This page has only limited features, please log in for full access.
The transportation sector is considered one of the driving forces behind the increased release of greenhouse gases (GHGs), with road transport being this sector’s main emissions contributor. In turn, efforts should be devoted to reducing emitted GHGs from this sector, and many such opportunities lie in the road transport life cycle. This paper investigated fourteen emission reduction scenarios based on the green initiatives issued by the Abu Dhabi Government. The explored measures are either related to road works and road municipal services or to traffic movement. The proposed measures were evaluated with reference to a baseline study previously reported by the authors for three different road projects in Abu Dhabi city. Findings reveal that normalized GHG emission reduction could be significantly reduced by (i) replacing 30% of internal combustion engine passenger cars with battery electric vehicles where the power demand is covered almost equally from nuclear and liquified natural gas (LNG) sources, (ii) reducing the number of passenger cars by 10%, and (iii) having one-fifth of passenger cars powered by LNG. A lesser significant reduction could be achieved by replacing conventional lamps with light-emitting diode (LED) lamps or by having one-fourth of lighting powered by solar energy. Even lesser reduction could be achieved by (i) replacing a portion of Portland cement with ground granulated blast furnace slag in concrete structures, (ii) fully utilizing treated sewage effluent for roadside-plant irrigation, (iii) reducing desalinated water used for roadside-plant irrigation by 20%, and (iv) increasing the number of higher efficiency passenger cars by 10%. Replacing hot-mix asphalt with warm-mix asphalt and using asphalt with a high stiffness modulus in the base layer results in low emission reduction. The use of 15% recycled asphalt or the use of 50% recycled aggregate in road construction has the least impact on emission reduction. When all explored scenarios were combined, an overall normalized GHG emissions reduction of 9–17% during the road project life cycle could be achieved.
Munjed Maraqa; Francisco Albuquerque; Mohammed Alzard; Rezaul Chowdhury; Lina Kamareddine; Jamal El Zarif. GHG Emission Reduction Opportunities for Road Projects in the Emirate of Abu Dhabi: A Scenario Approach. Sustainability 2021, 13, 7367 .
AMA StyleMunjed Maraqa, Francisco Albuquerque, Mohammed Alzard, Rezaul Chowdhury, Lina Kamareddine, Jamal El Zarif. GHG Emission Reduction Opportunities for Road Projects in the Emirate of Abu Dhabi: A Scenario Approach. Sustainability. 2021; 13 (13):7367.
Chicago/Turabian StyleMunjed Maraqa; Francisco Albuquerque; Mohammed Alzard; Rezaul Chowdhury; Lina Kamareddine; Jamal El Zarif. 2021. "GHG Emission Reduction Opportunities for Road Projects in the Emirate of Abu Dhabi: A Scenario Approach." Sustainability 13, no. 13: 7367.
Curriculum-based exit exams play a crucial role in program assessment and measuring student achievement of program learning outcomes (PLOs). This study aims to examine the validity of using an internal exit exam as a direct assessment tool to evaluate student learning and attainment of PLOs. The validation entails evaluating and correlating students’ performance in the exit exam to that in corresponding coursework and their perception regarding attainment of the PLOs. Results highlighted inferior student performance in the exit exam compared to corresponding coursework, with a moderate degree of correlation at the program level. The survey response analysis indicated that students tended to overestimate their attainment level of PLOs and their preparation for the exit exam was not sufficient. Findings of this study would assist in the continuous improvement of prospective engineering programs and provide a framework for a proper analysis capable of examining the validity of curriculum-based assessment tools.
Hilal El-Hassan; Mohamed Hamouda; Tamer El-Maaddawy; Munjed Maraqa. Curriculum-based exit exam for assessment of student learning. European Journal of Engineering Education 2021, 1 -25.
AMA StyleHilal El-Hassan, Mohamed Hamouda, Tamer El-Maaddawy, Munjed Maraqa. Curriculum-based exit exam for assessment of student learning. European Journal of Engineering Education. 2021; ():1-25.
Chicago/Turabian StyleHilal El-Hassan; Mohamed Hamouda; Tamer El-Maaddawy; Munjed Maraqa. 2021. "Curriculum-based exit exam for assessment of student learning." European Journal of Engineering Education , no. : 1-25.
