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Ekolu SO, Solomon F, de Beer F, Bitandi L, Kilula RN, Maseko KT, Mahlangu FG. Measurement of pore volume, connectivity and clogging of pervious concrete reactive barrier used to treat acid mine drainage. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:55743-55756. [PMID: 35322361 DOI: 10.1007/s11356-022-18850-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
It has recently been shown that pervious concrete is a promising, effective technology as a permeable reactive barrier system for treatment of acid mine drainage (AMD). However, pore clogging also occurs simultaneously during AMD treatment. In the present study, mixtures of pervious concrete were made and used in a column experiment during which pore clogging occurred in the samples. Pore volume, connectivity and other parameters of pervious concrete were evaluated using five (5) different methods comprising the volumetric method (VM), linear-traverse method (LTM), image analysis (IA), falling head permeability test and X-ray microcomputed tomography. It was found that pervious concrete effectively removed from AMD, about 90 to 99% of various heavy metals including Al, Fe, Zn, Mn and Mg. Cr concentration significantly increased in the treated effluent, owing to leaching from cementitious materials used in mixtures. The VM and LTM gave statistically similar pore volume results, while IA's values were 20 to 30% higher than those of the conventional methods. The falling head permeability test and IA were found to be effective in quantifying pore clogging effects. Pervious concrete exhibited high pore connectivity of 95.0 to 99.7%, which underlies its efficacious hydraulic conductivity.
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Affiliation(s)
- Stephen O Ekolu
- Department of Civil Engineering, Nelson Mandela University, Gqeberha, South Africa
| | - Fitsum Solomon
- Department of Civil Engineering, Nelson Mandela University, Gqeberha, South Africa.
| | - Frikkie de Beer
- Nuclear Technology Division, NECSA, Box 582, Pretoria, 0001, South Africa
| | - Louisette Bitandi
- Department of Civil Engineering Science, University of Johannesburg, Johannesburg, South Africa
| | - Rais N Kilula
- Department of Civil Engineering Science, University of Johannesburg, Johannesburg, South Africa
| | - Khaya T Maseko
- Department of Civil Engineering Science, University of Johannesburg, Johannesburg, South Africa
| | - Fatty G Mahlangu
- Department of Civil Engineering Science, University of Johannesburg, Johannesburg, South Africa
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Wijeyawardana P, Nanayakkara N, Gunasekara C, Karunarathna A, Law D, Pramanik BK. Improvement of heavy metal removal from urban runoff using modified pervious concrete. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 815:152936. [PMID: 34995593 DOI: 10.1016/j.scitotenv.2022.152936] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 12/22/2021] [Accepted: 01/02/2022] [Indexed: 06/14/2023]
Abstract
Heavy metals are one of the major chemical pollutant groups in urban runoff. The application of porous concrete is a potential alternative to conventional runoff management systems with the ability to remove heavy metals. Hence, a thorough understanding of the heavy metal removal mechanisms and constraints of conventional porous concrete opens a path for the development of effective modifications. This review critically discusses the major contributors in ordinary porous concrete which supports heavy metal removal. The effects of initial concentration, contact time and competing ions on heavy metal removal using porous concrete are also discussed. Additionally, the effect of decalcification, atmospheric carbonation, acid influent on heavy metal removal is reviewed. The major drawback of porous concrete is the high pH (>8.5) of the effluent water, decalcification of the porous concrete and leaching of adsorbed pollutants. Overall, the addition of adsorbent materials to the porous concrete increases removal efficiencies (7% - 65% increase) without neutralizing the effluent pH. Meanwhile, the addition of Reduced Graphene Oxide is successful in reducing the leachability of the removed heavy metals. The addition of pozzolanic materials can lower the effluent pH while maintaining similar removal efficiencies to unmodified porous concrete. Therefore, developing a novel method of neutralizing the effluent pH must be prioritized in future studies. Additionally, the toxicity that can occur due to the abrasion of modified porous concrete requires study in future research. Further, advanced characterization methods should be used in future studies to understand the mechanisms of removal via the modified porous concrete materials.
