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Characterisation and anaerobic digestion of fat, oil and grease (FOG) waste from wastewater treatment plants
Get PDFThe materials removed in the oil separation units of wastewater treatment plants can be referred to as fat, oil and grease (FOG) waste. FOG waste accumulation in treatment plants can cause clogging of pipes, production of excessive scums and foams, and negatively affect air/liquid oxygen transfer. While conventional disposal routes of this material can be limited by its water and organic content, FOG can represent a source of bio-energy other than bio-diesel production. This research determined the chemical and physical characteristics of FOG waste collected at four different wastewater treatment plants and defined the potential for energy recovery via dark fermentation and anaerobic digestion as treatment options for final disposal. The FOG samples featured markedly distinct physical aspects in connection with the oil separation technologies: solid agglomerate with a high content of lipids from vortex-type separation and semi-solid agglomerate with a low content of oils and fats from horizontal-flow chambers. All FOG waste presented high potential for methane production with values ranging from 460 to 865 Nm3CH4/tVS but low yields of biological hydrogen via dark fermentation. This study addresses a knowledge gap in the scientific literature on the characteristics of FOG waste from treatment plants and defines possible routes for sustainable management via bio-energy recovery.Journal of Environmental Managemen
Targeted enrichment of nucleic acid bionic arms enhances the hydrolysis activity of nanozymes for degradation and real-time monitoring of organophosphorus pesticides in water
Get PDFOrganophosphorus pesticides (OPs) pose significant environmental and health risks, and their detoxification through catalytic hydrolysis using zirconium-based metal-organic frameworks (Zr-MOFs) has attracted considerable interest due to the strong Lewis acid metal ions. Albeit important, the defects of the materials for OP hydrolysis (e.g., poor degradation efficiency, rate, and selectivity) limit their further application. Herein, a nucleic acid bionic arm-modified biomimetic nanozyme (MOF-808-Apt) was designed through a Zr-MOF and a specific aptamer against OPs, which was employed for the efficient and selective degradation of OPs. At the system, the functionalized biomimetic nanozyme can continuously capture trace OPs onto its catalytic sites for degradation with the fabricated nucleic acid bionic arms, significantly improving their catalytic activities compared to bare MOF-808 using paraoxon as a model of OPs, providing better performances including (i) an excellent degradation efficiency, boosting from 4 to over 60% within 6 min; (ii) a satisfactory catalytic rate (the pseudo-first-order rate constants of paraoxon hydrolysis improved from 0.09 to 0.14 min-1); and (iii) good selective degradation because of aptamers used. Besides, this dynamic degradation process could be visually recorded in real time with high sensitivity (limit of detection, 0.18 μM) because of the obvious color change of the reaction solution and signal amplification ascribed to increasing local concentrations of targets by the nucleic acid bionic arms. Summarily, this work provides a new strategy for the effective and selective degradation of typical OPs and concurrent monitoring of their dynamic degradation process.Leverhulme Trust, National Natural Science Foundation of China, Natural Environment Research CouncilThis work was supported by the National Natural Science Foundation of China (Grant Nos. 22176075 and 22476072)and the Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment. Besides, Z.Y. also thanks the Leverhulme Trust Research Leadership Awards (RL-2022-041) and the UKRI NERC Fellowship grant (NE/R013349/2).Environmental Science & Technolog
Mechanisms of electrochemical hydrogenation of aromatic compound mixtures over a bimetallic PtRu catalyst
Get PDFEfficient electrochemical hydrogenation (ECH) of organic compounds is essential for sustainability, promoting chemical feedstock circularity and synthetic fuel production. This study investigates the ECH of benzoic acid, phenol, guaiacol, and their mixtures, key components in upgradeable oils, using a carbon-supported PtRu catalyst under varying initial concentrations, temperatures, and current densities. Phenol achieved the highest conversion (83.17%) with a 60% Faradaic efficiency (FE). In mixtures, benzoic acid + phenol yielded the best performance (64.19% conversion, 74% FE), indicating a synergistic effect. Notably, BA consistently exhibited 100% selectivity for cyclohexane carboxylic acid (CCA) across all conditions. Density functional theory (DFT) calculations revealed that parallel adsorption of BA on the cathode (−1.12 eV) is more stable than perpendicular positioning (-0.58 eV), explaining the high selectivity for CCA. These findings provide a foundation for future developments in ECH of real pyrolysis oil.Engineering and Physical Sciences Research CouncilThe authors would like to thank EPSRC (EP/T518104/1) and Cranfield University for their support.Communications Chemistr
Environmental concerns when utilizing detonation as the clearance method for dumped munitions
