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The stability (longevity of activity) of three crude urease extracts was evaluated in a laboratory study as part of an effort to reduce the cost of urease for applications that do not require high purity enzyme. A low-cost, stable source of urease will greatly facilitate engineering applications of urease such as biocementation of soil. Inexpensive crude extracts of urease have been shown to be effective at hydrolyzing urea for carbonate precipitation. However, some studies have suggested that the activity of a crude extract may decrease with time, limiting the potential for its mass production for commercial applications. The stability of crude urease extracts shown to be effective for biocementation was studied. The crude extracts were obtained from jack beans via a simple extraction process, stored at room temperature and at 4 ℃, and periodically tested to evaluate their stability. To facilitate storage and transportation of the extracted enzyme, the longevity of the enzyme following freeze drying (lyophilization) to reduce the crude extract to a powder and subsequent re-hydration into an aqueous solution was evaluated. In an attempt to improve the shelf life of the lyophilized extract, dextran and sucrose were added during lyophilization. The stability of purified commercial urease following rehydration was also investigated. Results of the laboratory tests showed that the lyophilized crude extract maintained its activity during storage more effectively than either the crude extract solution or the rehydrated commercial urease. While incorporating 2% dextran (w/v) prior to lyophilization of the crude extract increased the overall enzymatic activity, it did not enhance the stability of the urease during storage.
Neda Javadi; Hamed Khodadadi Tirkolaei; Nasser Hamdan; Edward Kavazanjian. Longevity of Raw and Lyophilized Crude Urease Extracts. Sustainable Chemistry 2021, 2, 325 -334.
AMA StyleNeda Javadi, Hamed Khodadadi Tirkolaei, Nasser Hamdan, Edward Kavazanjian. Longevity of Raw and Lyophilized Crude Urease Extracts. Sustainable Chemistry. 2021; 2 (2):325-334.
Chicago/Turabian StyleNeda Javadi; Hamed Khodadadi Tirkolaei; Nasser Hamdan; Edward Kavazanjian. 2021. "Longevity of Raw and Lyophilized Crude Urease Extracts." Sustainable Chemistry 2, no. 2: 325-334.
A crude extract from jack beans (Canavalia gladiata) is demonstrated to be an effective source of urease enzyme for biocementation via enzyme-induced carbonate precipitation (EICP). Test tube tests of crude and purified extracts from jack beans, jack bean meal, soybeans, and watermelon seeds show that the crude jack bean extract results in the highest unit yield, defined as urease content per initial mass of source material, among these four plant sources. The efficacy of EICP using crude jack bean extract for biocementation was compared with the efficacy of three commercially available enzymes by biocementation of a granular soil. Unconfined compression tests on the granular soil specimens subject to biocementation via EICP demonstrated that the crude extract and the less purified commercially available enzyme were actually more effective than commercially available highly purified urease enzymes at enhancing soil strength, an effect attributed to the presence of complementary proteins in the less purified enzyme sources. The simple technique used to produce the crude extract from jack beans significantly lowers the cost of EICP, eliminating a major barrier to practical applications, including infrastructure construction and environmental protection.
Hamed Khodadadi Tirkolaei; Neda Javadi; Vinay Krishnan; Nasser Hamdan; Edward Kavazanjian Jr.. Crude Urease Extract for Biocementation. Journal of Materials in Civil Engineering 2020, 32, 04020374 .
AMA StyleHamed Khodadadi Tirkolaei, Neda Javadi, Vinay Krishnan, Nasser Hamdan, Edward Kavazanjian Jr.. Crude Urease Extract for Biocementation. Journal of Materials in Civil Engineering. 2020; 32 (12):04020374.
Chicago/Turabian StyleHamed Khodadadi Tirkolaei; Neda Javadi; Vinay Krishnan; Nasser Hamdan; Edward Kavazanjian Jr.. 2020. "Crude Urease Extract for Biocementation." Journal of Materials in Civil Engineering 32, no. 12: 04020374.
