Sustainable Waste Management Research Articles

Karakteristik limbah pertanian dan dampaknya: Mengapa pengelolaan ramah lingkungan penting?

Background: Agricultural waste is a significant by-product of the agrarian sector, with the potential for substantial environmental and economic impacts. This study aims to examine the characteristics of organic agricultural waste and analyze its effects on the environment, both in terms of threats and its potential utilization. Method: This study employs a systematic literature review method. The literature search focuses on articles discussing agricultural waste, its characteristics, and its environmental impacts. Findings: The results show that agricultural waste has diverse characteristics based on fiber composition, physical form, and protein content. The main threats from agricultural waste include water pollution due to nutrient runoff and greenhouse gas emissions, especially methane. However, this waste also holds significant potential as a source of organic mulch, animal feed, and raw material for bioenergy. Utilizing agricultural waste as mulch can improve soil quality and crop yields, while its use as animal feed supports the integration of agricultural and livestock systems. In the context of energy, converting waste into biogas and biofuel offers an effective solution. Conclusion: This study emphasizes the importance of integrated and sustainable agricultural waste management to minimize negative impacts and optimize its economic potential. Novelty/Originality of this article: By providing a comprehensive analysis of the characteristics and impacts of agricultural waste, this study offers insights into the importance of a holistic approach to agricultural waste management to support sustainable agriculture.

The pyrolytic distillation of waste lubricants with waste oilfield scale into value-added fuel

The ever-increasing generation of waste materials has become a major environmental concern, highlighting the need for sustainable waste management strategies. This study explores the catalytic pyrolysis of waste lubricant oils using a waste oilfield scale as a low-cost solid catalyst to produce value-added fuel products. The pyrolytic distillation of waste engine oil was carried out in a manual distillation unit, employing a calcium carbonate (CaCO3) scale as a catalyst under various reaction conditions. Distillation experiments were conducted at 300 °C, 320 °C, and 350 °C, with and without adding NaOH and CaCO3 catalysts. The distillate fractions were characterized, and their properties were compared to standard fuel specifications. The results demonstrated that increasing the pyrolysis temperature and employing CaCO3 as a catalyst significantly enhanced the distillate yield and improved key fuel properties. At 350 °C, the distillate yield reached 56 % with 4 g of CaCO3, exhibiting desirable density (0.8049 g/cm3), viscosity (2.31 cSt at 40 °C), sulfur content (0.43 wt%), and a calorific value of 43,152 kJ/kg. Further, the distillate fractions were separated into gasoline (80–150 °C), kerosene (180–270 °C), and gas oil/diesel (270–350 °C) ranges, with the diesel fraction showing a promising cetane number of 51. The catalytic pyrolysis fuel (CPF) obtained from distillation with 4 g CaCO3 at 350 °C, followed by bleaching with CaO, exhibited excellent properties, including a density of 0.8297 g/cm3, viscosity of 2.71 cSt at 40 °C, pour point of −12 °C, sulfur content of 0.201 wt%, and a calorific value of 43,961 kJ/kg. The GC analysis revealed a paraffin-rich composition in the desired fuel ranges, contributing to the desirable fuel properties.

Obtaining high H2-rich syngas yield and carbon conversion efficiency from biomass gasification: From characterization to process optimization using machine learning with experimental validation

Gasification, among the other thermochemical processes, stands as a promising method for sustainable waste management while generating valuable H2-rich syngas. In the last few years, there has been a significant surge in the adoption of machine learning (ML) techniques for modelling biomass as well as gasification and pyrolysis of waste. The present study unveiled the supremacy of Gaussian Process Regression (GPR) algorithm as compared to other ML models, in predicting syngas yield [Ysyn (Nm3/kg of biomass)] and carbon conversion efficiency[ηCarbon(%)] respectively, with a high prediction accuracy of R2 > 0.9 in both the cases. The necessary datasets were collected from experimental trials, at reaction conditions of temperature (T): 550–1000 °C, air flow rate (AFR): 0.02–0.04 L/min, and reaction time of 2 h, in a two-stage fixed bed reactor, which were identified on the Basis of thermodynamic as well as stoichiometric analysis. Additionally, the models were employed in Bayesian optimization within a weighted multi-objective framework to obtain the optimal operational parameters, focusing on maximizing both yield and conversion simultaneously. Finally, this result was validated experimentally to check the sanctity of the data-driven optimization.

