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Wang Z, Feng W, Tang S, Zhao J, Zheng G, Zhou L. Enhancing sludge dewaterability in sequential bioleaching: Degradation of dissolved organic matter (DOM) by filamentous fungus Mucor sp. ZG-3 and the influence of energy source. PLoS One 2024; 19:e0302311. [PMID: 38814929 PMCID: PMC11139263 DOI: 10.1371/journal.pone.0302311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 04/01/2024] [Indexed: 06/01/2024] Open
Abstract
This study aimed to enhance sludge dewatering through sequential bioleaching, employing the filamentous fungus Mucor sp. ZG-3 and the iron-oxidizing bacterium Acidithiobacillus ferrooxidans LX5. The mechanism by which Mucor sp. ZG-3 alleviates sludge dissolved organic matter (DOM) inhibition of A. ferrooxidans LX5 was investigated, and the optimal addition of energy source for enhanced sludge dewaterability during sequential bioleaching was determined. Sludge dissolved organic carbon (DOC) decreased to 272 mg/L with a 65.2% reduction by Mucor sp. ZG-3 in 3 days, and the degraded fraction of sludge DOM was mainly low-molecular-weight DOM (L-DOM) which inhibited the oxidization of Fe2+ by A. ferrooxidans LX5. By degrading significant inhibitory low-molecular-weight organic acids, Mucor sp. ZG-3 alleviated DOM inhibition of A. ferrooxidans LX5. In the sequential bioleaching process, the optimal concentration of FeSO4·7H2O for A. ferrooxidans LX5 was 4 g/L, resulting in the minimum specific resistance to filtration (SRF) of 2.60×1011 m/kg, 40.0% lower than that in the conventional bioleaching process with 10 g/L energy source. Moreover, the sequential bioleaching process increased the sludge zeta potential (from -31.8 to -9.47 mV) and median particle size (d50) of the sludge particle (from 17.90 to 27.44 μm), contributing to enhanced sludge dewaterability. Inoculation of Mucor sp. ZG-3 during the bioleaching process reduced the demand for energy sources by A. ferrooxidans LX5 while improving sludge dewaterability performance.
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Affiliation(s)
- Zhenyu Wang
- College of Ecology, Lishui University, Lishui, Zhejiang, China
| | - Wen Feng
- Department of Soil Pollution Prevention and Control, Zhejiang Huanlong Environmental Protection Co., LTD, Hangzhou, Zhejiang, China
| | - Shigang Tang
- College of Ecology, Lishui University, Lishui, Zhejiang, China
| | - Jing Zhao
- College of Materials Science and Engineering, Henan Institute of Technology, Xinxiang, Henan, China
| | - Guanyu Zheng
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Lixiang Zhou
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
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2
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Sarkodie EK, Jiang L, Li K, Yang J, Guo Z, Shi J, Deng Y, Liu H, Jiang H, Liang Y, Yin H, Liu X. A review on the bioleaching of toxic metal(loid)s from contaminated soil: Insight into the mechanism of action and the role of influencing factors. Front Microbiol 2022; 13:1049277. [PMID: 36569074 PMCID: PMC9767989 DOI: 10.3389/fmicb.2022.1049277] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/18/2022] [Indexed: 12/12/2022] Open
Abstract
The anthropogenic activities in agriculture, industrialization, mining, and metallurgy combined with the natural weathering of rocks, have led to severe contamination of soils by toxic metal(loid)s. In an attempt to remediate these polluted sites, a plethora of conventional approaches such as Solidification/Stabilization (S/S), soil washing, electrokinetic remediation, and chemical oxidation/reduction have been used for the immobilization and removal of toxic metal(loid)s in the soil. However, these conventional methods are associated with certain limitations. These limitations include high operational costs, high energy demands, post-waste disposal difficulties, and secondary pollution. Bioleaching has proven to be a promising alternative to these conventional approaches in removing toxic metal(loid)s from contaminated soil as it is cost-effective, environmentally friendly, and esthetically pleasing. The bioleaching process is influenced by factors including pH, temperature, oxygen, and carbon dioxide supply, as well as nutrients in the medium. It is crucial to monitor these parameters before and throughout the reaction since a change in any, for instance, pH during the reaction, can alter the microbial activity and, therefore, the rate of metal leaching. However, research on these influencing factors and recent innovations has brought significant progress in bioleaching over the years. This critical review, therefore, presents the current approaches to bioleaching and the mechanisms involved in removing toxic metal(loid)s from contaminated soil. We further examined and discussed the fundamental principles of various influencing factors that necessitate optimization in the bioleaching process. Additionally, the future perspectives on adding omics for bioleaching as an emerging technology are discussed.
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Affiliation(s)
- Emmanuel Konadu Sarkodie
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Luhua Jiang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Kewei Li
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Jiejie Yang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Ziwen Guo
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Jiaxin Shi
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Yan Deng
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Hongwei Liu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Huidan Jiang
- Hunan Agricultural Biotechnology Research Institute, Hunan Academy of Agricultural Sciences, Changsha, China
| | - Yili Liang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Huaqun Yin
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Xueduan Liu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
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3
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Huang JJ, Chen XF, Tsui CKM, Pang CJ, Hu ZD, Shi Y, Wang WP, Cui LY, Xiao YL, Gong J, Fan X, Li YX, Zhang G, Xiao M, Xu YC. Persistence of an epidemic cluster of Rhodotorula mucilaginosa in multiple geographic regions in China and the emergence of a 5-flucytosine resistant clone. Emerg Microbes Infect 2022; 11:1079-1089. [PMID: 35343400 PMCID: PMC9009924 DOI: 10.1080/22221751.2022.2059402] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Rhodotorula mucilaginosa, an environmental yeast widely used in industry and agriculture, is also an opportunistic pathogen resistant to multi-antifungals. During the national surveillance in China, R. mucilaginosa has been documented from various hospitals and regions. At present, the molecular epidemiology of invasive infections caused by R. mucilaginosa and their resistance profiles to antifungals were unknown. Here we collected 49 strains from four hospitals located in different geographic regions from 2009 to 2019 in China, determined their genotypes using different molecular markers and quantified susceptibilities to various antifungals. Sequencing of ITS and D1/D2 regions in rDNA indicated that 73.5% (36/49) of clinical strains belong to same sequence type (rDNA type 2). Microsatellite (MT) genotyping with 15 (recently developed) tandem repeat loci identified 5 epidemic MT types, which accounted for 44.9% (22/49) of clinical strains, as well as 27 sporadic MT types. Microsatellite data indicated that the presence of an epidemic cluster including 35 strains (71.4%) repeatedly isolated in four hospitals for eight years. Single nucleotide variants (SNVs) from the whole genome sequence data also supported the clustering of these epidemic strains due to low pairwise distance. In addition, phylogenetic analysis of SNVs from these clinical strains, together with environmental and animal strains showed that the closely related epidemic cluster strains may be opportunistic, zoonotic pathogens. Also, molecular data indicated a possible clonal transmission of pan echinocandins-azoles-5-flucytosine resistant R. mucilaginosa strains in hospital H01. Our study demonstrated that R. mucilaginosa is a multi-drug resistant pathogen with the ability to cause nosocomial infection.
