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Wang Y, Wang C, Feng R, Li Y, Zhang Z, Guo S. A review of passive acid mine drainage treatment by PRB and LPB: From design, testing, to construction. ENVIRONMENTAL RESEARCH 2024; 251:118545. [PMID: 38431067 DOI: 10.1016/j.envres.2024.118545] [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: 11/06/2023] [Revised: 02/21/2024] [Accepted: 02/22/2024] [Indexed: 03/05/2024]
Abstract
An extensive volume of acid mine drainage (AMD) generated throughout the mining process has been widely regarded as one of the most catastrophic environmental problems. Surface water and groundwater impacted by pollution exhibit extreme low pH values and elevated sulfate and metal/metalloid concentrations, posing a serious threat to the production efficiency of enterprises, domestic water safety, and the ecological health of the basin. Over the recent years, a plethora of techniques has been developed to address the issue of AMD, encompassing nanofiltration membranes, lime neutralization, and carrier-microencapsulation. Nonetheless, these approaches often come with substantial financial implications and exhibit restricted long-term sustainability. Among the array of choices, the permeable reactive barrier (PRB) system emerges as a noteworthy passive remediation method for AMD. Distinguished by its modest construction expenses and enduring stability, this approach proves particularly well-suited for addressing the environmental challenges posed by abandoned mines. This study undertook a comprehensive evaluation of the PRB systems utilized in the remediation of AMD. Furthermore, it introduced the concept of low permeability barrier, derived from the realm of site-contaminated groundwater management. The strategies pertaining to the selection of materials, the physicochemical aspects influencing long-term efficacy, the intricacies of design and construction, as well as the challenges and prospects inherent in barrier technology, are elaborated upon in this discourse.
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Affiliation(s)
- Yu Wang
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
| | - Chunrong Wang
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China.
| | - Rongfei Feng
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
| | - Yang Li
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
| | - Zhiqiang Zhang
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
| | - Saisai Guo
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
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Chai G, Wang D, Zhang Y, Wang H, Li J, Jing X, Meng H, Wang Z, Guo Y, Jiang C, Li H, Lin Y. Effects of organic substrates on sulfate-reducing microcosms treating acid mine drainage: Performance dynamics and microbial community comparison. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 330:117148. [PMID: 36584458 DOI: 10.1016/j.jenvman.2022.117148] [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: 09/30/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 06/17/2023]
Abstract
Bioremediation techniques utilizing sulfate-reducing bacteria (SRB) for acid mine drainage (AMD) treatment have attracted growing attention in recent years, yet substrate bioavailability for SRB is a key factor influencing treatment effectiveness and long-term stability. This study investigated the effects of external organic substrates, including four complex organic wastes (i.e., sugarcane bagasse, straw compost, shrimp shell (SS), and crab shell (CS)) and a small-molecule organic acid (i.e., propionate), on AMD removal performance and associated microbial communities during the 30-day operation of sulfate-reducing microcosms. The results showed that the pH values increased in all five microcosms, while CS exhibited the highest neutralization ability and a maximum alkalinity generation of 1507 mg/L (as CaCO3). Sulfate reduction was more effective in SS and CS microcosms, with sulfate removal efficiencies of 95.6% and 86.0%, respectively. All sulfate-reducing microcosms could remove heavy metals to different degrees, with the highest removal rate of >99.0% observed for aluminum. The removal efficiency of manganese, the most recalcitrant metal, was the highest (96%) in the CS microcosm. Correspondingly, SRB was more abundant in the CS and SS microcosms as revealed by sequencing analysis, while Desulfotomaculum was the dominant SRB in the CS microcosm, accounting for 10.8% of total effective bacterial sequences. Higher abundances of functional genes involved in fermentation and sulfur cycle were identified in CS and SS microcosms. This study suggests that complex organic wastes such as CS and SS could create and maintain preferable micro-environments for active growth and metabolism of functional microorganisms, thus offering a cost-efficient, stable, and environmental-friendly solution for AMD treatment and management.
