Waste Management Solutions Research Articles

The extraction of inorganic phase-change materials from sugar industry wastes with the purpose of solid waste management

ABSTRACT This study focused on the feasibility of identifying and recycling inorganic phase-change materials (PCMs) from sugar industry wastes in two cities of Qazvin and Hamadan in Iran. In this study, dry sugar beet pomace, sugar beet pomace, sugar beet molasses, leaves and plant residues of sugar beet and sugarcane bagasse were investigated. The inorganic materials were identified by X-ray Diffraction (XRD), thermal characteristics were determined by differential scanning calorimetry (DSC), and morphological characteristics were determined by scanning electron microscopy (SEM). Additionally, physical and thermal properties of molasses and bagasse samples were analyzed to determine their suitability as inorganic PCMs. The results of this study demonstrated that molasses and bagasse have the potential to be used as mineral PCMs in thermal energy storage applications. The results of this study demonstrated that in the wet sugar beet pomace the highest and lowest concentrations of inorganic PCMs were silicon dioxide (SiO2) and sodium chloride (NaCl), respectively. Moreover, the highest calcium fluoride (CaF₂) composition was reported in dry sugar beet pomace. In the samples of leaves and residues of sugar beet and sugarcane bagasse, the highest concentration of was NaCl. The detection and recycling of mineral PCMs from sugar industry wastes offer a sustainable solution for waste management and provide a renewable source of thermal energy storage materials. Implication Statement This study demonstrated the potential for the extraction of inorganic phase-change materials from sugar industry wastes as a means of solid waste management. By repurposing these materials, we can reduce the environmental impact of sugar production and contribute to sustainable practices in the industry.

Adaptation of Chlorella vulgaris immobilization on rice straw with liquid manure to create a sustainable feedstock for biogas production and potential feed applications

Rice straw (RS) is a widely available agricultural residue with significant potential for biogas production and feed applications; however, its poor digestibility and nutritional value limit its utilization. This study explores an innovative approach to enhance the digestibility and nutritional value of RS by cultivating Chlorella vulgaris through immobilization technology on RS, using liquid manure (LM) as an alternative to the traditional BG11 medium. The results showed an increase in chlorophyll a (Chl a) after 12 days for both the BG11 medium and LM-based treatments, from 0.13 to 0.34 and 0.24 mg Chl a/g product (DM), respectively. Additionally, the immobilized microalgal biomass increased to 284.18 and 170.14 mg algal biomass/g product (DM), respectively. Soaking under microaerobic conditions during cultivation led to the partial degradation of RS. This, combined with the formed microalgal biofilm, contributed to an improved digestibility of the dry matter, reaching 69.1% and 65.9% for the final products based on the BG11 medium and LM mediums, respectively, compared to 52.1% for the raw RS. Furthermore, the crude protein and lipids contents were significantly improved with the potential for applications in feed, reaching 21.4% and 4.1% for the BG11 medium-based product, while they were observed to be 12.8% and 3.0%, respectively, for the LM-based product. Additionally, carbon-to-nitrogen ratio was significantly reduced compared to the raw RS. The higher digestibility and improved nutritional value contributed to increased biogas production, reaching 129.3 and 118.7 mL/g (TS) for the products based on the traditional medium and LM medium, respectively, compared to 86.7 mL/g (TS) for the raw RS. The immobilization mechanism and biofilm development could be attributed to the roughness of the RS and extracellular polymer substances. This study demonstrates that integrating C. vulgaris cultivation on RS with LM as a nutrient source not only enhances the digestibility and nutritional value of RS but also offers a sustainable waste management solution with potential applications in biogas production and animal feed.

