Cleaner Engineering and Technology最新文献

The critical necessity of decreasing energy consumption and environmental effects is vital in various facets of urban life, particularly in urban waste management. This research aimed to evaluate the energy flow, CExD, and Life Cycle of a composting system for Municipal Solid Waste (MSW) in Tehran province, Iran. The initial phase entailed assessing the energy flow and effectiveness of the composting system, while the subsequent phase focused on enhancing energy efficiency through the application of Data Envelopment Analysis (DEA) to determine an optimal energy consumption strategy for conserving energy and reducing environmental impacts in Tehran's MSW composting system. Over a 90-day period, the analysis of energy usage revealed an energy input and output of 417.30 GJ (8500 t MSW)⁻¹, with 227.02 GJ (8500 t MSW)⁻¹ linked to transportation and 190.28 GJ (8500 t MSW)⁻¹ related to composting activities. The overall energy consumption in the composting system was determined to be 6424.77 GJ (8500 t MSW)⁻¹. By applying DEA optimization, energy savings of 14.45 GJ (8500 t MSW)⁻¹ were accomplished in the composting process, with a significant reduction in electricity usage contributing to these savings. The environmental impact of the energy consumption patterns identified by DEA was notably lower compared to current energy practices. The most notable decrease in impact was observed in the Photochemical Oxidation category. By following the energy usage pattern recommended by DEA, the Global Warming Potential impact reduced by 500 kg CO₂ eq. per 8500 t MSW. Additionally, the optimization of energy use through DEA led to a decrease in fossil energy resource depletion by around 4 GJ (8500 t MSW)⁻¹ in the composting process.

This study focuses on the sustainable utilization of Quinoa plant components, particularly its leaves, as a waste agricultural material for natural dyeing applications. Two distinct Quinoa genotypes, Titicaca and Giza, were selected for their natural dyeing properties. UV-VIS absorption spectra of Quinoa colorant extracts provided insights into their chemical composition, revealing distinctive peaks indicative of betalains (400–450 nm), chlorophyll (600–650 nm), carotenoids (400–500 nm), and aromatic amino acids (250–280 nm). Wool samples dyed with different plant parts such as flowers, leaves, and stalks exhibited distinct yellow hue, with leaves demonstrating the highest color strength. Metal mordants such as iron (II) sulphate, copper sulphate, and tin (II) chloride influenced color outcomes, highlighting their role in tailoring final appearance. Fastness properties of dyed wool samples were evaluated, with leaves showing moderate staining resistance and good light fastness. Additionally, antibacterial properties of leaves of Giza Quinoa variety were assessed, showing promising activity against Staphylococcus aureus. The antibacterial properties of fabrics dyed with the leaf extract by mordanting method with different metal salt mordants, particularly Fe, Cr, and Cu, exhibited significant enhancement. These results highlight the multifaceted benefits of Quinoa plant components in sustainable natural dyeing and textile applications, emphasizing their potential for eco-friendly practices in the textile industry.

The current conventional process for recovering NH₄Cl from wastewater generated by organotin mercaptide-based polyvinyl chloride thermal stabilizer plants through evaporative crystallization is energy intensive and has not yet been discussed. Three energy-saving process variants, namely mechanical vapor recompression (MVR), double-effect evaporation (DEE), and thermal vapor recompression (TVR) processes, have been proposed and evaluated in terms of both technical and economic feasibility, treating the case as a cost-cutting project aimed to avoid off-site wastewater treatment costs. Comparative evaluation has also been carried out with the conventional (CON) process used as a reference. Under the studied conditions, the MVR, DEE, and TVR processes provided energy savings in the ranges of 60%–76%, 35%–43%, and 26%–37%, respectively, confirming that applying the three alternative processes for recovering NH₄Cl results in a significantly cleaner and more sustainable recovery process. Under typical conditions and with a plant capacity of 5000 kg/h, the MVR, DEE, and TVR processes required an additional investment of 2.3, 1.0, and 0.2 million USD, respectively, compared to the CON process. The revenue was primarily driven by cost savings due to the elimination of off-site wastewater treatment, which accounted for 86.9% of the total revenue. Sensitivity analysis showed that the off-site wastewater treatment cost was found to be the most influential factor on economic feasibility. When economic targets can be traded off, MVR process is highly recommended as an alternative to the conventional energy-intensive process. If economic feasibility comparable to the conventional process is still targeted, DEE and TVR are recommended. The results of this study dismiss concerns that cleaner processes would have a negative economic impact.