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Affiliation(s)
- Guodong Chai
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China; Department of Municipal and Environmental Engineering, School of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China
| | - Dongqi Wang
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China; Department of Municipal and Environmental Engineering, School of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China; Shaanxi Key Laboratory of Water Resources and Environment, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China
| | - Yitong Zhang
- Department of Municipal and Environmental Engineering, School of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China
| | - Hui Wang
- Department of Municipal and Environmental Engineering, School of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China
| | - Jiake Li
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China; Department of Municipal and Environmental Engineering, School of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China
| | - Xiaosheng Jing
- Zhongsheng Environmental Technology Development Co., Ltd., Xi'an, Shaanxi, 710054, China
| | - Haiyu Meng
- Department of Municipal and Environmental Engineering, School of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China
| | - Zhe Wang
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China; Department of Municipal and Environmental Engineering, School of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China
| | - Yuan Guo
- Department of Municipal and Environmental Engineering, School of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China
| | - Chunbo Jiang
- Department of Municipal and Environmental Engineering, School of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China
| | - Huaien Li
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China; Department of Municipal and Environmental Engineering, School of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China.
| | - Yishan Lin
- Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an, 710127, China.
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Singh R, Chakma S, Birke V. Performance of field-scale permeable reactive barriers: An overview on potentials and possible implications for in-situ groundwater remediation applications. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 858:158838. [PMID: 36122715 DOI: 10.1016/j.scitotenv.2022.158838] [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: 05/18/2022] [Revised: 09/07/2022] [Accepted: 09/14/2022] [Indexed: 06/15/2023]
Abstract
Permeable reactive barriers (PRBs) are significant among all the promising remediation technologies for treating contaminated groundwater. Since the first commercial full field-scale PRB emplacement in Sunnyvale, California, in 1994-1995, >200 PRB systems have been installed worldwide. The main working principle of a PRB is to treat a variety of contaminants downstream from the contaminated source zone ("hot spot"). However, to accurately assess the longevity of PRBs, it is essential to know the total contaminant mass in the source area and its approximate geometry. PRBs are regarded as both a safeguarding and an advanced decontamination technique, depending on the contamination scenario and its outcome during the operational lifetime of the barrier. In the last three decades, many PRBs have performed very well, that is, met expected clean-up goals at a variety of contaminated sites. However, there is still the necessity of thoroughly evaluating the implications of the performance of different PRB designs and reactive or adsorptive materials worldwide. Therefore, this study presents a comprehensive overview of field-scale PRBs applications and their long-term performance after on-site emplacements. This paper provides in-depth insight into this passive in-situ remediation technology for treating and even eliminating a contaminated plume over a long time in the subsurface. The overview will help all stakeholders worldwide understand the implications of PRBs and guide them to take all the required measures before its on-site application to avoid any potential failure.
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Affiliation(s)
- Rahul Singh
- Department of Civil Engineering, Indian Institute of Technology (IIT) Delhi, Hauz Khas, New Delhi 110016, India; Faculty of Engineering Science, Department of Mechanical, Process, and Environmental Engineering, University of Wismar - University of Applied Sciences, Technology, Business, and Design, Philipp-Müller-Str. 14, 23966 Wismar, Germany.
| | - Sumedha Chakma
- Department of Civil Engineering, Indian Institute of Technology (IIT) Delhi, Hauz Khas, New Delhi 110016, India
| | - Volker Birke
- Faculty of Engineering Science, Department of Mechanical, Process, and Environmental Engineering, University of Wismar - University of Applied Sciences, Technology, Business, and Design, Philipp-Müller-Str. 14, 23966 Wismar, Germany
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Wang J, Long Y, Yu G, Wang G, Zhou Z, Li P, Zhang Y, Yang K, Wang S. A Review on Microorganisms in Constructed Wetlands for Typical Pollutant Removal: Species, Function, and Diversity. Front Microbiol 2022; 13:845725. [PMID: 35450286 PMCID: PMC9016276 DOI: 10.3389/fmicb.2022.845725] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/01/2022] [Indexed: 01/09/2023] Open
Abstract
Constructed wetlands (CWs) have been proven as a reliable alternative to traditional wastewater treatment technologies. Microorganisms in CWs, as an important component, play a key role in processes such as pollutant degradation and nutrient transformation. Therefore, an in-depth analysis of the community structure and diversity of microorganisms, especially for functional microorganisms, in CWs is important to understand its performance patterns and explore optimized strategies. With advances in molecular biotechnology, it is now possible to analyze and study microbial communities and species composition in complex environments. This review performed bibliometric analysis of microbial studies in CWs to evaluate research trends and identify the most studied pollutants. On this basis, the main functional microorganisms of CWs involved in the removal of these pollutants are summarized, and the effects of these pollutants on microbial diversity are investigated. The result showed that the main phylum involved in functional microorganisms in CWs include Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes. These functional microorganisms can remove pollutants from CWs by catalyzing chemical reactions, biodegradation, biosorption, and supporting plant growth, etc. Regarding microbial alpha diversity, heavy metals and high concentrations of nitrogen and phosphorus significantly reduce microbial richness and diversity, whereas antibiotics can cause large fluctuations in alpha diversity. Overall, this review can provide new ideas and directions for the research of microorganisms in CWs.
