Papers by Keyword: Waste Management

Abstract: Mining operations are integral to industrial development and economic growth, but they generate substantial waste, posing severe environmental and health risks. The environmental footprint of mining operations is significantly influenced by the nature and management of mining waste, which includes overburden, tailings, smelting slag, chemical effluents, radioactive residues, and gaseous emissions. This study provides a comprehensive analysis of these waste types, their associated ecological concerns, and prevailing mitigation strategies. Emphasis is placed on the adoption of science-based, economically viable, and scalable solutions that align with circular economy principles. A novel decision-support tool, the Composite Mining Waste Management Index (CMWMI) was developed to evaluate and rank various waste management strategies using weighted criteria: environmental effectiveness, economic feasibility, technological maturity, and scalability. The index reveals that backfilling and dry stacking score highest in sustainability and practicality. This integrative framework enables policymakers, engineers, and environmental managers to make informed decisions that enhance the sustainability of mining activities while mitigating long-term ecological and public health risks. Advanced technological solutions, including AI-driven waste monitoring, tailings reprocessing, bioremediation, and carbon capture, were examined for their role in minimizing the environmental footprint of mining activities. Regulatory frameworks and corporate social responsibility (CSR) initiatives were also discussed as crucial elements in enforcing sustainable mining practices. The study offers a replicable framework that can be tailored to specific mining contexts to guide responsible waste management, promote circular economy integration and ecological sustainability.

Abstract: The current experimental study aims to confirm some critical conclusions of the preliminary research regarding the possibilities of valorizing the residue material generated the Abrasive Water Jet (AWJ) procedures for industrial material processing, namely the Spent Garnets (SG), by innovatively integrating them in cement-based materials (mortar and concrete) and further on, in construction-eco products (paving pre-cast units, road construction, concrete for structural or non-structural elements, etc.). The use of SG wastes is considered as partial substitution of fine aggregates (sand) in cementitious materials, simultaneously offering the possibility of reducing the use and exploitation of aggregate, as limited natural resource. The methodology consists in developing a regular mortar mix, the Reference (R), on which several substitution percentages were applied with respect to the natural sand quantity, by Spent Garnets (SGs) provided by local producers. The substitution percentages initially ranged from 10 to 50% with respect to the Reference mix, as specified by recent, international studies, and they were also used in the preliminary evaluation, as well. Further on, the relevant substitution percentages were established as 30% and 50% values, and the corresponding mortar mixes were realized. The specific comparative analysis was performed in terms of mechanical performance at early age (7-day mechanical strengths) and also at 28 days. The obtained results are validating the initial results, proving the consistency of the previous conclusions and encouraging the use of SG wastes in cement-based construction materials. Complementary studies are further on considered and prepared, focused on using SGs as aggregate partial replacement in pavement eco-blocks, due to their high demand on the construction market.

Abstract: Nowadays, environmentally conscious manufacturers make their products from partly or fully recycled materials. However, recycling of polymer blends can be difficult. In immiscible polymer blends, the components often contain reactive functional groups, therefore polymers with reactive functional groups can be used as reactive compatibilizers. I investigated the mechanical, thermal, and morphological properties of different recycled rPET/rHDPE blends. I used an anhydride modified polyethylene (HDPE-g-MAH) as a compatibilizer. I found that without compatibilizer, the elongation at break decreased with the increase of rHDPE. As the amount of compatibilizer increases, the elongation at break is gradually increased. Furthermore, based on the SEM images, it can be observed that the size of the dispersed rHDPE phase in the rPET matrix decreased with the addition of a compatibilizer, and the dispersion of the dispersed phase also improved.