Conversion of PET bottles into carbonaceous adsorbents for Pb(II) removal from aqueous solutions via KOH activation

In this study, we present a novel approach to repurpose waste Polyethylene terephthalate (PET), a prominent contributor to global plastic usage, for the synthesis of efficient adsorbents via facial pyrolysis. The as-synthesized adsorbents were applied for the removal of lead (Pb(II)) ions in aqueous solution. Controlled batch experiments at pH 5 with 0.075 g of adsorbent at room temperature (20 °C) were conducted to measure Pb(II) adsorption capacities (mg/g) and fitted on isotherm models (Langmuir, Freundlich, and Temkin) and kinetics models (Pseudo-First order, Pseudo-Second order, and Elovich). Thermodynamic experiments conducted at four different temperatures (293 K, 303 K, 313 K, and 323 K) provided enthalpy, entropy, and Gibbs free energy change parameters, explaining the Pb(II) adsorption behaviors on PET-based adsorbents. The activation process involving KOH, followed by carbonization, yielded adsorbents with exceptional surface areas, pore volumes, and elevated oxygen contents (up to 22.8 %). The best adsorbent exhibited superior performance, achieving a maximum adsorption capacity of 219.7 mg/g within a rapid equilibrium time of 15 min. The adsorption behavior adhered well to the Langmuir isotherm model (R2 = 0.999) and Pseudo-Second Order kinetics model (R2 = 0.999). Furthermore, C600K600 displayed outstanding reusability, with negligible efficiency reduction (<5 %) even after five consecutive cycles. These results underscore the successful conversion of PET waste into a low-cost and highly effective adsorbent, offering a promising solution for sustainable waste management.

Valorizing Tea Waste: Green Synthesis of Iron Nanoparticles for Efficient Dye Removal from Water.

This study explores the valorization of tea leaf waste by extracting polyphenols through reflux extraction, subsequently using them to synthesize zero-valent iron nanoparticles (nZVI). The in situ generated nanoparticles, when combined with fixed amounts of hydrogen peroxide, facilitated the removal of various dyes (methylene blue, methyl orange, and orange G) via a hetero-catalytic Fenton process. The iron nanoparticles were thoroughly characterized by gas adsorption of N2 at 77 K, scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM), FT-IR spectroscopy, X-ray diffraction (XRD), and thermal analysis, including thermogravimetric analysis (TG) and temperature-programmed reduction (TPR). A statistical design of experiments and response surface methodology were employed to analyze the influence of polyphenol, Fe(III), and H2O2 concentrations on dye removal efficiency. The results demonstrated that optimizing the operational conditions could achieve 100% dye removal efficiency. This study highlights the potential of nZVI synthesized through eco-friendly methods as a promising solution for water decontamination involving diverse model dyes, thus contributing to sustainable waste management and environmental protection.

Experimental investigation on a solar-powered oxy-hydrogen gas system for enhanced plastic pyrolysis

The escalating environmental concerns associated with plastic waste have intensified the search for sustainable waste management solutions. Plastic dispersion in the environment poses severe threats to ecosystems, human well-being, and agriculture. Consequently, addressing plastic pollution stands as a pressing ecological concern. In contrast, the adoption of sustainable solar energy is harnessed for the production of HHO (Oxy-Hydrogen) gas, offering a promising avenue for clean energy generation. Gas production is achieved through the process of electrolysis, utilizing solar panels as the primary energy source. To address storage challenges, a spiral pipe configuration is employed for the interim containment of the generated HHO gas. Given the highly flammable nature of HHO gas, stringent safety protocols are imperative throughout the production and storage phases. To ensure the safe handling of HHO gas, a sophisticated MQ-8 Sensor is employed for real-time leak detection within the gas containment system. This sensor plays a critical role in maintaining operational safety by promptly identifying and addressing any potential gas leaks that may arise within the tubing infrastructure. The HHO gas, generated through the electrolysis process, serves as the primary fuel for the pyrolysis of plastic. This optimization is crucial to maximize the efficiency of the pyrolysis process. As a result of the pyrolysis process, crude oil is produced as an intermediary product. This crude oil holds the potential for subsequent refinement, offering versatility for various applications and end uses. Hence, the integration of solar energy-driven HHO gas in the pyrolysis of plastic demonstrates a promising avenue for mitigating plastic waste and contributing to environmental cleanliness. The intricate technological aspects, ranging from gas production through electrolysis, leak detection, optimized combustion, to crude oil production and refinement, collectively establish a comprehensive framework for sustainable waste management and resource recovery.

