DOCSLIB.ORG

Moderate Bioclogging Leading to Preferential Flow Paths in Biobarriers

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Moderate Bioclogging Leading to Preferential Flow Paths in Biobarriers Moderate Bioclogging Leading to Preferential Flow Paths in Biobarriers by Katsutoshi Seki, Martin Thullner, Junya Hanada, and Tsuyoshi Miyazaki Abstract Permeable reactive barriers (PRBs) are an alternative technique for the biological in situ remediation of ground water contaminants. Nutrient supply via injection well galleries is supposed to support a high microbial activity in these barriers but can ultimately lead to changes in the hydraulic conductivity of the biobarrier due to the accumulation of biomass in the aquifer. This effect, called bioclogging, would limit the remediation efficiency of the biobarrier. To evaluate the effects bio- clogging can have on the flow field of a PRB, flow cell experiments were carried out in the laboratory using glass beads as a porous medium. Two types of flow cells were used: a 20- 3 1- 3 1-cm cell simulating a single injection well in a one- dimensional flow field and a 20- 3 10- 3 1-cm cell simulating an injection well gallery in a two-dimensional flow field. A mineral medium was injected to promote microbial growth. Results of 9 d of continuous operation showed that conditions, which led to a moderate (50%) reduction of the hydraulic conductivity of the one-dimensional cell, led to a preferential flow pattern within the simulated barrier in the two-dimensional flow field (visualized by a tracer dye). The bioclogging leading to this preferential flow pattern did not change the hydraulic conductivity of the biobarrier as a whole but resulted in a reduced residence time of water within barrier. The biomass distribution measured after 9 d was consistent with the observed clogging effects showing step spatial gradients between clogged and unclogged regions. Introduction advantage of PRBs compared to other remediation tech- The efficiency optimization of in situ ground water niques is that after installation of the barrier only limited remediation as well as the minimization of costs and risks activities are required, e.g., periodical injection of reactive of such remediation measures is an active field of research material and monitoring of performance. Thus, the longev- for science and engineering. Among other techniques, e.g., ity of a PRB is an important issue for the efficiency of this pump-and-treat or monitored natural attenuation, perme- remediation technique. There are two main factors leading able reactive barriers (PRB) have been proposed for the in to a reduced PRB efficiency: first, the reactivity of the situ remediation of contaminated ground water. The basic reactive material can become exhausted, and second, the principle of this technique is to install a reactive zone permeability of the barrier can not be maintained, i.e., con- downgradient of the source of contamination. Until now, taminants can bypass the reactive zone without being the majority of PRBs are based on the abiotic degradation degraded. of contaminants using variable reactive media depending Processes potentially reducing the long-term perme- on the target contaminants (Scherer et al. 2000). However, ability of a PRB include the physical (e.g., particle deposi- during the past years there has been a considerable increase tion), chemical (e.g., mineral precipitation), and biological in studies focusing on engineered PRBs making use of the (e.g., biomass buildup or microbial gas production) clog- microbial remediation of contaminants (Kalin 2004). Tech- ging of the reactive zone. The latter process is of increased niques to construct a PRB depend on the reactive material relevance for microbial PRBs as the buildup of a sufficient used as well as on the site conditions. Microbial PRBs were amount of biomass is a necessary prerequisite for the bio- either installed by excavating parts of the aquifer and refill- remediation of the contaminants. Microbially induced ing the reactive material (Gavaskar 1998), or by installing clogging has been observed in many natural or artificial well arrays, which supply substrates supporting microbial porous media (Baveye et al. 1998), e.g., at the bottom of growth and activity (e.g., Dybas et al. 2002). The main waste water infiltration ponds (Davis et al. 1973), at septic tank effluents (Kristiansen 1981), or in the vicinity of ground water discharge wells (van Beek and van der Kooij Copyright ª 2006 The Author(s) 1982). More relevant for PRBs, the injection of substrates, Journal compilation ª 2006 National Ground Water Association. which promote microbial growth in an aquifer, is known to 68 Ground Water Monitoring & Remediation 26, no. 3/ Summer 2006/pages 68–76 clog waste water injection wells (e.g., Oberdorfer and Peterson 1985) or artificial recharge wells (e.g., Rebhun and Schwarz 1968; Vecchioli 1970). Furthermore, injecting growth- promoting substrates into an aquifer in order to enhance the