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Affiliation(s)
- Jing-Jing Huang
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.,Graduate School, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, People's Republic of China
| | - Xin-Fei Chen
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.,Graduate School, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, People's Republic of China
| | - Clement K M Tsui
- Department of Pathology, Sidra Medicine, Education City, Al Rayyan Municipality, Qatar.,Department of Pathology and Laboratory Medicine, Weill Cornell Medicine-Qatar, Doha, Qatar.,Division of Infectious Diseases, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Chong-Jie Pang
- Department of Infection Diseases, Tianjin Medical University General Hospital, Tianjin, People's Republic of China
| | - Zhi-Dong Hu
- Department of Clinical Laboratories, Tianjin Medical University General Hospital, Tianjin, People's Republic of China
| | - Yi Shi
- Department of Respiratory and Critical Care Medicine, Jinling Hospital, Medical School of Nanjing University, Nanjing, People's Republic of China
| | - Wei-Ping Wang
- Department of Clinical Laboratory, Jinling Hospital, Medical School of Nanjing University, Nanjing, People's Republic of China
| | - Lan-Ying Cui
- Department of Laboratory Diagnosis, the first Affiliated Hospital of Harbin Medical University, Harbin, People's Republic of China
| | - Yu-Ling Xiao
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Jie Gong
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
| | - Xin Fan
- Department of Infectious Diseases and Clinical Microbiology, Beijing Institute of Respiratory Medicine and Beijing Chao-Yang Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Ying-Xing Li
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, People's Republic of China.,Department of Medical Research Center, Peking Union Medical College Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, People's Republic of China
| | - Ge Zhang
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, People's Republic of China
| | - Meng Xiao
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, People's Republic of China
| | - Ying-Chun Xu
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, People's Republic of China
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4
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Yao J, Wang M, Wang L, Gou M, Zeng J, Tang YQ. Co-inoculation with beneficial microorganisms enhances tannery sludge bioleaching with Acidithiobacillus thiooxidans. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:48509-48521. [PMID: 35192165 DOI: 10.1007/s11356-022-19236-5] [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: 10/26/2021] [Accepted: 02/11/2022] [Indexed: 06/14/2023]
Abstract
Bioleaching of tannery sludge is an efficient and environmentally friendly way for chromium (Cr) removal, which supports the sustainable development of the leather industry. Acidithiobacillus thiooxidans has been reported effective in Cr bioleaching of tannery sludge. However, little is known about whether the presence of other benefiting species could further improve the Cr leaching efficiency of A. thiooxidans. Here, we studied the enhancing roles of four species namely Acidiphilium cryptum, Sulfobacillus acidophilus, Alicyclobacillus cycloheptanicus, and Rhodotorula mucilaginosa in chromium bioleaching of tannery sludge with A. thiooxidans by batch bioleaching experiments. We found that each of the four species facilitated the quick dominance of A. thiooxidans in the bioleaching process and significantly improved the bioleaching performance including bioleaching rate and efficiency. The bioleaching efficiency of Cr in the tannery sludge could reach 100% on the sixth day by co-inoculating A. thiooxidans and four auxiliary species. The achievements shed a light on the role of the community-level interactions on bioleaching and may also serve as guidance for managing bioleaching consortiums for better outcomes.
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Affiliation(s)
- Jian Yao
- College of Architecture and Environment, Sichuan University, No. 24, South Section 1, First Ring Road, Chengdu, 610065, Sichuan, China
| | - Miaoxiao Wang
- College of Architecture and Environment, Sichuan University, No. 24, South Section 1, First Ring Road, Chengdu, 610065, Sichuan, China
| | - Lu Wang
- State Key Laboratory of Enhanced Oil Recovery, Research Institute of Petroleum Exploration and Development, CNPC, Beijing, 100083, China
| | - Min Gou
- College of Architecture and Environment, Sichuan University, No. 24, South Section 1, First Ring Road, Chengdu, 610065, Sichuan, China
| | - Jing Zeng
- Institute of New Energy and Low-Carbon Technology, Sichuan University, No. 24, South Section 1, First Ring Road, Chengdu, 610065, Sichuan, China.
| | - Yue-Qin Tang
- College of Architecture and Environment, Sichuan University, No. 24, South Section 1, First Ring Road, Chengdu, 610065, Sichuan, China
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5
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Sodhi V, Bansal A, Jha MK. Effect of extracellular polymeric compositions on in-situ sludge minimization performance of upgraded activated sludge treatment for industrial wastewater. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 306:114516. [PMID: 35051823 DOI: 10.1016/j.jenvman.2022.114516] [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: 10/07/2021] [Revised: 01/07/2022] [Accepted: 01/13/2022] [Indexed: 06/14/2023]
Abstract
The sludge yield minimization from advanced biological treatment for industrial wastewater could be considered a poorly explored area, therefore, seeks serious attention of the scientific community. Up to best of the knowledge, the extracellular polymeric substances (EPS) profile underlying an upgraded activated sludge treatment (as MANODOX system) for real tannery wastewater has not been addressed in a desired manner. This study covers the elucidation of EPS degradation mechanism and floc morphology underlying MANODOX system for the treatment of real tannery influent. For this purpose, a modified heat extraction method was followed for the estimation of EPS fractions like protein (PN), polysaccharides (PS) and humic contents from the sludge. For the present investigation, the variation in floc characteristics including PN/PS ratio, sludge hydrophobicity, sludge volume index, and facultative microbiota at corresponding change in hydrodynamic sludge retention time (SRT) of 08-40 days was emphasized. The strict maintenance of adapted operational strategies including favoring range of SRT (24 days) for MANODOX implementation succeeded an outstanding in-situ sludge yield minimization lowered up to 0.39 gMLSS/gTCOD that attributed to three times lowered accumulation of PN and PS, comparably lower PN/PS ratio, higher salinity of the mixed liquid, weakened cell-to-cell attachment compared with a parallel run identical aerobic treatment. Here, the reason for improved hydrophobicity and corresponding decline in floc aggregation was attributed to change in sludge PN/PS ratio, carbon to nitrogen ratio of feed influent. The observations confirmed that the sludge yield minimization from MANODOX like systems could be effectively controlled by maintaining aforementioned operational tactics.
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Affiliation(s)
- Vijay Sodhi
- Department of Chemical Engineering, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar City, India; Climate Change Knowledge Center, Punjab State Council for Science & Technology, Chandigarh City, India.
| | - Ajay Bansal
- Department of Chemical Engineering, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar City, India.
| | - Mithilesh Kumar Jha
- Department of Chemical Engineering, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar City, India.