Wastewater-based epidemiology (WBE) is successful in the detection of the spread of SARS-CoV-2. This review examines the methods used and results of recent studies on the quantification of SARS-CoV-2 in wastewater. WBE becomes essential, especially with virus transmission path uncertainty, limitations on the number of clinical tests that could be conducted, and a relatively long period for infected people to show symptoms. Wastewater surveillance was used to show the effect of lockdown on the virus spread. A WBE framework tailored for SARS-CoV-2 that incorporates lessons learnt from the reviewed studies was developed. Results of the review helped outline challenges facing the detection of SARS-CoV-2 in wastewater samples. A comparison between the various studies with regards to sample concentration and virus quantification was conducted. Five different primers sets were used for qPCR quantification; however, due to limited data availability, there is no consensus on the most sensitive primer. Correlating the slope of the relationship between the number of gene copies vs. the cumulative number of infections normalized to the total population served with the average new cases, suggests that qPCR results could help estimating the number of new infections. The correlation is improved when a lag period was introduced to account for asymptomatic infections. Based on lessons learnt from recent studies, it is recommended that future applications should consider the following: 1) ensuring occupational safety in managing sewage collection and processing, 2) evaluating the effectiveness of greywater disinfection, 3) measuring viral RNA decay due to biological and chemical activities during collection and treatment, 4) assessing the effectiveness of digital PCR, and 5) conducting large scale international studies that follow standardized protocols.
Mohamed Hamouda; Farah Mustafa; Munjed Maraqa; Tahir Rizvi; Ashraf Aly Hassan. Wastewater surveillance for SARS-CoV-2: Lessons learnt from recent studies to define future applications. Science of The Total Environment 2020, 759, 143493 -143493.
AMA StyleMohamed Hamouda, Farah Mustafa, Munjed Maraqa, Tahir Rizvi, Ashraf Aly Hassan. Wastewater surveillance for SARS-CoV-2: Lessons learnt from recent studies to define future applications. Science of The Total Environment. 2020; 759 ():143493-143493.
Chicago/Turabian StyleMohamed Hamouda; Farah Mustafa; Munjed Maraqa; Tahir Rizvi; Ashraf Aly Hassan. 2020. "Wastewater surveillance for SARS-CoV-2: Lessons learnt from recent studies to define future applications." Science of The Total Environment 759, no. : 143493-143493.
Many studies have been carried out to evaluate the sustainability of transportation systems, but little attention has been given for the design of roadway intersections. This study aimed to establish a framework and develop a tool to assess the sustainability of roadway intersections from a road-user perspective. Sustainability indicators at the strategic level were extracted from the literature and were utilized with relative weights to develop economic, environmental, and social indices that would be combined into a composite sustainability index (CSI) tool. The tool was applied to four case studies of intersections in Al Ain, United Arab Emirates. For each case study, the sustainability of fifteen design alternatives was evaluated for different scenarios of traffic volume and operational speed. Dimensional indices and the overall CSI were determined using the Multi-Criteria Decision Making method. Results indicated that traffic volume had a significant impact on intersection sustainability ranking, while the effect of operational speed was insignificant. Moreover, weight assignment had an effect on determining the most sustainable design alternative, where the best alternatives of the dimension with the major weight would most likely be the most sustainable. The developed tool would assist decision-makers in other cities to assess intersection projects that correspond to their regional goals.
Maryam Al-Kaabi; Munjed Maraqa; Yasser Hawas. Development of a Composite Sustainability Index for Roadway Intersection Design Alternatives in the UAE. Sustainability 2020, 12, 8696 .
AMA StyleMaryam Al-Kaabi, Munjed Maraqa, Yasser Hawas. Development of a Composite Sustainability Index for Roadway Intersection Design Alternatives in the UAE. Sustainability. 2020; 12 (20):8696.
Chicago/Turabian StyleMaryam Al-Kaabi; Munjed Maraqa; Yasser Hawas. 2020. "Development of a Composite Sustainability Index for Roadway Intersection Design Alternatives in the UAE." Sustainability 12, no. 20: 8696.
This study investigates the impact of eggshell particle size and solid-to-water (s/w) ratio on lead (Pb2+) removal from aqueous solution. Collected raw eggshells were washed, crushed, and sieved into two particle sizes (2+ removal experiments were conducted at different s/w ratios with initial Pb2+ concentrations of up to 70 mg/L. The contribution of precipitation to Pb2+ removal was simulated by quantifying removal using eggshell water, whereas sorbed Pb2+ was quantified by acid digestion. Results indicated that eggshell particle sizes did not affect Pb2+ removal. High removal (up to 99%) of Pb2+ was achieved for low initial Pb2+ concentrations (2+ by eggshells. Yet, this role decreased as the s/w ratio and initial concentration of Pb2+ increased. A predictive relationship that relates the normalized removal capacity of eggshells to the s/w ratio was developed to potentially facilitate the design of the reactor.