Experimental Study of the Mechanical Properties of Mortar with Biobío Region Clam Shells Used as a Partial Replacement for Cement

The use of seashells as a partial substitute for cement in construction not only offers an innovative solution for marine waste management but also contributes to reducing the carbon footprint of the cement industry, decreasing the CO2 emissions associated with cement production and promoting more sustainable construction practices. This study addresses the mechanical behavior of mortar specimens with partial cement replacement using crushed Biobío region clam shells, both calcined and uncalcined, at substitution rates of 5% and 10%. This approach allows the analysis of their effect on the mechanical strength and properties of the mortar, which has not been widely investigated in the Chilean context or with this particular species of shell. For the mechanical characterization of the specimens, tensile flexural tests and compressive tests were were conducted at ages of 3, 7, 14, and 28 days. The compressive strengths of the samples that incorporated calcined residue with partial cement replacements of 5% and 10% were 83.69% and 78.27%, respectively, of the average strength of 20.97 MPa reached by the standard sample. In terms of their tensile flexural strength, these samples reached average strengths of 104.31% and 104.04% of the strength of 12.12 MPa obtained by the standard sample. In the case of the uncalcined samples, the 5% and 10% replacements reached 103.55% and 102.64% of the tensile strength of 15.54 MPa obtained by the standard sample, while they reached 92.32% and 80.07% of the compressive strength of 27.81 MPa achieved by the standard sample. From these results, it is determined that the calcined shells did not improve the mechanical resistance of the mortar, suggesting that the calcination process must be studied in depth.

Reimagining urban waste management: Addressing social, climate, and resource challenges in modern cities

Governments worldwide are seeking better solutions for solid waste management. Thermal treatment projects are presented as quick fixes for rising waste challenges, without addressing the limitations of incineration. Currently, there is a rise in proposals for thermal treatment technologies in developing countries. Scrutiny of the risks and impacts of these alternatives is necessary due to social, climate, and resource considerations. Energy from waste incineration is considered fossil energy since about half of the CO2 emissions come from fossil polymers in the waste. From a sustainability perspective, landfilling is a short-term option for materials currently unsuitable for recycling. Landfills act as bioreactors, producing valuable biogas, and serve as “resource banks,” storing unrecyclable resources until better recycling techniques are developed. In developing countries manual labor is abundant and material sorting and landfilling are more valuable and have a lower climate and resource footprint. This paper offers a novel, integrated perspective of waste management in view of poverty reduction, climate change and resource conservation.

Understanding the potential of coal gangue as photocatalyst for antibiotic degradation: The role of abundant oxygen vacancies and electron-hole pairs

Coal gangue (CG) offers promising potential as a cost-effective photocatalyst for antibiotic degradation. However, current approaches do not emphasize the origin of its photocatalytic activity. This study investigates the photocatalytic activity of CG through a comparative analysis with one-pot aerobic/anaerobic calcinated CG. The potential application of CG as a photocatalyst for tetracycline (TC) decontamination in water was evaluated under dark and light. Characterization results identified anatase and kaolinite as the critical photosensitive minerals in CG. Batch removal experiments indicated that CG achieved up to 98 % TC removal at 1 g/L dosage, with most biotoxic intermediates reduced to below 0.9 mg L−1 Lethal Concentration 50 (LC50) of Fathead minnow (Pimephales promelas). Degradation pathways identified by density functional theory (DFT) and quantitative structure-activity relationship (QSAR) indicated that superoxide anion (⁎O2−) and electron-hole (e−-h+) pairs were predominant contributors to TC photodegradation. Theoretical calculations suggest that the oxygen vacancies on the CG surface can accelerate the production of ⁎O2−, while fast electron transport channels within surface hydroxyl groups facilitate e− and h+ separation. The findings of this research elucidate the origin of CG's photocatalytic activity and highlight the potential to serve as a photocatalyst for low-cost antibiotic removal, offering a promising solution for coal waste management and utilization.

