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Sava C, Iluţiu-Varvara DA, Mare R, Roman MD, Rada S, Pică EM, Jäntschi L. Physico-chemical characterization and possible uses of sludge processed from an urban sewage treatment plant. Heliyon 2024; 10:e29576. [PMID: 38699733 PMCID: PMC11063455 DOI: 10.1016/j.heliyon.2024.e29576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 04/09/2024] [Accepted: 04/10/2024] [Indexed: 05/05/2024] Open
Abstract
Nowadays, the challenge is to transform dehydrated sewage sludge resulting from wastewater treatment plants from waste into resource. Following this objective, the sludge was further dried and submitted to X-ray diffraction (XRD) and FTIR analysis. The sludge was first dried in ventilated and unventilated spaces at 50 ∘C and 100 ∘C, for 60 and 100 minutes (min) in each case. The final mass and evaporation degree of the sludge depends on the initial mass, ventilation type, drying time, and temperature. The ventilated drying space is preferred for temperature control, homogeneity, and higher evaporation degree. The influence of the drying process on the structure and behavior of the sewage sludge was emphasized through X-ray diffraction (XRD) and FTIR analysis. The XRD shows good structural properties of the sludge samples given by the reduction of the particle size through evaporation. According to FTIR, evaporation influences the depolymerization of the silicate network. The hydroxyl units and metallic ion modifiers can improve the sludge structure, but its intensity decreases through evaporation. With high content of solid substance, and good relation between the composition of the sludge and its structure and behavior, the dried sewage sludge can be used in: (i) agriculture, (ii) construction, (iii) the energy sector.
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Affiliation(s)
- Cornel Sava
- Department of Physics and Chemistry, Technical University of Cluj-Napoca, 28 Memorandumului st., Cluj-Napoca, 400114, Cluj, Romania
| | - Dana-Adriana Iluţiu-Varvara
- Faculty of Building Services Engineering, Technical University of Cluj-Napoca, 28 Memorandumului st., Cluj-Napoca, 400114, Cluj, Romania
| | - Roxana Mare
- Faculty of Building Services Engineering, Technical University of Cluj-Napoca, 28 Memorandumului st., Cluj-Napoca, 400114, Cluj, Romania
| | - Marius Daniel Roman
- Faculty of Building Services Engineering, Technical University of Cluj-Napoca, 28 Memorandumului st., Cluj-Napoca, 400114, Cluj, Romania
| | - Simona Rada
- Department of Physics and Chemistry, Technical University of Cluj-Napoca, 28 Memorandumului st., Cluj-Napoca, 400114, Cluj, Romania
| | - Elena Maria Pică
- Department of Physics and Chemistry, Technical University of Cluj-Napoca, 28 Memorandumului st., Cluj-Napoca, 400114, Cluj, Romania
| | - Lorentz Jäntschi
- Department of Physics and Chemistry, Technical University of Cluj-Napoca, 28 Memorandumului st., Cluj-Napoca, 400114, Cluj, Romania
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Lakavathu S, Reddy VK, Singh N, Kamble P, Jadhav J, Choudhury AR, Palani SG. Feasibility study of faecal sludge treatment by Geotube and jute tube-based technologies. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:124382-124400. [PMID: 37950778 DOI: 10.1007/s11356-023-30746-8] [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: 02/23/2023] [Accepted: 10/25/2023] [Indexed: 11/13/2023]
Abstract
The decentralized standalone treatment of faecal sludge is a generally cumbersome, energy-intensive, and expensive process. Particle size enlargement, dewatering, and disinfection are the crucial unit operations that contribute to the major portion of the operational expenditure. Therefore, the present study took up the task to investigate and yield a natural alternative to each of the above-delineated unit operations. Crushed seed powders of Moringa, Guilandina bonduc, Nirmali, tamarind, soap nut, nutmeg, jackfruit, and custard apple were experimented as natural coagulants, while a double-stitched cow dung-lined jute tube was utilized as the media for solid-liquid separation. Finally, the powder of Neem and custard apple seed and leaf were considered herbal disinfectants for the separated liquid and solid fractions, respectively. The findings of the physicochemical and biological analyses of the above unit operations were compared with a conventional polymer-based Geotube-driven treatment scheme. The natural alternatives registered some promising outcomes. However, the combined treatment efficiency of 79.32% (mean value of TS, TSS, TDS, COD, and BOD percentage removal) for pollutant removal and disinfection could not exceed the value of 97.98% offered by the conventional method. Further, the financial comparison for processing a 10 KL batch of FS indicates that the conventional scheme is considerably cheaper (USD 7.95) than the herbal alternate (USD 22.1). Therefore, though the present findings depict promising alternatives for sustainable and eco-friendly faecal sludge treatment, the authors advocate conducting further research to address the existing challenges to facilitate their seamless implementation on a field-scale level.