An in-depth Analysis of Soil Quality and Heavy Metal Contamination in the vicinity of the Visakhapatnam Municipal Solid Waste Dumpsite

The study conducts a comprehensive analysis of soil quality and heavy metal contamination in the vicinity of the Visakhapatnam Municipal Solid Waste Dumpsite, with a focus on the Gajuwaka municipality. The research addresses the escalating global concerns arising from improper waste disposal practices and their environmental repercussions. The Gajuwaka dumpsite, receiving diverse waste types, poses significant threats due to the leaching of heavy metals into the soil, impacting environmental components and human health. The study employs a robust experimental methodology involving soil sampling, metal extraction and Atomic absorption spectroscopy for elemental analysis. Waste characterization reveals the predominant presence of organic fractions and inert materials in the dumpsite. Seasonal physicochemical analysis of soil samples indicates variations in pH, moisture content, soil texture, organic matter and nutrient availability. Metal content generally decreases during the post-monsoon period. Phytotoxicity analysis of selected plant species demonstrates their capacity to accumulate heavy metals, particularly lead. The study emphasizes the urgent need for effective waste management practices, continuous soil monitoring and community engagement to mitigate environmental and health risks associated with waste dumping sites. The findings underscore the critical importance of sustainable waste management and environmental health. The study contributes valuable insights into the complex challenges posed by improper waste disposal practices and provides a foundation for the development of comprehensive strategies aimed at addressing environmental concerns.

Plausible Avenues and Applications of Bioformulations from Symbiotic Culture of Bacteria and Yeast

Microbial cellulose, especially the bacterial cellulose produced by symbiotic co-cultures of acetic acid bacteria and yeast (SCOBY) that exists in a mutualistic interaction opens plausible strategies in the field of food as well as sustainable regenerative eco-system and waste management. Cultivated on sweetened black tea, the mutually proliferating bacteria (Acetobacter xylinum, A. xylinoides, and Bacterium gluconicum) and yeast strains (Schizosaccharomyces pombe, Saccharomycodes ludwigii and Saccharomyces cerevisiae) produces a fermented liquor along with the floating bacterial cellulosic pellicle called as Kombucha. This review explores the possible applications of kombucha SCOBY to use bacterial cellulose-based engineered living materials, commercial superabsorbent spheres by various marketing ventures like food, pharmaceutics, biomedical applications for bio-sensing and bio-catalysis, crop biostimulants, biocontrol agents in the management of plant and animal illnesses, post-harvest management in crops, water purification, pollutant detection, environmental biotechnology, and production of SCOBY from alternative substrates and agrarian waste management. The plausible use of bacterial cellulose hydrogels in dryland agriculture for their exceptional water-absorbing capability, eco-friendly nature, capacity to break down naturally, and compatibility with other living organisms is also elaborated in this paper. Furthermore, diverse microbial species to enhance the variety and functional properties of SCOBY, health benefits and its influence on human welfare is vividly discussed in the paper. The very in-depth study on the uses of SCOBY also paves way for the research exploration of this under-utilized microbial boon in food and farm sector for circular based regenerative agriculture in near future.

Consumer perspectives on restaurant sustainability: an S-O-R Model approach to affective and cognitive states

ABSTRACT This study explores how sustainable practices in restaurants affect consumer behavior through the Stimulus-Organism-Response (S-O-R) model. It defines sustainability with multi-faceted dimensions of sustainable food, waste management, energy/water conservation, and social engagement. This research also examines how positive emotions and perceived value mediate the relationship between consumers’ perceptions of sustainability and their behavior. Results show that sustainable practices positively impact perceived value and emotions, influencing consumer intentions toward the restaurant. The research extends the S-O-R model to restaurant sustainability and offers insights for managers to enhance customer experience. The study highlights the need for restaurants to effectively communicate their sustainability efforts, emphasizing the importance of integrating sustainability into all aspects of restaurant operations and marketing.