Get PDFCommon methods for clearing dumped munitions include low-order and high-order detonations. Low-order detonations produce subsonic explosions, typically leaving behind large explosive fragments, while high-order detonations involve supersonic explosions, usually destroying the entire munition. However, both methods may result in incomplete combustion and the release of explosive materials into the aquatic environment. Additional environmental impacts include noise pollution, shock waves, metal toxicity, and the spread of bomb fragments. To therefore estimate the detonation hazards further experiments were conducted under controlled conditions using six 1000L Intermediate bulk container tanks. Explosive charges were detonated at both low-order and high-order detonations. On average, the low-order detonations (Tanks A & B) left 8.76 ppm of explosive residues, while high-order detonations (Tanks C & D) left significantly less residue, averaging 1.18 ppm. These values were based on a starting explosive concentration of 115 ppm before detonation. The findings confirmed that low-order detonations leave more explosive residue, leading to a higher risk of toxicity. High-order detonations, though resulting in less explosive residue, release fragments at high velocity, posing a serious environmental threat and increasing the risk of accidental explosions.DNV Energy Systems, UKDefence and Security Doctoral Symposia 2024 (DSDS24
Assessing the functionality of sand dams as a dryland water source through an evaluation of water loss pathways
No full textParker, Alison - Associate SupervisorBetween 1 - 2 billion people worldwide suffer from water scarcity, most of whom
live in drylands. Irregular but intense rainfall have led to the proliferation of water
harvesting. Sand dams, one such technique, comprise a concrete dam wall
constructed across ephemeral rivers, which facilitate the accumulation of
alluvium. Such dams can store and lose water to varying degrees, the extent of
which is unclear.
This research therefore aimed to evaluate spatial and temporal water losses from
sand dams in order to understand their storage potential and their contribution to
water availability within the river channel and surrounding weathered basement
aquifer. Through monitoring telemetered abstraction data and employing
analytical modelling, this thesis explored variations in rates of water use and
seepage from sand dams in Kenya. By being the first study to use 2D geophysics
at sand dams, it improved the understanding of how sand dams interact with the
surrounding hydrogeological environment.
Contrary to assumptions, geophysical inversions successfully showed that the
trapped alluvium of sand dams typically overlies weathered basement material
up to approximately 25 m in thickness, rather than impermeable bedrock.
Alongside simulated flow rates, averaging 32.4 m³/day and empirical evidence,
results highlight a partial recharge function performed by sand dams, primarily
driven by lateral flow. Despite this, estimated groundwater volumes at full
capacity, of up to 4,200 m³, were sufficient to meet community water needs
throughout the dry seasons, in part due to recharge to the sand dams. This
indicates the storage capabilities of the studied sites.
By identifying site and hydrogeological characteristics that may result in lower
levels of seepage from the dams, and greater recharge to the dams, the findings
aim to enhance site selection and dam construction, enabling more sand dams
to better meet storage requirements. This will contribute to facilitating the
implementation and scaling-up of sand dams in areas where they are physically
suitable and appropriate to the specific needs of a community.PhD in Water and Waste Infrastructure and Services Engineered for Resilienc
Data for "Standoff measurement of ageing-related carbonyl bonding in bitumen. Part 2 - Instrument development and results"
No full textWe describe the development and experimental performance of instrumentation to measure ageing-related spectroscopic changes in bitumen. Oxidation of bitumen at the surface increases the number of carbonyl (C=O) bonds, and this can be measured in the 6μm region (1700cm-1) of the mid-infrared. Standoff measurements of surface reflectivity were performed using 4 discrete wavelengths, 3 for the carbonyl absorption and the fourth as a spectral reference. The standoff height of 20cm caused problems resulting from the presence of numerous strong absorption lines of atmospheric water in the optical path, which was solved by use of wavelengths centred within available “water windows” and a pathlength-matched reference channel. The instrument was tested using bitumen samples aged artificially using UV exposure. Results illustrating the instrument’s response to bitumen age, along with tolerance to changes in height and tilt, are shown. Measurements made during preliminary field trials on outdoor asphalt are also demonstrated. Part 1 of this paper describes the scientific challenges involved in designing this instrument.Engineering and Physical Sciences Research Council (EPSRC
A review of polymer composites and adhesives for aircraft landing gear applications
No full textThis article belongs to the Section AeronauticsThis review paper explores the transformative potential of polymer composites and adhesives in reducing the weight of aircraft landing gear, thereby improving fuel efficiency and lowering emissions. The replacement of conventional metallic materials and mechanical fastenings with advanced thermoset/thermoplastic composites and adhesives can significantly enhance durability and performance in demanding operational environments. Unlike traditional fastening methods, the structural adhesives eliminate the weight penalties associated with mechanical fasteners, offering a lighter and more reliable solution that meets the rigorous demands of modern aerospace engineering. Furthermore, the review highlights a variety of manufacturing techniques and innovative materials, including bio-based polymers, self-healing materials, noobed composites, helicoid composites, and hybrid composites. The use of thermosets and vitrimers in adhesive bonding are presented, illustrating their ability to create robust and durable joints that enhance the structural integrity of landing gear systems. The paper also addresses current challenges, including recycling limitations and high material costs. Sustainability considerations, including the integration of self-healing materials, structural health monitoring systems, and circular economy principles, are discussed as essential for aligning the aerospace sector with global climate goals.This research was funded by Airbus Operations Limited, and the reference number for the funding is CU01921121Aerospac