Mohamed A. Hamouda; Haliemeh Sweidan; Munjed A. Maraqa; Hilal El-Hassan. Mechanistic Study of Pb2+ Removal from Aqueous Solutions Using Eggshells. Water 2020, 12, 2517 .
AMA StyleMohamed A. Hamouda, Haliemeh Sweidan, Munjed A. Maraqa, Hilal El-Hassan. Mechanistic Study of Pb2+ Removal from Aqueous Solutions Using Eggshells. Water. 2020; 12 (9):2517.
Chicago/Turabian StyleMohamed A. Hamouda; Haliemeh Sweidan; Munjed A. Maraqa; Hilal El-Hassan. 2020. "Mechanistic Study of Pb2+ Removal from Aqueous Solutions Using Eggshells." Water 12, no. 9: 2517.
Limited work has been done to assess the types and levels of PACs in domestic and treated wastewater in arid and semi-arid countries. In these countries, reuse or artificial recharge of treated sewage effluent is commonly practiced. Thus, the objectives of this study were to quantify the levels of selected PACs in domestic wastewater in the United Arab Emirates (UAE) and to assess the effectiveness of domestic wastewater treatment plants in their removal. An analytical protocol was developed for the analysis of 15 PACs using a UPLC-MS/MS system. Four batches of water and sludge samples were collected from different locations at Al Saad Wastewater Treatment Plant in Al Ain, UAE. Aliquots of each sample were enriched by solid phase extraction. Results show that phenylephrine, dapsone, noscapine, propyl gallate, genistein, and ketoconazole were present in the raw wastewater at low levels (10 μg/L). The overall removal efficiency of the tested PACs from the water stream exceeded 99% for cotinine, acetaminophen, caffeine, naproxen, and ibuprofen, but significantly drops (<50%) for phenylephrine, amoxicillin, dapsone, noscapine, spiramycin, noscapine, genistein and ketoconazole. Analysis of the results indicate that, for highly removed PACs, the main mechanism of removal is possibly aerobic biodegradation. However, for tyramine, dapsone, 9-aminoacridine, noscapine, propyl gallate, and ketoconazole sorption onto the mixed liquor suspended solids first occurs followed by removal by anaerobic digestion. Results of the study should be useful for properly managing treated sewage effluent and sewage sludge.
M A Maraqa; Mohammed Meetani; A M Alhalabi. Effectiveness of conventional wastewater treatment processes in removing pharmaceutically active compounds. IOP Conference Series: Earth and Environmental Science 2020, 424, 012014 .
AMA StyleM A Maraqa, Mohammed Meetani, A M Alhalabi. Effectiveness of conventional wastewater treatment processes in removing pharmaceutically active compounds. IOP Conference Series: Earth and Environmental Science. 2020; 424 (1):012014.
Chicago/Turabian StyleM A Maraqa; Mohammed Meetani; A M Alhalabi. 2020. "Effectiveness of conventional wastewater treatment processes in removing pharmaceutically active compounds." IOP Conference Series: Earth and Environmental Science 424, no. 1: 012014.
Assessing the current levels of greenhouse gas (GHG) emissions from road transportation projects allows for benchmarking and is essential for potential emissions reduction. The objective of this study was to estimate the GHG emissions associated with the construction and operation of three road cases—two primary roads and one secondary road network—in Abu Dhabi, United Arab Emirates. The GHG emissions produced by the study cases were estimated using the RoadCO2 estimation tool. Results showed that the total emissions (in kg CO2e/m2/y) range from 76 for the secondary road case to 1100 for the primary road cases. The operation phase is responsible for 94–98% of these emissions; the construction phase is responsible for the rest. Road works contributed the most to GHG emissions during the construction phase. The contribution of the remaining categories of the construction phase fluctuates within a certain case and among the considered cases. The equipment used in the construction phase for the three cases contributed 15–70% of the total phase emissions, while the remaining emissions were due to construction materials. In the operation phase, emissions were mainly generated by vehicle movement. Street lighting also contributed to emissions during the operation phase. On the other hand, the irrigation of planted trees along the road had a very low impact on GHG emissions, and carbon sequestration by these trees had a negligible effect in terms of acting as a carbon sink. The results obtained from this study were compared with other cases reported in the literature.
