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Qatar's population has been rapidly increasing in recent years, and the country's long-term vision, QNV 2030, aims to sustain this growth by transforming the country into a sustainable state. One aspect of this vision is to convert waste into value-added products, which will reduce the environmental and spatial burden associated with waste in Qatar, while contributing to a circular economy. This study describes methods for producing biochar and activated carbon (AC) from gas-to-liquids derived biosolids, cardboard waste and mixed samples using pyrolysis and activation techniques. The characterisation of products revealed that the yield of biochar samples was higher than AC, and that the pH of the biochar samples was more alkaline than the feed samples due to metals after pyrolysis and reduced acid surface functional groups. Proximate analysis of samples showed lowered moisture and enhanced ash in feeds upon pyrolysis and activation due to increased temperature with reduced volatile content. AC application to water treatment is considered a potential benefit due to the increased surface area, pore volume and magnetic properties based on the Brunauer–Emmett–Teller (BET) and X-ray Powder Diffraction (XRD) analysis. The X-ray photoelectron spectroscopy (XPS) analysis also showed increased –CO3/O–C = O and potassium in the ACs as a result of potassium carbonate activation. The study proposes various applications that can support a circular economy, but future studies should investigate actual applications and potential health and environmental effects and evaluate the feasibility and environmental impact of production methods. [ABSTRACT FROM AUTHOR]

One of the primary sources of waste in Qatar is animal waste, which includes poultry litter. Annually, Qatar produces approximately 0.83 x 106 t of poultry litter. Consequently, there is a need for a more sustainable waste treatment approach to handle it. Hence, this study's principal objective is to investigate the suitability of poultry litter as a feedstock for pyrolysis, with a specific emphasis on its potential for biochar generation. The physicochemical evaluations of poultry litter were performed. The potential for biochar formation from poultry litter was assessed using empirical equations at two different pyrolysis temperatures, namely 250 °C and 500 °C. Additionally, an economic analysis was conducted in order to ascertain the potential revenue generated by biochar derived from poultry litter. The composition of poultry litter, characterised by a moderate volatile content of 60 % and a fixed carbon content of 16 %, along with a moderate higher heating value (HHV) of 16 MJ/kg, indicates its potential suitability as a highly suitable feedstock material for biochar generation through pyrolysis. According to the findings of the technical analysis, biochar yields of up to 50 % and 31 % can potentially be achieved at 250 °C and 500 °C, respectively. Moreover, the findings of the study indicate that Qatar has the capacity to generate up to 0.35 x 106 t of biochar annually from its poultry litter. Additionally, the economic analysis suggests that the country can generate annual revenue of about 69 x 106 USD from the selling of biochar. [ABSTRACT FROM AUTHOR]

• First food waste study at a university campus in Qatar. • Mixture of large-scale catering services and specialized franchise food outlets. • The per person food waste generation exceeds the highest globally reported rates. • Overproduction is the main driver for food wastage resulting from food display. • Highlights the possible scale of issue at cafeterias and need for caterer education. Food waste is a pressing issue that imposes economic, social and environmental impacts on both developing and developed countries. This study analyzes quantitatively and qualitatively the generated food waste at various food outlets of a university campus in Qatar. It is a fundamental step to manage the issue of food waste from educational institutes. The investigation comprised four stages: screening, sampling, surveying, and synthesis. Food waste generation at the sampled locations was estimated at 329.5 kg/day or 80 t/year. Based on per sales estimates, total food waste was 980 g/sale and 757 g/sale at the student male and female housing complexes, respectively, equating to roughly one wasted meal for each sold meal. The majority of this waste was avoidable waste and the root cause for the excessive food waste generation was overproduction rather than consumer wastage. The study found that the main food provider, who primarily serves buffet style meals, lacks the proper tools to measure food waste generated at their cafeterias. Past experience was the primary tool to support the company's demand management estimation which has proven unsuccessful and highlights the need to not only educate the consumer but also food providers. Possible treatments routes are discussed based on food waste characterization findings. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hybrid biorefinery is developed for jet biofuel production. • The system provides a unique integration of technologies, streams, and heat. • The system accommodates multiple biomass from different solid and liquid categories. • A 22% reduction in jet fuel price is achieved as compared to the conventional Jet-A. • A 41% mitigation of associated emissions is attained relative to Jet-A. Jet biofuel (JBF) is identified as an essential solution to mitigate the carbon footprint of the aviation sector. Since aeroplanes rely solely on liquid fuels, the development of pathways that generates JBF as a major product has become crucial. Thus far, seven pathways to produce JBF have been developed and certified over the past decade. Each of these pathways accommodates a specific type of biomass. However, the availability, sustainability and feasibility of feedstocks to fulfil the growing demand on jet fuel remains an issue. As such, this study presents a holistic approach for the design of a state-of-the-art hybrid biorefinery that accommodates multiple biomass feedstocks across different categories including energy crops (i.e., Jatropha energy crop), dry biomass (i.e., municipal solid waste) and wet biomass (i.e., livestock manure). A Qatar-based industrial scale biorefinery was modelled in Aspen Plus® considering a pre-defined geospatial distribution of biomass and the optimal biorefinery site in the country. The hybrid system integrated advanced technologies such as hydroprocessing, Fischer-Tropsch, gasification, dry-reforming and hydrothermal liquefaction. While biomass optimal insertion streams were evaluated using a prediction model. Besides, intensive materials, heat, water and power integrations were performed to maximise JBF production, mitigate its environmental impact and control its cost. The system generated 328, 94 and 44 million litres of JBF, gasoline and diesel, respectively. Produced JBF was characterised and found to comply with all international standards. The generated JBF can substitute 15.3 % of Qatar's jet fuel needs, while it can power around one third of its fleet considering a maximum allowable jet biofuel blend of 50 %. The proposed model achieved a minimum selling price of JBF at 0.43 $/kg, which is 22 % lower than the market price of conventional Jet-A fuel (2019). In addition, the environmental analysis of the model indicated a 41 % mitigation in greenhouse gas emissions achieved by JBF throughout its lifecycle, relative to Jet-A fuel. [ABSTRACT FROM AUTHOR]

