Theme 1: Energy and Environment
http://hdl.handle.net/10576/24264
2024-03-28T22:03:31ZA Case Study of Qatar: Health Risk Assessment associated with Bisphenol A
http://hdl.handle.net/10576/24331
A Case Study of Qatar: Health Risk Assessment associated with Bisphenol A
Bello, Suraj Adewale
This study is aimed at evaluating exposure to bisphenol A in drinkable water. Much studies have not been conducted on Bisphenol A in the drinkable water globally, in Arabian Gulf and particularly in Qatar. This assessment studies the probable risks associated with exposure of children as well as adults to bisphenol A in drinkable water around Doha. The risk assessment was conducted based on the water analyses collected over the two seasons (winter and summer) as well as most recent bisphenol A toxicity data published by the Environmental Protection Agency, USA (US EPA). It was found that the concentration levels of bisphenol A (0.0002205mg/kg b.w./day, 0.0001515mg/kg b.w./day) in both seasons fell below acceptable levels (0.05mg/kg b.w./day). Statistical analysis established that there is no variation in the concentration levels during summer and winter. The calculated health risk assessment measured in terms of hazard quotient or hazard ratio and hazard index were less than one (summer 6.18E-02 < 1, winter 14.24E-02 < 1). Hence, non-carcinogenic health risk was found to be within the safety limit for bisphenol.
2021-01-01T00:00:00ZQatari tight Gas Reservoirs: Molecular Simulation insights toward Estimation of Ultimate Recovery (EUR) from Carbonated Reservoirs
http://hdl.handle.net/10576/24330
Qatari tight Gas Reservoirs: Molecular Simulation insights toward Estimation of Ultimate Recovery (EUR) from Carbonated Reservoirs
Elbashier, Elkhansa; Hussein, Ibnelwaleed
The geometrical properties of the reservoir rocks are usually affected by natural thermodynamics or environmental changes that may affect the amount of gas in place in the reservoir. To address these properties, we conduct density functional theory calculations to study the effect of gas composition on the adsorption (Eads), considering surface strain and curvature effects. Additional analyses, like geometrical analysis, and surface energy, were conducted to explain the results. The results of the strain effect showed that regardless of the strain values or curvature levels, all considered gases are physisorbed, with CO2 having the largest Eads. In addition to their weak interaction with the surface, CH4 shows no particular changing trend of the Eads with strain. The effect of strain becomes more pronounced in the case of CO2 and C2H6. A new model of the nanopore, which is the cylindrical-shaped nanopore, is introduced. Cylindrical nanopores have greater adsorption affinity compared to the flat surface, which demonstrates their higher gas capacity. Additionally, a mathematical model of the Eads vs. the diameter is developed. The capacity test of CH4 and CO2 showed adsorption of >24 molecules. These findings can be useful for determining the estimated ultimate recovery in carbonaceous tight gas reservoirs.
2021-01-01T00:00:00ZAn Integrated Approach to Produced Water Treatment using Sand Filtration, Activated Carbon and Microemulsions modified Activated Carbon
http://hdl.handle.net/10576/24333
An Integrated Approach to Produced Water Treatment using Sand Filtration, Activated Carbon and Microemulsions modified Activated Carbon
Al-Kaabi, Maryam Ali; Al-Ghouti, Mohammad Ahmad; Zouari, Nabil A.; Ahmed, Talaat Abdelfattah
The produced water from natural gas production process in the North field offshore is considered as the largest wastewater volume in Qatar, which could be potentially used for clean water resources for the industry as well as for some other domestic uses, if it is treated properly. This research aims to study the physical and chemical characterizations of the produced water from the North field and examine the removal of major inorganic and organic pollutants and heavy metals from the PW by using different treatments method such as using the sand filtration, activated carbon filtration and modified activated carbon filtration. The physical and chemical characterization of produced water was examined followed by treatment through sand filtration coupled with activated carbon and microemulsion modified activated carbon techniques. The results of characterization showed that the produced water had high concentration of COD, TOC, BTEX and various metals. After sand filtration, considerable reduction in TSS and COD was achieved. Furthermore, BTEX were also removed by more than 93% except for toluene. However, sand filtration was not enough to remove most of the metals and ions. Therefore, further treatment was done through activated carbon and modified activated carbon and their treatment efficiency was compared. Both techniques were able to achieve higher removal efficiencies for BTEX, metals and ions. Thus, the treated water was free from all major pollutants of PW and can be considered suitable for reuse at industrial application. Further studies and applications could be applied on produced water such as studying the biological characterization and applying biological treatment processes.
2021-01-01T00:00:00ZPrevalence of Toxigenic Fungi and Mycotoxins in Arabic Coffee: Protective Effect of Traditional Coffee Roasting, Brewing and Microbial Volatiles
http://hdl.handle.net/10576/24334
Prevalence of Toxigenic Fungi and Mycotoxins in Arabic Coffee: Protective Effect of Traditional Coffee Roasting, Brewing and Microbial Volatiles
Al-Attiya, Wadha Ahmed Khalifa; UI Hassan, Zahoor; Al-Thani, Roda; Jaoua, Samir
Like other agricultural crops, fungal infection and synthesis of mycotoxins in coffee leads to significant economic losses. This study is aimed at investigating the prevalence of toxigenic fungi, their metabolites, and the effect of traditional roasting and brewing on ochratoxin A (OTA) and aflatoxins (AFs) contents of naturally contaminated coffee samples. In addition, in vivo biocontrol assays were performed to explore the antagonistic activities of Bacillus simplex 350-3 (BS350-3) on the growth and mycotoxins synthesis potential of Aspergillus ochraceus and A. flavus. The relative density of A. niger, A. flavus, Penicillium verrucosum and A. carbonarius on green coffee bean was 60.82%, 7.21%, 3.09% and 1.03%, respectively. OTA contents were lowest in green coffee beans (2.15 µg/kg), followed by roasted (2.76 µg/kg) and soluble coffee (8.95 µg/kg). Likewise, AFs levels were highest in soluble coffee (90.58 µg/kg) followed by roasted (33.61 µg/kg) and green coffee (9.07 µg/kg). Roasting naturally contaminated coffee beans by three traditional styles; low, medium and high, followed by brewing resulted in reduction of 58.74%, 60.88% and 64.70% in OTA and 40.18%, 47.86% and 62.38% AFs contents, respectively. BS350-3 volatiles resulted in significant inhibition in AFs and OTA synthesis by A. flavus and A. carbonarius on infected coffee beans, respectively. Gas chromatography mass spectrochemistry (GC-MS/MS) analysis of headspace BS350-3 volatiles showed quinoline, benzenemethanamine and 1-Octadecene as bioactive antifungal molecules. These findings suggest that marketed coffee samples are generally contaminated with OTA and AFs; with a significant number of roasted and soluble coffee contaminated at the levels above EU permissible limits for OTA. Further, along with coffee roasting and brewing; microbial volatiles possess a promising potential, which can be optimized to minimize the dietary exposure to mycotoxins.
2021-01-01T00:00:00Z