Excess nutrients in water such as nitrogen and phosphorus result in microbial growth and overfertilization of aquatic plants, increasing the rate of eutrophication in water bodies. This work investigated the application of an in situ nutrient removal technology utilizing the recycled materials basic oxygen furnace (BOF) slag and wood mulch. Thin layer column experiments and batch denitrification tests were conducted to determine the optimum combination of materials and conditions that allowed for phosphate removal by mineral precipitation using BOF slag as an alkaline substrate to stimulate phosphate removal by calcium phosphate precipitation and through binding with iron on the slag, and microbial denitrification using mulch as an organic substrate under the high-pH conditions necessary for calcium phosphate precipitation. The results of batch tests using cedar mulch and BOF slag leachates showed that denitrification was possible at initial pH values as high as 11. Thin-layer column experiments using BOF slag showed that unsaturated flow conditions and a high percentage of slag fines produced phosphate removal between 90% and 100%, whereas saturated flow conditions produced phosphate removal only between 20% and 60%.
Michael Edgar; Hannah Ray; Dennis G. Grubb; Leon A. Van Paassen; Nasser Hamdan; Treavor H. Boyer. Removal of Phosphate and Nitrate from Impacted Waters via Slag-Driven Precipitation and Microbial Transformation. Journal of Sustainable Water in the Built Environment 2020, 6, 04020007 .
AMA StyleMichael Edgar, Hannah Ray, Dennis G. Grubb, Leon A. Van Paassen, Nasser Hamdan, Treavor H. Boyer. Removal of Phosphate and Nitrate from Impacted Waters via Slag-Driven Precipitation and Microbial Transformation. Journal of Sustainable Water in the Built Environment. 2020; 6 (2):04020007.
Chicago/Turabian StyleMichael Edgar; Hannah Ray; Dennis G. Grubb; Leon A. Van Paassen; Nasser Hamdan; Treavor H. Boyer. 2020. "Removal of Phosphate and Nitrate from Impacted Waters via Slag-Driven Precipitation and Microbial Transformation." Journal of Sustainable Water in the Built Environment 6, no. 2: 04020007.
Specimens of silica sand treated via enzyme induced carbonate precipitation (EICP) showed surprisingly high strength at a relatively low carbonate content when non-fat powdered milk was included in the treatment solution. EICP is a biologically-based soil improvement technique that uses free urease enzyme to catalyze the hydrolysis of urea in an aqueous solution, producing carbonate ions and alkalinity that in the presence of calcium cations leads to precipitation of calcium carbonate. The strength achieved at less than 1.4% carbonate content via a single cycle of treatment was unprecedented compared to results reported in the literature from both EICP and microbially induced carbonate precipitation (MICP). Scanning electron microscope images show that in the specimens treated with the solution containing powdered milk the carbonate precipitate was concentrated at interparticle contacts. The impact of these results include reductions in the concentration of substrate and enzyme required to achieve a target compressive strength, reduction in the undesirable ammonium chloride by-product, and, depending on the desired strength, reduction in the number of cycles of EICP treatment. These advantages enhance the potential for development of a sustainable method of soil improvement via hydrolysis of urea.
Abdullah Almajed; Hamed Khodadadi Tirkolaei; Edward Kavazanjian Jr.; Nasser Hamdan. Enzyme Induced Biocementated Sand with High Strength at Low Carbonate Content. Scientific Reports 2019, 9, 1 -7.
AMA StyleAbdullah Almajed, Hamed Khodadadi Tirkolaei, Edward Kavazanjian Jr., Nasser Hamdan. Enzyme Induced Biocementated Sand with High Strength at Low Carbonate Content. Scientific Reports. 2019; 9 (1):1-7.
Chicago/Turabian StyleAbdullah Almajed; Hamed Khodadadi Tirkolaei; Edward Kavazanjian Jr.; Nasser Hamdan. 2019. "Enzyme Induced Biocementated Sand with High Strength at Low Carbonate Content." Scientific Reports 9, no. 1: 1-7.