Global steel production, a major contributor to anthropogenic carbon dioxide, heavily relies on manganese, a key ingredient that significantly impacts the carbon footprint during the production of high-carbon ferromanganese. A single-step generation of low-carbon ferromanganese (LC-FeMn) from manganese ore in an electric arc furnace (EAF) was investigated. The theoretical and experimental investigations helped to balance the required and supplied energy. The process sustainability was predicted based on the enthalpy of the reaction. Pre-reduction of manganese ore decreased energy consumption in the smelting process and saved raw materials costs. The simulation studies revealed a significant effect of lime and silica on the slag-metal equilibrium. It further confirmed the best-reducing condition with the basicity 1.5–1.77 by smelting tests in EAF. Experimental results showed an optimal charge mixture comprising appropriate ratios of ore:SiMn:lime ratio, producing a standard-grade product. Simultaneous melting and smelting sensibly used the exothermic heat, consuming 410–880 kWh/ton, much lower than the international benchmark, i.e. approximately 2000 kWh/ton. The characterization of resulting slags corroborated the advantages of the manganese ore pre-reduction on the energy and reductant consumption, alloy grade, and slag characteristics. The present study's findings can potentially contribute to the ongoing low-carbon initiatives of steel.

In various cities/other urban settlements, buildings are replaced with newer stocks, ending many buildings' lives. Unfortunately, these buildings nearing or at end-of-useful lives are mostly not deconstructed; instead, they get demolished, resulting in waste generation and pollution, among other environmental concerns. Deconstruction supports closing the material loop in construction, facilitating reuse at end-of-life of the building; however, it is not always easy to assess the feasibility of deconstruction for existing buildings – deconstructability. For this purpose, this paper investigated critical factors that needed to be checked to make informed decisions about the deconstructability of buildings. These factors cover economic, social, environmental, legal, and technical dimensions. Based on the exploratory factor analysis (EFA) and confirmatory factor analysis (CFA), 31 significant drivers were identified. These drivers were classed into seven factors. The findings in this paper contribute to the practice of deconstruction, mainly supporting deconstructability decision-making and are helpful for deconstruction/demolition auditors, waste-management consultants and/or other stakeholders with waste minimisation goals, particularly for buildings nearing or at the end-of-useful lives.

This study aimed to enhance the efficiency of the solar water heater (SWH) due to the increasing demand of renewable energy. It compared use three different solar collector models, namely Model A (square-shaped polycarbonate), Model B (v-corrugated zinc), and Model C (trapezoidal aluminium) to identify the most cost-effective configuration. The models were subjected to experiments in real operating conditions during the summer season in Indonesia. Various parameters, including solar radiation intensity, wind speed, inlet and outlet temperatures, and flow rate, were measured every 10 min from morning to afternoon. Additionally, the study employed a trickle and one-way flow rate system. The results showed that Model B achieved the highest total efficiency at 50%, followed by Models A and C at 47% and 34%, respectively. The 120 Lph flow rate exhibited better performance in absorbing useful heat energy than the 240 Lph flow rate. Based on these findings, all three models were recommended for the household-scale SWH applications. Model A showed the most promising economic value but had a shorter lifespan due to the tendency of polycarbonate to deform. In contrast, Model B and Model C, using zinc and aluminium, offered longer lifespans.