Abstract: Dross formation during the melting of twitch aluminium scrap using boric acid washing method, was investigated employing a Taguchi-based approach. The study aimed to analyse the impact of different treatment durations with a 1M concentration of boric acid on dross formation characteristics. Experimental trials involved treating twitch aluminium scrap samples with boric acid solutions for 15 to 60 minutes. Subsequently, dross formation characteristics were analysed using statistical techniques based on Taguchi analysis. Results unveiled significant variations in dross formation among treatment durations, indicating that longer treatment times led to decreased dross formation, particularly notable beyond the 30-minute mark. Taguchi's analysis confirmed the significance of treatment duration on dross formation, underscoring the effectiveness of the boric acid washing method in reducing dross formation during twitch aluminium scrap melting. This study offers valuable insights into optimising the boric acid washing method to diminish dross formation during twitch aluminium scrap melting, thereby enhancing efficiency and quality in aluminium recycling processes. Notably, the aim of the research systematically investigate the influence of treatment duration with a 1M concentration of boric acid on dross formation characteristics, providing practical guidance for implementing the boric acid washing method in industrial settings. Keywords: Dross, twitch aluminium scrap, boric acid, Taguchi analysis, recycling, waste management.

Abstract: Soil stabilization is crucial for enhancing the engineering properties of soil and constructing durable infrastructure, such as highways, airports, and roadways. The study's constituents were previously employed separately, and the soil's strength improved when they were coupled with other ingredients. Experimental investigations were conducted to assess the effects of varying proportions of C&D waste, CCR, and molasses on key soil characteristics, including compaction, shear strength, and plasticity. A series of crucial tests, including Atterberg limits, compaction characteristics, differential swell index, unconfined compressive strength (UCS), California Bearing Ratio (CBR), and Scanning Electron Microscope (SEM) analysis, were conducted to evaluate the performance of the stabilized soil. Test results indicated marked improvements in the Atterberg limits, reduced swell potential, and elevated values of UCS and CBR, demonstrating the effectiveness of the proposed stabilization method. CDW, CCR, and molasses enhance Unconfined Compressive Strength (UCS) by improving strength and cohesion. The addition of these chemicals significantly improved the performance of the soil, as seen by the decreased settling, enhanced strength, and greater infrastructure durability. Molasses served as an effective natural binder, while glass fibers improved tensile strength and durability by distributing stress evenly. This approach addresses waste management issues and promotes sustainable construction practices, offering a cost-effective solution for enhancing soil performance and paving the way for resilient infrastructure development.

Abstract: In recent years, palm oil has become an essential vegetable since it is the most produced and consumed. The growth of the palm oil industry and global expansion of the plantations pose economic, social, and environmental issues. These conditions have caused a rise in calls for sustainable palm oil production, primarily motivated by worries regarding the consequences. This study aims to identify factors influencing sustainability development in the palm oil industry. The results indicate that waste management, green transportation, and policy and regulation are the most important aspects for achieving sustainability in the palm oil industry. The internal economics dimension of the palm oil industry has become a priority aspect of implementing sustainability. In addition, economic benefit, productivity, and efficiency factors must take precedence for the palm oil sector to be sustainable. The findings can help palm oil supply chain actors and decision maker in preparing sustainable development strategies.

Abstract: The increasing global demand for denim jeans necessitates sustainable practices in both production and disposal. This study investigates the mechanical properties of recycled cotton denim fabric, focusing on tensile strength, tear strength, and fabric density (GSM), in accordance with international testing standards. Results show a decrease in tensile strength but an increase in tear strength for recycled cotton denim. Specifically, there is a strong positive correlation between the tearing strength of the weft yarns in waste and recycled denim (r = 0.797, p < 0.001). Additionally, the recycled fabric has a higher GSM, indicating improved material density. These findings suggest that recycled cotton denim could be used in various durable products, such as handbags and shoes, promoting sustainability within the textile industry. Limitations include the reduced fiber length after recycling, which necessitated blending with raw cotton to achieve optimal quality. Despite equipment limitations, this research provides valuable insights into the potential of recycling cotton denim. Future work should explore advanced recycling techniques to improve quality and broaden application opportunities.