As part of an effort to lower the cost of urease enzyme used in enzyme induced carbonate precipitation (EICP) for soil improvement, urease enzyme was extracted from watermelon seeds. EICP is a biologically-based ground improvement technique in which a solution containing calcium, urea, and urease enzyme is used to induce calcium carbonate precipitation in a granular soil, enhancing strength, and stiffness. To reduce the enzyme cost by obtaining it from a waste material, the effectiveness of urease enzyme extracted from watermelon seeds, a urease-rich agricultural waste, was evaluated. Low-tech methods were employed for extraction and purification of the enzyme. The extracted enzyme, which showed urease activity of around 611 U/ml, was used to treat Ottawa 20/30 sand. Results of scanning electron microscope imaging and energy dispersive X-ray analysis demonstrated calcium carbonate precipitation. The ratio of the precipitated carbonate content to the theoretical maximum was found to be around 64%.
Neda Javadi; Hamed Khodadadi; Nasser Hamdan; Edward Kavazanjian. EICP Treatment of Soil by Using Urease Enzyme Extracted from Watermelon Seeds. IFCEE 2018 2018, 1 .
AMA StyleNeda Javadi, Hamed Khodadadi, Nasser Hamdan, Edward Kavazanjian. EICP Treatment of Soil by Using Urease Enzyme Extracted from Watermelon Seeds. IFCEE 2018. 2018; ():1.
Chicago/Turabian StyleNeda Javadi; Hamed Khodadadi; Nasser Hamdan; Edward Kavazanjian. 2018. "EICP Treatment of Soil by Using Urease Enzyme Extracted from Watermelon Seeds." IFCEE 2018 , no. : 1.
Jean Larson; Medha Dalal; Wilhelmina Savenye; Claudia Zapata; Nasser Hamdan; Edward Kavazanjian. Complete Research Paper: Implementation of an Introductory Module on Biogeotechnics in a Freshman Engineering Course. 2017 ASEE Annual Conference & Exposition Proceedings 2018, 1 .
AMA StyleJean Larson, Medha Dalal, Wilhelmina Savenye, Claudia Zapata, Nasser Hamdan, Edward Kavazanjian. Complete Research Paper: Implementation of an Introductory Module on Biogeotechnics in a Freshman Engineering Course. 2017 ASEE Annual Conference & Exposition Proceedings. 2018; ():1.
Chicago/Turabian StyleJean Larson; Medha Dalal; Wilhelmina Savenye; Claudia Zapata; Nasser Hamdan; Edward Kavazanjian. 2018. "Complete Research Paper: Implementation of an Introductory Module on Biogeotechnics in a Freshman Engineering Course." 2017 ASEE Annual Conference & Exposition Proceedings , no. : 1.
Enzyme induced carbonate precipitation (EICP) for vertical columnar stabilization and soil nailing has been demonstrated in bench scale testing. In EICP, precipitation of calcium carbonate (CaCO3) is induced via hydrolysis of urea using free urease enzyme. The enzyme is introduced into the soil in an aqueous solution containing urea and calcium ions to precipitate CaCO3. The precipitated CaCO3 improves the strength and stiffness and increases dilatancy of the soil by filling soil pores, roughening the soil particles, and binding the particles together. EICP was used to improve soil around 51 mm- and 76 mm-diameter vertical perforated plastic pipes in 19 L buckets and a 1 m3 soil box, respectively. EICP solution was also injected through a 9.5-mm diameter perforated tube to create inclined columns to model soil nails. These tests demonstrate the feasibility of using EICP to create cemented soil columns for foundation support and soil nailing.
Edward Kavazanjian Jr.; Abdullah Almajed; Nasser Hamdan. Bio-Inspired Soil Improvement Using EICP Soil Columns and Soil Nails. Grouting 2017 2017, 1 .
AMA StyleEdward Kavazanjian Jr., Abdullah Almajed, Nasser Hamdan. Bio-Inspired Soil Improvement Using EICP Soil Columns and Soil Nails. Grouting 2017. 2017; ():1.