3D printing in construction presents numerous advantages, such as geometric flexibility, potential cost and time savings, the incorporation of recycled and sustainable materials, and reduced waste, thereby reducing the construction sector's environmental impact. Despite these advantages, the widespread adoption of AM in construction faces hurdles, primarily due to the prohibitive costs of large-scale concrete printers — typically ranging from $180,000 to over $1 million — and technological constraints that impede research and development efforts within the construction sector. To address these challenges, our study focuses on designing, developing, calibrating and evaluating an affordable lab-scale 3D printer specifically tailored for cement-based materials, aiming to lower the entry barrier for AM research in construction. This paper presents a proof-of-concept for a simple, yet functional printing technology that meet the requirements for research studies. The study details the development process, from the conceptual design to the calibration of printing parameters. The development process included the assessment of preliminary extrusion system designs integrated with the motion systems of a fused deposition modeling 3D printer. Subsequently, material studies were carried out to determine optimal material mix compositions and ratios. A comprehensive calibration of printing parameters using statistical analysis was proposed to ensure consistent and quality printing. The printability and applicability of the proposed small-scale 3D printer were assessed by printing samples and testing their thermal properties. Cost analysis showed that the proposed 3D printer, costing $273, offers benefits compared to existing market alternatives. The study illustrates the potential of small-scale 3D printers to facilitate construction research and practices, thereby promoting the development of sustainable construction methods.

In the agricultural industry, coconut shells are one of the most generated wastes worldwide. In particular, studies in the Philippines show that the maximum capacity of the organic decomposition processes of agricultural products is exceeded due to the increasing agricultural activities. On the other hand, in the construction industry, cement production accounts for billions of tons of carbon dioxide emissions yearly. To address the said biowaste disposal problem, and environmental implications of the growing construction industry, this study evaluated the potential of utilizing coconut shell ash (CSA) and coconut shell granules (CSG) in concrete production as alternatives to cement and sand, being the conventional aggregates, respectively. Additionally, coconut coir (CC) was incorporated as fiber reinforcements in concrete. The experiment consisted of 15 mix designs using different proportions of CSA and CSG, ranging from 0% to 20%, and CC fiber reinforcements, ranging from 0% to 2%. The tests conducted on fresh concrete involved measuring its slump and unit weight, while the 28-day cured samples were tested for compressive and tensile strengths. Results showed that high concentrations of CSA, CSG and CC, when combined in the concrete mix, leads to poor workability; on the other hand, the modified mixes generally had lower unit weights than the conventional concrete. These are associated to the higher absorption rate, but lower density of the said agri-wastes than the conventional aggregates. In terms of the compressive and tensile strengths, all modified mixes produced lower strengths than the conventional concrete. Nonetheless, Response Surface Methodology (RSM) was utilised to model the relationship between the different independent variables considered in the study, namely CSA, CSG and CC contents, and their corresponding response to the compressive and tensile strengths. Based on the generated RSM Model, the optimum combination for obtaining the maximum strength consisted of 2% CC, resulting in a compressive and tensile strength of 23.046 MPa and 3.315 MPa, respectively. Overall, CSG-CSA coconut coir reinforced concrete is found to be a viable sustainable alternative for structures requiring low-strength, non-structural concrete, such as concrete slab patios and pathways.

This study presents a conceptual design of an Internet of Things (IoT) communication system for monitoring power generation systems in Colombian Non-Interconnected Zones (NIZs), which lack IoT connectivity due to complex geographical factors. The proposed system aims to ensure the proper operation and energy efficiency of off-grid systems while tracking the variables that influence their performance.

The methods used in this study include identifying the needs of such a system, identifying requirements, obtaining technical specifications, and developing a conceptual design. The study also analyses and compares various technologies, including Wi-Fi, Bluetooth, LoRa and ZigBee, to determine which ones are best suited for IoT system design.

The conceptual design of the proposed IoT monitoring system considers the geographical, communication and coverage characteristics of the NIZs and the technical characteristics of the energy projects to provide a complete functional system that can connect approximately 2 million people located in these isolated and vulnerable zones. Finally, the defined system can serve as a precedent for building prototypes in various NIZs, and research on IoT technologies suitable for NIZs can help us seek the technologies that are most suitable for these areas. Depending on the application and conditions of the energy project, the most appropriate technology can be determined on a case-by-case basis.