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6
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Lu Y, Wu R, Zhang J, Liu H, Dai Y. Effects of phase separation on dewaterability promotion and heavy metal removal of sewage sludge during bioleaching. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:13971-13982. [PMID: 34599453 DOI: 10.1007/s11356-021-16630-3] [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: 05/18/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
Bioleaching is of increasing interest because of its high efficiency in improving sludge dewaterability and removing heavy metals from sewage sludge. However, in traditional single-phase bioleaching, a high-efficiency level cannot be maintained continuously, wherein the microbial synergistic effect is disrupted at a low pH environment. Therefore, in this study, a series of multi-compartment-baffled flow trials were performed to assess the effects of phase separation on sludge bioleaching by comparing a two-phase trial with two single-phase trials. Energy substrate and part of the bioleached sludge were introduced separately into two compartments to form two phases, namely selection phase and bioleaching phase. The results show that phase separation apparently shortened the start-up duration of sludge bioleaching from 7 days in a single-phase bioleaching to 4 days in two-phase bioleaching. The dewaterability of bioleached sludge was also enhanced by phase separation with relative decreases of 25.0-33.3% for specific resistance to filtration and 14.2% for capillary suction time, which was attributed to lower pH values, zeta potential closer to zero, and less dissolved organic matter in bioleached sludge after two-phase bioleaching. Phase separation generally increased the removal ratios of heavy metals during sludge bioleaching by -0.79 to 2.60%, 11.06 to 15.04%, 4.45 to 11.03%, 17.98 to 23.46%, 7.20 to 9.28%, -9.22 to -2.46%, and -6.72 to -10.68% for As, Cd, Cr, Cu, Ni, Pb, and Zn, respectively. Phase separation also enriched the Acidithiobacillus spp. and reduced the inactivation of acid-tolerant fungi, which can be conducive to better synergistic effect, and therefore maintain long-term stable state in the bioleaching phase of the two-phase bioleaching process.
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Affiliation(s)
- Yulan Lu
- Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, 12 Jiangan Road, Guilin, 541004, China
| | - Rongjun Wu
- Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, 12 Jiangan Road, Guilin, 541004, China
| | - Jun Zhang
- Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, 12 Jiangan Road, Guilin, 541004, China.
| | - Hongtao Liu
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A Datun Road, Beijing, 100101, China
| | - Yu Dai
- Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, 12 Jiangan Road, Guilin, 541004, China
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7
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Cai G, Ebrahimi M, Zheng G, Kaksonen AH, Morris C, O'Hara IM, Zhang Z. Effect of ferrous iron loading on dewaterability, heavy metal removal and bacterial community of digested sludge by Acidithiobacillus ferrooxidans. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 295:113114. [PMID: 34171779 DOI: 10.1016/j.jenvman.2021.113114] [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: 03/25/2021] [Revised: 05/13/2021] [Accepted: 06/16/2021] [Indexed: 06/13/2023]
Abstract
Acidithiobacillus ferrooxidans ILS-2 was adapted in digested sludge and used to treat sludge for dewaterability improvement. Results showed that increasing ferrous iron loading increased sludge dewaterability, but the inoculation of the bioleaching strain had little effect on sludge dewaterability compared to controls without the strain. The total extracellular polymeric substances (EPS) contents of sludges with and without bioleaching treatment were similar except for bioleaching treatment at 10% ferrous iron loading (on sludge total solids) where total EPS was higher with bioleaching treatment. However, bioleaching treatment for 48 h had a notable effect on removal of heavy metals, such as Mn, Ni and Zn, especially at the high loadings of ferrous iron. In the presence of A. ferrooxidans, the removal of Ni, Mn and Zn reached 93%, 88% and 80%, respectively, at a ferrous iron loading of 21%. The sequencing of 16S rRNA genes indicated that increasing ferrous iron loadings to 15% and 21% increased the relative abundance of Acidithiobacillus, Acidocella (with A. ferrooxidans) and Carboxylicivirga (without A. ferrooxidans) but decreased the abundance of Pseudomonas and Acinetobacter after 48 h treatment. This study enhanced the understanding of the correlations between bioleaching treatment of digested sludge, sludge dewaterability, heavy metal removal and bacterial communities.
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Affiliation(s)
- Guiqin Cai
- Centre for Agriculture and the Bioeconomy, Faculty of Science, Queensland University of Technology, Brisbane, QLD 4000, Australia; School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Majid Ebrahimi
- Centre for Agriculture and the Bioeconomy, Faculty of Science, Queensland University of Technology, Brisbane, QLD 4000, Australia; School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Guanyu Zheng
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Anna H Kaksonen
- Commonwealth Scientific and Industrial Research Organisation, Land and Water, Wembley, WA 6913, Australia
| | - Christina Morris
- Commonwealth Scientific and Industrial Research Organisation, Land and Water, Wembley, WA 6913, Australia
| | - Ian M O'Hara
- Centre for Agriculture and the Bioeconomy, Faculty of Science, Queensland University of Technology, Brisbane, QLD 4000, Australia; School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia; ARC Centre of Excellence in Synthetic Biology, Queensland University of Technology, QLD 4000, Australia
| | - Zhanying Zhang
- Centre for Agriculture and the Bioeconomy, Faculty of Science, Queensland University of Technology, Brisbane, QLD 4000, Australia; School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia; ARC Centre of Excellence in Synthetic Biology, Queensland University of Technology, QLD 4000, Australia.
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8
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Yang W, Zeng L, Zhang W, Yang Q, Wang T, Xiong H. The influence of different sludge concentrations on its dewaterability during bioleaching. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2020; 81:2585-2598. [PMID: 32857745 DOI: 10.2166/wst.2020.319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Bioleaching, a technologically and economically feasible technology, is considered as the high efficiency method to improve dewaterability in sewage sludge. The objective of this study was to investigate the effect of different sludge concentrations on bioleaching dewaterability and understand the mechanism of the effect of bioleaching on sludge dewaterability. Variation in pH, oxidation-reduction potential (ORP), capillary suction time (CST), specific resistance to filtration (SRF) and different fractions of extracellular polymeric substances (EPS) including slime EPS (S-EPS), loosely bound EPS (LB-EPS), and tightly bound EPS (TB-EPS) were determined. Different sludge concentrations (5, 10, 15, 20 and 30 g·L-1) were selected to investigate during bioleaching. Results indicated that sludge buffering capacity significantly inhibited bioleaching efficiency as sludge concentrations increased. Optimum enhancements in sludge dewaterability were observed during the 10 g·L-1 sludge concentration treatment, and reached a maximum when the pH was 2.11. The variation of different fractions of EPS revealed that the ratio of S-EPS/TB-EPS significantly affected sludge dewaterability. Principal component analysis and Pearson's correlation analysis both provided evidence that the higher TB-EPS followed by a very large reduction was positively correlated with sludge dewaterability. However, the increase of protein and DNA in S-EPS content was negatively correlated with sludge dewaterability.