Mohammed H. Alzard; Munjed A. Maraqa; Rezaul Chowdhury; Qasim Khan; Francisco D. B. Albuquerque; Timur Ibrahim Mauga; Khaled Nazmi Aljunadi. Estimation of Greenhouse Gas Emissions Produced by Road Projects in Abu Dhabi, United Arab Emirates. Sustainability 2019, 11, 2367 .
AMA StyleMohammed H. Alzard, Munjed A. Maraqa, Rezaul Chowdhury, Qasim Khan, Francisco D. B. Albuquerque, Timur Ibrahim Mauga, Khaled Nazmi Aljunadi. Estimation of Greenhouse Gas Emissions Produced by Road Projects in Abu Dhabi, United Arab Emirates. Sustainability. 2019; 11 (8):2367.
Chicago/Turabian StyleMohammed H. Alzard; Munjed A. Maraqa; Rezaul Chowdhury; Qasim Khan; Francisco D. B. Albuquerque; Timur Ibrahim Mauga; Khaled Nazmi Aljunadi. 2019. "Estimation of Greenhouse Gas Emissions Produced by Road Projects in Abu Dhabi, United Arab Emirates." Sustainability 11, no. 8: 2367.
When chemical disinfection is performed before or after desalination, a number of harmful compounds are formed. Thus, efforts have been directed toward developing alternative methods for water disinfection. In this study, seven nanoparticles (NPs) were evaluated for disinfecting water produced from reverse osmosis and multi-stage flash desalination plants. The tested NPs were silver, copper, silver-copper, zinc oxide, magnesium oxide, silicon dioxide, and carbon nanotubes. The antimicrobial activity of the NPs was investigated by batch studies in desalinated water samples spiked with E. coli, Enterobacter, Salmonella, and Enterococci. The Chick-Watson model was fitted to the inactivation data to evaluate the kinetic constant for each combination of NPs, water type, and indicator bacteria. The results indicated that silver and silver-copper NPs have the highest disinfection efficiency among the tested NPs. Among the bacteria, Enterobacter (strain TPC129) appears to be the most inactivated, while Enterococci (strain NCTC775) seems to be the least influenced by the NPs. Variations in the chemical characteristics of the tested water samples appeared to cause noticeable differences in the antibacterial efficacies of copper and magnesium oxide NPs, but not in those of the other NPs.
Laila Al-Issai; Walid Elshorbagy; Munjed A. Maraqa; Mohamed Hamouda; Ahmed M. Soliman. Use of Nanoparticles for the Disinfection of Desalinated Water. Water 2019, 11, 559 .
AMA StyleLaila Al-Issai, Walid Elshorbagy, Munjed A. Maraqa, Mohamed Hamouda, Ahmed M. Soliman. Use of Nanoparticles for the Disinfection of Desalinated Water. Water. 2019; 11 (3):559.
Chicago/Turabian StyleLaila Al-Issai; Walid Elshorbagy; Munjed A. Maraqa; Mohamed Hamouda; Ahmed M. Soliman. 2019. "Use of Nanoparticles for the Disinfection of Desalinated Water." Water 11, no. 3: 559.
Siham Alshanti; Amr El-Dieb; Munjed Maraqa. Characterization of sewage sludge ash as affected by different incineration temperature and time. 2019, 1 .
AMA StyleSiham Alshanti, Amr El-Dieb, Munjed Maraqa. Characterization of sewage sludge ash as affected by different incineration temperature and time. . 2019; ():1.
Chicago/Turabian StyleSiham Alshanti; Amr El-Dieb; Munjed Maraqa. 2019. "Characterization of sewage sludge ash as affected by different incineration temperature and time." , no. : 1.
We investigated the effect of different window designs employed in Abu Dhabi Emirate- UAE on the level of noise transmission. For that, 21 window cases were tested in the laboratory. Several factors were considered, including window glass thickness, glazing, lamination, opening style, area, frame type, frame style, and use of shutters. Results showed that sound transmission loss is improved significantly with the use of shutters and the use of hinged, not sliding, windows. The instalment of glass thicker than 6 mm did not cause any improvement. As for the double glazed windows, no noticeable improvement was detected with an air gap of 12 mm or less, but increasing the air gap to 20 mm causes a moderate improvement. Slight improvement was found when a lamination layer or uPVC frame (instead of aluminum) was used. It was further found that box umbrella and curtain wall frames did not seal as well as half umbrella frames, and thus resulted in a lower acoustic performance of the windows.
Maraqa M A; Hawas Y S; Alam Md D; El Zarif J; Aljunadi K N. Laboratory testing of different window design cases for noise transmission. IOP Conference Series: Materials Science and Engineering 2018, 383, 012027 .