A Study of the Knowledge, Awareness and Behaviour Regarding Plastic Waste Management in Pune City

Plastic waste is a problem for us all. Even though plastic is one of the wonder products the problem starts when it becomes a waste. As the populations grows so does the amount of waste. The waste generation is much more in the urban areas which creates a problem because of the volume and as the waste is not segregates Keshav Sita Memorial Foundation trust is a one of the leading trust in Pune city the works on plastic waste management wherein they create awareness of segregation at source and also collect waste plastic from various households this plastic is usually the post-consumer plastic which includes mainly packaging wrapping and other traditionally non recycling plastic Around 665 people from various backgrounds from various WhatsApp groups respondent to the questionnaire. The basic statistical analysis was done on a various subject ranging from the behind the participation in plastic Warrior project and to understand the Habit change which has resulted into the long lasting behavioural change. It has been shown in many previous studies that for a sustainable waste management one needs active participation from the garbage producers I the people who generate the waste at their home workplace or other places. The behavioural change takes more time but also has longer lasting affect not only on the behaviour of the person but the behaviour of the householders also.

Toward sustainable waste management in peri-urban areas: a comprehensive analysis of household practices in Rawalpindi, Pakistan

Toward sustainable waste management in peri-urban areas: a comprehensive analysis of household practices in Rawalpindi, Pakistan

Consumption and Digestion of Plastics by Greater Hive Moth Larvae.

The accumulation and unsustainable management of plastic waste generate environmental pollution that affects ecosystems, wildlife, and human health. We studied the possibility of using the consumption and digestion of oxo-biodegradable, compostable plastics and polypropylene from face masks by the fifth-instar larvae of G. mellonella as a strategy for the sustainable management of plastic waste. We used Fourier transform infrared spectrophotometry (FTIR) to determine the percentage of consumption and presence of microplastics in the digestive tract and excreta for 10 treatments evaluated for 135 h. The effects of plastics on the continuity of the life cycle of the greater hive moth were also determined. We established that the larvae fragmented and consumed 35.2 ± 23% of the plastics evaluated, with significant differences between treatments. Larvae were able to consume more of the intermediate layers of masks (86.31%) than the other plastics. However, none of the plastics were digested. Instead, microplastics accumulated in the excreta, resulting in nutritional deficits that affected the continuity of the life cycle, including the induction of the early formation of pupae after 24 h and a reduction in the number of eggs laid by the females.

Comprehensive life cycle assessment of garden organic waste valorisation: A case study in regional Australia

This study evaluates the environmental impacts associated with the conversion of garden organic waste into value-added products, namely compost or biochar, employing various processes. Three distinct scenarios are considered: composting garden organic waste followed by screening of oversized materials (CBP), pyrolysis of oversized screenings of compost into biochar AP(I), and in-situ conversion of garden organics into biochar AP(II). A comprehensive Life Cycle Assessment (LCA) was conducted using OpenLCA software and life cycle impact assessment was conducted using Recipe 2016 midpoint methodology. The environmental ramifications of each scenario were assessed, optimising transport distances in AP(II) to achieve a functional unit of one tonne of biochar produced within a cradle-to-gate system boundary. For the first time, this study offers a holistic exploration of the benefits of soil biochar application, extending its scope to climate change mitigation, incorporating the optimisation of transport distance and its influence when scaling up the technology. The results revealed that global warming was increased from 125 kgCO2 eq during composting of garden waste to 232 kgCO2 eq where oversized screenings of compost is converted to biochar at an off-site facility. However, direct conversion of the oversized organic waste to biochar, without composting, showed reduced global warming impact of 56 kgCO2 eq, and is thus the most favourable scenario to limit climate impacts of this fraction of organic garden waste. However, among 18 environmental impact indicators studied, eight indicators were either not influenced or did not significantly increase by transport distance to an off-site pyrolysis facility, while the magnitude of 10 impact indicators increased with transport distance. The insights and methodologies presented in this study hold global relevance, based on an actual case study in regional Australia, offering valuable recommendations for sustainable waste management practices and establishing biochar as a carbon-neutral or carbon-negative solution. The findings contribute to existing waste management knowledge and provide guidance for accessible carbon dioxide removal and soil carbon sequestration technologies.