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Affiliation(s)
- Pamodithya Wijeyawardana
- School of Engineering, RMIT University Melbourne, Australia; Faculty of Engineering, University of Peradeniya, Sri Lanka
| | | | | | | | - David Law
- School of Engineering, RMIT University Melbourne, Australia
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Debnath B, Sarkar PP. Clogging in Pervious Concrete Pavement Made with Non-conventional Aggregates: Performance Evaluation and Rehabilitation Technique. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2021. [DOI: 10.1007/s13369-021-05380-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Permeability and Strength of Pervious Concrete According to Aggregate Size and Blocking Material. SUSTAINABILITY 2021. [DOI: 10.3390/su13010426] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The purpose of this study is to identify the differences in porosity and permeability coefficients when the mixing ratio of aggregates is different and to present the mixing ratio satisfying the strength requirement of compressive specified in a specification of Korea. Three mix ratios were suggested by considering various aggregate sizes and three cylinders were made for each ratio. The porosities of those cylinders were evaluated through the compression and water permeability test, measuring the weight of specimens in underwater and analysis of the pictured Computed Tomography (CT) image. Experiments have shown that it is best to mix 50% for 5–10 mm aggregates, 45% for 2–5 mm aggregates, and 5% for sand in terms of strength and permeability. In addition, as the proportion of fine aggregates increased, the porosity and permeability decreased. Moreover, the effectiveness of maintenance method was also examined in this study.
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Influence of Clogging and Unbound Base Layer Properties on Pervious Concrete Drainage Characteristics. MATERIALS 2020; 13:ma13112455. [PMID: 32481642 PMCID: PMC7321344 DOI: 10.3390/ma13112455] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/21/2020] [Accepted: 05/27/2020] [Indexed: 12/03/2022]
Abstract
This paper aims to assess the influence of clogging on paving material (pervious concrete) drainage characteristics as well as the influence of the properties of an unbound base layer on drainage characteristics of the whole paving system. The clogging influence has been studied measuring the drainage characteristics on pervious concrete flags before and after their clogging, according to ASTM C1701-09. Additionally, the drainage characteristics of uncontaminated pervious concrete as a paving material was assessed using the falling head method. To assess the influence of properties of an unbound base course (UBC) on drainage characteristics of the whole paving system, the unbound base layer was compacted in two different levels of compaction and the drainage characteristics were measured (according to ASTM C1701-09). It is concluded that pervious concrete prepared with a smaller aggregate fraction is more prone to clogging. Regarding the influence of UBC, it is important to find a balance between pervious concrete infiltration and UBC exfiltration rate, particularly in a case of pervious concrete flags made of coarse aggregate.
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Study on the Permeability of Recycled Aggregate Pervious Concrete with Fibers. MATERIALS 2020; 13:ma13020321. [PMID: 31936714 PMCID: PMC7013612 DOI: 10.3390/ma13020321] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 12/31/2019] [Accepted: 01/08/2020] [Indexed: 11/17/2022]
Abstract
Pervious concrete is considered to be porous concrete because of its pore structure and excellent permeability. In general, larger porosity will increase the permeability coefficient, but will significantly decrease the compressive strength. The effects of water-cement ratio, fiber types, and fiber content on the permeability coefficient, porosity, compressive strength, and flexural strength were investigated. The pore tortuosity of the pervious concrete was determined by volumetric analysis and two-dimensional cross-sectional image analysis. The concept and calculation method of porosity tortuosity were further proposed. Results show that the permeability coefficient of the pervious concrete is the most suitable with a water-cement ratio of 0.30; the water permeability of the pervious concrete is influenced by fiber diameter. The permeability coefficient of pervious concrete with polypropylene thick fiber (PPTF) is greater than that with copper coated steel fiber (CCF) and the polypropylene fiber (PPF). The permeability coefficient is related to tortuosity and porosity, but when porosity is the same, the permeability coefficient may be different. Finally, general relations between the permeability coefficient and porosity tortuosity are constructed.