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Affiliation(s)
- Wenfeng Yang
- College of Chemistry and Environmental Engineering, Jiujiang University, Jiujiang 332005, China and Jiujiang Key Laboratory of basin management and ecological protection, Jiujiang University, Jiujiang Jiangxi, 332005, China E-mail: ; School of Resource and Environmental Sciences, Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan Hubei, 430079, China
| | - Liyuan Zeng
- College of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou Gansu, 730050, China
| | - Weihao Zhang
- School of Resource and Environmental Sciences, Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan Hubei, 430079, China
| | - Qiyong Yang
- College of Chemistry and Environmental Engineering, Jiujiang University, Jiujiang 332005, China and Jiujiang Key Laboratory of basin management and ecological protection, Jiujiang University, Jiujiang Jiangxi, 332005, China E-mail:
| | - Tianfeng Wang
- College of Chemistry and Environmental Engineering, Jiujiang University, Jiujiang 332005, China and Jiujiang Key Laboratory of basin management and ecological protection, Jiujiang University, Jiujiang Jiangxi, 332005, China E-mail:
| | - Houfeng Xiong
- College of Chemistry and Environmental Engineering, Jiujiang University, Jiujiang 332005, China and Jiujiang Key Laboratory of basin management and ecological protection, Jiujiang University, Jiujiang Jiangxi, 332005, China E-mail:
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9
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Xu M, Liu Y, Deng Y, Zhang S, Hao X, Zhu P, Zhou J, Yin H, Liang Y, Liu H, Liu X, Bai L, Jiang L, Jiang H. Bioremediation of cadmium-contaminated paddy soil using an autotrophic and heterotrophic mixture. RSC Adv 2020; 10:26090-26101. [PMID: 35519775 PMCID: PMC9055442 DOI: 10.1039/d0ra03935g] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 06/26/2020] [Indexed: 12/02/2022] Open
Abstract
Cadmium (Cd) pollution poses a serious risk to human health and ecological security. Bioremediation can be a promising and effective remediation technology for treating Cd contaminated soils. In this study, seven heterotrophic strains were isolated from Cd contaminated soil and 7 autotrophic strains were isolated from acid mine drainage. Cd removal efficiencies were compared after leaching with autotrophic bacteria (Att-sys), heterotrophic isolates (Htt-sys) and cooperative leaching systems (Co-sys) in laboratory agitating reactors. The results indicated that Cd removal efficiency of Co-sys (32.09%) was significantly higher than that of Att-sys (23.24%) and Htt-sys (0.74%). By analyzing the soil microbial community in different bioleaching systems, we found that the addition of heterotrophic isolates significantly promoted the growth of some heavy metal resistant inhabitants (Massilia, Alicyclobacillus, Micromonospora, etc.), and Co-sys had a minor effect on the growth of soil indigenous microbes. In Co-sys, the content of the four Cd fractions all decreased compared with other leaching systems. The analysis of soil physicochemical parameters during the leaching process showed that pH and ORP (oxidation reduction potential) were not the only determinants for Cd removal efficiency in Co-sys, synergistic metabolic activities of autotrophic and heterotrophic strains may be other determinants. This study demonstrated that cooperative bioremediation may prove to be a safe and efficient technique for field application in heavy metal soil pollution. Bioremediation can be a promising and effective remediation technology for treating Cd contaminated soils. Cooperative bioremediation using heterotrophic and autotrophic mixtures proved to be an efficient, short-term bioremediation strategy for heavy metal contaminated soil.![]()
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10
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Singh R, Ryu J, Kim SW. Microbial consortia including methanotrophs: some benefits of living together. J Microbiol 2019; 57:939-952. [PMID: 31659683 DOI: 10.1007/s12275-019-9328-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/30/2019] [Accepted: 09/25/2019] [Indexed: 01/13/2023]
Abstract
With the progress of biotechnological research and improvements made in bioprocessing with pure cultures, microbial consortia have gained recognition for accomplishing biological processes with improved effectiveness. Microbes are indispensable tool in developing bioprocesses for the production of bioenergy and biochemicals while utilizing renewable resources due to technical, economic and environmental advantages. They communicate with specific cohorts in close proximity to promote metabolic cooperation. Use of positive microbial associations has been recognized widely, especially in food industries and bioremediation of toxic compounds and waste materials. Role of microbial associations in developing sustainable energy sources and substitutes for conventional fuels is highly promising with many commercial prospects. Detoxification of chemical contaminants sourced from domestic, agricultural and industrial wastes has also been achieved through microbial catalysis in pure and co-culture systems. Methanotrophs, the sole biological sink of greenhouse gas methane, catalyze the methane monooxygenasemediated oxidation of methane to methanol, a high energy density liquid and key platform chemical to produce commodity chemical compounds and their derivatives. Constructed microbial consortia have positive effects, such as improved biomass, biocatalytic potential, stability etc. In a methanotroph-heterotroph consortium, non-methanotrophs provide key nutrient factors and alleviate the toxicity from the culture. Non-methanotrophic organisms biologically stimulate the growth and activity of methanotrophs via production of growth stimulators. However, methanotrophs in association with co-cultured microorganisms are in need of further exploration and thorough investigation to study their interaction mode and application with improved effectiveness.
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Affiliation(s)
- Rajendra Singh
- Department of Environmental Engineering, Chosun University, Gwangju, 61452, Republic of Korea
| | - Jaewon Ryu
- Department of Energy Convergence, Chosun University, Gwangju, 61452, Republic of Korea
| | - Si Wouk Kim
- Department of Environmental Engineering, Chosun University, Gwangju, 61452, Republic of Korea. .,Department of Energy Convergence, Chosun University, Gwangju, 61452, Republic of Korea.
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11
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Lu Y, Zhang C, Zheng G, Zhou L. Improving the compression dewatering of sewage sludge through bioacidification conditioning driven by Acidithiobacillus ferrooxidans: dewatering rate vs. dewatering extent. ENVIRONMENTAL TECHNOLOGY 2019; 40:3176-3189. [PMID: 29649956 DOI: 10.1080/09593330.2018.1465129] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 04/09/2018] [Indexed: 06/08/2023]
Abstract
Prior to mechanical dewatering, sludge conditioning is indispensable to reduce the difficulty of sludge treatment and disposal. The effect of bioacidification conditioning driven by Acidithiobacillus ferrooxidans LX5 on the dewatering rate and extent of sewage sludge during compression dewatering process was investigated in this study. The results showed that the bioacidification of sludge driven by A. ferrooxidans LX5 simultaneously improved both the sludge dewatering rate and extent, which was not attained by physical/chemical conditioning approaches, including ultrasonication, microwave, freezing/thawing, or by adding the chemical conditioner cationic polyacrylamide (CPAM). During the bioacidification of sludge, the decrease in sludge pH induced the damage of sludge microbial cell structures, which enhanced the dewatering extent of sludge, and the added Fe2+ and the subsequent bio-oxidized Fe3+ effectively flocculated the damaged sludge flocs to improve the sludge dewatering rate. In the compression dewatering process consisting of filtration and expression stages, high removal of moisture and a short dewatering time were achieved during the filtration stage and the expression kinetics were also improved because of the high elasticity of sludge cake and the rapid creeping of the aggregates within the sludge cake. In addition, the usefulness of bioacidification driven by A. ferrooxidans LX5 in improving the compression dewatering of sewage sludge could not be attained by the chemical treatment of sludge through pH modification and Fe3+ addition. Therefore, the bioacidification of sludge driven by A. ferrooxidans LX5 is an effective conditioning method to simultaneously improve the rate and extent of compression dewatering of sewage sludge.