Synthesis of biocompatible hydroxyapatite from quail eggshell, oyster shell, and periwinkle snail shell

This study focuses on the synthesis of hydroxyapatite (HA, Ca10(PO4)6(OH)2) from calcium carbonate (CaCO3)-rich quail eggshells, oyster shells, and periwinkle snail shells (Filopaludina bengalensis) through the use of the wet precipitation method. The methodology involved calcining the shell waste to convert CaCO3 to calcium oxide (CaO), undergoing hydration, and reacting with phosphoric acid (H3PO4) to synthesize HA. The results indicated that periwinkle snail shells had the highest percent yield of HA at 92.12%, followed closely by quail eggshells at 92.01%, and oyster shells at 73.65%. For producing CaO, oyster shells provided the highest percent yield of CaO at 103.72%, followed by quail eggshells at 98.6% and periwinkle snail shells at 92.09%. The synthesized HA exhibited high biocompatibility, which is crucial for its potential applications in medical fields such as bone replacement and regeneration. The X-ray diffraction (XRD) analysis confirmed the successful synthesis of high-quality HA, with characteristic peaks indicative of excellent crystallinity and purity and near identicality to the standard XRD pattern of HA of ICDD 9-432 and the XRD pattern of successfully synthesized HA in other studies, indicating high biocompatibility. The research highlights the potential of recycling food waste, specifically shell waste, into valuable biomaterials. This not only addresses environmental concerns but also supports sustainable practices in the food industry. Moreover, the study contributes to advancements in biomaterials for medical applications, emphasizing the viability of utilizing organic waste for high-value products. By transforming food waste into useful medical materials, this research offers promising solutions for waste management and resource utilization, particularly within Thailand's ecological and industrial framework.

Characterizing nano-indentation and microstructural properties of mine tailings-based geopolymers

The mining industry's extraction processes produce vast amounts of waste, including mine tailings (MT), traditionally stored in large ponds, causing significant environmental harm due to a lack of effective recycling methods. This research explores the potential of converting MT into a resource i.e., precursors in geopolymer synthesis. By analyzing the physicochemical and mineralogical properties of MT, the study formulates four geopolymer composites, substituting up to 30 wt% MT for fly ash. The composites' mechanical and microstructural properties show a contribution of MT in the stability of the matrix. Compressive strength of 59 MPa when incorporating 30 wt% MT, along with water absorption, microstructural analysis, and environmental impact assessments, support the hypothesis that the matrix is improved. Nano-indentation techniques further evaluated the nanomechanical properties, such as Young's modulus and fracture toughness. The findings reveal that geopolymers with 30 wt% MT exhibits up to 130 % increased strength. This research highlights the potential for innovative, eco-friendly solutions in waste management and material production, contributing to sustainable mining practices and advancing the field of geopolymer technology.

Objective: To investigate the use of biological ensiling of organic residues generated by pectiniculture as a nutritive medium in the production of the microalgae Tetraselmis suecica. Theoretical Framework: Biological ensiling is a process that transforms organic residues into a nutritive source through fermentation. In this context, pectiniculture residues, specifically the soft parts of fan shells, can be recycled and used

Objective: To investigate the use of biological ensiling of organic residues generated by pectiniculture as a nutritive medium in the production of the microalgae Tetraselmis suecica. Theoretical Framework: Biological ensiling is a process that transforms organic residues into a nutritive source through fermentation. In this context, pectiniculture residues, specifically the soft parts of fan shells, can be recycled and used as alternative media. Microalgae, such as T. suecica, are photosynthetic organisms that require nutrients for their growth, and their cultivation can benefit from these residues. Method: Twelve vertical bioreactors were used with three experimental treatments (T1, T2, T3) and treatments, one control (CT), with three replicates per treatment. The microalgae were inoculated at a density of 70 x 104 cells mL-1 in a culture volume of 80 L. Cultures were grown in open air with constant aeration. 0-, 60-, 70-, and 80-mL L-1 of the biological silage of fan shell soft parts (EBCA) were dosed. The silage was also chemically characterized and the growth of the microalgae and its relationship with temperature, salinity and pH were determined. Results and Discussion: The results showed that the dosage of 70 mL L-1 of EBCA in T. suecica cultures favors the growth of the microalgae. A significant increase in biomass and cell density was observed compared to the other treatments, indicating that this concentration of silage provides a suitable nutrient medium. The study also analyzed how temperature, salinity and pH conditions affect the growth of T. suecica, finding that certain optimal ranges of these factors can maximize biomass production. Research Implications: Our study demonstrates that pectin culture waste can be effectively recycled as a culture medium for T. suecica production, offering a sustainable and environmentally friendly solution for waste management. This could reduce reliance on traditional culture media and promote more sustainable practices in aquaculture and the microalgal industry. Originality/Value: This study stands out for its innovative approach in the use of organic waste from pectiniculture, such as the soft parts of the fan shell, for the generation of an alternative nutrient medium for microalgae. In addition, large volumes of fan shell wastes are currently being generated, so our work contributes to the management of these wastes.

