Papers by Keyword: Waste

Abstract: Theoretical and experimental investigations have revealed significant spatial variations in the chemical element content of wastewater, primarily due to anthropogenic pressures from mining and industrial complexes. This indicates the diverse nature of pollution sources and the complex impact they exert. The most pronounced exceedances of permissible concentrations were observed for manganese, potassium, magnesium, and calcium, attributed to the leaching of elements from rock dumps and chemical weathering processes. Analysis of the total pollution index (Zc) helped identify areas with high levels of technogenic impact, necessitating urgent environmental protection and reclamation measures. Spatial models illustrating element distribution demonstrate a direct correlation between toxicant concentrations in aquatic environments and the location of technogenic objects, particularly spoil heaps. The findings are crucial for future planning of environmental protection initiatives in mining and industrial regions. They enable the identification of areas with the highest ecotoxicological burden and will be utilized for environmental monitoring of water bodies, forecasting ecological risks, and establishing a database for decision-making regarding reclamation and water resource quality management.

Abstract: Prior studies have emphasised the drawbacks of the linear economy (LE), which uses resources inefficiently and functions on the "take-consume-throw away" tenet. However, there is a noticeable gap in studies examining the transition from a LE to circular economy (CE) adoption, as a practice necessary to limit the weaknesses of LE. This study examined CE practices adoption by identifying key enablers and challenges, emphasising the benefits, and developing a statistical model to predict it adoption in Ondo State's building construction sector. Using a structured questionnaire, data were collected from 175 construction professionals in Ondo State. Data obtained were analysed using frequencies, percentages, relative importance index, linear regression and ANOVA. Results revealed that “research and development”, “awareness of circular economy”, and “policy support” were the primary driver of CE. The study also identified “lack of proper technology”, “unfavourable policies”, and “limited knowledge” as top barriers impeding CE adoption while “cost savings”, “job creation” and “improved corporate image” were salient benefits of CE adoption. Further analysis produced a predictive model that combine the most prominent factors that drive CE adoption, such as organizational infrastructure (X₁), client’s interest and awareness (X₂), training and education (X₃), research and development (X₄), organisational alignment (X₅), and cost savings (X₆). The model finding revealed that only 57% of the respondents aligned with CE practices, meaning an increase in the dependent variables will lead to higher levels of adoption in the building construction industry. This study serves as a theoretical base for policymakers, stakeholders, and construction professionals towards promoting a more sustainable and circular construction sector.

Abstract: This study explores the feasibility of utilizing a thermoplastic elastomer seal made from a blend of rubber and recycled polypropylene (PP) derived from disposable plastic bottles. Thermoplastic elastomers develop by blending natural rubber (NR), epoxidized natural rubber (ENR), and maleated natural rubber (MNR) with PP in a 60/40 rubber-to-PP ratio. The results indicate that NR exhibits superior tensile strength, tear resistance, and compression set compared to ENR and MNR, attributed to NR's crystallization upon stretching and its inherent high elasticity. Both NR and ENR demonstrated good ozone resistance with no observed cracking, while MNR showed the lowest resistance, evidenced by visible cracks after the ozone explosion. NR emerged as the most suitable rubber for thermoplastic elastomer preparation, outperforming ENR and MNR. Comparative analysis between the prototype and commercial products revealed that the prototype's mechanical properties, ozone resistance, and thermal degradation resistance were largely comparable to those of the commercial counterparts. However, to improve flame resistance, further development is needed, particularly through the incorporation of flame-retardant additives.

Abstract: PT Surya Plastindo is a company that produces plastic sacks. The finishing workstation often encounters various issues, including an excessive number of defective printed products and production quantities consistently exceeding order specifications. This study aims to eliminate waste and implement improvements in the finishing workstation. The lean manufacturing method is suitable for reducing waste at PT Surya Plastindo. The waste elimination process begins with describing the production flow and calculating cycle times for each process, using Value Stream Mapping (VSM) to depict the current state. Subsequently, the Waste Assessment Model (WAM) is employed to weight and rank critical waste. The most critical wastes are further analyzed using value stream mapping tools, with the VALSAT tool selected to map the value flow during production. Finally, a five-why analysis is performed to recommend improvements. According to WAM’s waste weighting calculations, defects (20.76%), motion (18.32%), and overproduction (17.54%) are identified as the most significant wastes. The analysis, combined with discussions with production heads and detailed mapping using VALSAT tools, resulted in three recommendations for improvement: the creation of daily production cards, checklists for printing machines, and plastic sack supports for the printing machines. The implementation of these improvements resulted in a reduction in delays and increased efficiency in plastic sack production.

Abstract: In this article, a regulatory processes study and technological properties of polyamide waste agglomerate modification is carried out. The legal support issues for polymer waste management in Ukraine are considered, ways to improve the most problematic aspects in this area are proposed. The technological properties of polyamide-6 waste agglomerate modification processes were studied in order to improve its technological and strength characteristics. MW-PA CB10 masterbatch modifier impact on the polyamide-6 waste agglomerate technological and strength characteristics complex was studied. It was established that the best is polyamide-6 waste agglomerate with 2 % wt. of masterbatch MW-PA CB10. For this composition the impact strength is 43.5 MPa, breaking stress during bending is 126.4 MPa, tensile strength is 342 N and elongation at break is 117 %. It can be recommended for reuse in traditional fields of primary polyamide-6 to obtain engineering and technical products.