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Affiliation(s)
- Sakkubai Lakavathu
- Centre for Environment, Institute of Science and Technology, Jawaharlal Nehru Technological University Hyderabad, Hyderabad, Telangana, 500085, India
| | - Vamshi Krishna Reddy
- Centre for Environment, Institute of Science and Technology, Jawaharlal Nehru Technological University Hyderabad, Hyderabad, Telangana, 500085, India
| | - Neha Singh
- Chadwick's FSM Laboratory, Banka BioLoo Limited, Shed no-37, Industrial Development Area, Mallapur, Secunderabad, 500076, India
| | - Pramod Kamble
- Department of Environmental Science, School of Earth Sciences, Central University of Rajasthan, Ajmer, Rajasthan, 305817, India
| | - Jayesh Jadhav
- Department of Environmental Sciences, Savitribai Phule Pune University, Pune, Maharashtra, 411007, India
| | - Atun Roy Choudhury
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, Hyderabad Campus, Secunderabad, Telangana, 500078, India
| | - Sankar Ganesh Palani
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, Hyderabad Campus, Secunderabad, Telangana, 500078, India.
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Chatema T, Mercer E, Septien S, Pocock J, Buckley C. Effect of ageing on the physicochemical properties of human faeces in the context of onsite sanitation. ENVIRONMENTAL CHALLENGES (AMSTERDAM, NETHERLANDS) 2023; 11:None. [PMID: 37214236 PMCID: PMC10199408 DOI: 10.1016/j.envc.2023.100717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 02/08/2023] [Accepted: 04/16/2023] [Indexed: 05/24/2023]
Abstract
Sanitation systems involving onsite storage of faecal matter cause excreta to undergo transformation and primary treatment in-situ. However, little is known about the transformation pathway followed by fresh faeces while contained in situ. The current paper investigated this transformation under ambient conditions during a 16-week in-situ-storage period. Moisture content, drying kinetics, rheological, physicochemical, and thermal properties were analysed to determine the effects of ageing. The faeces experienced dehydration, mainly affecting moisture-dependent characteristics. Moisture content decreased from 79%wt to 26%wt, and water activity of 0.67, which corresponds mainly to the removal of interstitial bound water, reducing mass by 72%. The decreasing moisture content expectantly reduced drying ability, flowability and thermal properties (heat capacity and thermal conductivity). During this period, negligible biodegradation was recorded (volatile solids reduced by 3%), resulting in consistent chemical oxygen demand, particle size, carbon content and calorific values. Ammonium and nitrates decreased, but total nitrogen remained unchanged. Therefore, ageing affects nitrogen chemical forms and not nutrient composition. The findings demonstrate the benefits of source separation and in particular ventilated storage as a passive way to pre-treat and recover resources from faecal material.