Integrating Natural Photosynthesis, Artificial Photosynthesis, and Biohydrogen Production for a Sustainable Energy Future

The interrelated topics of artificial photosynthesis, natural photosynthesis, and biohydrogen production are examined in this thorough analysis as viable avenues for achieving sustainable energy solutions. This piece offers a comprehensive assessment of the present situation and prospective future applications of these technologies by looking at the underlying dynamics of these processes, recent technological developments, and enduring difficulties. Combining knowledge from natural photosynthetic pathways with the latest findings in artificial photosynthesis and developing techniques for producing biohydrogen offers a multifaceted strategy to meet the world's energy needs while reducing the effects of climate change. By clarifying the potential of these technologies to transform the production of renewable energy, lessen reliance on fossil fuels, and offer creative solutions for waste management and carbon sequestration, this analysis benefits society. This article intends to stimulate more interdisciplinary research and development towards a sustainable energy future by highlighting the synergies between various sectors.

Metaheuristic optimizing energy recovery from plastic waste in a gasification-based system for waste conversion and management

In an era where sustainable waste management and clean energy production are paramount, this study presents an innovative integration of plastic waste gasification with solid oxide fuel cell (SOFC) technology, optimized through metaheuristic particle swarm optimization (PSO). The research explores the conversion of polypropylene (PP) waste into syngas via gasification, which is then utilized as a fuel for SOFCs to generate electricity. The optimization process focuses on maximizing power and heating outputs while minimizing carbon dioxide emissions. The study's findings demonstrate the potential of integrating gasification and SOFC technologies to create a sustainable energy system that addresses the challenges of plastic waste. Key findings from the metaheuristic PSO multi-objective optimization reveal that optimal power production, approximately 360 kW, is achieved at temperatures exceeding 1140 K, irrespective of the steam/PP waste ratio. Heating production peaks at 1000 kW with temperatures above 1120 K and utilization factors over 0.765, while the minimum heating output is 700 kW. Emission analysis indicates a significant reduction in carbon dioxide emissions with increased temperatures and utilization factors, achieving a minimum of 700 kg/MWh at temperatures above 1120 K. The study's results demonstrate the effectiveness of the PSO optimization in fine-tuning the operational parameters of the integrated system, leading to improved energy efficiency and reduced environmental impact. Power production of 366.37 kW, a significant heating rate of 995.20 g/s, and emissions of 714.06 kg/MWh are the optimum performances. The research provides valuable insights into the potential of plastic waste-to-energy technologies as sustainable solutions for energy production and waste management.

IoT- enabled crop waste mulching machine for sustainable farming: perspective of circular economy

Abstract A large amount of crop waste is generated after crop harvesting. A substantial quantity of waste on the farm is burnt to clear the field, contributing to environmental harm and global warming. The study aims to develop a technological solution for crop waste management (CWM) by designing and developing an IoT-enabled crop waste mulching machine. This initiative addresses the environmental and health issues caused by burning crop waste on farms. The research involves designing and developing an IoT-enabled mulching machine that can be attached to the back side of a tractor. The machine consists of power-transmitting elements, supports, and mechanisms to distribute mulching material evenly onto the plant bed. It incorporates advanced IoT load cell sensors, soil moisture sensors, and proximity sensors to optimize the mulching process based on soil moisture content and to prevent machinery blockages. The IoT-enabled mulching machine effectively manages crop waste by utilizing it in mulch, thus preventing the harmful practice of burning waste. This machine ensures a more efficient, safer, and environmentally friendly approach to mulching, offering significant improvements over traditional manual mulching methods.
The novelty of this research lies in integrating IoT technologies within mulching machine. The mulching machine uses sensors to automate and optimize the mulching process, representing a significant technological advancement over conventional methods. The study offers practical benefits by reducing labour requirements, minimizing the risk of injuries, and ensuring a more uniform mulch application. This technology facilitates more sustainable farming practices, aligning with global sustainability goals. The study can potentially revolutionize the agricultural equipment manufacturing industry (AEMI) by shifting the focus toward environmental sustainability. It promotes replacing plastic film mulching machines with more eco-friendly crop waste mulching solutions. This technology has the potential to reduce air pollution, carbon emissions, and mitigate climate. It also enhances soil health through better mulching practices.