Chicago/Turabian StyleEdward Kavazanjian Jr.; Abdullah Almajed; Nasser Hamdan. 2017. "Bio-Inspired Soil Improvement Using EICP Soil Columns and Soil Nails." Grouting 2017 , no. : 1.
A discrete-element method (DEM)–based numerical model was developed to simulate the triaxial compression response of sand strengthened using microbially induced carbonate precipitation (MICP). A three-dimensional (3D) sphere packing algorithm that uses a particle-growth model was used to generate the initial assemblage of particles. A parameter identification approach was used to evaluate the five microscale parameters of the DEM model (two elastic and three rupture parameters) using experimental results from drained triaxial compression tests on sand. The interparticle friction angle was found to be the most influential of the five parameters with respect to modeling the constitutive response. A particle homogenization approach was used to model the particles when they are strengthened with low amounts of calcium carbonate (<1% by mass). The particle contacts are assigned a cohesive shear strength when higher amounts of calcium carbonate (≥1% by mass) are present to model the effect of cementation between sand grains. This DEM model was shown to be capable of adequately simulating the drained triaxial compressive response of MICP-strengthened sands. The increase in microstructural heterogeneity as the carbonate content is increased was visualized through normal contact force distributions. The model can be used to estimate the desired level of cementation for the design of MICP treatment strategies with minimal experimentation.
Pu Yang; Sean O’Donnell; Nasser Hamdan; Edward Kavazanjian; Narayanan Neithalath. 3D DEM Simulations of Drained Triaxial Compression of Sand Strengthened Using Microbially Induced Carbonate Precipitation. International Journal of Geomechanics 2017, 17, 04016143 .
AMA StylePu Yang, Sean O’Donnell, Nasser Hamdan, Edward Kavazanjian, Narayanan Neithalath. 3D DEM Simulations of Drained Triaxial Compression of Sand Strengthened Using Microbially Induced Carbonate Precipitation. International Journal of Geomechanics. 2017; 17 (6):04016143.
Chicago/Turabian StylePu Yang; Sean O’Donnell; Nasser Hamdan; Edward Kavazanjian; Narayanan Neithalath. 2017. "3D DEM Simulations of Drained Triaxial Compression of Sand Strengthened Using Microbially Induced Carbonate Precipitation." International Journal of Geomechanics 17, no. 6: 04016143.
We have developed a novel method to synthesize a hyper-branched biomimetic hydrogel network across a soil matrix to improve the mechanical strength of the loose soil and simultaneously mitigate potential contamination due to excessive ammonium. This method successfully yielded a hierarchical structure that possesses the water retention, ion absorption, and soil aggregation capabilities of plant root systems in a chemically controllable manner. Inspired by the robust organic–inorganic composites found in many living organisms, we have combined this hydrogel network with a calcite biomineralization process to stabilize soil. Our experiments demonstrate that poly(acrylic acid) (PAA) can work synergistically with enzyme-induced carbonate precipitation (EICP) to render a versatile, high-performance soil stabilization method. PAA-enhanced EICP provides multiple benefits including lengthening of water supply time, localization of cementation reactions, reduction of harmful byproduct ammonium, and achievement of ultrahigh soil strength. Soil crusts we have obtained can sustain up to 4.8 × 103 kPa pressure, a level comparable to cementitious materials. An ammonium removal rate of 96% has also been achieved. These results demonstrate the potential for hydrogel-assisted EICP to provide effective soil improvement and ammonium mitigation for wind erosion control and other applications.
Zhi Zhao; Nasser Hamdan; Li Shen; Hanqing Nan; Abdullah Almajed; Edward Kavazanjian; Ximin He. Biomimetic Hydrogel Composites for Soil Stabilization and Contaminant Mitigation. Environmental Science & Technology 2016, 50, 12401 -12410.