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Affiliation(s)
- Yi Lu
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University , Nanjing , People's Republic of China
| | - Chunmei Zhang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University , Nanjing , People's Republic of China
| | - Guanyu Zheng
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University , Nanjing , People's Republic of China
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization , Nanjing , People's Republic of China
| | - Lixiang Zhou
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University , Nanjing , People's Republic of China
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization , Nanjing , People's Republic of China
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12
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Wang J, Yang M, Liu R, Hu C, Liu H, Qu J. Anaerobically-digested sludge conditioning by activated peroxymonosulfate: Significance of EDTA chelated-Fe 2. WATER RESEARCH 2019; 160:454-465. [PMID: 31174073 DOI: 10.1016/j.watres.2019.05.067] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 05/10/2019] [Accepted: 05/21/2019] [Indexed: 06/09/2023]
Abstract
This study investigates the efficiency of anaerobically-digested sludge (ADS) conditioning using peroxymonosulfate (PMS) activated by EDTA chelated-Fe2+ process (PMS-EDTA-Fe2+), and the roles and mechanism of EDTA are explored by investigating the capillary suction time (CST), specific resistance to filtration (SRF), bound water content (BWC), extracellular polymeric substances (EPS), iron species transformation, sludge morphology, and active radicals formation. PMS-EDTA-Fe2+ process exhibits better performance in sludge dewatering than PMS-Fe2+ process. Upon the introduction of EDTA at optimum molar ratio of EDTA to Fe2+ [Formula: see text] of 1 : 3, CST, SRF, and BWC are decreased by 60.0%, 70.6%, and 1.5%, and the cell viability is decreased from 75.4% to as low as 24.7%. EDTA introduction significantly enhances the yield of active radicals (i.e., SO4-· and O⋅H) by nearly 50% as compared to PMS-Fe2+ process. This effect contributes to stronger cells lysis as indicated by SEM and CLSM, and the contents of polysaccharide and protein in total EPS fractions are increased by 19.2% and 37.4% accordingly. Additionally, EDTA increases the iron mobility by forming FeII/III-EDTA complexes and potentially inhibits ADS coagulation at high doses. The total dissolved iron (FeTot_dis) concentration increases from 203.4 mg/L to 601.4 mg/L due to the introduction of EDTA at 0.4 mmol/g VSS, and the dominant iron species in supernatant transformed from Fe2+ to Fe3+ accordingly. The optimization of EDTA doses is significant to balance oxidation and coagulation effects and to achieve better dewatering performance.
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Affiliation(s)
- Jiaqi Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Min Yang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ruiping Liu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Chengzhi Hu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Huijuan Liu
- Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China
| | - Jiuhui Qu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China
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13
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Ban Y, Li L, Liu C, Yan Y, Gao J, Zhang J, Gao J. Enhancing sludge dewatering and heavy metal removal by bioleaching with Na 2S 2O 3 as substrates. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2018; 78:1545-1555. [PMID: 30427795 DOI: 10.2166/wst.2018.432] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Bioleaching has been demonstrated to be an effective technology for the removal of heavy metals and sludge dewaterability. Since bacteria gain nutrients by diffusion of soluble compounds, the insolubility of elemental sulfur may slow the growth of bacteria. Thus, it is very important to find an energy substance quickly become available to Acidithiobacillus thiooxidans. This paper studies the improvement of sludge dewaterability and heavy metal removal with sodium thiosulfate as the source of energy for Acidithiobacillus thiooxidans. Through orthogonal experiments with specific resistance to filtration (SRF) as the target index, four factors (FeSO4 dosage, Na2S2O3 dosage, sludge reflux ratio and sludge moisture content) were identified to be the important influencing parameters. The optimal conditions were: FeSO4 dosage, 8 g/L; Na2S2O3 dosage, 1.5 g/L; sludge reflux ratio, 30%; sludge moisture content, 97%. Results indicated that the SRF of the sludge decreased from 9.89 × 1012 to 1.03 × 1011 m/kg. The removal efficiencies of heavy metals Cu, Zn, Pb and Cr could reach 83%, 78%, 31% and 38% within 3 days, respectively. These results confirm the potential of sodium thiosulfate as an alternative energy substance in bioleaching to improve sludge dewaterability as well as removal of metals.
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Affiliation(s)
- Yafei Ban
- School of Water Conservancy and Environment, Zhengzhou University, Zhengzhou 450001, China E-mail:
| | - Linshuai Li
- Zhengzhou University Multi-Functional Design and Research Academy Co., Zhengzhou 450002, China
| | - Chun Liu
- Beijing Urban Construction Design and Development Group Co., Ltd, Beijing 100032, China
| | - Yixin Yan
- School of Water Conservancy and Environment, Zhengzhou University, Zhengzhou 450001, China E-mail:
| | - Jingqing Gao
- School of Water Conservancy and Environment, Zhengzhou University, Zhengzhou 450001, China E-mail:
| | - Jingshen Zhang
- School of Water Conservancy and Environment, Zhengzhou University, Zhengzhou 450001, China E-mail: ; Zhengzhou Yuanzhihe Environmental Protection Technology Co., Ltd, Zhengzhou, Henan 450000, China
| | - Jianlei Gao
- School of Water Conservancy and Environment, Zhengzhou University, Zhengzhou 450001, China E-mail:
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14
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Wu Y, Wang K, He C, Wang Z, Ren N, Tian Y. Effects of bioleaching pretreatment on nitrous oxide emission related functional genes in sludge composting process. BIORESOURCE TECHNOLOGY 2018; 266:181-188. [PMID: 29966928 DOI: 10.1016/j.biortech.2018.06.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 06/17/2018] [Accepted: 06/18/2018] [Indexed: 06/08/2023]
Abstract
The effect of bioleaching pretreatment on N2O generation in sludge composting process was firstly investigated in this study. The relationships among physicochemical factors, N2O and NH3 emission and related functional genes were analyzed in 60 days composting of bioleaching dewatering sludge (BDS) and filter press dewatering sludge (FDS), respectively. The results showed the cumulative amounts of NH3 and N2O emission from the BDS composting system were reduced by 83.52% and 54.76% after bioleaching pretreatment, respectively. The lower moisture and pH, and the higher ORP and the concentrations of NH4+-N, NO3--N and NO2--N were observed in BDS during the composting compared to FDS. Furthermore, bioleaching pretreatment improved the relative abundance of hao but reduced amoA, nirK and norB in the BDS during the composting. The low pH level and the reduction of nirK and norB in BDS were the main reasons mitigating NH3 and N2O emissions, respectively.
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Affiliation(s)
- Yiqi Wu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, Heilongjiang 150090, China
| | - Ke Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, Heilongjiang 150090, China.
