Evaluation of microbial quality of ready-to-eat foods sold in Doha, Qatar

Food safety is an integral part of environmental public health. According to Kunová et al. (2015), there has been many reports on ready-to-eat foods (RTEF) being the basis for foodborne outbreaks in recent years. In Qatar, 5.4% of the total communicable diseases reported from 2008 to 2011 were due to foodborne disease (SCH, 2013). There is very limited information regarding the microbial quality of food sold in mainly fast-food restaurants and cafeterias in Qatar. Therefore, this preliminary study was carried out to evaluate the microbial quality of ready-to-eat foods sold in selected food establishments in Qatar. Chicken and burger sandwiches and green salads were collected on a monthly basis from selected cafeterias and fast-food restaurants. The total aerobic, coliform, Salmonella spp., and Listeria spp. counts were determined using plate count agar (PCA), MacConkey Agar (MCA), Violet Red Bile Agar (VRBA), Listeria Selective Agar (LSA), respectively. The results indicated that the APC counts of the chicken and burger sandwiches were considered unsatisfactory since their counts were above the set international standards. For instance, the average total aerobic microorganism count for burger sandwich was 7.13 Log10 CFU/g, which is much higher than the safety guideline set at ≥5 Log10 CFU/g. Additionally, the total aerobic counts of green salads were determined to be 7.24 log10 CFU/g which is higher than the set guideline of 6 Log10 CFU/g. The total counts were ≥7 Log10 CFU/g for Salmonella spp., coliform, and Listeria spp. which are also considered to be unsatisfactory levels. These results demonstrate that it is necessary to improve awareness on food handling and sanitation practices applied in these restaurants to avoid any future foodborne outbreak

Waste Management in Qatar: A Systematic Literature Review and Recommendations for System Strengthening

Billions of tons of waste are generated annually, with the amount of waste rapidly increasing and its management expected to worsen. Qatar is a small and wealthy country in the Arabian Peninsula that is undergoing enormous economic and urban development. This study presents the results of a systematic literature review on waste management in Qatar and offers recommendations for system strengthening based on an analysis of the available evidence. The PRISMA guidelines were followed to review literature from the ProQuest and SCOPUS platforms, from which 82 unique publications were analyzed according to ten themes. The results draw upon diverse disciplinary and research focus areas related to waste management, ranging from the generation of value-added products from wastes to the role of religion in waste management awareness. The main recommendations emerging from the available evidence include the need for a holistic approach to address increasing waste generation, which must include diverse stakeholders such as government entities, researchers, and broad community representation for decision making as well as raising awareness for behavior change. Additionally, the main waste types, including construction, food, plastic, and electronic wastes, require specific attention since the cause of generation and type of management varies accordingly. The rise of interest in improving waste management, in particular to work toward meeting the targets of the Qatar National Vision and the National Development Strategy should bring about positive outcomes for strengthening waste management systems

Potential of GTL-Derived Biosolids for Water Treatment: Fractionization, Leachate, and Environmental Risk Analysis

This study aims to understand the potential of using biosolids produced from the world’s largest gas-to-liquid (GTL) plant for water treatment applications. The metal fractionization of the two samples: raw biosolid (BS) and the pyrolyzed biosolid-BS char (BSC) (temperature: 450 °C, heating rate: 5 °C/min, residence time: 30 min) into exchangeables (F1), reducible (F2), oxidizable (F3), and residual (F4) were carried out following the Community Bureau of Reference (BCR) procedure. Characterization showed an increased carbon content and reduced oxygen content in the biochar sample. Additionally, the presence of calcium, magnesium, and iron were detected in smaller quantities in both samples. Based on the extraction results for metals, the environmental risk analysis was determined based on RAC (Risk Assessment Code) and PERI (Potential Ecological Risk Index) indices. Furthermore, leaching studies following the TCLP (Toxicity Characteristic Leaching Procedure) were conducted. The results prove that pyrolyzing stabilizes the metals present in the raw material as BS sample had high F1 fractions, and the BS char had a greater F4 fraction. While the RAC and PERI indices show that the pyrolyzed BS has a ‘low risk’, much reduced compared to the original BS sample, this is confirmed by the leaching studies that displayed minimal leaching from the pyrolyzed sample. Overall, this study proves that the GTL biosolids can best be applied for water treatment after pyrolysis

Removal of Methylene Blue from Water Using Magnetic GTL-Derived Biosolids: Study of Adsorption Isotherms and Kinetic Models