AMA StyleZhi Zhao, Nasser Hamdan, Li Shen, Hanqing Nan, Abdullah Almajed, Edward Kavazanjian, Ximin He. Biomimetic Hydrogel Composites for Soil Stabilization and Contaminant Mitigation. Environmental Science & Technology. 2016; 50 (22):12401-12410.
Chicago/Turabian StyleZhi Zhao; Nasser Hamdan; Li Shen; Hanqing Nan; Abdullah Almajed; Edward Kavazanjian; Ximin He. 2016. "Biomimetic Hydrogel Composites for Soil Stabilization and Contaminant Mitigation." Environmental Science & Technology 50, no. 22: 12401-12410.
Benchtop experiments demonstrate the promise of hydrogel-assisted enzyme-induced carbonate precipitation (EICP) as a means of enhancing EICP for soil stabilization. Enzyme-induced carbonate precipitation uses hydrolysis of urea (ureolysis) catalyzed by the urease enzyme to precipitate CaCO3 in the presence of urea and calcium in a water-based solution. Xanthan and guar gum biopolymers and an inert polyol-cellulose hydrogel were used to assess the ability of a hydrogel to enhance EICP by retaining reaction product around the soil particles. The experiments were conducted in sand-filled paper cups and soilless glass beakers at 1.66 and 0.33 M of initial calcium chloride (CaCl2) concentrations using high-activity and low-activity plant urease. Ureolysis and CaCO3 precipitation occurred in all hydrogel-assisted EICP tests, suggesting that the hydrogels used in this study do not interfere with EICP. Furthermore, hydrogel-assisted EICP appeared to retain moisture for extended periods of time and reduce penetration of the EICP solution into the soil, extending reaction time, increasing precipitation efficiency, and enhancing the formation of a crust. Gas bubble formation in the hydrogel solutions suggests that ammonia (NH3) and/or carbon dioxide (CO2) off-gassing may be reduced, which may also increase precipitation efficiency. Guar and xanthan gums were found to have the greatest water retention ability and to significantly reduce water evaporation.
Nasser Hamdan; Zhi Zhao; Maritza Mujica; Edward Kavazanjian; Ximin He. Hydrogel-Assisted Enzyme-Induced Carbonate Mineral Precipitation. Journal of Materials in Civil Engineering 2016, 28, 04016089 .
AMA StyleNasser Hamdan, Zhi Zhao, Maritza Mujica, Edward Kavazanjian, Ximin He. Hydrogel-Assisted Enzyme-Induced Carbonate Mineral Precipitation. Journal of Materials in Civil Engineering. 2016; 28 (10):04016089.
Chicago/Turabian StyleNasser Hamdan; Zhi Zhao; Maritza Mujica; Edward Kavazanjian; Ximin He. 2016. "Hydrogel-Assisted Enzyme-Induced Carbonate Mineral Precipitation." Journal of Materials in Civil Engineering 28, no. 10: 04016089.
A stoichiometric model was developed for predicting the amount of carbonate precipitation and gas production from two different biogeotechnical soil improvement techniques: enzyme-induced hydrolysis of urea and microbial denitrification. Carbonate precipitation via hydrolysis of urea, or ureolysis, and via dissimilatory nitrate reduction, or denitrification, has been shown in laboratory testing to improve the shear strength and cyclic resistance of granular soils. Desaturation via denitrification has also shown the ability to improve cyclic resistance. For effective implementation of these techniques in the field, it is important to understand the material requirements necessary to achieve the desired degree of improvement. Therefore, a model for predicting carbonate precipitation and gas production from these techniques was developed using stoichiometry, thermodynamics, and microbial growth patterns and calibrated with laboratory test data. The model will facilitate the implementation of cost-effective, non-intrusive, and sustainable ground improvement.
Sean T. O’Donnell; Nasser Hamdan; Bruce E. Rittmann; Edward Kavazanjian. A Stoichiometric Model for Biogeotechnical Soil Improvement. Geo-Chicago 2016 2016, 1 .