bioremediation of contaminants can also lead to micro- bially induced clogging of the vicinity of the well, which reduces the efficiency of this well significantly (McCarty et al. 1998). In contrast, injecting growth-promoting sub- strates into an aquifer via well galleries is a technique to establish impermeable subsurface barriers making use of the microbial clogging—or bioclogging effect (Trefry et al. 1998; Hiebert et al. 2001). Therefore, bioclogging might also occur around well galleries used to install microbial PRBs, severely challenging their remediation performance. Unfortunately, only little is known on bioclogging of PRBs under field conditions because controlled experiments that address the significance and extent of such phenomena on the hydrodynamic characteristics of PRBs are lacking (Scherer et al. 2000). In contrast, bioclogging has been investigated in sev- eral laboratory studies showing that in columns or flow cells with a one-dimensional flow field the growth of biomass can lead to severe reductions of hydraulic conductivity of the system (e.g., Taylor and Jaffe´ 1990; Cunningham et al. 1991; Vandevivere and Baveye 1992a; Seki et al 1998). Furthermore, it has been shown in flow cells having a two- Figure 1. Setup of flow cell A (top) and flow cell B (bottom). dimensional flow field that bioclogging in the vicinity of an injection well can lead to significant changes in the flow field causing a flow bypass of the clogged zone without thickness 1 cm) simulating a two-dimensional flow field. changing the average hydraulic conductivity of the entire Both flow cells were made of light transparent acrylic plas- system (Kildsgaard and Engesgaard 2002; Thullner et al. tic material and were uniformly packed with glass beads 2002a). Extrapolating the latter observations to the field of 0.1-mm mean diameter resulting in a bulk density of scale implies that bioclogging might limit the performance 1.59 Mg/m3, which corresponds to total porosity of 0.383. of a PRB without necessarily being recognized by the moni- Inlet and outlet of the flow cells were supported by 0.1-mm toring system of the PRB. nylon mesh screens. The inflow and the outflow of the flow Up to now, an explicit comparison with conditions lead- cells (one port each for flow cell A and three ports each for ing to the bioclogging of a column and conditions leading flow cell B) were kept at a constant pressure head with to the flow bypass of a bioclogged zone has not been a head difference between inlet and outlet of 6 cm resulting done. Addressing this question would help verify the abil- in an average hydraulic gradient along the flow cells of 0.3. ity of predicting the risk for bioclogging occurring in Additional injection ports were installed in flow cell A at a PRB based on the results of laboratory studies. Further- 4 cm distance (tracer injection port) and in flow cells A and more, the investigation of a clogged laboratory-scale bio- B at 10 cm distance from the inlet (nutrient injection ports). barrier would help to determine criteria, which can be used At the bottom of both flow cells, water manometers were to determine the occurrence of bioclogging in the field. installed for monitoring the local distribution of the pres- The objective of this study is to investigate the condi- sure heads. The manometers were located at 4, 7, 10, 13, tions leading to a bioclogging-induced flow bypass of an and 16 cm from the inlet. Flow cell A was equipped with injection well. Results on the bioclogging in flow cells one row of manometers and one nutrient injection port, with one-dimensional and with two-dimensional flow fields whereas flow cell B was equipped with three parallel rows were compared to clarify to what extent the processes in of manometers (with 3-cm distance between each manome- a two-dimensional flow field, typical for a biobarrier, might ter row and 2-cm distance between the outer manometers be predicted based on column experiments. and the wall of the flow cell; Figure 1 bottom) and three tracer and nutrient injection ports each. Each flow cell was operated under water-saturated con- Materials and Methods ditions, in horizontal position, and at a constant tempera- ture of 20°C. After packing, the inoculum was injected Setup and Operation of the Flow Cells into the nutrient injection ports. This injection lasted until Experiments were conducted in two different flow a 2-cm region around the injection ports was inoculated cells. Flow cell A (Figure 1 top: length 20 cm; width 1 cm; using Brilliant Blue FCF dye in the inoculum to determine thickness 1 cm) simulating a one-dimensional flow field the inoculated area visually. After 24-h incubation time, and cell B (Figure 1 bottom: length 20 cm; width 10 cm; continuous flow was started. Deionized water was supplied K. Seki et al./ Ground Water Monitoring & Remediation 26, no. 3: 68–76 69 to the inlet ports, and the mineral medium was supplied to Results the nutrient injection ports using Mariotte bottles, both kept at the same pressure head.