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Affiliation(s)
- T.M. Chatema
- WASH R&D Centre (formerly the Pollution Research Group), University of KwaZulu-Natal, Howard College, 4041, Durban, South Africa
| | - E. Mercer
- WASH R&D Centre (formerly the Pollution Research Group), University of KwaZulu-Natal, Howard College, 4041, Durban, South Africa
| | - S. Septien
- WASH R&D Centre (formerly the Pollution Research Group), University of KwaZulu-Natal, Howard College, 4041, Durban, South Africa
| | - J. Pocock
- WASH R&D Centre (formerly the Pollution Research Group), University of KwaZulu-Natal, Howard College, 4041, Durban, South Africa
- Chemical Engineering, University of KwaZulu-Natal, Howard College, 4041, Durban, South Africa
| | - C.A. Buckley
- WASH R&D Centre (formerly the Pollution Research Group), University of KwaZulu-Natal, Howard College, 4041, Durban, South Africa
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Kumar N, Gupta SK. Exploring drying kinetics and fate of nutrients in thermal digestion of solid organic waste. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 837:155804. [PMID: 35561929 DOI: 10.1016/j.scitotenv.2022.155804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
Thermal digestion has emerged as a novel technique for the rapid treatment of solid organic waste (SOW). Dehydration mechanism and fate of nutrients during the thermal digestion of the SOW were explored. A series of experiments were carried out in a specially designed laboratory-scale dehydrator to determine its drying kinetics. The statistical analysis revealed that the diffusion model predicted the dehydration profile most accurately than other models. The effective moisture diffusivity coefficient depended on the temperature and varied from 2.81 × 10-08 m2/s to 8.68 × 10-08 m2/s at the tested temperature range. The activation energy required for complete dehydration was found to be 26.56 kJ/mol. The artificial neural network (ANN) model was found highly efficient (R2 - 0.983) in predicting the total drying time required for attaining equilibrium moisture content. The total N decreased from 2.2% to 1.81% due to evaporation of ammonical nitrogen, while the availability of P and K was increased from 0.38% to 0.43% and 1.47% to 1.75%, respectively when the temperature was increased from 110 °C to 170 °C. The thermal dehydration technique was found effective in digesting the organics and improving the bioavailability of the nutrients, which favours for its re-utilization in agriculture.
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Affiliation(s)
- Nitin Kumar
- Department of Environmental Science & Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad 826004, India
| | - Sunil Kumar Gupta
- Department of Environmental Science & Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad 826004, India.
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Disaster Risk Management, Ventilated Improved Pit Latrines, and Sanitation Challenges in South Africa. SUSTAINABILITY 2022. [DOI: 10.3390/su14116934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
The current paper provides a review and meta-analysis of the practical implications of disaster risk management related to the ventilated improved latrines in South Africa. This technology is evaluated through its legacy and novel challenges of disaster risk reduction. In the current article, the methodology adopted was a literature review and meta-analyses. The results indicate that the in-situ treatment and breakdown of faecal sludge in the ventilated improved pit latrines is not always taking place and that anaerobic digestion might not always be feasible. New strategies are proposed to manage the sanitation-related risks in South Africa by specifying more exact dimensions for the newly built ventilated improved pit latrines by suggesting the use of novel sanitation additives such as fly ash to enhance on-site and in situ treatment, as well as ex situ treatment of the pit latrine faecal sludge. Regular maintenance can lead to prevention of the dysfunctional character of the ventilated improved pit latrines as a functional sanitation technology and a user-friendly hygiene barrier to the spread of sanitation/WASH-related epidemics or infectious diseases. The implementation of the novel strategies should be enhanced by the application of the (Environmental) Technology Assessment in sanitation service delivery in South Africa.
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Kynkäänniemi E, Lahtinen MH, Jian C, Salonen A, Hatanpää T, Mikkonen KS, Pajari AM. Gut microbiota can utilize prebiotic birch glucuronoxylan in production of short-chain fatty acids in rats. Food Funct 2022; 13:3746-3759. [DOI: 10.1039/d1fo03922a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Birch-derived polyphenol and fiber (glucuronoxylan, GX)-rich extract and highly purified GX-rich extract support the growth of beneficial gut bacteria, suppress the harmful ones, and increase the production of total short-chain fatty acids (SCFA).
