Novel integrated mechanical biological chemical treatment (MBCT) systems for the production of levulinic acid from fraction of municipal solid waste: A comprehensive techno-economic analysis.

This paper, for the first time, reports integrated conceptual MBCT/biorefinery systems for unlocking the value of organics in municipal solid waste (MSW) through the production of levulinic acid (LA by 5wt%) that increases the economic margin by 110-150%. After mechanical separation recovering recyclables, metals (iron, aluminium, copper) and refuse derived fuel (RDF), lignocelluloses from remaining MSW are extracted by supercritical-water for chemical valorisation, comprising hydrolysis in 2wt% dilute H2SO4 catalyst producing LA, furfural, formic acid (FA), via C5/C6 sugar extraction, in plug flow (210−230°C, 25bar, 12s) and continuous stirred tank (195−215°C, 14bar, 20mins) reactors; char separation and LA extraction/purification by methyl isobutyl ketone solvent; acid/solvent and by-product recovery. The by-product and pulping effluents are anaerobically digested into biogas and fertiliser. Produced biogas(6.4MWh/t), RDF(5.4MWh/t), char(4.5MWh/t) are combusted, heat recovered into steam generation in boiler (efficiency:80%); on-site heat/steam demand is met; balance of steam is expanded into electricity in steam turbines (efficiency:35%)

Decarbonised polygeneration from fossil and biomass resources

Utilisation of biomass resources and CO2 abatement systems in currently exploited fossil resource based energy systems are the key strategies in resolving energy sustainability issue and combating against global climate change. These strategies are affected by high energy penalty and high investment. Therefore, it is imperative to assess the viability of these energy systems and further identify niche problem areas associated with energy efficiency and economic performance improvement. The current research work has two parts. The first part presents techno-economic investigation of thermochemical conversion of biomass into the production of fuels (Fischer-Tropsch liquid or methanol) and electricity. The work encompasses centralised bio-oil integrated gasification plant, assuming that the bio-oil is supplied from distributed pyrolysis plant. Bio-oil is a high energy density liquid derived from biomass fast pyrolysis process, providing advantages in transport and storage. Various bio-oil based integrated gasification system configurations were studied. The configurations were varied based on oxygen supply units, once-through and full conversion configurations and a range of capacities from small to large scale. The second part of this thesis considers integration of various CO2 abatement strategies in coal integrated gasification systems. The CO2 abatement strategies under consideration include CO2 capture and storage, CO2 capture and reuse as well as CO2 reuse from flue gas. These facilities are integrated into cogeneration or polygeneration systems. The cogeneration concept refers to the production of combined heat and power while polygeneration concept is an integrated system converting one or more feedstocks into three or more products. Polygeneration is advocated in this work attributed to its high efficiency and lower emission. Furthermore, it can generate a balanced set of products consisting of fuels, electricity and chemicals. It is regarded as a promising way of addressing the future rapidly growing energy demands. A holistic approach using systematic analytical frameworks comprising simulation modelling, process integration and economic analysis has been developed and adopted consistently throughout the study for the techno-economic performance evaluation of decarbonised fossil and bio-oil based systems. Important design methodology, sensitivity analysis of process parameters and process system modifications are proposed. These are to enhance the efficiency as well as lower the economic and environmental impacts of polygeneration systems. A shortcut methodology has also been developed as a decision-making tool for effective selection from a portfolio of CO2 abatement options and integrated systems. Critical and comprehensive analyses of all the systems under considerations are presented. These embrace the impact of carbon tax, product price evaluation and recommendations for sustainability of low carbon energy systems.EThOS - Electronic Theses Online ServiceOverseas Research Scholarship (ORS)The University of Manchester Alumni FundProcess Integration Research Consortium (PIRC)School of Chemical Engineering and Analytical Science (CEAS)GBUnited Kingdo

Material flow and sustainability analyses of biorefining of municipal solid waste

This paper presents material flow and sustainability analyses of novel mechanical biological chemical treatment system for complete valorization of municipal solid waste (MSW). It integrates material recovery facility (MRF); pulping, chemical conversion; effluent treatment plant (ETP), anaerobic digestion (AD); and combined heat and power (CHP) systems producing end products: recyclables (24.9% by mass of MSW), metals (2.7%), fibre (1.5%); levulinic acid (7.4%); recyclable water (14.7%), fertiliser (8.3%); and electricity (0.126 MWh/t MSW), respectively. Refuse derived fuel (RDF) and non-recyclable other waste, char and biogas from MRF, chemical conversion and AD systems, respectively, are energy recovered in the CHP system. Levulinic acid gives profitability independent of subsidies; MSW priced at 50 Euro/t gives a margin of 204 Euro/t. Global warming potential savings are 2.4 and 1.3 kg CO2 equivalent per kg of levulinic acid and fertiliser, and 0.17 kg CO2 equivalent per MJ of grid electricity offset, respectively