AMA StyleMaraqa M A, Hawas Y S, Alam Md D, El Zarif J, Aljunadi K N. Laboratory testing of different window design cases for noise transmission. IOP Conference Series: Materials Science and Engineering. 2018; 383 (1):012027.
Chicago/Turabian StyleMaraqa M A; Hawas Y S; Alam Md D; El Zarif J; Aljunadi K N. 2018. "Laboratory testing of different window design cases for noise transmission." IOP Conference Series: Materials Science and Engineering 383, no. 1: 012027.
Fuel consumed in collecting municipal solid waste (MSW) accounts for a major portion of the cost of waste management. In this study, several cases were developed using the ArcGIS Network Analyst to establish optimum conditions for MSW collection in Um Gafa district in Al Ain city, UAE. A GIS model was created based on data collection and GPS tracking of collection route and bins position in the area. Results show that current waste collection at Um Gafa does not strictly follow U-turn and curb approach policies. When route optimization is applied for similar conditions, a saving of 14.3% in fuel consumption is gained. Two models were tested for optimal number and location of bins. One model was based on a 40-m service zone while the other was based on population density and land use. By adopting model 1, the number of bins was reduced by 12%, while in model 2 the number of bins was reduced by 20%. Model 2 showed higher superiority, compared to model 1, in terms of fuel consumption.
M A Maraqa; E Z Swar Aldahab; M Ghanma; S K Al Kaabi. Optimization of fuel consumption for municipal solid waste collection in Al Ain city, UAE. IOP Conference Series: Materials Science and Engineering 2018, 383, 012026 .
AMA StyleM A Maraqa, E Z Swar Aldahab, M Ghanma, S K Al Kaabi. Optimization of fuel consumption for municipal solid waste collection in Al Ain city, UAE. IOP Conference Series: Materials Science and Engineering. 2018; 383 (1):012026.
Chicago/Turabian StyleM A Maraqa; E Z Swar Aldahab; M Ghanma; S K Al Kaabi. 2018. "Optimization of fuel consumption for municipal solid waste collection in Al Ain city, UAE." IOP Conference Series: Materials Science and Engineering 383, no. 1: 012026.
Construction safety education for engineering students may involve two main aspects: construction site safety and design for construction safety (DfCS). Progress has been made in the developed countries to incorporate both aspects in the engineering curriculum. However, the extent to which engineering students in the Middle East and North Africa (MENA) region receive construction safety education during their undergraduate study is not known. To assess this extent, two survey forms were designed and distributed to engineering practitioners and construction-related engineering programs in the MENA region. The practitioners’ survey was also utilized to assess the need for comprising construction safety education in the engineering curriculum. The study showed that about 70 % of the surveyed practitioner engineers did not receive construction safety knowledge during their university education. Of those who did, almost half received such knowledge during internship. Meanwhile, about 50 % of those who received some construction safety education ranked the received level as being “average.” Results also showed that the majority of the surveyed practitioners believe that there is a need for more construction safety education at the university level. In terms of inclusion in the engineering curriculum, surveyed practitioners ranked 15 suggested safety aspects as important to very important to be included in the undergraduate curriculum. Responses received from contacted engineering programs indicated that assigning an entire course to cover construction safety is not common in the MENA region. While the majority of construction safety coverage was shown to be either as an integral part of a core course or through the internship, only 40 % of the programs indicated inclusion of construction safety topics as integral parts of elective courses that are commonly offered once a year. A major observation was that construction safety is included in less than 15 % of the graduation project courses offered by the responding programs, indicating a possibly high deficiency in comprising DfCS in the curriculum. In addition, Occupational Safety and Health Administration (OSHA) standards and in-house developed materials were reported as the most common data sources for teaching construction safety. The study proposes enhancing the current level of construction safety education for engineering students in the MENA region by incorporating a core course in the curriculum and by integrating several suggested topics of DfCS in traditional design courses.
Munjed A. Maraqa; Amr Sweedan; Essam Zaneldin. Inclusion of Construction Health and Safety in Engineering Programs in the MENA Region: Assessment and Potential Enhancement. Advances in Engineering Education in the Middle East and North Africa 2015, 261 -299.
AMA StyleMunjed A. Maraqa, Amr Sweedan, Essam Zaneldin. Inclusion of Construction Health and Safety in Engineering Programs in the MENA Region: Assessment and Potential Enhancement. Advances in Engineering Education in the Middle East and North Africa. 2015; ():261-299.