Jatropha curcas L. (JCL) is one of the most prominent energy crops due to its superior agronomical traits, where it can grow in non-arable lands and harsh climates with minimal water requirements. A significant number of studies were published on the utilisation of JCL for biofuel production, whereas there are no studies on its use in greenbelt (GB) or windbreak technologies reported thus far. Meanwhile, a few approaches on the delineation of greenbelts to fight desertification in the arid regions exist in literature. This study presents a novel approach to delineate a multipurpose energy-greenbelt using JCL crop for biofuel production, as well as to preserve the soil and enhance air quality, thereby helping to combat desertification and sand-dust storms (SDS). The methodology is demonstrated using a case study in the state of Qatar for the diversification of its renewable energy resources. Moreover, Qatar is also suffering from land degradation due to erosion factors and desert creep. A multi-dimensional approach is proposed for this purpose using satellite and meteorological data to initially select the optimal plantation sites that potentially contribute to the highest possible biofuel yield. The spatial analysis was carried out using the analytical hierarchy process (AHP) technique for multi-criteria decision making in the geographic information system (ArcGIS). In addition, the Landsat and MODIS satellite imagery were utilised in combination with historical records from the weather stations to evaluate the patterns of SDS, land degradation and urban expansion, to best define optimal GB pathway. COMSOL Multiphysics software was subsequently employed to evaluate the performance of Jatropha -GB and determine its optimal density. The different solutions for GB delineation spans 166.6–227.8 km length and (6 × 6 m) of field density. It is expected that the economic and environmental benefits from the derived GB configuration include: (a) protection of up to 87% of Qatar farms against further deterioration; (b) yield of up to 36 M gallon of green liquid fuels; (c) capture of 0.33 M tonnes of CO 2 per 1 km GB-depth annually; and (d) provide a better air quality for around 95% of the Qatar population. [Display omitted] • Jatropha curcas is proposed for establishing a greenbelt to combat desertification. • Dust storms patterns are defined using a novel combination of satellite and meteorological data. • Greenbelt was delineated considering agronomical, environmental, and social aspects. • Defined greenbelt provides protection to 87% of Qatar's farms and 95% of population. • Greenbelt of 1 km-depth generates 36 M gallons of fuels and capture 0.3 M tonnes of CO 2. [ABSTRACT FROM AUTHOR]