Potential Utilization of Rice Waste in the Construction Sector: A Multi-Criteria Decision Analysis Approach

Effective management of agricultural waste is an important contribution to environmental sustainability and economic development, especially considering the significant volume of agricultural residues produced worldwide. Rice is a widely cultivated crop in Colombia, and its high production results in a high amount of wastes, which is often underutilized due to a lack of knowledge regarding its potential value-added applications. On the other hand, the construction industry has become increasingly aware of the necessity to develop materials with reduced environmental impact. Therefore, this study explores the application of the Analytic Hierarchy Process (AHP) to evaluate various alternatives for utilizing rice waste in construction materials; the alternatives were evaluated based on criteria tailored to the needs of local agricultural communities in the Tolima region of Colombia. The findings highlight the potential of rice husk ash (RHA) as an environmentally responsible alternative in the construction sector, offering a viable solution for waste management while contributing to the economic development of small-scale farmers.

Pemanfaatan Sampah Plastik dengan Metode Ecobrick Sebagai Upaya Mengurangi Limbah Sampah Plastik di Desa Cempaka Mulia Timur

The implementation of this service program is intended so that the community can contribute to reducing environmental pollution as well as so that the community can also utilize plastic waste into valuable products. East Cempaka Mulia Village is a village located along the Cempaga River, the problem in this village is one of them related to plastic waste. This program aims to encourage residents to utilize waste that produces use value and also provide creative solutions in more sustainable waste management. The PAR (Participatory Action Research) method is a service approach that focuses on identifying problems in society and finding solutions to them (Problem Solving). The result of the service, namely overcoming plastic waste, is by recycling plastic waste using the ecobrick method, namely utilizing waste through plastic bottles.

Identification of optimal waste-to-energy strategies for sustainable development in Iran: SWOT analysis, hybrid MCDM methods, and game theory

The growing global focus on environmental sustainability and the pressing need for efficient waste management and energy crisis mitigation have prompted extensive investigations into sustainable waste management strategies. Given Iran's economic development and population growth, the country faces challenges in energy supply and waste management, making waste-to-energy (WtE) applications a promising solution for sustainable waste management. This study employs a combination of SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis, Multi-Criteria Decision-Making (MCDM) approaches, and game theory to explore WtE technologies and processes, evaluate their applicability within Iran's context, and identify the most effective WtE strategies for the country. Furthermore, game theory and fuzzy Shapley value analysis were utilized to determine the optimal combination of WtE development strategies. The strategy player “SO” held the highest position of power, with a fuzzy Shapley value of (0.391, 1.744, 3.264), resulting in the identification of the optimal strategy combination of SO2ST2WO1WT2, with a value of (0.429, 0.679, 0.893). The recommended combination emphasizes landfill with gas capture, development of incineration power plants, and integrated resource recovery through residue-derived fuel (RDF) implementation. Achieving these objectives necessitates energy policy reforms, pricing adjustments, improvements in the energy subsidy system, and infrastructure and market development.