Chicago/Turabian StyleMunjed A. Maraqa; Amr Sweedan; Essam Zaneldin. 2015. "Inclusion of Construction Health and Safety in Engineering Programs in the MENA Region: Assessment and Potential Enhancement." Advances in Engineering Education in the Middle East and North Africa , no. : 261-299.
Changes in soil hydraulic conductivity (K) as a function of total suspended solids (TSS) concentration in the infiltrating water were studied in the laboratory using the constant-head technique. Soil samples collected from Alshuwaib dam site in the United Arab Emirates were selected for the study. The soil samples were collected from two distinct layers at the dam site; an upper layer which is composed of silt and clay and a lower layer which is mainly composed of sand. Formation of the upper layer is believed to be due to deposition of TSS originally present in the intercepted stormwater or due to dust deposition at the site. Temporal variations in the saturated K of the soil were studied using water with various TSS concentrations. The infiltrating turbid solution was prepared using tap water mixed with soil samples collected from the upper layer. Results show that presence of TSS in the water introduced into the columns caused a drop in K over time. Changes in K follow a sharp drop shortly after injecting the turbid solution and a slower drop at later times. The sharp initial drop was more pronounced for cases with higher injected TSS concentration. For an experimental time of about 80 h, K dropped an order of magnitude for cases with low influent concentration. Changes in K were simulated using a mechanistically based model that assumes formation of new layers with lower K values as a result of particle entrapment below the soil surface followed by particle deposition on the surface. The developed layers model closely predicts variations of K over time, with no observed particle entrapment, except at low TSS concentration. Meanwhile, predicted deposited masses of TSS are in agreement with those determined after the completion of the experiments. Results presented here could also be useful to managers of surface recharge facilities in the country and elsewhere.
Munjed A. Maraqa; Hassan D. Imran; Salem Hegazy. Modeling changes in hydraulic conductivity due to siltation using soil columns from Alshuwaib dam site, United Arab Emirates. Environmental Earth Sciences 2015, 74, 4345 -4354.
AMA StyleMunjed A. Maraqa, Hassan D. Imran, Salem Hegazy. Modeling changes in hydraulic conductivity due to siltation using soil columns from Alshuwaib dam site, United Arab Emirates. Environmental Earth Sciences. 2015; 74 (5):4345-4354.
Chicago/Turabian StyleMunjed A. Maraqa; Hassan D. Imran; Salem Hegazy. 2015. "Modeling changes in hydraulic conductivity due to siltation using soil columns from Alshuwaib dam site, United Arab Emirates." Environmental Earth Sciences 74, no. 5: 4345-4354.
Single-rate transport models are commonly used for interpreting sorption-related mass transfer in porous media, often with the intention of approximating the kinetics of the sorption process. Among the most commonly used single-rate models are the two-site first-order (TSFO) and the two-site radial diffusion (TSRD) models. We fitted the parameters of the TSFO and TSRD models to simulated breakthrough data of hypothetical column experiments in which sorption rates were described by a γ-distributed sorption sites (GS) model. Our objective was to determine the conditions under which the assumption of a single-rate sorption parameter will be applicable to systems with heterogeneous sorption rates. We were further interested in knowing in what manner the fitted single-rate nonequilibrium model parameters depend upon the conditions under which the data were obtained. The considered hypothetical cases covered a range of experimental conditions and involved compounds with different sorption characteristics. The study revealed that the goodness of fit of the single rate models in simulating the transport of solutes exhibiting heterogeneous sorption rates is affected by solute residence time and pulse injection duration. Compared to the TSFO model, the TSRD model generally results in better prediction of solute transport affected by heterogeneous sorption kinetics. In addition, for such systems, the nonequilibrium parameters fitted using the TSFO model and their counterparts in the TSRD model are highly correlated. Moreover, an increase in the fitted mass transfer timescale of each of the single-rate models is coupled with an increase in the associated fraction of instantaneous sorption sites. A strong correlation was found between the time of the experiment and the product of the fitted characteristic time for mass transfer, pulse duration, and solute residence time. The correlation explains many of the variations in the mass transfer timescale encountered when single-rate sorption approaches were utilized to model solute transport in previous miscible displacement studies.
Munjed A. Maraqa; Saud Khashan. Modeling solute transport affected by heterogeneous sorption kinetics using single-rate nonequilibrium approaches. Journal of Contaminant Hydrology 2014, 157, 73 -86.
AMA StyleMunjed A. Maraqa, Saud Khashan. Modeling solute transport affected by heterogeneous sorption kinetics using single-rate nonequilibrium approaches. Journal of Contaminant Hydrology. 2014; 157 ():73-86.