AMA StyleSean T. O’Donnell, Nasser Hamdan, Bruce E. Rittmann, Edward Kavazanjian. A Stoichiometric Model for Biogeotechnical Soil Improvement. Geo-Chicago 2016. 2016; ():1.
Chicago/Turabian StyleSean T. O’Donnell; Nasser Hamdan; Bruce E. Rittmann; Edward Kavazanjian. 2016. "A Stoichiometric Model for Biogeotechnical Soil Improvement." Geo-Chicago 2016 , no. : 1.
Microbially induced carbonate precipitation (MICP) and associated biogas production may provide sustainable means of mitigating a number of geotechnical challenges associated with granular soils. MICP can induce interparticle soil cementation, mineral precipitation in soil pore space and/or biogas production to address geotechnical problems such as slope instability, soil erosion and scour, seepage of levees and cutoff walls, low bearing capacity of shallow foundations, and earthquake-induced liquefaction and settlement. Microbial denitrification has potential for improving the mechanical and hydraulic properties of soils because it promotes precipitation of calcium carbonate (CaCO3) and produces nitrogen (N2) gas without generating toxic by-products. We evaluated the potential for inducing carbonate precipitation in soil via bacterial denitrification using bench-scale experiments with the facultative anaerobe Pseudomonas denitrificans. Bench-scale experiments were conducted (1) without calcium in an N-rich bacterial growth medium in 2.0 L glass batch reactors and (2) with a source of calcium in sand-filled acrylic columns. Changes of pH, alkalinity, NO3− and NO2− in the batch reactors and columns, quantification of biogas production and observations of calcium-carbonate precipitation in the sand-filled columns indicate that denitrification led to carbonate precipitation and particle cementation in the pore water as well as a substantial amount of biogas production in both systems. These results document that bacterial denitrification has potential as a soil improvement mechanism.
Nasser Hamdan; Edward Kavazanjian; Bruce E. Rittmann; Ismail Karatas. Carbonate Mineral Precipitation for Soil Improvement Through Microbial Denitrification. Geomicrobiology Journal 2016, 34, 139 -146.
AMA StyleNasser Hamdan, Edward Kavazanjian, Bruce E. Rittmann, Ismail Karatas. Carbonate Mineral Precipitation for Soil Improvement Through Microbial Denitrification. Geomicrobiology Journal. 2016; 34 (2):139-146.
Chicago/Turabian StyleNasser Hamdan; Edward Kavazanjian; Bruce E. Rittmann; Ismail Karatas. 2016. "Carbonate Mineral Precipitation for Soil Improvement Through Microbial Denitrification." Geomicrobiology Journal 34, no. 2: 139-146.
Wind tunnel tests show that enzyme-induced carbonate precipitation (EICP) holds promise as a method for mitigation of fugitive dust emissions. Fugitive dust (wind-blown fine-grained soil) is a significant environmental problem in semi-arid and arid environments. Conventional methods for fugitive dust control, including the application of water, salt, or synthetic polymers, are either ineffective in arid climates, limited to short-term stabilisation, or very expensive. EICP employs hydrolysis of urea (ureolysis), a process catalysed by the urease enzyme, to precipitate calcium carbonate (CaCO3) in the presence of calcium ions. Urease is a widely occurring enzyme found in many plants and microorganisms. Wind tunnel experiments were conducted to evaluate the use of a topically applied EICP solution containing plant-derived urease to stabilise soil against fugitive dust emission. Three different soils were tested: a native Arizona silty sand, a uniform medium-grained silica sand and fine sand-sized mine tailings from southern Arizona. The wind tunnel tests established the treatment concentrations at which EICP was more effective in suppressing fugitive dust than specimens prepared by either thoroughly wetting the soil or treatment with a salt–urea solution. These tests demonstrate the potential of EICP treatment as a means of mitigating fugitive dust emissions.
Nasser Hamdan; Edward Kavazanjian. Enzyme-induced carbonate mineral precipitation for fugitive dust control. Géotechnique 2016, 66, 546 -555.