| | - Chao He
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China
| | - Zhe Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, Heilongjiang 150090, China
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, Heilongjiang 150090, China
| | - Yu Tian
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, Heilongjiang 150090, China
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15
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Song Y, Liu Y, Wang H. Comparison of the Biological and Chemical Synthesis of Schwertmannite at a Consistent Fe 2+ Oxidation Efficiency and the Effect of Extracellular Polymeric Substances of Acidithiobacillus ferrooxidans on Biomineralization. MATERIALS (BASEL, SWITZERLAND) 2018; 11:E1739. [PMID: 30223571 PMCID: PMC6164185 DOI: 10.3390/ma11091739] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 09/13/2018] [Accepted: 09/13/2018] [Indexed: 11/26/2022]
Abstract
Schwertmannite is an environmental mineral material that can promote the natural passivation of heavy metal elements, thereby reducing environmental pollution from toxic elements. However, the fundamental reason for the difference between the chemically (H₂O₂-FeSO₄) and biologically (Acidithiobacillus ferrooxidans-FeSO₄) synthesized schwertmannite is still unclear. In this study, X-ray diffraction, scanning electron microscopy, the Brunauer⁻Emmett⁻Teller method, and X-ray fluorescence spectrometry were used to compare the structure, specific surface area, and elemental composition of schwertmannite synthesized by biological and chemical methods. The removal capacity of As(III) by the two kinds of schwertmannite and the effects of extracellular polymeric substances (EPS) on biogenetic schwertmannite were also investigated. At a consistent Fe2+ oxidation efficiency, the chemical method synthesized more schwertmannite than the biological method over a 60-h period. The biosynthesized schwertmannite had a "chestnut shell" shape, with a larger particle size and specific surface than the chemically synthesized schwertmannite, which was relatively smooth. The saturated adsorption capacities of the biologically and chemically synthesized schwertmannite were 117.0 and 87.0 mg·g-1, respectively. After exfoliation of the EPS from A. ferrooxidans, the biosynthesized schwertmannite displayed a "wool ball" shape, with rough particle surfaces, many microporous structures, and a larger specific surface area. The schwertmannite yield also increased by about 45% compared with that before exfoliation, suggesting that the secretion of EPS by A. ferrooxidans can inhibit the formation of schwertmannite.
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Affiliation(s)
- Yongwei Song
- School of Information and Safety Engineering, Zhongnan University of Economics and Law, Wuhan 430073, China.
| | - Yelin Liu
- School of Information and Safety Engineering, Zhongnan University of Economics and Law, Wuhan 430073, China.
| | - Heru Wang
- School of Information and Safety Engineering, Zhongnan University of Economics and Law, Wuhan 430073, China.
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16
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Potysz A, van Hullebusch ED, Kierczak J. Perspectives regarding the use of metallurgical slags as secondary metal resources - A review of bioleaching approaches. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 219:138-152. [PMID: 29738933 DOI: 10.1016/j.jenvman.2018.04.083] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Revised: 04/09/2018] [Accepted: 04/19/2018] [Indexed: 05/09/2023]
Abstract
Smelting activity by its very nature produces large amounts of metal-bearing waste, often called metallurgical slag(s). In the past, industry used to dispose of these waste products at dumping sites without the appropriate environmental oversight. Once there, ongoing biogeochemical processes affect the stability of the slags and cause the release of metallic contaminants. Rather than viewing metallurgical slags as waste, however, such deposits should be viewed as secondary metal resources. Metal bioleaching is a "green" treatment route for metallurgical slags, currently being studied under laboratory conditions. Metal-laden leachates obtained at the bioleaching stage have to be subjected to further recovery operations in order to obtain metal(s) of interest to achieve the highest levels of purity possible. This perspective paper considers the feasibility of the reuse of base-metal slags as secondary metal resources. Special focus is given to current laboratory bioleaching approaches and associated processing obstacles. Further directions of research for development of more efficient methods for waste slag treatment are also highlighted. The optimized procedure for slag treatment is defined as the result of this review and should include following steps: i) slag characterization (chemical and phase composition and buffering capacity) following the choice of initial pH, ii) the choice of particle size, iii) the choice of the liquid-to-solid ratio, iv) the choice of microorganisms, v) the choice of optimal nutrient supply (growth medium composition). An optimal combination of all these parameters will lead to efficient extraction and generation of metal-free solid residue.
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Affiliation(s)
- Anna Potysz
- University of Wroclaw, Institute of Geological Sciences, Cybulskiego 30, 50-205 Wrocław, Poland.
| | - Eric D van Hullebusch
- IHE Delft Institute for Water Education, Department of Environmental Engineering and Water Technology, P.O. Box 3015, 2601 DA Delft, The Netherlands
| | - Jakub Kierczak
- University of Wroclaw, Institute of Geological Sciences, Cybulskiego 30, 50-205 Wrocław, Poland
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17
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Zhang Q, Yang W, Yang Q, Wang T, Chen S, Zou M, Yang Z. Effect of using different proportions of inoculum during bioleaching on sludge dewaterability. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2018; 2017:802-811. [PMID: 30016298 DOI: 10.2166/wst.2018.234] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Bioleaching, the addition of bacteria to geological materials, has been applied to sludge to remove metals and improve upon sludge dewaterability. This paper investigates the effect of using different quantities of inoculum (bacteria) during bioleaching on sludge dewaterability. The analysis was based on bioleaching experiments conducted in a 20 L bio-reactor using different quantities of inoculum (20%, 10%, 5%, 2%, 0%). Changes in pH, oxidation reduction potential (ORP), capillary suction time (CST), specific resistance to filtration (SRF) and extracellular polymeric substances (EPS) were determined to gauge sludge dewatering. Results indicate that sludge dewaterability during the 2%, 10%, and 20% inoculum experiments declined through time. Decreased dewaterability is attributed to increases in the quantity of proteins and polysaccharides in slime EPS. Dewaterability improved during the 5% inoculum experiment, and reached a maximum when pH was 2.3. During this latter experiment, CST and SRF were reduced by 74% and 62%, respectively, in comparison to control conditions, while total EPS content decreased by 71%. The decrease in total EPS was primarily due to a decrease in proteins associated with tightly bound EPS (TB-EPS). Thus, changes in the amount of proteins in TB-EPS and sludge pH played a crucial role in sludge dewaterability.
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Affiliation(s)
- Qingfang Zhang
- College of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou Gansu, 730050, China
| | - Wenfeng Yang
- College of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou Gansu, 730050, China; College of Chemistry and Environmental Engineering, Jiujiang University, Jiujiang Jiangxi, 332005, China
| | - Qiyong Yang
- Poyang Lake Eco-economy Research Center, Jiujiang University, Jiujiang Jiangxi, 332005, China E-mail: ; Jiujiang Key Laboratory of Basin Management and Ecological Protection, Jiujiang University, Jiujiang Jiangxi, 332005, China; College of Chemistry and Environmental Engineering, Jiujiang University, Jiujiang Jiangxi, 332005, China
| | - Tianfeng Wang
- Jiujiang Key Laboratory of Basin Management and Ecological Protection, Jiujiang University, Jiujiang Jiangxi, 332005, China; College of Chemistry and Environmental Engineering, Jiujiang University, Jiujiang Jiangxi, 332005, China
| | - Shenliang Chen
- College of Chemistry and Environmental Engineering, Jiujiang University, Jiujiang Jiangxi, 332005, China
| | - Moliang Zou
- College of Chemistry and Environmental Engineering, Jiujiang University, Jiujiang Jiangxi, 332005, China
| | - Zengye Yang
- College of Chemistry and Environmental Engineering, Jiujiang University, Jiujiang Jiangxi, 332005, China
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18
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Ghosh S, Chowdhury R, Bhattacharya P. Mixed consortia in bioprocesses: role of microbial interactions. Appl Microbiol Biotechnol 2016; 100:4283-95. [DOI: 10.1007/s00253-016-7448-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/03/2016] [Accepted: 03/08/2016] [Indexed: 12/22/2022]
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19
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Study of bioleaching under different hydraulic retention time for enhancing the dewaterability of digestate. Appl Microbiol Biotechnol 2015; 99:10735-43. [DOI: 10.1007/s00253-015-6895-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 07/26/2015] [Accepted: 07/29/2015] [Indexed: 10/23/2022]
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20
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Ngom B, Liang Y, Liu Y, Yin H, Liu X. Use of an acidophilic yeast strain to enable the growth of leaching bacteria on solid media. Arch Microbiol 2014; 197:339-46. [DOI: 10.1007/s00203-014-1051-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 10/16/2014] [Accepted: 10/18/2014] [Indexed: 11/25/2022]
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21
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Huo M, Zheng G, Zhou L. Enhancement of the dewaterability of sludge during bioleaching mainly controlled by microbial quantity change and the decrease of slime extracellular polymeric substances content. BIORESOURCE TECHNOLOGY 2014; 168:190-197. [PMID: 24650613 DOI: 10.1016/j.biortech.2014.02.098] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 02/13/2014] [Accepted: 02/16/2014] [Indexed: 06/03/2023]
Abstract
Contribution rates of factors controlling sludge dewaterability during bioleaching, such as sludge pH, microbial quantity, extracellular polymeric substances (EPS), etc., were investigated in this study. Results showed that the dewaterability of bioleached sludge was jointly enhanced by the growth of Acidithiobacillus sp., the increase of Fe(3+) concentration, the decreases of sludge pH, heterotrophic microorganism quantity change, and the decreases of EPS and bound water contents. Ridge regression analysis further revealed that the contribution rates of microbial quantity change, bound water content and slime EPS content on sludge dewaterability enhancement were 32.50%, 24.24%, and 22.37%, respectively, all of which are dominant factors. Therefore, the enhancement of sludge dewaterability was mainly controlled by microbial quantity change and the decrease of bound water and slime EPS contents during bioleaching.