Due to growing concerns about carbon emissions, using zero-carbon fuels has become an interesting alternative to overcome this problem. The NH 3 (70%)-H 2 (30%) fuel blend is an innovative fuel example that has the potential to replace conventional hydrocarbon fuels. Studies on the NH 3 (70%)-H 2 (30%) fuel blend have shown its superior combustion performance and its effect on enhancing cycle efficiency compared to other compositions of the NH 3 –H 2 blends. However, without calibrating ammonia plants and simply mixing portions of the produced pure ammonia to hydrogen at the desired molar fraction essentially requires coupling ammonia plants with other hydrogen-producing plants, leading to potential difficulties in commercializing the unused (as fuel in the NH 3 –H 2 /air gas turbines) hydrogen portions from the hydrogen-producing plan. Therefore, in this paper, as an attempt to utilize the existing ammonia production infrastructure and facility without acquiring major changes that could lead to resisting the adoption of the NH 3 (70%)-H 2 (30%) fuel blend, the independent parameters of a conventional ammonia plant have been calibrated, and the reactors have been sized to provide a continuous supply of the NH 3 (70%)-H 2 (30%) fuel blend with the exact molar fraction to run a power plant. Calibrating of the ammonia plant has been performed using an ASPEN PLUS model. • A recalibrated ammonia plant to produce the NH3(70%)-H2(30%) fuel blend. • A reduced ammonia plant to produce the NH3(70%)-H2(30%) fuel blend. • Identifying the sensitivities of the reduced ammonia plant. • Utilizing the existing facilities of ammonia plants to produce carbon-free fuel. [ABSTRACT FROM AUTHOR]

• Hydrogen rich syngas can be produced from gasified waste biomass. • Optimum feedstock blending options are utilised to maximise hydrogen production. • A hybrid environmental and economic optimisation methodology is implemented. • Steam gasification demonstrates excellence in providing hydrogen-rich syngas. • Date pits indicates high potential in maximising the hydrogen content in syngas. Concerns related to global warming and the depletion of fossil fuels have propelled the global community to explore alternative renewable energy sources. Biomass is a nonconventional and renewable energy resource that can potentially be utilised for the production of sustainable heat and power. The thermal gasification process is an effective biomass conversion and utilisation method producing syngas as the product gas. This study details a biomass gasification process and subsequent optimisation, considering multiple parameters, including the type of feedstock and gasifying agent (gasifier) to maximise hydrogen production. Aspen Plus software is used to develop three agent-based biomass gasification models considering the characteristics of certain materials from Qatar built environment. The ultimate goal of the study is to optimise the gasification processes to yield different biomass blending options satisfying the maximisation of hydrogen generation through different scenarios. The capabilities of the built-in activated analysis package using Aspen Energy Analyser and Aspen Process Economic Analyser are utilised to evaluate the environmental and economic perspectives. The results demonstrate the excellence of steam-only biomass gasification in providing profitable and cleaner products. The yield of hydrogen production from blending of biomass feedstock achieved a high fraction of 5.23% with the steam-only gasification, while the yield increased from 1.63% to 5.22% for the oxygen/steam gasification when maximising the hydrogen fraction. Moreover, the selective limiting of biomass capacity enhances the quality of syngas through enriching the hydrogen production and lowers the need for subsequent adjustment and the manipulation of gasifying agent quantity and operating energy. [ABSTRACT FROM AUTHOR]

Considering changes in the global climate, there is an impetus to diversify away from fossil fuels as part of efforts to reduce greenhouse gas emissions. Biomass, as a source of energy, has the potential to generate sustainable power and fuels and contribute towards a cleaner future. In fact, the utilisation of biomass as a carbon dioxide neutral organic source in an integrated system generates valuable products, and reduces waste and the consumption of non-renewable resources. Gasification, the preferred option for converting biomass to combustible gas, provides higher electrical efficiencies than combustion, whereby the syngas generated from the gasification process can be utilised to generate clean energy. In addition, syngas can be utilised for the production of ammonia and methanol thus reducing their respective dependencies on natural gas. This study will detail an optimised biomass gasification process considering multiple parameters, including the thermodynamic operating conditions, the type of gasifier (gasifying agent) and feedstock. Fundamentally, this study considers the process pathways for the recycling of multiple sources of biomass to generate high energy syngas from the available biomass options when used in combination as blends or individually. To achieve this aim, an Aspen Plus simulation model is developed for four different biomass agent-based gasification techniques using the biomass characteristics of certain Qatar biomass materials, which include date pits, manure and sewage sludge. Outcomes of the study included an optimisation of the gasification processes to yield different blending options of the biomass feedstock satisfying the downstream operations of power and fuels production. The results demonstrate the domination of date pits for two of the considered configurations with over 99% w/w date pit feed composition. Moreover, the sensitivity analysis conducted on the different configurations highlighted specific optimum operation points in terms of temperature, pressure, and oxygen and steam feed ratios. The hydrogen content in the generated syngas, considered important for the downstream production, yields a peak at approximately 850 °C and 1 bar with a modified equivalence ratio of approximately 2.5, and a ratio of oxygen supplied by an air-steam combination of approximately 0.6. The process can be further optimised by considering trade-offs between product purity or yield, profit, operating efficiency, quality of raw materials blends, and carbon footprint. • Biomass as a source of energy has the potential to generate sustainable products. • Syngas is an important intermediary in the production of power, fuels and chemicals. • Different pathways for recycling of multiple biomass sources are evaluated. • Optimum biomass feedstock blending options are determined. • The effect of changing key gasification performance parameters is analysed. [ABSTRACT FROM AUTHOR]