Assessing the carbonation potential of wood ash for CO2 sequestration

Wood ash, a byproduct of wood combustion, poses environmental challenges when disposed of in landfills. This study explores a sustainable alternative by investigating the carbonation of wood ash, a process converting CO2 into stable carbonate minerals. With increasing concerns about waste management, this research aims to identify optimal carbonation conditions by varying relative humidity, liquid-to-solid ratio (L/S), and temperature. Results demonstrate that the ideal conditions for wood ash carbonation involve a moderate relative humidity of 55%, room temperature at 25 °C, and a lower L/S ratio. Thermogravimetric analysis (TGA) indicates that extended curing times increase CaCO3 formation. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) confirm the presence of carbonate phases. Mechanical strength tests reveal that samples with lower porosity and higher carbonation products exhibit superior strength. This study contributes to the understanding of wood ash carbonation but also emphasizes its potential practical applications in construction materials as light aggregates in cement concrete. The research explores the implications for sustainable waste management, offering insights into environmentally and economically viable solutions for wood ash recycling.

Inventory of Electronic Waste (E-Waste) and Residues in Junkshops: A Step Towards Residual Waste Management

The improper management of Waste Electrical and Electronic Equipment (WEEE) constitutes a critical global environmental challenge, with a significant proportion of e-waste ending up in landfills, posing substantial ecological and health risks. In the Philippines, particularly in areas like Marilao and Bulacan, many individuals rely on the recycling of e-waste for their livelihoods, primarily through junkshops and informal recycling networks. Despite providing economic benefits, these practices often result in substantial residual waste, exacerbating landfill overflow and environmental degradation. This study aims to establish a detailed e-waste inventory and propose practical strategies for improving residual waste management. This research used a mixed-method approach to collect data via surveys, interviews, and direct observations at selected junkshops in Marilao. The findings enabled a comprehensive categorization of e-waste based on economic value, highlighting "temperature exchange equipment" as the most economically valuable category while identifying "small IT and telecommunication equipment" as the least. Among the significant residual wastes identified were base/black plastics, styrofoam, and glass, which are commonly mishandled. The study proposes several management strategies, including partnerships with local governmental bodies and recycling companies to enhance recycling processes, improving dismantling techniques to reduce waste, and implementing rigorous waste segregation practices to prevent contamination and improve recycling rates. This expansion is critical for a more comprehensive understanding and monitoring of e-waste management practices, facilitating the development of more effective and sustainable waste management solutions. By adopting these strategies, junkshops and informal recyclers can optimize e-waste management, reducing environmental impact while maintaining economic viability.

Analysis of the Impact of Biomass/Water Ratio, Particle Size, Stirring, and Catalysts on the Production of Chemical Platforms and Biochar in the Hydrothermal Valorization of Coffee Cherry Waste

In Colombia alone, 12.6 million bags of green coffee are produced, but at the same time, 784,000 tons of waste biomass are dumped in open fields, of which only 5% is recovered or used, and 10 million tonnes of coffee emit 28.6 million tonnes of CO2 eq annually. This presents a worrying dilemma, and the need to develop a technology to transform the waste into usable products is increasing. As a response to this, the valorization of coffee waste was explored through the production of biochar and platform chemicals by implementing a set of hydrothermal experiments with different biomass/water ratios (1:5, 1:10, 1:20, 1:40), particle sizes (0.5, 1, 2, 5 mm), stirring rates (5000 and 8000 rpm), and catalysts (H2SO4, NaHCO3 and CH3COOH) at 180, 220, and 260 °C in a batch reactor with autogenous pressure. Notably, the smaller B:W ratios of 1:20 and 1:40, as well as smaller particle sizes of 0.5 and 1 mm, yielded higher amounts of platform chemicals, while stirring showed minimal influence. CH3COOH significantly enhanced the process compared to other catalysts. The biochar was characterized as anthracite, and this obtaining of coal-like materials from biomass itself represents a remarkable feat. Said anthracite presented little to no variation in physical parameters, while catalysts induced functionalization. By optimizing factors like B:W ratio, particle size, and catalyst application, valuable insights have been gained into enhancing the yield of platform chemicals and quality of biochar from coffee waste. The findings not only contribute to sustainable waste management practices but also highlight the importance of exploring innovative solutions for utilizing agricultural by-products effectively.