Load more

Recommended publications
  • Impact of Biological Clogging on the Barrier Performance of Landfill Liners1
    Impact of biological clogging on the barrier performance of landfill liners1 Qiang Tanga, b, Fan Gue,*, Yu Zhanga, Yuqing Zhangd, Jialin Mob a School of Rail Transportation, Soochow University, Yangchenghu Campus, Xiangcheng District, Suzhou, 215131, China b Graduate School of Global Environmental Studies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan c National Center for Asphalt Technology, Auburn University, 277 Technology PKWY, Auburn, Alabama 36830, USA d School of Engineering and Applied Science, Aston University, Aston Triangle, Birmingham, B4 7ET, UK *Corresponding author, Ph.D., E-mail: [email protected] 1 This is an Accepted Manuscript of an article published by Journal of Environmental Management. The final publication is available online via https://doi.org/10.1016/j.jenvman.2018.05.039 1 Abstract The durability of landfill mainly relies on the anti-seepage characteristic of liner system. The accumulation of microbial biomass is effective in reducing the hydraulic conductivity of soils. This study aimed at evaluating the impact of the microorganism on the barrier performance of landfill liners. According to the results, Escherichia coli. produced huge amounts of extracellular polymeric substances and coalesced to form a confluent plugging biofilm. This microorganism eventually resulted in the decrease of soil permeability by 81% - 95%. Meanwhile, the increase of surface roughness inside the internal pores improved the adhesion between microorganism colonization and particle surface. Subsequently, an extensive parametric sensitivity analysis was undertaken for evaluating the contaminant transport in landfill liners. Decreasing the hydraulic conductivity from 1×10-8 m/s to 1×10-10 m/s resulted in the increase of the breakthrough time by 345.2%.
    [Show full text]
  • Geotechnical Properties of Biocement Treated Sand and Clay
    This document is downloaded from DR‑NTU (https://dr.ntu.edu.sg) Nanyang Technological University, Singapore. Geotechnical properties of biocement treated sand and clay Li, Bing 2015 Li, B. (2015). Geotechnical properties of biocement treated sand and clay. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/62560 https://doi.org/10.32657/10356/62560 Downloaded on 07 Oct 2021 07:43:27 SGT GEOTECHNICAL PROPERTIES OF BIOCEMENT TREATED SAND AND CLAY LI BING SCHOOL OF CIVIL AND ENVIRONMENTAL ENGINEERING 2015 GEOTECHNICAL PROPERTIES OF BIOCEMENT TREATED SAND AND CLAY LI BING School of Civil and Environmental Engineering A thesis submitted to the Nanyang Technological University in partial fulfillment of the requirement for the degree of Doctor of Philosophy 2015 Acknowledgements This project would not have been possible and successful without the continuous guidance from my supervisor Prof Chu Jian. I would like to express the most sincere gratitude for his inspiration, patience and guidance. His endlessly support and invaluable experience came handy throughout all these years. His close monitoring and encouragement are especially appreciated. I would also like to express my special thanks to Prof Andrew Whittle and Dr Volodymyr Ivanov as co-supervisors. I sincerely thank them for the wonderful opportunity to be part of this project, and their patience, guidance and invaluable knowledge sharing. I wish to acknowledge the help provided by Mr. Heng Hiang Kim Vincent, Mr. Tan Hiap Guan Eugene, Ms Lim-Ding Susie and Mr. Koh Sun Weng Andy from the Geotechnical Laboratory, and Mr. Ong Chee Yung, Mr. Tan Han Khiang, Ms See Shen Yen, Pearlyn, Ms Maria Chong Ai Shing and the rest of the staff from the Environmental Laboratory for rendering the help on equipment, chemicals and laboratory testing.