AMA StyleNasser Hamdan, Edward Kavazanjian. Enzyme-induced carbonate mineral precipitation for fugitive dust control. Géotechnique. 2016; 66 (7):546-555.
Chicago/Turabian StyleNasser Hamdan; Edward Kavazanjian. 2016. "Enzyme-induced carbonate mineral precipitation for fugitive dust control." Géotechnique 66, no. 7: 546-555.
Columns of improved soil created by Enzyme Induced Carbonate Precipitation (EICP) offer the potential for non-disruptive, cost effective ground improvement for a variety of geotechnical purposes. EICP employs urease enzyme to precipitate CaCO3 from an aqueous solution of calcium chloride and urea to fill the soil pores (increasing dilatancy and reducing compressibility) and cement soil particles (increasing shear strength). EICP is similar to Microbially Induced Carbonate Precipitation (MICP) except that, instead of employing microbes to generate the urease enzyme, the enzyme is obtained from agricultural sources. A major advantage of agriculturally-derived urease compared to microbial urease is its small size and water solubility, which allows penetration through the pore throat of finer grained soils such as silts, whereas ureolytic MICP is essentially restricted to soils of fine to medium sized sand or larger. The small size of the enzyme can also mitigate the potential for bio-clogging due to carbonate precipitation and biofilm formation, both of which my limit the applicability of MICP. Bench top tests in the laboratory show that cemented columns of soil can be created by infusing a cementation solution through a perforated tube or pipe or by mix and compact methods. EICP columns can be installed in patterns similar to root piles (pali radicii) for slope stability, micro piles for foundation support, and stone columns or soil cement columns to support embankments and restrict lateral spreading in liquefiable soils. Furthermore, EICP piles could be installed under existing structures without causing heave or settlement, making them ideal for remediation of poor (e.g. liquefiable) foundation soils.
Edward Kavazanjian; Nasser Hamdan. Enzyme Induced Carbonate Precipitation (EICP) Columns for Ground Improvement. IFCEE 2015 2015, 1 .
AMA StyleEdward Kavazanjian, Nasser Hamdan. Enzyme Induced Carbonate Precipitation (EICP) Columns for Ground Improvement. IFCEE 2015. 2015; ():1.
Chicago/Turabian StyleEdward Kavazanjian; Nasser Hamdan. 2015. "Enzyme Induced Carbonate Precipitation (EICP) Columns for Ground Improvement." IFCEE 2015 , no. : 1.
Consideration of soil as a living ecosystem offers the potential for innovative and sustainable solutions to geotechnical problems. This is a new paradigm for many in geotechnical engineering. Realising the potential of this paradigm requires a multidisciplinary approach that embraces biology and geochemistry to develop techniques for beneficial ground modification. This paper assesses the progress, opportunities, and challenges in this emerging field. Biomediated geochemical processes, which consist of a geochemical reaction regulated by subsurface microbiology, currently being explored include mineral precipitation, gas generation, biofilm formation and biopolymer generation. For each of these processes, subsurface microbial processes are employed to create an environment conducive to the desired geochemical reactions among the minerals, organic matter, pore fluids, and gases that constitute soil. Geotechnical applications currently being explored include cementation of sands to enhance bearing capacity and liquefaction resistance, sequestration of carbon, soil erosion control, groundwater flow control, and remediation of soil and groundwater impacted by metals and radionuclides. Challenges in biomediated ground modification include upscaling processes from the laboratory to the field, in situ monitoring of reactions, reaction products and properties, developing integrated biogeochemical and geotechnical models, management of treatment by-products, establishing the durability and longevity/reversibility of the process, and education of engineers and researchers.