Statistical modeling and optimization of volatile fatty acids production by anaerobic digestion of municipal wastewater sludge.

Obtaining value-added products from renewable resources is limited by the lack of specific operating conditions optimized for the physico-chemical characteristics of the biomass and the desired end product. A mathematical model and statistical optimization were developed for the production of volatile fatty acids (VFAs) by anaerobic digestion of municipal sewage sludge. The experimental tests were carried out in triplicate and investigated a wide range of conditions: pH 9.5, 10.5, and 11.5; temperatures 25°C, 35°C, 45°C, and 55°C; primary sludge with organic loading (OL) of 10 and 14g VS (volatile solids); and digested sludge with 4 and 6g VS. Subsequently, a statistical search was performed to obtain optimal production conditions, then a statistical model of VFA production was developed and the optimal conditions were validated at pilot plant scale. The maximum VFA concentration predicted was 6975mg COD (chemical oxygen demand)/L using primary sludge at 25°C, initial OL of 14g VS, and pH 10.5. The obtained third-degree model (r2 = 0.83) is a powerful tool for bioprocess scale-up, offering a promising avenue for sustainable waste management and biorefinery development.

Waste management optimization with NLP modeling and waste-to-energy in a circular economy

This work presents a methodology integrating Non-Linear Programming (NLP) for multi-objective and multi-period optimization, addressing sustainable waste management and energy conversion challenges. It integrates waste-to-energy (WtE) technologies such as Anaerobic Digestion (AD), Incineration (Inc), Gasification (Gsf), and Pyrolysis (Py), and considers thermochemical, technical, economic, and environmental considerations through rigorous non-linear functions. Using Mexico City as a case study, the model develops waste management strategies that balance environmental and economic aims, considering social impacts. A trade-off solution is proposed to address the conflict between objectives. The economical optimal solution generates 1.79M$ with 954 tons of CO2 emissions while the environmental one generates 0.91M$ and reduces emissions by 54%, where 40% is due to gasification technology. Moreover, the environmentally optimal solution, with incineration and gasification generates 9500 MWh/day and 5960 MWh/day, respectively, demonstrates the capacity of the model to support sustainable energy strategies. Finally, this work presents an adaptable framework for sustainable waste management decision-making.

Process Model and Life Cycle Assessment of Biorefinery Concept Using Agricultural and Industrial Residues for Biohydrogen Production

Sustainable waste management strategies are urgently needed due to an increasing global population and increased waste production. In this context, biorefineries have recently emerged as a promising approach to valorize waste streams and supply a broad range of products. This study presents the process model and life cycle assessment (LCA) of a biorefinery concept using a novel biochemical method, a so-called “dark photosynthesis” conversion. This process is coupled to a photo-fermentation using microalgae. Overall, the biorefinery concept can produce hydrogen, lutein, β-carotene, and proteins for animal feed. Apple pomace from apple juice production is used as feedstock for the primary conversion step. A process model was created with the process simulation software Aspen Plus® using experimental and literature data. Results from this model were then used in an LCA. The environmental impacts of the proposed biorefinery concept are relatively high, showing the need for process optimization in several areas. Energy system integration, stream recycling, and higher hydrogen yields are recognized as especially important for improving the environmental performance of this concept. Despite these findings, the model shows the feasibility of implementing the biochemical conversion technologies in a biorefinery concept for effectively utilizing residue streams.

Revitalizing municipal solid waste recycling: Review of current U.S. policies and potential directions for the circular economy

Municipal Solid Waste (MSW) recycling is a pivotal pillar in waste reduction and sustainable resource management. However, the United States (U.S.) is behind its schedule for the national recycling rate goal of 50% by 2030, which California is almost achieving. To this end, we review and compare the national and California recycling policies. Our analysis reveals that while there have been some positive changes toward sustainable waste management practices, significant gaps remain, particularly in the lack of a comprehensive national recycling law. The current federal allocation of funds has also been inadequate for achieving the national goal. Therefore, we identify policy options to grow toward a national policy and funding for recycling infrastructure and education. Using California as a model, we provide federal law options to balance recyclable supply and demand. These options are paired with future U.S. MSW policy and research directions.