Feasibility of Using Ferronickel Slag as a Sustainable Alternative Aggregate in Hot Mix Asphalt

Ferronickel slag (FNS) is a byproduct produced during ferronickel alloy manufacturing, primarily used in the manufacturing of stainless steel and iron alloys. This material is produced by cooling molten slag with water or air, posing significant disposal challenges, as improper storage in industrial yards can lead to environmental contamination. This study investigates the chemical and mineralogical characteristics of reduction ferronickel slag (RFNS) and its potential use as an alternative aggregate in hot mix asphalt (HMA). The research is based on the practical application of HMA containing RFNS in an experimental area, specifically the parking lot used by buses transporting employees of Anglo American, located at the Codemin Industrial Unit in Niquelândia, Goiás, Central Brazil. Chemical analysis revealed that RFNS primarily consists of MgO, Fe2O3, and SiO2, which are elements with minimal environmental impact. The lack of significant calcium content minimizes concerns about expansion issues commonly associated with calcium-rich slags. The X-ray diffractogram indicates a predominantly crystalline structure with minerals like Laihunite and Magnetite, which enhances wear and abrasion resistance. HMA containing 40% RFNS was tested using the Marshall methodology, and a small experimental area was subsequently constructed. The HMA containing RFNS met regulatory specifications and technological controls, achieving an average resilient modulus value of 6323 MPa. Visual inspections conducted four years later confirmed that the pavement remained in excellent condition, validating RFNS as a durable and effective alternative aggregate for asphalt mixtures. The successful application of RFNS not only demonstrates its potential for local road paving near industrial areas but also underscores the importance of sustainable waste management solutions. This research highlights the value of academia–industry collaboration in advancing environmentally responsible practices and reinforces the contribution of RFNS to enhancing local infrastructure and promoting a more sustainable future.

Nanoscale Biochar for Fertilizer Quality Optimization in Waste Composting: Microbial Community Regulation

Conventional composting faces challenges of nitrogen loss, product instability, and limited humic substance formation. This study investigated the effects of nanoscale biochars (nano-BCs) derived from rice straw (nano-RSB) and corn stover (nano-CSB) on manure composting. A randomized design with five treatments was used: control, regular biochars (RSB and CSB), and nano-BCs. Nano-BCs, especially nano-CSB, significantly improved compost maturity and reduced phytotoxicity, achieving a 146.20 % germination index. They increased total nitrogen (55.09–63.64 %) and phosphorus (10.25–12.33 %) retention, reduced NH4+-N loss, and promoted nitrification. Nano-CSB showed the highest final NO3−-N content (8.63 g/kg). Bacterial richness and diversity increased by 25–30 % in nano-BC treatments, with selective enrichment of beneficial species. The unique properties of nano-BCs, including high surface area and microporous structure, improved nutrient retention and compost quality. Nano-BCs offers a promising solution for sustainable waste management and high-quality compost production in agriculture, significantly enhancing nutrient retention and microbial community regulation during composting process.

Strategies for Household Waste Management in Winong Village Waste Bank

Background: Legal frameworks are vital for guiding village autonomy and waste management practices. Specific Background: In Indonesia, laws such as Law No. 6/2014 and Law No. 18/2008 regulate these areas but face implementation challenges. Knowledge Gap: There is a lack of integration between community perspectives and local governance practices. Aims: This study analyzes the legal foundations of waste management in rural settings and assesses practical implementation through stakeholder input. Results: Using a normative legal approach alongside Focus Group Discussions with various stakeholders, the research identifies gaps in the application of waste management laws and emphasizes the need for tailored legal recommendations. Novelty: By merging legal analysis with empirical insights, the study provides a comprehensive view of waste management in rural contexts. Implications: Findings highlight the necessity for adapting legal frameworks to local systems and engaging communities, offering practical solutions for rural waste management that contribute to environmental governance. Highlights : Legal Foundations: Examines laws governing waste management and village autonomy. Stakeholder Input: Utilizes Focus Group Discussions to gather community perspectives. Contextual Adaptation: Emphasizes the need for tailored legal solutions for effective implementation. Keywords: legal frameworks, waste management, village governance, community engagement, empirical analysis

A Comprehensive Review of Engineering Strategies for Environmental Sustainability in Sustainable Waste Management