• An integrated framework for optimizing waste valorisation methods is developed. • Three technologies are evaluated: pyrolysis, liquefaction and gasification. • The framework considers technical, economic and environmental factors. • The model supports stakeholders' decision-making on waste management strategies. Waste is the most abundant biomass worldwide for renewable energy and value-added products generation. While technologies for the treatment of multiple waste categories continue to evolve, frameworks that facilitate strategic decision-making within bio-economies are required. Therefore, the aim of this research is to develop a framework that can identify optimal processing route for converting different biomass wastes into valuable products. This study considers five different waste types available in Qatar, including date seed, camel manure, municipal solid waste (MSW), food waste, and sewage sludge. Whereas the investigated technologies include pyrolysis, gasification, and hydrothermal liquefaction (HTL). The three processes were simulated in Aspen Plus® and evaluated in terms of their technical, environmental, and economic performance for the different selected biomass feedstocks. A two-stage optimisation framework was then developed to identify the optimal processing technology for each biomass considering multiple products generation (i.e., syngas, biochar, and bio-oil). Investigating the waste to energy pathways, the presented model maximised net profit and energy generation while minimised the total associated emissions. The model indicated that gasification is the optimal processing technology to achieve higher economic return. While pyrolysis is recommended for the achievement of highest energy return. Nevertheless, HTL exhibited the best environmental performance with the lowest associated emissions. In addition, various wastes such as MSW and food waste are best processed by gasification to fulfil the environmental and economic criteria, while pyrolysis is more energy efficient in processing these wastes. Whereas HTL has been recommended only for high moisture containing biomass like manure and sludge, demonstrating relatively high energy efficiency, but lower economic return relative to gasification and pyrolysis. The presented optimisation framework may provide insights for decision-makers to optimally valorise waste considering national priorities. [ABSTRACT FROM AUTHOR]

• A water planning framework using EWF nexus to cultivate alfalfa is developed. • The water and nutrient demands of alfalfa are determined using weather and soil data. • The model reduces the burden on water energy, and the overall carbon footprint (CF). • The optimisation is conducted considering irrigation water standards. • The model can optimally meet the water and nutrients demand of alfalfa. The state of Qatar is challenged by food insecurity due to its limited water resources. Considering its large industrial infrastructure and municipal water usage, treated wastewater with varying nutritional content can alleviate the stress on groundwater resources and enhance food production. Using an energy-water-food nexus approach, this study presents a planning framework that identifies the optimum allocation of 13 sources of treated wastewater to be used in cultivating alfalfa, achieving reductions in greywater footprint, energy for transportation, and carbon footprint. The treated wastewater sources are allocated according to their nitrogen-phosphorus-potassium contents to meet alfalfa requirements while respecting irrigation water standards. Results demonstrate that treated wastewater optimally provides the water and nutrient requirements to both farms. Greywater footprint, energy for transportation, and carbon footprint associated with the growth of 1 ton of alfalfa are found to be -917m3, 70 kWh and -34kg-Co 2,eq for Er-rakhiya farm, and -1,770m3, 68 kWh and -18kg-Co 2,eq for Wadi Al Araig farm. [ABSTRACT FROM AUTHOR]

• A critical review on type and point of generation of Oil and gas industry waste. • Discussion on commercial and emerging treatment methods of produced water. • Detailed analysis of oil sludge commercial and emerging treatment technologies. • A comprehensive review on the treatment of flue gases and their possible utilisation. • Potential for the oil and gas industry utilisation in Qatar. Globally, the oil and gas industry produces a large volume of waste in the form of produced water, oil sludge, and flue gases that can pose a negative impact on environment. As such there is a need for the treatment and safe handling of this waste. Although, several techniques have been developed for the treatment of oil and gas industry waste, recent research trends have highlighted that for the sustainable treatment and management of oil and gas industry waste, it should be coupled with resource recovery and re-utilization concepts in line with circular economy perspectives. Essentially, converting waste into economic value added products, reducing environmental impacts and supporting sustainability within the oil and gas industry is of paramount importance. This study reviews basic three types of wastes streams, including solid waste (oil sludge), flue gases (CO 2 and SO 2), and liquids (produced water) originating from the oil and gas industry. The second aim is to review their characterization and respective treatment technologies, challenges, and possible emerging opportunities. An insight into the resource recovery and reuse potential for all three type of wastes considered is also provided. Finally, a case study from the State of Qatar is provided to assess the theoretical resource recovery and market/economic potential from selected wastes. [ABSTRACT FROM AUTHOR]

