO loading conditions. The CO utilization was very high at 85% throughout the study, except during the last phase of the continuous bioreactor operation it was around 70%. An artificial neural network based model was successfully developed and optimized to accurately predict the bioreactor performance in terms of both sulfate reduction and CO utilization. Overall, this study showed an excellent potential of the moving bed biofilm bioreactor for efficient sulfate reduction even under high loading conditions.
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Affiliation(s)
- Arindam Sinharoy
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
| | - Divya Baskaran
- Department of Chemical Engineering, Annamalai University, Annamalai Nagar, 608002, Tamil Nadu, India
| | - Kannan Pakshirajan
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
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