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Affiliation(s)
- Minbo Huo
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Guanyu Zheng
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing 210095, China
| | - Lixiang Zhou
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
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22
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Song Y, Zheng G, Huo M, Zhao B, Zhou L. Extracellular polymeric substances and bound water drastically affect bioleached sludge dewaterability at low temperature. ENVIRONMENTAL TECHNOLOGY 2014; 35:2538-2545. [PMID: 25145209 DOI: 10.1080/09593330.2014.911755] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
It is well documented that bioleaching with the co-inoculation ofAcidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans can drastically enhance sludge dewaterability under ambient temperature condition, but little information on low temperature effect on bioleached sludge dewaterability is available. In this study, the optimum sludge retention time of bioleaching treatment and the mechanisms responsible for the dewaterability enhancement ofbioleached sludge were studied in two bioleaching systems conducted at a low temperature of 10 degrees C and a normal temperature of 28 degrees C, respectively. Results showed that Acidithiobacillus bacteria involved in the bioleaching were still active at 10 degrees C, and sludge capillary suction time (CST) decreased in the first 3 days of bioleaching. Nevertheless, the degree of sludge dewaterability enhancement by bioleaching was much lower at 10 degrees C than that at 28 degrees C. The only slight decreases in the sludge pH value and relative high contents of extracellular polymeric substances (EPS) and bound water at a low temperature were responsible for the relatively lower dewaterability enhancement of bioleached sludge compared to that at the normal temperature. Moreover, statistical results showed that sludge CST had significant positive correlations with the sludge pH value, and EPS and bound water contents in the optimum bioleaching process (from day 0 to day 3). Therefore, reducing medium pH, and/or removing EPS from bioleaching bacteria and bound water ofbioleached sludge through forced physical-chemical approaches prior to mechanical dewatering might be a good method to greatly improve sludge dewatering at a low temperature.
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Zhou J, Zheng G, Zhang X, Zhou L. Influences of extracellular polymeric substances on the dewaterability of sewage sludge during bioleaching. PLoS One 2014; 9:e102688. [PMID: 25050971 PMCID: PMC4106846 DOI: 10.1371/journal.pone.0102688] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Accepted: 06/21/2014] [Indexed: 12/02/2022] Open
Abstract
Extracellular polymeric substances (EPS) play important roles in regulating the dewaterability of sludge. This study sought to elucidate the influence of EPS on the dewaterability of sludge during bioleaching process. Results showed that, in bioleaching system with the co-inoculation of Acidithiobacillus thiooxidans TS6 and Acidithiobacillus ferrooxidans LX5 (A. t+A. f system), the capillary suction time (CST) of sludge reduced from 255.9 s to 25.45 s within 48 h, which was obviously better than the controls. The correlation analysis between sludge CST and sludge EPS revealed that the sludge EPS significantly impacted the dewaterability of sludge. Sludge CST had correlation with protein content in slime and both protein and polysaccharide contents in TB-EPS and Slime+LB+TB layers, and the decrease of protein content in slime and decreases of both protein and polysaccharide contents in TB-EPS and Slime+LB+TB layers improved sludge dewaterability during sludge bioleaching process. Moreover, the low sludge pH (2.92) and the increasing distribution of Fe in the solid phase were another two factors responsible for the improvement of sludge dewaterability during bioleaching. This study suggested that during sludge bioleaching the growth of Acidithiobacillus species resulted in the decrease of sludge pH, the increasing distribution of Fe in the solid phase, and the decrease of EPS content (mainly including protein and/or polysaccharide) in the slime, TB-EPS, and Slime+LB+TB layers, all of which are helpful for sludge dewaterability enhancement.
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Affiliation(s)
- Jun Zhou
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Guanyu Zheng
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing, China
| | - Xueying Zhang
- College of Environment, Nanjing Tech University, Nanjing, China
| | - Lixiang Zhou
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing, China
- * E-mail:
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Zhu Y, Zeng G, Zhang P, Zhang C, Ren M, Zhang J, Chen M. Feasibility of bioleaching combined with Fenton-like reaction to remove heavy metals from sewage sludge. BIORESOURCE TECHNOLOGY 2013; 142:530-534. [PMID: 23765003 DOI: 10.1016/j.biortech.2013.05.070] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 05/17/2013] [Accepted: 05/19/2013] [Indexed: 06/02/2023]
Abstract
Feasibility of bioleaching combining with Fenton-like reaction to remove heavy metals from sewage sludge was investigated. After 5-day bioleaching, the sludge pH decreased from 6.95 to 2.50, which satisfied the acidic conditions for Fenton-like reaction. Meanwhile, more than 50% of sludge-borne heavy metals were dissolved except for Pb. The bioleached sludge was further oxidized with Fenton-like reaction, with an optimal H2O2 dosage of 5 g/L, the Cu, Zn, Pb and Cd removal reached up to 75.3%, 72.6%, 34.5% and 65.4%, respectively, and the residual content of heavy metals in treated sludge meets the requirement of Disposal of Sludge from Municipal Wastewater Treatment Plant - Control Standards for Agricultural Use (CJ/T 309-2009) of China for A grade sludge. Bioleaching combined with Fenton-like reaction was the most effective method for heavy metal removal, compared with 15-day bioleaching and inorganic acid leaching with 10% H2SO4, 10% HCl and 10% HNO3.
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Affiliation(s)
- Yi Zhu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China.