    [Show full text]
  • Society Science Impact of Bioclogging on Peat Versus Sand Biofilters Nine
    Published June 9, 2015 Science Society Science Nine-Year Effort to Reduce Nitrate Leaching Impact of Bioclogging on Peat versus Sand Leaching of nitrate from agricul- tural fields is of major concern in many Biofilters countries. Several methods have been suggested for reducing nitrate leach- Although the bacteria in biofilter sys- ing, such as non-inversion tillage, straw tems are critical to filtering and treating retention, and catch crops (cover crops). wastewater streams, their growth can However, conflicting results are often re- also clog these systems, causing them ported, and there is a shortage of studies to fail. A recent study in Vadose Zone in which combinations of methods have Journal compared the impact of bacterial biomass growth been allowed to continue for several on unsaturated, hydraulic conductivity and flow rate in years. biofilters composed of four media: filter media sand, septic bed sand, loose peat, and dense peat. In the May–June issue of the Journal of Environmental Quality, researchers report on nitrate leaching in a nine-year For each medium, five columns were constructed and study that combined different tillage methods with differ- tested. In the peat columns, saturation profiles measured ent crop rotations, straw handling, and catch crops at two over time showed an increase in water content over the locations in Denmark, Northern Europe. entire column, suggesting that wastewater flowed easily through the peat and bacterial biomass developed over a The researchers found that using a well-established fod- wide range of depths. In the sand columns, in contrast, a der radish as a catch crop was the most effective method to pronounced increase in saturation was detected at the col- reduce nitrate leaching under the region’s prevailing tem- umn top due to biomat formation.
    [Show full text]
  • Modelling Bioclogging in Variably Saturated Porous Media and the Interactions Between Surface/Subsurface Flows: Application to Constructed Wetlands R
    Modelling bioclogging in variably saturated porous media and the interactions between surface/subsurface flows: Application to Constructed Wetlands R. Samso, J. Garcia, Pascal Molle, N. Forquet To cite this version: R. Samso, J. Garcia, Pascal Molle, N. Forquet. Modelling bioclogging in variably satu- rated porous media and the interactions between surface/subsurface flows: Application to Con- structed Wetlands. Journal of Environmental Management, Elsevier, 2016, 165, pp.271-279. 10.1016/j.jenvman.2015.09.045. hal-01700725 HAL Id: hal-01700725 https://hal.archives-ouvertes.fr/hal-01700725 Submitted on 5 Feb 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Author-produced version of the article published in Journal of Environmental Management (2016), vol. 165, p. 271–279 The original publication is available at http://www.sciencedirect.com/ doi : 10.1016/j.jenvman.2015.09.045 ©. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ Modelling bioclogging in variably saturated porous media and the interactions between surface/subsurface flows: application to Constructed Wetlands Roger Sams´oa,b, Joan Garc´ıaa, Pascal Molleb, Nicolas Forquetb,∗ aGEMMA, Group of Environmental Engineering and Microbiology, Department of Hydraulic, Maritime and Environmental Engineering, Universitat Polit`ecnica de Catalunya-BarcelonaTech, c/Jordi Girona, 1-3, Building D1, E-08034, Barcelona, Spain.
    [Show full text]
  • A Bilayer Coarse-Fine Infiltration System Minimizes Bioclogging: 2 the Relevance of Depth Dynamics
    1 A bilayer coarse-fine infiltration system minimizes bioclogging: 2 The relevance of depth dynamics 3 4 N. Perujo,a,b,c* A.M. Romaní,c and X. Sanchez-Vilaa,b 5 a Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya 6 (UPC), Jordi Girona 1-3, 08034 Barcelona, Spain 7 b Hydrogeology Group (UPC−CSIC), Barcelona, Spain 8 c GRECO - Institute of Aquatic Ecology, Universitat de Girona, 17003 Girona, Spain 9 *Corresponding author: [email protected] 10 11 Keywords: biofilm attachment/detachment; extracellular polymeric substances (EPS); 12 biofilm activity; porous media; deep clogging, grain size distribution 13 1 14 Abstract 15 Bioclogging is a main concern in infiltration systems as it may significantly shorten the 16 service life of these low-technology water treatment methods. In porous media, biofilms 17 grow to clog partially or totally the pore network. Dynamics of biofilm accumulation 18 (e.g., by attachment, detachment, advective transport in depth) and their impact on both 19 surface and deep bioclogging are still not yet fully understood. To address this concern, 20 a 104 day-long outdoor infiltration experiment in sand tanks was performed, using 21 secondary treated wastewater and two grain size distributions (GSDs): a monolayer 22 system filled with fine sand, and a bilayer one composed by a layer of coarse sand 23 placed on top of a layer of fine sand. Biofilm dynamics as a function of GSD and depth 24 were studied through cross-correlations and multivariate statistical analyses using 25 different parameters from biofilm biomass and activity indices, plus hydraulic 26 parameters measured at different depths.