Novel thermal modification of phosphate tailings for enhanced heavy metals immobilization in soil
No full textRecent interest in amendments derived from industrial by-products has highlighted their potential for both resource recycling and heavy metal remediation. Phosphate tailings (PT), primarily dolomite-based solid waste with low utilization rates, offer a promising yet underexplored solution. This study pioneers the thermal modification of PT into a novel amendment, thermally modified phosphate tailings (TPT), to assess its adsorption performance, underlying mechanisms, and effectiveness in immobilizing heavy metals in soils. The thermal modification process transformed dolomite in PT into calcite and periclase, dramatically enhancing the maximum adsorption capacities by 28-fold for both Cd2+ and Cu2+, and 7-fold for Pb2+, with the capacities reaching 248, 531, and 433 mg·g-1 for Cd2+, Pb2+, and Cu2+, respectively. The dominant removal mechanism for TPT was surface precipitation, complemented by electrostatic adsorption, surface complexation, and ion exchange. Practical applications of TPT in contaminated soil reduced TCLP-extracted Cd, Pb, and Cu by up to 44%, 60%, and 61%, respectively, effectively transforming heavy metals into relatively stable form. This study demonstrates the potential of TPT as a novel amendment for heavy metal immobilization, providing both effective contamination control and enhanced resource utilization, thus addressing a critical gap in the remediation of contaminated soils. Given its low-cost nature derived from industrial waste, TPT holds significant promise for large-scale application, making it a practical and sustainable solution for soil remediation.Science and Technology project of Fujian Province [2024T3021, 2024N0027]National Key R&D Program of China [2022YFC3703300]Environmental Researc
Emissivity measurements of metals used in wire-arc-directed energy deposition processes
No full textAccurate temperature measurement is a key parameter that determines the quality of additive manufactured components in directed energy deposition processes. Optical pyrometers which are used to provide in-process temperature data require accurate emissivity data of the metal surface. Process-specific emissivity data for metals used in these processes is not readily available. This paper provides the emissivity of a variety of metals used in wire-arc directed energy deposition processes. For the first time, the test samples were fabricated using typical deposition processes and systems. The metals evaluated were titanium alloy (Ti-6Al-4V), Inconel 718, mild steel, aluminum alloy 2319, and nickel aluminum bronze. At ambient temperature, the measured normal emissivity was 0.26–0.28 for Ti-6Al-4V; for Inconel 718, it was 0.45–0.54; for mild steel, it was 0.4–0.72; for aluminum 2319, it was 0.14; and for nickel aluminum bronze, it was 0.35. The approximate emissivity values are also given over the temperature range 20–1400 °C. The effect of residual oxygen in the shield gas on emissivity is explored for the first time. The spectrophotometric technique was used to measure the metal thermo-optical properties.Engineering and Physical Sciences Research Council (EPSRC), UK|EP/R027218/1The authors acknowledge support from the Engineering and Physical Sciences Research Council (EPSRC), UK under grant EP/R027218/1, New Wire Additive Manufacturing (NEWAM).Metal
Data underpinning "Measurement of strain and vibration, at ambient conditions, on a dynamically pressurised aircraft fuel pump using optical fibre sensors "
No full textEver-increasing demands to improve fuel burn efficiency of aero gas turbines lead to rises in fuel system pressures and temperatures, posing challenges for the structural integrity of the pump housing and creating internal deflections that can adversely affect volumetric efficiency. Non-invasive strain and vibration measurements could allow transient effects to be quantified and considered during the design process, leading to more robust fuel pumps. Fuel pumps used on a high bypass turbofan engine were instrumented with optical fibre Bragg grating (FBG) sensors, strain gauges and thermocouples. A hydraulic hand pump was used to facilitate measurements under static conditions, while dynamic measurements were performed on a dedicated fuel pump test rig. The experimental data were compared with the outputs from a finite element (FE) model and, in general, good agreement was observed. Where differences were observed, it was concluded that they arose from the sensitivity of the model to the selection of nodes that best matched the sensor location. Strain and vibration measurements were performed over the frequency range of 0 to 2.5 kHz and demonstrated the ability of surface-mounted FBGs to characterise vibrations originating within the internal sub-components of the pump, offering potential for condition monitoring.Engineering and Physical Sciences Research Council (EPSRC)Innovate U