J.T. De Jong; K.S. Soga; Edward Kavazanjian; S. Burns; Leon van Paassen; A. Al Quabany; A. Aydilek; S.S. Bang; Malcolm Burbank; L.F. Caslake; Chien-Yen Chen; X. Cheng; Jian Chu; Stefano Ciurli; A. Esnault-Filet; S. Fauriel; Nasser Hamdan; T. Hata; Y. Inagaki; S. Jefferis; M. Kuo; L. Laloui; Joan Larrahondo; David Manning; B. Martinez; B.M. Montoya; D.C. Nelson; A. Palomino; Phil Renforth; J.C. Santamarina; E.A. Seagren; B. Tanyu; Michael Tsesarsky; T. Weaver. Biogeochemical processes and geotechnical applications: progress, opportunities and challenges. Géotechnique 2013, 63, 287 -301.
AMA StyleJ.T. De Jong, K.S. Soga, Edward Kavazanjian, S. Burns, Leon van Paassen, A. Al Quabany, A. Aydilek, S.S. Bang, Malcolm Burbank, L.F. Caslake, Chien-Yen Chen, X. Cheng, Jian Chu, Stefano Ciurli, A. Esnault-Filet, S. Fauriel, Nasser Hamdan, T. Hata, Y. Inagaki, S. Jefferis, M. Kuo, L. Laloui, Joan Larrahondo, David Manning, B. Martinez, B.M. Montoya, D.C. Nelson, A. Palomino, Phil Renforth, J.C. Santamarina, E.A. Seagren, B. Tanyu, Michael Tsesarsky, T. Weaver. Biogeochemical processes and geotechnical applications: progress, opportunities and challenges. Géotechnique. 2013; 63 (4):287-301.
Chicago/Turabian StyleJ.T. De Jong; K.S. Soga; Edward Kavazanjian; S. Burns; Leon van Paassen; A. Al Quabany; A. Aydilek; S.S. Bang; Malcolm Burbank; L.F. Caslake; Chien-Yen Chen; X. Cheng; Jian Chu; Stefano Ciurli; A. Esnault-Filet; S. Fauriel; Nasser Hamdan; T. Hata; Y. Inagaki; S. Jefferis; M. Kuo; L. Laloui; Joan Larrahondo; David Manning; B. Martinez; B.M. Montoya; D.C. Nelson; A. Palomino; Phil Renforth; J.C. Santamarina; E.A. Seagren; B. Tanyu; Michael Tsesarsky; T. Weaver. 2013. "Biogeochemical processes and geotechnical applications: progress, opportunities and challenges." Géotechnique 63, no. 4: 287-301.
Microbially induced calcium carbonate precipitation (MICP) is attracting increasing attention as a sustainable means of soil improvement. Microbial denitrification has the potential to become the preferred method for MICP because denitrification does not produce toxic byproducts, does not require a water-soluble electron donor, can utilize nearly 100% of the electron donor, does not require exogenous organic nitrogen, is thermodynamically more favorable than other processes, readily occurs under anoxic conditions, and potentially has a greater carbonate yield per mole of substrate than other MICP processes. Bench scale bioreactor and column tests using Pseudomonas denitrificans have shown that calcite can be precipitated from calcium-rich pore water using denitrification. Recent experiments at Arizona State University and by others have sought to reduce potential environmental impacts and lower costs associated with denitrification by reducing the total dissolved solids in the reactors and columns and by addressing the loss of free calcium in the form of calcium phosphate precipitate from the pore fluid.
Nasser Hamdan; Jr. Edward Kavazanjian; Bruce E. Rittmann; Ismail Karatas. Carbonate Mineral Precipitation for Soil Improvement through Microbial Denitrification. Geo-Frontiers 2011 2011, 1 .
AMA StyleNasser Hamdan, Jr. Edward Kavazanjian, Bruce E. Rittmann, Ismail Karatas. Carbonate Mineral Precipitation for Soil Improvement through Microbial Denitrification. Geo-Frontiers 2011. 2011; ():1.
Chicago/Turabian StyleNasser Hamdan; Jr. Edward Kavazanjian; Bruce E. Rittmann; Ismail Karatas. 2011. "Carbonate Mineral Precipitation for Soil Improvement through Microbial Denitrification." Geo-Frontiers 2011 , no. : 1.