Livestock manures significantly contribute to greenhouse gas emissions and soil contamination if not valorised or disposed of properly. Meanwhile, hydrothermal liquefaction has emerged as a promising technology for the conversion of wet wastes into value-added products. As such, this study investigates the potential of hydrothermal liquefaction of camel manure and subsequent upgrading into drop-in fuels in Qatar. Experimental characterisation of manure samples is conducted, while a small-scale plant is simulated and evaluated using Aspen Plus®. Excess treated wastewater of Qatar is utilised as an alternative to fresh water in the process, while power is completely generated on-site. The demonstrated results are promising; whereby, a biocrude yield of 37.9% (on dry and ash-free basis) is achieved, while the biocrude is upgraded into a high-quality bio-gasoline. The produced bio-gasoline contributes to a 7% reduction in greenhouse gas emissions relative to conventional gasoline. The project capital investment is estimated to be 38 M$, while the bio-gasoline's minimum selling price is at 0.87 $/kg, which is still above the market price of conventional gasoline in Qatar (∼0.6 $/kg). However, the conducted sensitivity analysis indicates that scaling-up the plant by 5-fold can shift the fuel's minimum selling price below the average market price. As such, it has a high potential to be locally commercialised especially at times of petroleum price hikes. [Display omitted] • Drop-in biofuel production from camel manure via liquefaction is investigated. • The process delivered a considerable biocrude yield of 37.9%. • The biocrude oil is upgraded into a high-performance bio-gasoline fuel. • Produced bio-gasoline can be sold at 0.87 $/kg. • Emissions reduction of 7% is achieved as compared to conventional gasoline. [ABSTRACT FROM AUTHOR]

Ensuring a consistent and regular availability of food is crucial for food security. Food markets, supplied through both domestic production and international trade, are governed by several risks emerging from unpredictable supply chain disruptions, volatility of commodity prices, along with other unforeseen circumstances such as natural disasters. To mitigate the challenges threatening the stability of food systems, decision-making within the food sector should be enhanced and robust to accommodate any changes that might cause food shortages. Dynamic models, that can predict the behavior of food systems in order to avoid potential future knock-on effects and deficits, are incumbent to ensure the sustainable performance of food systems. This study proposes a dynamic decision-making scheme that simulates strategies of the perishable food market under different circumstances. An agent-based model (ABM) is developed and implemented using python MESA library for a case study in Qatar, illustrating the potential performance of tomato under three different scenarios to be considered, namely: (a) baseline scenario - aiming to reflect current production and market conditions; (b) water resource efficiency scenario - basing decisions on crop water requirement (CWR) depending on weather conditions; and (c) economic risk scenario - applying the concept of forward contracts to hedge against future uncertainties in crop prices. The findings of this study demonstrate that under the baseline conditions, a tomato crop can be supplied through a combination of domestic production and imports depending on the available inventories and prices imposed by exporters. The results obtained for the CWR scenario suggest the need for total reliance on imports in order to meet domestic demand, as there is potentially high-water loss, which amounts to an average of 4.9 Billion m3 per year, if tomato is grown locally. In contrast, the results from the forward contract scenario recommend a 57% dependency on local production in order to mitigate the effects of volatility in global food prices, which contributes to a 63% reduction in environmental emissions. Findings of this research provide insight into the factors that influence strategic decision making by the food sector to enhance its economic and environmental performances under diverse circumstances. • A dynamic decision-making framework to ensure consistent availability of food is developed. • An agent-based simulated is used to advise the strategic planning of tomato crops supply in Qatar. • Three scenarios are investigated to demonstrate the impact of crop water requirement and forward contracts on strategies of the food sector. • A yearly average of 4.9 Bm3 is globally saved when the water requirement is considered in the decision-making. • A reduction of 63% in environmental emissions is recorded while adopting forward contracts. [ABSTRACT FROM AUTHOR]