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25
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Zhou J, Zheng G, Wong JWC, Zhou L. Degradation of inhibitory substances in sludge by Galactomyces sp. Z3 and the role of its extracellular polymeric substances in improving bioleaching. BIORESOURCE TECHNOLOGY 2013; 132:217-223. [PMID: 23411451 DOI: 10.1016/j.biortech.2012.12.179] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 12/26/2012] [Accepted: 12/26/2012] [Indexed: 06/01/2023]
Abstract
This study sought to elucidate the effect and mechanism of Galactomyces sp. Z3 in improving the bioleaching of heavy metals from sludge. Results showed that co-inoculation of Galactomyces sp. Z3 and two Acidithiobacillus strains (Acidithiobacillus ferrooxidans LX5 and Acidithiobacillus thiooxidans TS6) reduced the period required for sludge bioleaching by 4.5days compared to Acidithiobacillus alone. Further, removal efficiencies of Cu, Zn and oxidation rate of Fe(2+) and S(0) were higher in co-inoculation system than the Acidithiobacillus alone. Galactomyces sp. Z3 consumed the acetate, propionate, iso-butyrate, butyrate, and iso-valerate in sludge from the initial concentrations of 109.50, 28.80, 7.70, 34.30, and 18.40mg/L to 10.20, 0.61, 0.63, 19.40 and 1.30mg/L, respectively, after 12h in the co-inoculation system, significantly lower than the concentrations observed in the Acidithiobacillus alone. Meanwhile, the surfactant properties of the extracellular polymeric substances produced by the Galactomyces accelerated the rate of sulfur oxidization by A. thiooxidans.
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Affiliation(s)
- Jun Zhou
- Sino-Forest Applied Research Centre for Pearl River Delta Environment, Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region, China
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26
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Zhou J, Zheng G, Zhou L, Liu F, Zheng C, Cui C. The role of heterotrophic microorganism Galactomyces sp. Z3 in improving pig slurry bioleaching. ENVIRONMENTAL TECHNOLOGY 2013; 34:35-43. [PMID: 23530313 DOI: 10.1080/09593330.2012.679699] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The feasibility of removing heavy metals and eliminating pathogens from pig slurry through bioleaching involving the fungus Galactomyces sp. Z3 and two acidophilic thiobacillus (A. ferrooxidans LX5 and A. thiooxidans TS6) was investigated. It was found that the isolated pig slurry dissolved organic matter (DOM) degrader Z3 was identified as Galactomyces sp. Z3, which could grow well at pH 2.5-7 and degrade pig slurry DOM from 1973 to 942 mg/l within 48 h. During the successive multi-batch bioleaching systems, the co-inoculation of pig slurry degrader Galactomyces sp. Z3 and the two Acidithiobacillus species could improve pig slurry bioleaching efficiency compared to the single system without Galactomyces sp. Z3. The removal efficiency of Zn and Cu exceeded 94% and 85%, respectively. In addition, the elimination efficiencies of pathogens, including both total coliform and faecal coliform counts, exceeded 99% after bioleaching treatment. However, the counts of Galactomyces sp. Z3 decreased with the fall of pH and did not restore to the initial level during successive multi-batch bioleaching systems, and it is necessary to re-inoculate Galactomyces sp. Z3 cells into the bioleaching system to maintain its role in degrading pig slurry DOM. Therefore, a bioleaching technique involving both Galactomyces sp. Z3 and Acidithiobacillus species is an efficient method for removing heavy metals and eliminating pathogens from pig slurry.
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Affiliation(s)
- Jun Zhou
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
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27
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Bai S, Xu Z, Wang M, Liao Y, Liang J, Zheng C, Zhou L. Both initial concentrations of Fe(II) and monovalent cations jointly determine the formation of biogenic iron hydroxysulfate precipitates in acidic sulfate-rich environments. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2012. [DOI: 10.1016/j.msec.2012.07.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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28
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Xin B, Jiang W, Li X, Zhang K, Liu C, Wang R, Wang Y. Analysis of reasons for decline of bioleaching efficiency of spent Zn-Mn batteries at high pulp densities and exploration measure for improving performance. BIORESOURCE TECHNOLOGY 2012; 112:186-192. [PMID: 22437046 DOI: 10.1016/j.biortech.2012.02.133] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Revised: 02/26/2012] [Accepted: 02/28/2012] [Indexed: 05/31/2023]
Abstract
The reasons for decline of bioleaching efficiency of Zn and Mn from spent batteries at high pulp densities were analyzed; the measures for improving bioleaching efficiency were investigated. The results showed that extraction efficiency of Zn dropped from 100% at 1% of pulp density to 29.9% at 8% of pulp density, with Mn from 94% to only 2.5%. It was almost the linear reduction of the activity of the sulfur-oxidizing bacteria with increase of pulp density that witnessed declined bioleaching efficiency of Zn; it was the complete inactivation of the iron-oxidizing bacteria at 2% of pulp density or higher that witnessed declined bioleaching dose of Mn. By means of reducing initial pH value of leaching media, increasing concentration of energy matters and exogenous acid adjustment of media during bioleaching, the maximum extraction efficiency of almost 100% for Zn and 89% for Mn at 4% of pulp density was attained, respectively.
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Affiliation(s)
- Baoping Xin
- School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081, PR China.
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29
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Huang S, Zhou L. Fe2+ oxidation rate drastically affect the formation and phase of secondary iron hydroxysulfate mineral occurred in acid mine drainage. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2012. [DOI: 10.1016/j.msec.2012.02.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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30
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Zheng G, Zhou L. Supplementation of inorganic phosphate enhancing the removal efficiency of tannery sludge-borne Cr through bioleaching. WATER RESEARCH 2011; 45:5295-5301. [PMID: 21864881 DOI: 10.1016/j.watres.2011.07.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Revised: 07/14/2011] [Accepted: 07/25/2011] [Indexed: 05/31/2023]
Abstract
Four inorganic mineral nutrients including NH4+, K+, Mg2+ and soluble inorganic phosphate (Pi) were investigated to reveal the potential limiting nutrients for tannery sludge bioleaching process driven by Acidithiobacillus species, and the feasibility of supplementing the limiting nutrients to accelerate tannery sludge bioleaching was studied in the present study. It was found that the concentration of Pi was lower than 3.5 mg/L throughout the whole bioleaching process, which is the most probable restricting nutrient for tannery sludge bioleaching. Further experiments revealed that the deficiency of Pi could seriously influence the growth of Acidithiobacillus thiooxidans and lower its oxidization capacity for S0, and the limiting concentration of Pi for the growth of A. thiooxidans was 6 mg/L. The low concentration of soluble Pi in sludge matrix was resulted from the extremely strong sorbing/binding capacity of tannery sludge for phosphate. The supplementation of more than 1.6 g/L KH2PO4 into tannery sludge bioleaching system could effectively stimulate the growth of Acidithiobacillus species, enhance Cr removal rate and further shorten tannery sludge bioleaching period from 10 days to 7 days. Therefore, inorganic phosphate supplementation is an effective and feasible method to accelerate tannery sludge bioleaching process, and the optimum dosage of KH2PO4 was 1.6 g/L for tannery sludge with 5.1% of total solids.
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Affiliation(s)
- Guanyu Zheng
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu Province 210095, China
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