    [Show full text]
  • Experimental Study on Bioclogging in Porous Media During the Radioactive Effluent Percolation
    Hindawi Advances in Civil Engineering Volume 2018, Article ID 9671371, 6 pages https://doi.org/10.1155/2018/9671371 Research Article Experimental Study on Bioclogging in Porous Media during the Radioactive Effluent Percolation Rong Gui ,1,2,3 Yu-xiang Pan ,2,3 De-xin Ding ,1,2,3 Yong Liu,2,3 and Zhi-jun Zhang 2,3 1School of Resources and Safety Engineering, Central South University, Changsha, Hunan 420083, China 2Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, Hunan 421001, China 3Nuclear Resource Engineering College, University of South China, Hengyang, Hunan 421001, China Correspondence should be addressed to De-xin Ding; [email protected] and Zhi-jun Zhang; [email protected] Received 8 June 2018; Revised 22 September 2018; Accepted 3 October 2018; Published 8 November 2018 Guest Editor: Zhongwei Chen Copyright © 2018 Rong Gui et al. .is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. .e sand columns inoculated with the indigenous microorganism (Aspergillus niger) were used to investigate the effect of bioclogging during the radioactive effluent percolation. .e hydraulic gradient, volumetric flow rate, and uranyl ions con- centration were monitored over time. .e sand columns were operated with continuous radioactive effluent of uranium tailings reservoir. After 68 days, the hydraulic conductivity of the sand columns decreased more than 72%, and the adsorption rate of uranyl ions by Aspergillus niger reached more than 90%. Environmental scanning electron microscope imaging confirmed the biofilm covering the surface of sand particles and connecting sand particles together, which resulted in a reduction of hydraulic conductivity.
    [Show full text]
  • Bioclogging Effects in Constructed Wetlands for Wastewater Treatment
    Modelling bioclogging effects in Constructed Wetlands for wastewater treatment Roger Samsó, Nicolas Forquet, Pascal Molle and Joan García [email protected] Intensive WWTPs Extensive WWTPs (based on Constructed Wetlands (CWs)) Land requirements Low environmental impacts Low construction, operation and maintenance costs Verdú (Lleida, Spain) Close-up of a CW Missery (Côte d’Or, France) ≈ 0.5m 10 – 50 m 15 – 30 m Impermeable basin Filled with a porous media (gravel) Planted with aquatic macrophytes Fed with wastewater Main operational problem of CWs High bacterial yields High load of OM and nutrients Biological clogging Objective To build a bioclogging model for unsaturated porous media to simulate clogging development and the subsequent overland flow in Constructed Wetlands Model description • 2D domain (longitudinal section of a CW) • Surface and Subsurface flow (Richards equation) • Advective-dispersive reactive transport • Bacterial growth (Monod, 1949) 휕푋 퐶 = 휇푋 X− kX 휕푡 퐾푋,퐶+퐶 • Bioclogging Model (Rosenzweig et al., 2009) Bioclogging model (Rosenzweig et al., 2009) Van Genucthen (1980) Initial pore size distribution Capillary model 2휎 cos 훽 푟 = − 훾ℎ ∆휃 푁푖 = 2 휋푟푖 Biofilm-affected pore size distribution Bacteria volume fraction 휃푚= X 휌푋 푟푏,푖= 푟푓,푖 1 − 푆푒푚 Microbial effective saturation 휃푚 푆푒푚 = 휃푠 − 휃푟 푁푏,푖 = 푁푓,푖 Relative permeability (Hagen-Poiseuille) Unsaturated, biofilm-affected flow 푗 4 푖=1 푁푏,푖 푟푏,푖 푘푏(휃푤,푗) = 푀 4 푖=1 푁푓,푖 푟푓,푖 Saturated, biofilm-free flow Numerical experiment • Two simulations of 30 days – Simulation 1: considering clogging – Simulation 2: neglecting clogging • Comparison of different model outputs Results (1/3): Porosity occupation Results (2/3): Bacteria distribution 5 days 10 days 퐾 푚3 15 days 30 days Results (3/3): Overland vs Subsurface flow Conclusions • A new study of bioclogging in unsaturated porous media • Bioclogging changes bacterial distribution and causes overland flow, reducing CWs lifespan • Still a work in progress Further development • The model of Rosenzweig et al.