Abstract: The determination of minimum performance criteria for residential buildings has encouraged the development of new technologies by companies linked to the construction industry. In this context, the acoustic performance of floor systems is of great importance. One of the solutions to improve the performance of these systems is the incorporation of lightweight aggregates to replace natural fine aggregates in the subfloor mortars, with the aim of attenuating the noise caused by impact, thus improving acoustic performance. Therefore, the objective of this study was to analyze the properties of a subfloor mortar in a 1:4 ratio (cement:sand), with the incorporation of silicone mold residue, replacing natural fine aggregate, in proportions of 10%, 20%, and 30%. %, and a water/cement ratio (w/c) of 0.93. Tests were performed in the fresh and hardened state, such as incorporated air content, mass density, consistency index, flexural tensile strength, compressive strength, water absorption by capillarity, in addition to a specific test to determine the difference in sound pressure level between specimens. The results indicated that the mortar consistency was influenced by the incorporation of waste, increasing with its incorporation. The increase in consistency positively influenced the mechanical resistance of the mortars, which showed an increase with higher residue content, due to the reduction in the amount of voids. Consequently, densities also increased with high waste content. The acoustic test showed satisfactory results, with good attenuation of 10%, indicating an 8 dB improvement in the sound pressure level. The results presented show that the residue has great potential for acoustic attenuation.

Abstract: Footsteps are a foothold for motorbike riders and passengers; they also play a role in maintaining stability when driving. Footsteps must have a solid and lightweight material to support the load from the feet and body of the rider and passengers. In this study, the footstep with the material made from the waste drum brake shoe varied by reducing mass through the static structural simulation process and topology optimization process using Ansys Workbench to get optimal mass, total deformation, equivalent stress, maximum principal stress, and safety factor from each variation. The footstep geometry will be subjected to a load of 1000N and provided with the necessary support. Based on the data obtained during this study, the initial footstep geometry produces data in the form of total deformation (1.383 mm), equivalent stress (21.013 MPa), and safety factor (1.227). The 10% variation produces data in the form of total deformation (1.4368 mm), equivalent stress (20,564 MPa), ,and safety factor ( 1.2538). The 20% variation yields data in the form of total deformation (0.98037 mm), equivalent stress (18.111 MPa), maximum principal stress (18.41 MPa), and safety factor (yield strength: 1.4236,. At the same time, the 25% variation produces data in the form of total deformation (1.3058 mm), equivalent stress (22.27 MPa), and safety factor (1.1577).

Abstract: Biomass waste is one of the promising resource for the production of bio oil. In this study, a mixture of biomass waste will be pyrolyzed in the presence of activated carbon and zeolite as the catalyst. The catalyst concentrations were varied at 2%, 4%, 6%, respectively. While, the pyrolysis process was carried out at 500°C, for 60 minutes, with a nitrogen flow of 3 L/min. The highest bio oil yield was obtained the pyrolysis process by using zeolite with 35% at 4% w/w of the catalyst concentration. The lowest acid number obtained was 42.92 on 4% zeolite catalyst with rice husk biomass as the raw material, the best viscosity was obtained on 4% activated carbon multi feedstock with a viscosity value of 4.96 cP. The best density was obtained in multi feedstock with 4% zeolite catalyst and rice husk with 4% zeolite of 0.996 g/mL.

Abstract: For the creation of underground works such as road and railway tunnels, critical infrastructure facilities, collectors, multi-purpose halls, it is necessary to excavate rock material from the massif. This generates surplus and unnecessary rock material, which in most cases ends up as waste in a nearby stockpile or waste dump. Often this material can meet the quality requirements for construction aggregate. Therefore, this material can be reused as a source of aggregate, thereby reducing construction costs in a circular economy. The article briefly describes the methodology of the evaluation and testing of waste rock from tunnels for various purposes of its reuse as aggregate.

Abstract: In the framework of the iWAYS project, a synergy between energy and water reclamation and exploitation is addressed by means of the development and the installation of a wide array of technologies in three different industrial sectors: ceramic tile manufacturing, aluminium fluoride production and steel tubes manufacturer. The aim of the project is the creation of customized and integrated systems to achieve a substantial reduction in the thermal waste and in the freshwater consumption; this is the principal challenge the iWAYS project is solving by developing a set of technologies capable of recovering water and energy from challenging exhaust streams for productive use in the industrial processes. iWAYS systems will then treat steam condensate to meet the water quality requirements of each industrial process, while the recovered heat will be used to reduce primary energy consumption. iWAYS will recover additional materials from flue gas such as valuable acids or particulates, improving the production’s raw material efficiency and reducing detrimental emissions to the environment. The iWAYS technology will provide a reduction in the freshwater consumption greater that the 30% in each industrial case; with regards to the energy recovery, iWAYS will recover 6 GWh/y in the ceramic sector, more than 5 GWh/y in the chemical scenario and approximately 1 GWh/y in the steel sector. The iWAYS solution will have a payback lower than 5 years.