Global waste production is significantly rising with the increase in population. Efforts are being made to utilize waste in meaningful ways and increase its economic value. This research makes one such effort by utilizing gas-to-liquid (GTL)-derived biosolids, a significant waste produced from the wastewater treatment process. To understand the surface properties, the biosolid waste (BS) that is activated directly using potassium carbonate, labelled as KBS, has been characterized using scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), and Brunauer–Emmett–Teller (BET). The characterization shows that the surface area of BS increased from 0.010 to 156 m2/g upon activation. The EDS and XPS results show an increase in the metal content after activation (especially iron); additionally, XRD revealed the presence of magnetite and potassium iron oxide upon activation. Furthermore, the magnetic field was recorded to be 0.1 mT using a tesla meter. The magnetic properties present in the activated carbon show potential for pollutant removal. Adsorption studies of methylene blue using KBS show a maximum adsorption capacity of 59.27 mg/g; the adsorption process is rapid and reaches equilibrium after 9 h. Modelling using seven different isotherm and kinetic models reveals the best fit for the Langmuir-Freundlich and Diffusion-chemisorptionmodels, respectively. Additional thermodynamic calculations conclude the adsorption system to be exothermic, spontaneous, and favoring physisorption

Removal of Methylene Blue from Water Using Magnetic GTL-Derived Biosolids: Study of Adsorption Isotherms and Kinetic Models

Global waste production is significantly rising with the increase in population. Efforts are being made to utilize waste in meaningful ways and increase its economic value. This research makes one such effort by utilizing gas-to-liquid (GTL)-derived biosolids, a significant waste produced from the wastewater treatment process. To understand the surface properties, the biosolid waste (BS) that is activated directly using potassium carbonate, labelled as KBS, has been characterized using scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), and Brunauer–Emmett–Teller (BET). The characterization shows that the surface area of BS increased from 0.010 to 156 m2/g upon activation. The EDS and XPS results show an increase in the metal content after activation (especially iron); additionally, XRD revealed the presence of magnetite and potassium iron oxide upon activation. Furthermore, the magnetic field was recorded to be 0.1 mT using a tesla meter. The magnetic properties present in the activated carbon show potential for pollutant removal. Adsorption studies of methylene blue using KBS show a maximum adsorption capacity of 59.27 mg/g; the adsorption process is rapid and reaches equilibrium after 9 h. Modelling using seven different isotherm and kinetic models reveals the best fit for the Langmuir-Freundlich and Diffusion-chemisorptionmodels, respectively. Additional thermodynamic calculations conclude the adsorption system to be exothermic, spontaneous, and favoring physisorption

Novel high capacity model for copper binary ion exchange on e-waste derived adsorbent resin

Heavy metal water pollution is a global concern in recent years. Copper is a toxic metal at higher concentrations (> 20 μg /g) and needs to be removed using ion exchanger systems. This study investigates the removal efficiencies of copper by the non-metallic fraction (NMF) waste printed circuit boards (PCBs). The high maximum adsorption capacity of copper by the PCB-derived material after activation with KOH was 2.65 mmol/g, and the experimental isotherm was best correlated by the Temkin model. Finally, this study presents a novel dual site adsorption/ion exchange mechanism, wherein the potassium (from the activation) and calcium (present in the structure) served as ion exchange sites for the copper in the solution. Therefore, this recycling study, focusing on cyclic environmental management, converts a major waste material to an activated ion exchange resin (high capacity) for the removal of copper from wastewater solutions and successfully regenerates the resin for re-use while producing an acidic copper solution for recovery by electrolysius or chemical salt precipitation.Other Information Published in: Adsorption License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1007/s10450-022-00360-0</p

A review of prospects and current scenarios of biomass co-pyrolysis for water treatment

With ever-growing population comes an increase in waste and wastewater generated. There is ongoing research to not only reduce the waste but also to increase its value commercially. One method is pyrolysis, a process that converts wastes, at temperatures usually above 300 °C in a pyrolysis unit, to carbon-rich biochars among with other useful products. These chars are known to be beneficial as they can be used for water treatment applications; certain studies also reveal improvements in the biochar quality especially on the surface area and pore volume by imparting thermal and chemical activation methods, which eventually improves the uptake of pollutants during the removal of inorganic and organic contaminants in water. Research based on single waste valorisation into biochar applications for water treatment has been extended and applied to the pyrolysis of two or more feedstocks, termed co-pyrolysis, and its implementation for water treatment. The co-pyrolysis research mainly covers activation, applications, predictive calculations, and modelling studies, including isotherm, kinetic, and thermodynamic adsorption analyses. This paper focuses on the copyrolysis biochar production studies for activated adsorbents, adsorption mechanisms, pollutant removal capacities, regeneration, and real water treatment studies to understand the implementation of these co-pyrolyzed chars in water treatment applications. Finally, some prospects to identify the future progress and opportunities in this area of research are also described. This review provides a way to manage solid waste in a sustainable manner, while developing materials that can be utilized for water treatment, providing a double target approach to pollution management.Other Information Published in: Biomass Conversion and Biorefinery License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1007/s13399-022-03011-0</p