Sugarcane Bagasse Valorization Strategies for Bioethanol and Energy Production

The use of sugarcane bagasse pith as solid substrate for fungi and microbial growth is well known, as well as a source of microorganisms that can be isolated from it. Pith has also been used as a bulking agent for soil bioremediation. More recently, bagasse pith has been used for bioethanol production involving pretreatment and hydrolysis followed by fermentation and dehydration. However, little is reported about biomass valorization for the development of environmentally sound and innovative strategies to process sugarcane bagasse from sugar mills. Incineration of sugarcane bagasse pith is a very common and mature technology for waste disposal and generation of electrical and thermal energy. However, this approach may not be satisfactory in organic waste management due to pollutant emissions, economic and labor costs, loss of energy, and bad odor. In addition, no valuable product is generated from its decomposition process. Instead of incineration, recent research has focused on its utilization as biofuel source. In this chapter, the use of sugarcane bagasse pith as a waste material for incineration versus biomass to produce bioethanol is discussed in terms of energy ratio and emissions, in addition to elucidate the potential of sugarcane bagasse valorization for a more sustainable society

Perspectives on "game changer" global challenges for sustainable 21st century : Plant-based diet, unavoidable food waste biorefining, and circular economy

Planet Earth is under severe stress from several inter-linked factors mainly associated with rising global population, linear resource consumption, security of resources, unsurmountable waste generation, and social inequality, which unabated will lead to an unsustainable 21st Century. The traditional way products are designed promotes a linear economy that discards recoverable resources and creates negative environmental and social impacts. Here, we suggest multi-disciplinary approaches encompassing chemistry, process engineering and sustainability science, and sustainable solutions in "game changer" challenges in three intersecting arenas of food: Sustainable diet, valorisation of unavoidable food supply chain wastes, and circularity of food value chain systems aligning with the United Nations' seventeen Sustainable Development Goals. In the arena of sustainable diet, comprehensive life cycle assessment using the global life cycle inventory datasets and recommended daily servings is conducted to rank food choices, covering all food groups from fresh fruits/vegetables, lentils/pulses and grains to livestock, with regard to health and the environment, to emphasise the essence of plant-based diet, especially plant-based sources of protein, for holistic systemic sustainability and stability of the earth system. In the arena of unavoidable food supply chain wastes, economically feasible and synergistically (energy and material) integrated innovative biorefinery systems are suggested to transform unavoidable food waste into functional and platform chemical productions alongside energy vectors: Fuel or combined heat and power generation. In the arena of circularity of food value chain systems, novel materials and methods for plant-based protein functionalisation for food/nutraceutical applications are investigated using regenerative bio-surfactants from unavoidable food waste. This circular economy or industrial symbiosis example thus combines the other two arenas, i.e., plant-based protein sourcing and unavoidable food waste valorisation. The multi-disciplinary analysis here will eventually impact on policies for dietary change, but also contribute knowledge needed by industry and policy makers and raise awareness amongst the population at large for making a better approach to the circular economy of food

Microbial Reduction of Natural Fe(III) Minerals; Toward the Sustainable Production of Functional Magnetic Nanoparticles

The microbial synthesis of biominerals offers a potentially sustainable green solution for the production of a wide range of industrially relevant functional nanomaterials. Metal-reducing bacteria are of particular relevance, as they can enzymatically reduce a wide spectrum of high oxidation state metals and metalloids, forming cell-templated nanomagnets, catalysts, remediation agents, and quantum dots. Although these bioprocesses have been shown to be both scalable and tunable (with respect to particle size, reactivity, magnetic properties, and light emitting properties), they have yet to be taken up by industry. Here, we show that naturally abundant Fe(III) minerals are appropriate raw materials for the production of magnetic Fe(II)-bearing nanoparticles by the subsurface bacterium Geobacter sulfurreducens, and these bionanomaterials have the potential for remediation applications–here confirmed by the efficient reduction of toxic, mobile Cr(VI) to less toxic and soluble Cr(III). Detailed molecular-scale characterization of the bioreduced nanominerals, alongside life cycle assessments, and life cycle costings, confirm the efficient production of highly reactive and magnetic nanomaterials from waste materials. This adds further weight to the adoption of microbial technologies for sustainable, functional nanomaterials in a circular economy

Bread waste valorization: a review of sustainability aspects and challenges

Bread waste (BW) poses a significant environmental and economic challenge in the United Kingdom (UK), where an estimated 20 million slices of bread are wasted daily. BW contains polysaccharides with great potential for its valorization into building block chemicals. While BW valorization holds tremendous promise, it is an emerging field with low technology readiness levels (TRLs), necessitating careful consideration of sustainability and commercial-scale utilization. This review offers a comprehensive assessment of the sustainability aspects of BW valorization, encompassing economic, environmental, and social factors. The primary objective of this review article is to enhance our understanding of the potential benefits and challenges associated with this approach. Incorporating circular bioeconomy principles into BW valorization is crucial for addressing global issues stemming from food waste and environmental degradation. The review investigates the role of BW-based biorefineries in promoting the circular bioeconomy concept. This study concludes by discussing the challenges and opportunities of BW valorization and waste reduction, along with proposing potential strategies to tackle these challenges