    [Show full text]
  • Impact of Carbon and Nitrogen on Bioclogging in a Sand Grain Managed Aquifer Recharge (MAR)
    Environ. Eng. Res. 2020; 25(6): 841-846 pISSN 1226-1025 https://doi.org/10.4491/eer.2019.373 eISSN 2005-968X Impact of carbon and nitrogen on bioclogging in a sand grain managed aquifer recharge (MAR) Heonseop Eom1, Sami Flimban1, Anup Gurung1, Heejun Suk2, Yongcheol Kim2, Yong Seong Kim3, Sokhee P. Jung4, Sang-Eun Oh1† 1Department of Biological Environment, Kangwon National University, Chuncheon-si, 200-701, Republic of Korea 2Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources, Daejeon 305-350, Republic of Korea 3Department of Regional Infrastructure Engineering, Kangwon National University, Republic of Korea 4Department of Environment and Energy Engineering, Chonnam National University, Gwangju, Republic of Korea ABSTRACT Managed aquifer recharge (MAR), an intentional storage of excess water to an aquifer, is becoming a promising water resource management tool to cope with the worldwide water shortage. Bioclogging is a commonly encountered operational issue that lowers hydraulic conductivity and overall performance in MAR. The current study investigates the impact of carbon and nitrogen in recharge water on bioclogging in MAR. For this investigation, continuous-flow columns packed with sand grains were operated with influents having 0 (C1), 5 (C2), and 100 mg/L (C3) of glucose with or without introduction of nitrate. Hydraulic conductivity was analyzed to evaluate bioclogging in the systems. In C1 and C2, hydraulic conductivity was not significantly changed overall. However, hydraulic conductivity in C3 was decreased by 28.5% after three weeks of operation, which appears to be attributed to generation of fermentation bacteria. Introduction of nitrogen to C3 led to a further decrease in hydraulic conductivity by 25.7% compared to before it was added, most likely due to stimulation of denitrifying bacteria.
    [Show full text]
  • Bioclogging in Porous Media: Model Development And
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Infoscience - École polytechnique fédérale de Lausanne Accepted Version 1 Bioclogging in porous media: Model development and 2 sensitivity to initial conditions 3 1 2 4 A. Brovelli , F. Malaguerra and D. A. Barry 5 6 Laboratoire de technologie écologique, Institut des sciences et technologies de 7 l’environnement, Station 2, Ecole Polytechnique Fédérale de Lausanne, CH-1015 8 Lausanne, Switzerland 9 Emails: [email protected] , [email protected] , [email protected] 10 11 12 Submitted to: Environmental Modelling and Software 13 July 2, 2008 14 Revision #1: October 6, 2008 1 Author to whom all correspondence should be addressed. Telephone: +41 (21) 693-5919, Facsimile: +41 (21) 693-5670 2 Now at Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, 2800 Kgs. Lingby, Denmark. 1 Accepted Version 15 Abstract 16 This work presents a numerical model able to simulate the effect of biomass growth on the hydrau- 17 lic properties of saturated porous media, i.e., bioclogging. A new module for an existing coupled 18 flow and reactive-transport code-PHWAT-was implemented. Laboratory experiments were used to 19 validate the model.. Good agreement with the experimental data was found. Model behavior was 20 satisfactory in terms of numerical discretization errors and parameter calibration, although-grid- 21 independent results were difficult to achieve. The new code was applied to investigate the effect of 22 the initial conditions on clogging development. A set of simulations was conducted considering 1D 23 and 2D flow conditions, for both uniform and heterogeneous initial biomass concentrations.
    [Show full text]
  • Microbial Ecology of Biofiltration Units Used for the Desulfurization of Biogas
    chemengineering Review Microbial Ecology of Biofiltration Units Used for the Desulfurization of Biogas Sylvie Le Borgne 1,* and Guillermo Baquerizo 2,3 1 Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana- Unidad Cuajimalpa, 05348 Ciudad de México, Mexico 2 Irstea, UR REVERSAAL, F-69626 Villeurbanne CEDEX, France 3 Departamento de Ingeniería Química, Alimentos y Ambiental, Universidad de las Américas Puebla, 72810 San Andrés Cholula, Puebla, Mexico * Correspondence: [email protected]; Tel.: +52–555–146–500 (ext. 3877) Received: 1 May 2019; Accepted: 28 June 2019; Published: 7 August 2019 Abstract: Bacterial communities’ composition, activity and robustness determines the effectiveness of biofiltration units for the desulfurization of biogas. It is therefore important to get a better understanding of the bacterial communities that coexist in biofiltration units under different operational conditions for the removal of H2S, the main reduced sulfur compound to eliminate in biogas. This review presents the main characteristics of sulfur-oxidizing chemotrophic bacteria that are the base of the biological transformation of H2S to innocuous products in biofilters. A survey of the existing biofiltration technologies in relation to H2S elimination is then presented followed by a review of the microbial ecology studies performed to date on biotrickling filter units for the treatment of H2S in biogas under aerobic and anoxic conditions. Keywords: biogas; desulfurization; hydrogen sulfide; sulfur-oxidizing bacteria; biofiltration; biotrickling filters; anoxic biofiltration; autotrophic denitrification; microbial ecology; molecular techniques 1. Introduction Biogas is a promising renewable energy source that could contribute to regional economic growth due to its indigenous local-based production together with reduced greenhouse gas emissions [1].