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Rodak CM, Moore TL, David R, Jayakaran AD, Vogel JR. Urban stormwater characterization, control, and treatment. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2019; 91:1034-1060. [PMID: 31243836 DOI: 10.1002/wer.1173] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 06/21/2019] [Accepted: 06/21/2019] [Indexed: 06/09/2023]
Abstract
This review summarizes over 250 studies published in 2018 related to the characterization, control, and management of urban stormwater runoff. The review covers three broad themes: (a) quantity and quality characterization of stormwater, (b) control and treatment of stormwater runoff, and (c) implementation and assessment of watershed-scale green stormwater infrastructure (GSI). Each section provides an overview of the 2018 literature, common themes, and future work. Several themes emerged from the 2018 literature including exploration of contaminants of emerging concern within stormwater systems, characterization and incorporation of vegetation-driven dynamics in stormwater control measures, and the need for interdisciplinary perspectives on the implementation and assessment of GSI. PRACTITIONER POINTS: Over 250 studies were published in 2018 related to the characterization, control, and treatment of stormwater. Studies cover general stormwater characteristics, control and treatment systems, and watershed-scale assessments. Trends in 2018 include treatment trains, vegetation dynamics, and interdisciplinary perspectives.
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Affiliation(s)
- Carolyn M Rodak
- Civil Engineering, State University of New York Polytechnic Institute, Utica, New York
| | - Trisha L Moore
- Biological and Agricultural Engineering, Kansas State University, Manhattan, Kansas
| | - Ray David
- Greeley and Hansen, San Francisco, California
| | - Anand D Jayakaran
- Washington Stormwater Center, Washington State University, Puyallup, Washington
| | - Jason R Vogel
- Civil Engineering and Environmental Science, University of Oklahoma, Norman, Oklahoma
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Perujo N, Romaní AM, Sanchez-Vila X. A bilayer coarse-fine infiltration system minimizes bioclogging: The relevance of depth-dynamics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 669:559-569. [PMID: 30889445 DOI: 10.1016/j.scitotenv.2019.03.126] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 03/08/2019] [Accepted: 03/08/2019] [Indexed: 06/09/2023]
Abstract
Bioclogging is a main concern in infiltration systems as it may significantly shorten the service life of these low-technology water treatment methods. In porous media, biofilms grow to clog partially or totally the pore network. Dynamics of biofilm accumulation (e.g., by attachment, detachment, advective transport in depth) and their impact on both surface and deep bioclogging are still not yet fully understood. To address this concern, a 104 day-long outdoor infiltration experiment in sand tanks was performed, using secondary treated wastewater and two grain size distributions (GSDs): a monolayer system filled with fine sand, and a bilayer one composed by a layer of coarse sand placed on top of a layer of fine sand. Biofilm dynamics as a function of GSD and depth were studied through cross-correlations and multivariate statistical analyses using different parameters from biofilm biomass and activity indices, plus hydraulic parameters measured at different depths. Bioclogging (both surface and deep) was found more significant in the monolayer fine system than in the bilayer coarse-fine one, possibly due to an early low-cohesive biofilm formation in the former, driven by lower porosity and lower fluxes; under such conditions biomass is favorably detached from the top layer, transported and accumulated in depth, so that new biomass might colonize the surface. On the other hand, in the bilayer system, fluxes are highest, and the biofilm is still in a growing phase, with low biofilm detachment capability from the top sand layer and high microbial activity in depth, resulting in low bioclogging. Overall, the bilayer coarse-fine system allows infiltrating higher volume of water per unit of surface area than the monolayer fine one, minimizing surface and deep bioclogging, and thus increasing the longevity and efficiency of infiltration systems.
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Affiliation(s)
- N Perujo
- Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya (UPC), Jordi Girona 1-3, 08034 Barcelona, Spain; Hydrogeology Group (UPC-CSIC), Barcelona, Spain; GRECO - Institute of Aquatic Ecology, Universitat de Girona, 17003 Girona, Spain.
| | - A M Romaní
- GRECO - Institute of Aquatic Ecology, Universitat de Girona, 17003 Girona, Spain
| | - X Sanchez-Vila
- Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya (UPC), Jordi Girona 1-3, 08034 Barcelona, Spain; Hydrogeology Group (UPC-CSIC), Barcelona, Spain
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