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Affiliation(s)
- Emma Kynkäänniemi
- Department of Food and Nutrition, University of Helsinki, 00014 Helsinki, Finland
| | - Maarit H. Lahtinen
- Department of Food and Nutrition, University of Helsinki, 00014 Helsinki, Finland
| | - Ching Jian
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
| | - Anne Salonen
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
| | - Timo Hatanpää
- Department of Chemistry, University of Helsinki, 00014 Helsinki, Finland
| | - Kirsi S. Mikkonen
- Department of Food and Nutrition, University of Helsinki, 00014 Helsinki, Finland
- Helsinki Institute of Sustainability Science (HELSUS), University of Helsinki, P.O. Box 65, 00014, Finland
| | - Anne-Maria Pajari
- Department of Food and Nutrition, University of Helsinki, 00014 Helsinki, Finland
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Somorin T, Getahun S, Septien S, Mabbet I, Kolios A, Buckley C. Isothermal drying characteristics and kinetics of human faecal sludges. Gates Open Res 2021; 4:67. [PMID: 34056550 PMCID: PMC8135097 DOI: 10.12688/gatesopenres.13137.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2021] [Indexed: 11/20/2022] Open
Abstract
Background: Drying is an important step for the thermochemical conversion of solid fuels, but it is energy-intensive for treating highly moist materials. Methods: To inform the thermal treatment of faecal sludge (FS), this study investigated the drying characteristics and kinetics of various faecal wastes using thermogravimetric analysis and isothermal heating conditions. Results: The findings show that FS from the anaerobic baffled reactor (ABR) and ventilated improved pit latrines (VIP) exhibit similar drying characteristics, with maximum drying rates at 0.04 mg/min during a constant rate period that is followed by a distinct falling rate period. On the contrary, fresh human faeces (HF) and FS from urine diversion dry toilets (UDDT) exhibited a falling rate period regime with no prior or intermittent constant rate periods. The absence of a constant rate period in these samples suggested limited amounts of unbound water that can be removed by dewatering and vice versa for VIP and ABR faecal sludges. The activation energies and effective moisture diffusivity for the sludges varied from 28 to 36 kJ/mol and 1.7·10
-7 to 10·10
-7 m
2/s at 55°C and sludge thickness of 3mm. The Page model was consistent in modelling the different sludges across all temperatures. Conclusions: These results presented in this study can inform the design and development of innovative drying methods for FS treatment.
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Affiliation(s)
- Tosin Somorin
- Chemical and Process Engineering, University of Strathclyde, Glasgow, G1 1XQ, UK
| | - Samuel Getahun
- Pollution Research Group, University of Kwazulu-Natal, Durban, 4041, South Africa
| | - Santiago Septien
- Pollution Research Group, University of Kwazulu-Natal, Durban, 4041, South Africa
| | - Ian Mabbet
- Department of Chemistry, Swansea University, Swansea, UK
| | - Athanasios Kolios
- Naval Architecture, Ocean & Marine Engineering, University of Strathclyde, Glasgow, G1 1XQ, UK
| | - Chris Buckley
- Pollution Research Group, University of Kwazulu-Natal, Durban, 4041, South Africa
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Krueger BC, Fowler GD, Templeton MR. Critical analytical parameters for faecal sludge characterisation informing the application of thermal treatment processes. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 280:111658. [PMID: 33246749 DOI: 10.1016/j.jenvman.2020.111658] [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: 06/26/2020] [Revised: 10/22/2020] [Accepted: 11/06/2020] [Indexed: 06/12/2023]
Abstract
Thermal processes for the treatment of faecal sludge such as pyrolysis or combustion offer complete destruction of pathogens, whilst allowing for energy and nutrient recovery. The development of such processes is currently constrained by a lack of knowledge on thermally relevant faecal sludge characteristics. This study investigated thirty faecal sludge samples from three sanitation technologies (ventilated improved pit latrines (VIP), urine diverting dry toilets (UD), septic tanks (ST)) and compared these by non-parametric statistical analysis. A focus was placed on parameters necessary for thermal process development and recoverable nutrient concentrations. The relevant characteristics ranged widely within technology groups. Calorific values and ash concentrations of 2.1-25.7 MJ/kg and 9.5-88.4% were observed for STs, of 9.2-13.9 MJ/kg and 40.9-61.5% for VIPs and of 3.9-18.1 MJ/kg and 18.8-81.3% for UDs. These two parameters show a strong linear inverse correlation and determine the minimum dewatering requirements from which a net energy recovery may be possible. Results suggest that more than 90% of samples can meet these requirements following commonly used dewatering technologies. A comparison across technologies provided strong evidence that the faecal sludge source significantly influences sludge composition, emphasized by higher median ratios of fixed carbon to volatile matter in VIPs (0.23) and UDs (0.23) compared to STs (0.15). The sanitation technology also influenced recoverable nutrient concentrations, with phosphorus and potassium concentrations generally ranging between 5.8-49.2 g/kg and 1.4-26.1 g/kg respectively. Compared to STs, median concentrations of phosphorus and potassium in VIPs were 3.4 and 3.8 times higher respectively, and 3.0 and 8.8 times higher in UDs. The findings highlight the importance of considering the faecal sludge source in the development of thermal treatment processes. This study provides critical knowledge to further develop such processes through modelling, experimental and scaled approaches.