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Affiliation(s)
- Jianwu Wang
- School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha, China.,Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha, China
| | - Yuannan Long
- School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha, China.,Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha, China
| | - Guanlong Yu
- School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha, China.,Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha, China.,Engineering and Technical Center of Hunan Provincial Environmental Protection for River-Lake Dredging Pollution Control, Changsha, China
| | - Guoliang Wang
- School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha, China.,Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha, China
| | - Zhenyu Zhou
- School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha, China.,Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha, China
| | - Peiyuan Li
- School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha, China.,Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha, China
| | - Yameng Zhang
- School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha, China.,Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha, China
| | - Kai Yang
- School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha, China.,Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha, China
| | - Shitao Wang
- School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha, China.,Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha, China
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Schwarz A, Pérez N. Long-term operation of a permeable reactive barrier with diffusive exchange. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 284:112086. [PMID: 33571852 DOI: 10.1016/j.jenvman.2021.112086] [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: 08/20/2019] [Revised: 01/23/2021] [Accepted: 01/28/2021] [Indexed: 06/12/2023]
Abstract
In this study, we evaluate the long term operation of a bench-scale reactor which simulates a permeable reactive barrier with sulfidic diffusive exchange (SDES PRB) to treat acid mine drainage (AMD), considering that treatment costs are very sensitive to the useful life for passive reactors. Its functioning was evaluated for a much longer period of 591 days compared to previous SDES PRB studies, with two influents simulating moderately and highly acid groundwater contaminated by AMD. First, we fed water amended with 200 mg/L Zn2+ and 3300 mg/L SO42- at pH 4.9; and after, water with 450 mg/L Fe2+, 100 mg/L Zn2+, 10 mg/L Ni2+, 5 mg/L Cu2+ and 3600 mg/L SO42- at pH 2.5. Biologically produced sulfide and alkalinity were enough to remove both metals and acidity (~99%) from the moderately acidic water, while with the highly acidic water, they resulted in significant removal of the metals reaching up to 87% and 79% of total Fe and Zn, respectively. Furthermore, no inhibitory effect was apparent, as the sulfate reduction rates in the two experiments did not vary significantly (averages close to 0.2 mol/m3-d), despite the much higher acidity and metal load in the second case. Hence, the SDES PRB protected the microbial consortium from metal toxicity and acidity in the long-term, and thus is suitable for remediation of AMD contaminated groundwater with high concentrations of metals, extending the operational range of conventional biological PRBs. Furthermore, an economic evaluation shows that SDES costs can be competitive with the costs of conventional chemical precipitation if the enhanced reactivity that SDES technology offers is realized.
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Affiliation(s)
- Alex Schwarz
- Departamento de Ingeniería Civil y Centro de Recursos Hídricos para La Agricultura y Minería (CRHIAM), Universidad de Concepción, Barrio Universitario, Concepción, Chile.
| | - Norma Pérez
- Departamento de Acuicultura, Universidad Católica del Norte, Larrondo, 1281, Coquimbo, Chile; Escuela de Prevención de Riesgos y Medio Ambiente, Universidad Católica del Norte, Larrondo, 1281, Coquimbo, Chile.
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Chen J, Li X, Jia W, Shen S, Deng S, Ji B, Chang J. Promotion of bioremediation performance in constructed wetland microcosms for acid mine drainage treatment by using organic substrates and supplementing domestic wastewater and plant litter broth. JOURNAL OF HAZARDOUS MATERIALS 2021; 404:124125. [PMID: 33049629 DOI: 10.1016/j.jhazmat.2020.124125] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/20/2020] [Accepted: 09/26/2020] [Indexed: 06/11/2023]
Abstract
Gravel-based subsurface-flow constructed wetlands (CWs) amended with a walnut shell (WS) substrate were established to treat synthetic acid mine drainage (AMD) in this study, and artificial domestic wastewater (DW) and plant litter broth (PLB) were supplemented to enhance the performance. The CW media rapidly reached adsorption saturation with respect to metals (except Fe and Cr) without an external carbon source, while the addition of DW and PLB stimulated sulfate reduction activity and achieved efficient biogenic metal removal, primarily by the formation of hydroxide and sulfide precipitates and concomitant co-precipitation. The WS-amended CWs performed notably better than the control systems, not only in sequestering more metals and rapidly establishing favourable environments for biogenic metal abatement but also in supporting better growth of plants and functional microbes. The external organic carbon input greatly shaped the bacterial community compositions in the CWs, with substantial increases in the proportions of core functional populations involved in AMD biotreatment. Cooperation among Cellulomonas, Propioniciclava and sulfate-reducing bacteria (SRB), dominated by Desulfobulbus and Desulfatirhabdium, was the primary biogenic mechanism of AMD remediation in the CWs. Cellulosic waste-amended CWs with DW and PLB addition offer a promising eco-technology for AMD remediation.