Abstract: The current paper intends to present the directory lines and paths for the development and implementing construction eco-products, with advanced functionality (materials, elements and structures, models and technologies), considering the efficient and customized valorization of by-products and generated waste of local industries, in the context of National Strategy for Research, Innovation and Smart Specialization 2022-2027 regarding the transition to Circular Economy (EC). This represents one of the two main axes of the research project Nucleu Programme of the National Research Development and Innovation Plan 2022-2027, supported by MCID, "ECODIGICONS" project no. PN 23 35 04 01: “Fundamental-applied research into the sustainable development of construction products (materials, elements, and structures, as well as methods and technologies) that utilizes current national resources to enhance the eco-innovative and durable aspects of Romania's civil and transport infrastructure”, financed by the Romanian Government starting with the beginning of 2023. One of the novelties of the proposed approach of the project is considering the entrepreneurial environment of construction industry or complementary branches as essential stakeholders for the future results of the current scientific research. This dramatically changes the dynamic of the project, in terms of specific objectives, namely their focus on solving the current wastes’ problem by innovatively integrating them into competitive construction products with fast applicability and in accordance with support market requests. By the use of strategic management specific methods (e.g., External Environment (EE) and Internal Environment (IE) evaluation, SWOT analysis and derived specific strategies, etc.), four research directions have been identified for the valorization, at regional or even national level, of mineral additions (inert/hydraulically latent/pozzolanic, etc., derived from waste and industrial by-products (metallurgy, processing industry, construction/demolition, etc.)) by development of eco-smart materials and products for construction. The three directions are related to the considered mineral additions: Power plant ashes (fly ash and/or bottom ash), Steel slag and Garnet type residue Hence, the paper is willing to present the identification and the preliminary analyses of the specified research axes, plotted as necessary steps for achieving an intelligent and sustainable transition of the Romanian construction infrastructure. This approach implicitly ensures in the short and medium term, the increase of the degree of implementation of the principles of the Circular Economy (EC) in Romania, in the existing context which includes relevant factors like: geo-political, industrial and economic, urban and demographic, scientific, socio-cultural and environmental, in accordance with the imperatives of National, European and World Sustainable Development strategies.

Abstract: The increase in copper productivity in Zambia has resulted in the expansion of disposal areas occupied by mineral wastes and tailings. This not only consumes land but also, due to insufficient management, poses negative environmental impacts and health risks to people. Therefore, efficient and sustainable approaches for the proper management of these waste materials must be developed. In this study, the potential utilization of copper mine tailings was assessed. After analyzing the physical and chemical properties of copper mine tailings from Kitwe Tailings Dam (TD25), hollow concrete block specimens were prepared. Copper mine tailings were used as a partial replacement for cement in the mix design, with replacement ratios as follows: 0% for CBCMT O% (control specimen), 10% for CBCMT1O%, 20% for CBCMT2O%, 30% for CBCMT3O%, 40% for CBCMT4O%, and 50% for CBCMT5O%, all aimed at achieving a target strength of 5 MPa. Specimen compressive strength was evaluated, and it was found that CBCMT1O% and CBCMT2O% achieved the target compressive strength at 28 days of age. Water absorption rates and resistance to acid attack were also assessed. Findings revealed that all specimens outperformed the control specimen in terms of these properties. Furthermore, the environmental feasibility of the hollow concrete blocks specimens was examined, and the results showed limited leaching of heavy metals from the specimens, with concentrations within permissible thresholds. Additionally, a statistical analysis was conducted to study the influence cell shape has on the specimens’ compressive strength. Aimed at identifying the optimal specimen type for achieving compressive strength at an early age, results indicated that cell shape had a significant impact on the 28-day age of hollow concrete blocks. The study proposes a novel copper mine tailings (waste) management approach, by utilizing the potential it has to replace cement in the production of hollow concrete blocks, evident from the observed enhancement of the mechanical and durability properties.

Abstract: Municipal solid waste management continues to be an enormous challenge for developing countries such as Nigeria. With a rapidly increasing population and change in consumption choices in urban cities in Nigeria, the need to cater for and properly manage the increased volume and more diversified waste generated becomes an urgent issue for consideration. Storage and Collection of generated waste make up the crucial elements of waste management systems in any city. Sadly, though, just about a quarter of waste generated in Nigeria is collected. This paper compiles relevant information from recent studies made by researchers and authors on waste management systems in Nigeria to review the current state of the waste storage and waste collection systems in major cities in Nigeria using Lagos and Abuja as case studies. This study also summarizes the methods majorly used for the storage and collection of waste in Nigeria, making recommendations as and when necessary.