Waste management and environmental sustainability are intricately linked aspects crucial for maintaining ecological balance and human well-being. This study synthesizes research findings and scholarly insights to underscore the significance of effective waste management practices in achieving environmental sustainability goals. It examines waste treatment approaches, including recycling, waste-to-energy systems, and waste reduction strategies, highlighting their role in mitigating environmental impact. Additionally, the study explores the environmental consequences of inadequate waste management, emphasizing the urgent need for holistic solutions to address water, soil, and air pollution. Engineering solutions for sustainable waste management, such as the 3R principle (Reduce, Reuse, Recycle), thermal treatment methods, and landfill management, are discussed as essential components of a comprehensive strategy. By integrating these approaches, policymakers, industries, and communities can minimize waste generation, conserve resources, and safeguard the environment for current and future generations. Challenges like regulatory barriers, lack of awareness, and inadequate infrastructure pose obstacles to sustainable waste management practices. Thus, a collaborative effort involving governments, businesses, and civil society is crucial to implementing effective waste management policies and initiatives. Through concerted action, we can transition to a circular economy model that promotes resource efficiency, environmental protection, and human well-being on a global scale.

Enhancing biogas production from vinasse through optimizing hydraulic retention time and added load using the response surface methodology

Vinasse, a byproduct of ethanol production from sugarcane, is a rich organic matter and poses environmental challenges due to its high pollutant content. Effective biomethane production from vinasse can mitigate its environmental impact by converting organic matter into a useful energy source while reducing its pollutant load. The biomethane production by anaerobic digestion (AD) process of the vinasse byproduct was examined on a laboratory scale. In this regard, several loads from 0.5 to 7 g VS/L were investigated to assess AD performance and methane production. This study investigated how two separate factors, namely the load and hydraulic retention time (HRT), affect both cumulative methane production (CMP) and methane yield (YCH4). This investigation utilized a response surface methodology known as the central composite design (RSM-CCD). Statistical analysis of variance (ANOVA) was employed to evaluate the effectiveness of the model generated. Thus, the model's fit, YCH4 has a maximum R2 value of 0.9759. The results revealed an astounding level of agreement between the experimental data and the proposed model. The RSM results revealed maximum CMP and YCH4 values of 409.82 ml and 178.95 ml/g VS respectively, obtained for optimum load values of 2.17 g VS/L and HRT of 15 h. The results emphasize the environmental and economic significance of AD, providing a sustainable waste management solution that helps reduce greenhouse gas emissions and organic pollution. Additionally, it generates valuable biogas and biofertilizers, presenting economic opportunities through renewable energy production and resource recovery. This approach not only alleviates the environmental burden of vinasse but also enhances the economic viability of ethanol production by creating additional revenue streams.

A Final Study: The Role of Plastic-Modified Bitumen in Enhancing Durability and Sustainability in Road Construction

Abstract: This study systematically evaluates the influence of integrating varying percentages of plastic waste into bitumen on the mechanical properties and performance characteristics of bituminous pavements. Experimental results indicate that the incorporation of plastic waste enhances the performance of bitumen up to an optimal threshold of 8% by weight; exceeding this concentration results in negligible improvements or deterioration in performance. Rigorous laboratory assessments, including Dynamic Shear Rheometer (DSR) analyses, demonstrate that plastic-modified bitumen exhibits a significantly elevated complex modulus (G*) and a reduced phase angle (δ) in comparison to unmodified bitumen, with the 8% modification yielding the most favourable outcomes. Enhanced Marshall Stability, improved flow values, reduced penetration, and increased softening points further signify superior resistance to load and thermal variations. The elevated viscosity of plastic-modified bitumen contributes to enhanced pavement strength and durability. Future investigations should encompass additional evaluations, such as ductility, elastic recovery, and flash/fire point tests utilizing the wet process, alongside an exploration of the dry process involving the coating of aggregates with shredded plastic. The findings substantiate that the incorporation of plastic waste into bitumen not only augments pavement performance but also presents a viable eco-friendly solution for plastic waste management, thereby fostering sustainable construction methodologies. The findings confirm that using plastic waste in bitumen improves pavement quality and offers an eco-friendly solution for plastic waste management, promoting sustainable construction practices.