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Affiliation(s)
- Jinquan Chen
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China; Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, Yunnan University, Kunming 650091, China
| | - Xuan Li
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China; Institute of International Rivers and Eco-security, Yunnan University, Kunming 650091, China
| | - Wei Jia
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China; China Machinery International Engineering Design and Research Institute Co., Ltd, Changsha 410007, China
| | - Shili Shen
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China; Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, Yunnan University, Kunming 650091, China
| | - Shengjiong Deng
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China; Institute of International Rivers and Eco-security, Yunnan University, Kunming 650091, China
| | - Bohua Ji
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China; Institute of International Rivers and Eco-security, Yunnan University, Kunming 650091, China
| | - Junjun Chang
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China; Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, Yunnan University, Kunming 650091, China.
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Viadero RC, Zhang S, Hu X, Wei X. Mine drainage: Remediation technology and resource recovery. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2020; 92:1533-1540. [PMID: 32671879 DOI: 10.1002/wer.1401] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/18/2020] [Accepted: 07/09/2020] [Indexed: 06/11/2023]
Abstract
Drainage from current and historic mining operations remains a persistent environmental problem. Numerous research and development efforts were made in 2019 with a goal to minimize the impact of mine drainage on the environment, while other research endeavors addressed the mine drainage issue from a different perspective, where mine drainage was considered a resource for water and valuable products, such as metals, sulfuric acid, and rare earth elements. Thus, this review has two main sections: (a) focusing on research efforts in mine drainage remediation technology, and (b) emphasizing advances in resource recovery from mine drainage. The first section covers traditional and emerging passive and active treatment technologies. The second section summarizes resource recovery efforts using various technologies, such as selective precipitation, membrane process, and biological systems. PRACTITIONER POINTS: Significant progress continued to be made in the management of mine drainage and related issues. Recent remediation technology advances in mine drainage were presented. Technologies focusing on resource recovery from mine drainage were reviewed.
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Affiliation(s)
- Roger C Viadero
- Institute for Environmental Studies, Western Illinois University, Macomb, Illinois
| | - Shicheng Zhang
- Department of Environmental Science and Technology, Fudan University, Shanghai, China
| | - Xiaomin Hu
- School of Resources and Civil Engineering, Northeastern University, Shenyang, China
| | - Xinchao Wei
- School of Engineering, Slippery Rock University, Slippery Rock, Pennsylvania
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Evaluation of Dispersed Alkaline Substrate and Diffusive Exchange System Technologies for the Passive Treatment of Copper Mining Acid Drainage. WATER 2020. [DOI: 10.3390/w12030854] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The study evaluates the performance of the novel ADES (alkaline diffusive exchange System), SDES (sulfidogenic diffusive exchange system) and DAS (Dispersed Alkaline Substrate) technologies for the passive treatment of high-strength acid mine drainage (AMD) from copper mining (pH~3, 633 mg Cu L−1). The chemical DAS and ADES prototypes showed the best performance in the removal of Cu, Al, and Zn (98–100%), while the biochemical SDES reactors achieved a high sulfate removal rate (average of 0.28 mol m−3 day-1). Notably, the DES technology was effective in protecting the sulfate-reducing communities from the high toxicity of the AMD, and also in maintaining bed permeability, an aspect that was key in the ADES reactor. The DAS reactor showed the highest reactivity, accumulating the metallic precipitates in a lower reactor volume, allowing to conclude that it requires the lowest hydraulic residence time among all the reactors. However, the concentration of precipitates resulted in the formation of a hardpan, which may trigger the need of removing it to avoid compromising the continuity of the treatment process. This study suggests the development of new treatment alternatives by combining the strengths of each technology in combined or serial treatments.
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