    [Show full text]
  • Modeling Precipitate-Dominant Clogging for Landfill Leachate With
    Journal of Hazardous Materials 274 (2014) 413–419 Contents lists available at ScienceDirect Journal of Hazardous Materials j ournal homepage: www.elsevier.com/locate/jhazmat Modeling precipitate-dominant clogging for landfill leachate with NICA-Donnan theory ∗ Zhenze Li Wuhan Institute of Rock and Soil Mechanics, China Academy of Science, Wuhan, Hubei, China h i g h l i g h t s • An interesting theoretical investigation into the clogging of landfill drainages. • First time advanced modeling of precipitate-dominant clogging of DOC rich leachate. • Up-to-date model parameters to estimate speciation of calcium and DOCs. • Modelings calibrated with experimental results on clogging of gravel aggregates. • NICA-Donnan theory is robust to model speciation of cation–DOC complexes. a r t i c l e i n f o a b s t r a c t Article history: Bioclogging of leachate drains is ubiquitous in landfills for municipal solid wastes. Formation of calcium Received 20 February 2014 precipitates and biofilms in pore space is the principal reason for clogging. But the calcium speciation Received in revised form 5 April 2014 in leachte rich in dissolved organic matters (DOM) remains to be uncovered. In spite of its complexity, Accepted 7 April 2014 NICA-Donnan model has been used to compute the speciation of metals and the binding capacities of Available online 13 April 2014 humic substances. This study applies NICA-Donnan theory into the simulation of calcium speciation during the formation of precipitate-dominant clogging in leachate drainage aggregates for the first time. Keywords: The consideration of DOC–Ca complexation gives reasonable explanation to the speciation of calcium, Clogging Modeling which is viewed as oversaturated, in leachate with concentrated DOM.
    [Show full text]
  • Optimization of Calcium‑Based Bioclogging and Biocementation of Sand
    This document is downloaded from DR‑NTU (https://dr.ntu.edu.sg) Nanyang Technological University, Singapore. Optimization of calcium‑based bioclogging and biocementation of sand Chu, Jian; Ivanov, Volodymyr; Naeimi, Maryam; Stabnikov, Viktor; Liu, Han‑Long 2013 Chu, J., Ivanov, V., Naeimi, M., Stabnikov, V., & Liu, H.‑L. (2014). Optimization of calcium‑based bioclogging and biocementation of sand. Acta Geotechnica, 9(2), 277‑285. https://hdl.handle.net/10356/81878 https://doi.org/10.1007/s11440‑013‑0278‑8 © 2013 Springer‑Verlag Berlin Heidelberg. This is the author created version of a work that has been peer reviewed and accepted for publication by Acta Geotechnica, Springer‑Verlag Berlin Heidelberg. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1007/s11440‑013‑0278‑8]. Downloaded on 01 Oct 2021 14:41:31 SGT Optimization of calcium-based bioclogging and biocementation of sand Jian Chu, Volodymyr Ivanov, Maryam Naeimi, Viktor Stabnikov, and Han- Long Liu J. Chu (c), V. Ivanov Department of Civil, Construction & Environmental Engineering, Iowa State University, Ames, Iowa, 50011, USA. Tel.: +1-515-294-3157 Fax: +1-515-294-8216 Email: [email protected]; Formerly School of Civil and Environmental Engineering, Nanyang Technological University, Singapore. M. Naeimi School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Ave, Singapore, 639798. V. Stabnikov Department of Biotechnology and Microbiology, National University of Food Technologies, 60 Volodymyrskaya Str., Kiev 01033, Ukraine H.-L. Liu, College of Civil and Transportation Engineering, Hohai University, Nanjing, China Abstract Bioclogging and biocementation can be used to improve the geotechnical properties of sand.
    [Show full text]