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Affiliation(s)
- Benedict C Krueger
- Department of Civil and Environmental Engineering, Imperial College London, SW7 2AZ, UK.
| | - Geoffrey D Fowler
- Department of Civil and Environmental Engineering, Imperial College London, SW7 2AZ, UK
| | - Michael R Templeton
- Department of Civil and Environmental Engineering, Imperial College London, SW7 2AZ, UK
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Li Y, Cheng S, Li Z, Song H, Guo M, Li Z, Mang HP, Xu Y, Chen C, Basandorj D, Zhang L, Li T. Using system dynamics to assess the complexity of rural toilet retrofitting: Case study in eastern China. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 280:111655. [PMID: 33309109 PMCID: PMC7816123 DOI: 10.1016/j.jenvman.2020.111655] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/26/2020] [Accepted: 11/06/2020] [Indexed: 06/12/2023]
Abstract
Rural toilet retrofitting (RTR) is a complex, dynamic system that is affected by many factors and the positive/negative feedback relationships between subsystems and variables. Traditional technologies and management methods face challenges in fundamentally describing and solving problems in RTR. To bridge this gap, this study utilizes system dynamics and causal loop diagrams to explain such problems based on data collected from the stakeholders of the RTR in Jiaozhou from 2018 to 2019. Specifically, this study examines the RTR system from the perspectives of household users, wastewater treatment plants, local governments, grassroots promoters, operation and maintenance personnel, toilet supplier and construction teams, and fecal sludge end users. The factors and processes involved in RTR are identified, and the feedback and relationships among its major stakeholders are established. Results show that the motivation of farmers to engage in RTR is a key variable that affects their final decisions regarding retrofitting and maintaining toilet functions. Meanwhile, the important variables related to the feedback and relationships among the major stakeholders of RTR are mostly focused on policies, subsidies, technology, satisfaction, and cooperation. A scientific analysis method and the updated RTR plan for toilet revolution are then formulated to promote the implementation of RTR in developing countries.
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Affiliation(s)
- Yong Li
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing, 100083, PR China.
| | - Shikun Cheng
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing, 100083, PR China.
| | - Zhengyi Li
- School of Civil and Resource Engineering, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing, 100083, PR China.
| | - Hongqing Song
- School of Civil and Resource Engineering, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing, 100083, PR China.
| | - Miao Guo
- Department of Engineering, Faculty of Natural & Mathematical Sciences, King's College London. Strand Building S2.22, London, WC2R 2LS, United Kingdom.
| | - Zifu Li
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing, 100083, PR China.
| | - Heinz-Peter Mang
- German Toilet Organization, Paulsenstr. 23/12163 Berlin, Germany.
| | - Yuning Xu
- Jiaozhou Committee for Patriotic Sanitation Campaign, Beijing Road No.61, Jiaozhou, Qingdao, 266300, PR China.
| | - Cong Chen
- School of Economics and Management, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing, 100083, PR China.
| | - Davaa Basandorj
- Water Research Center, Mongolian University of Science and Technology, Baga toiruu, Khoroo No.8 Sukhbaatar District, Ulaanbaatar, 14191, Mongolia.
| | - Lingling Zhang
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing, 100083, PR China.
| | - Tianxin Li
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing, 100083, PR China.
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