Chicago/Turabian StyleMunjed A. Maraqa; Saud Khashan. 2014. "Modeling solute transport affected by heterogeneous sorption kinetics using single-rate nonequilibrium approaches." Journal of Contaminant Hydrology 157, no. : 73-86.
Sorption of dimethyl phthalate (DMP), diethyl phthalate (DEP) and dipropyl phthalate (DPP) to two soil materials that vary in organic matter content was investigated using miscible displacement experiments under saturated flow conditions. Generated breakthrough curves (BTCs) were inversely simulated using linear, equilibrium sorption (LE), nonlinear, equilibrium sorption (NL), linear, first-order nonequilibrium sorption (LFO), linear, radial diffusion (LRD), and nonlinear, first-order nonequilibrium sorption (NFO) models. The Akaike information criterion was utilized to determine the preferred model. The LE model could not adequately describe phthalate ester (PE) BTCs in higher organic matter soil or for more hydrophobic PEs. The LFO and LRD models adequately described the BTCs but a slight improvement in curve-fitting was gained in some cases when the NFO model was used. However, none of the models could properly describe the desorptive tail of DPP for the high organic matter soil. Transport of DPP through this soil was adequately predicted when degradation or sorption hysteresis was considered. Using the optimized parameter values along with values reported by others it was shown that the organic carbon distribution coefficient (Koc) of PEs correlates well with the octanol/water partition coefficient (Kow). Also, a strong relationship was found between the first-order sorption rate coefficient normalized to injection pulse size and compound residence time. A similar trend of timescale dependence was found for the rate parameter in the radial diffusion model. Results also revealed that the fraction of instantaneous sorption sites is dependent on Kow and appears to decrease with the increase in the sorption rate parameter.
Munjed A. Maraqa; Xianda Zhao; Jae-Ug Lee; Fathi Allan; Thomas C. Voice. Comparison of nonideal sorption formulations in modeling the transport of phthalate esters through packed soil columns. Journal of Contaminant Hydrology 2011, 125, 57 -69.
AMA StyleMunjed A. Maraqa, Xianda Zhao, Jae-Ug Lee, Fathi Allan, Thomas C. Voice. Comparison of nonideal sorption formulations in modeling the transport of phthalate esters through packed soil columns. Journal of Contaminant Hydrology. 2011; 125 (1-4):57-69.
Chicago/Turabian StyleMunjed A. Maraqa; Xianda Zhao; Jae-Ug Lee; Fathi Allan; Thomas C. Voice. 2011. "Comparison of nonideal sorption formulations in modeling the transport of phthalate esters through packed soil columns." Journal of Contaminant Hydrology 125, no. 1-4: 57-69.
The impact of the assumption of linear sorption on retardation of nonlinearly sorbed solutes in porous media is numerically explored in this paper. Breakthrough data of nonlinearly sorbed solutes are generated using the BIO1D simulation code along with the Freundlich-type nonlinear sorption model. Retardation coefficients (R) from generated breakthrough curves are estimated using first-moment analysis. Variations of R with experimental conditions revealed that R of a nonlinearly sorbed solute is a function of the input concentration, the injection period and the pore-water velocity but is independent of the length scale. This study also showed that it is appropriate to estimate R of a nonlinearly sorbed solute using a linearized isotherm if all soil particles experience sorption with liquid concentration equal to the induced concentration. Otherwise, the estimated linearized R will be either under- or overestimated depending on the applied experimental conditions and Freundlich parameters. The study further revealed that inability to account for sorption nonlinearity may in some cases erroneously be interpreted as evidence of the presence of transport nonequilibrium. A method is suggested to determine nonlinear sorption parameters from miscible displacement experiments.
Munjed A. Maraqa. Retardation of Nonlinearly Sorbed Solutes in Porous Media. Journal of Environmental Engineering 2007, 133, 1080 -1087.
AMA StyleMunjed A. Maraqa. Retardation of Nonlinearly Sorbed Solutes in Porous Media. Journal of Environmental Engineering. 2007; 133 (12):1080-1087.
Chicago/Turabian StyleMunjed A. Maraqa. 2007. "Retardation of Nonlinearly Sorbed Solutes in Porous Media." Journal of Environmental Engineering 133, no. 12: 1080-1087.
Several previously reported laboratory studies related to transport of solutes through packed columns were utilized to develop predictive relationships for mass-transfer rate coefficient. The data were classified into two groups: those obtained under rate-limited mass transfer between mobile and immobile water regions (physical nonequilibrium conditions), and those derived from rate-limited mass transfer between instantaneous and slow sorption sites (sorption nonequilibrium conditions). The mass-transfer coefficient in all these studies was obtained by fitting breakthrough data to a transport model employing a first-order rate limitations with a "constant" mass-transfer coefficient, independent of flow conditions. This study demonstrated that the mass-transfer coefficient in these models is dependent on system parameters including pore-water velocity, length-scale, retardation coefficient, and particle or aggregate size. Predictive relationships were developed, through regression analysis, relating mass-transfer coefficient to residence time. The developed relationships adequately estimated previously reported field mass-transfer values. Successful simulations of field desorption data reported by Bahr [J. Contam. Hydrol. 4 (1989) 205] further demonstrate the potential applicability of the developed relationships.
Munjed A Maraqa. Prediction of mass-transfer coefficient for solute transport in porous media. Journal of Contaminant Hydrology 2001, 53, 153 -71.
AMA StyleMunjed A Maraqa. Prediction of mass-transfer coefficient for solute transport in porous media. Journal of Contaminant Hydrology. 2001; 53 (1):153-71.
Chicago/Turabian StyleMunjed A Maraqa. 2001. "Prediction of mass-transfer coefficient for solute transport in porous media." Journal of Contaminant Hydrology 53, no. 1: 153-71.
A circulation-through-column (CTC) technique was developed and employed to evaluate the influence of fundamental differences between batch and miscible displacement (MD) techniques on the value of the sorption distribution coefficient (K). Batch, MD, and CTC experiments were conducted to determine sorption equilibrium parameters for dimethylphthalate (DMP), diethylphthalate (DEP), and dipropylphthalate (DPP) using two natural soil samples with 0.36 and 1.48% organic carbon. Batch sorption isotherms of DMP and DEP were linear while that of DPP was nonlinear. Batch-determined K values for the compounds were 30 to 170% higher than the corresponding values obtained from breakthrough curves (BTCs) generated through MD experiments. Similarities between values of K derived from batch and CTC techniques suggest that underestimation of K determined from BTCs is not due to fundamental differences between batch and MD techniques. The extent of deviation between the K values determined by batch and MD experiments was inversely related to the value of K. This was well explained by a fixed percent reduction in the retardation coefficient determined from solute BTCs, suggesting a possible leftward shift of these curves.
M. Maraqa. Effects of fundamental differences between batch and miscible displacement techniques on sorption distribution coefficient. Environmental Earth Sciences 2001, 41, 219 -228.
AMA StyleM. Maraqa. Effects of fundamental differences between batch and miscible displacement techniques on sorption distribution coefficient. Environmental Earth Sciences. 2001; 41 (1-2):219-228.
Chicago/Turabian StyleM. Maraqa. 2001. "Effects of fundamental differences between batch and miscible displacement techniques on sorption distribution coefficient." Environmental Earth Sciences 41, no. 1-2: 219-228.
Several previously reported laboratory studies related to transport of solutes through packed columns were utilized to develop predictive relationships for mass-transfer rate coefficient. The data were classified into two groups: those obtained under rate-limited mass transfer between mobile and immobile water regions (physical nonequilibrium conditions), and those derived from rate-limited mass transfer between instantaneous and slow sorption sites (sorption nonequilibrium conditions). The mass-transfer coefficient in all these studies was obtained by fitting breakthrough data to a transport model employing a first-order rate limitations with a “constant” mass-transfer coefficient, independent of flow conditions. This study demonstrated that the mass-transfer coefficient in these models is dependent on system parameters including pore-water velocity, length-scale, retardation coefficient, and particle or aggregate size. Predictive relationships were developed, through regression analysis, relating mass-transfer coefficient to residence time. The developed relationships adequately estimated previously reported field mass-transfer values. Successful simulations of field desorption data reported by Bahr [J. Contam. Hydrol. 4 (1989) 205] further demonstrate the potential applicability of the developed relationships.
Munjed A Maraqa. Prediction of mass-transfer coefficient for solute transport in porous media. Journal of Contaminant Hydrology 2001, 50, 1 -19.
AMA StyleMunjed A Maraqa. Prediction of mass-transfer coefficient for solute transport in porous media. Journal of Contaminant Hydrology. 2001; 50 (1-2):1-19.
Chicago/Turabian StyleMunjed A Maraqa. 2001. "Prediction of mass-transfer coefficient for solute transport in porous media." Journal of Contaminant Hydrology 50, no. 1-2: 1-19.