Sustainability

Research

Jump to: Review

19 pages, 2603 KiB

Open AccessArticle

Raw and Calcined Eggshells as P-Reactive Materials in a Circular Economy Approach

by Agnieszka Bus, Kamila Budzanowska, Agnieszka Karczmarczyk and Anna Baryła

Sustainability 2025, 17(3), 1191; https://doi.org/10.3390/su17031191 - 1 Feb 2025

Viewed by 588

Abstract

Phosphorus (P) is a crucial factor influencing both plant growth and the enrichment of the aquatic environment. Agriculture is the primary sector of the economy where the demand for phosphorus is the highest. Due to the depletion of P, more and more attention [...] Read more.

Phosphorus (P) is a crucial factor influencing both plant growth and the enrichment of the aquatic environment. Agriculture is the primary sector of the economy where the demand for phosphorus is the highest. Due to the depletion of P, more and more attention is being paid to the possibility of recovering and reusing P through the idea of a circular economy (CE). The main objective of this study was to compare raw eggshells (R-ESs) and calcined eggshells (C-ESs) for P removal from wastewater and assess the possible use of agro-waste materials according to CE requirements in non-flow conditions. A synthetic indicator, the zeroed unitarization method, was calculated to evaluate the critical aspects of materials according to the CE. The sorption of R-ESs and C-ESs equaled 0.90 and 1.66 mgP-PO₄/g for an initial concentration of 17.3 mgP-PO₄/L. The C-ESs were characterized by an almost two times higher reduction rate than R-ESs. The calculated indicator for the CE requirements equaled 0.89 and 0.72 for R-ESs and C-ESs, respectively. This means that R-ESs are more sustainable than C-ESs. Although C-ESs potentially have a more significant environmental impact, it is worth considering that this method of P elimination is beneficial from an ecological perspective. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

21 pages, 51133 KiB

Open AccessArticle

Energy Cane Ash: Property Assessment for Its Valorization in Sustainable Cementing Systems

by Gabriela Pitolli Lyra, Lisiane Brichi, Josefa Roselló, María Victoria Borrachero, Lourdes Soriano, Jordi Payá and João Adriano Rossignolo

Sustainability 2025, 17(2), 803; https://doi.org/10.3390/su17020803 - 20 Jan 2025

Viewed by 486

Abstract

Cogeneration with energy cane, a highly productive variety compared to conventional sugarcane, significantly increases ash generation, presenting waste management challenges for the sugar and ethanol industries. This study evaluates the potential of energy cane ash as a sustainable alternative material for partial cement [...] Read more.

Cogeneration with energy cane, a highly productive variety compared to conventional sugarcane, significantly increases ash generation, presenting waste management challenges for the sugar and ethanol industries. This study evaluates the potential of energy cane ash as a sustainable alternative material for partial cement replacement in construction, contributing to circular economy practices. A productivity analysis was conducted for planted areas, and the different parts of sugarcane and energy cane were dried and examined using scanning electron microscopy. These parts were calcined at 450 °C and 600 °C and analyzed using scanning electron microscopy, X-ray fluorescence, particle size distribution, and thermal analysis. The reactivity of the ashes was tested in cement mortars with 5%, 10%, and 20% cement replacement using washed ash. The results revealed that energy cane produces approximately four times more ash per hectare than sugarcane, with leaf ash containing up to 60% silica and stalk ash being rich in potassium. The highest compressive strength was observed in a mortar with 10% cement replacement using washed energy cane ash, achieving 102.43% of the reference value after 28 days of curing, indicating excellent pozzolanic reactivity. These findings highlight the potential of energy cane ash to enhance sustainability in cementitious systems by reducing Portland cement use and promoting waste valorization. Furthermore, the reuse of ash can mitigate waste accumulation and support the development of more sustainable construction materials, contributing to a circular economy and a low-carbon society. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

16 pages, 1366 KiB

Open AccessArticle

Environmental Sustainability Assessment of pH-Shift Technology for Recovering Proteins from Diverse Fish Solid Side Streams

by Erasmo Cadena, Ozan Kocak, Jo Dewulf, Ingrid Undeland and Mehdi Abdollahi

Sustainability 2025, 17(1), 323; https://doi.org/10.3390/su17010323 - 3 Jan 2025

Viewed by 823

Abstract

The demand for clean-cut seafood fillets has led to an increase in fish processing side streams, which are often considered to be low-value waste despite their potential as a source of high-quality proteins. Valorizing these side streams through innovative methods could significantly enhance [...] Read more.

The demand for clean-cut seafood fillets has led to an increase in fish processing side streams, which are often considered to be low-value waste despite their potential as a source of high-quality proteins. Valorizing these side streams through innovative methods could significantly enhance global food security, reduce environmental impacts, and support circular economy principles. This study evaluates the environmental sustainability of protein recovery from herring, salmon, and cod side streams using pH-shift technology, a method that uses acid or alkaline solubilization followed by isoelectric precipitation to determine its viability as a sustainable alternative to conventional enzymatic hydrolysis. Through a Life Cycle Assessment (LCA), five key environmental impact categories were analyzed: carbon footprint, acidification, freshwater eutrophication, water use, and cumulative energy demand, based on a functional unit of 1 kg of the protein ingredient (80% moisture). The results indicate that sodium hydroxide (NaOH) use is the dominant environmental impact driver across the categories, while energy sourcing also significantly affects outcomes. Compared to conventional fish protein hydrolysate (FPH) production, pH-shift technology achieves substantial reductions in carbon footprint, acidification, and water use, exceeding 95%, highlighting its potential for lower environmental impacts. The sensitivity analyses revealed that renewable energy integration could further enhance sustainability. Conducted at a pilot scale, this study provides crucial insights into optimizing fish side stream processing through pH-shift technology, marking a step toward more sustainable seafood production and reinforcing the value of renewable energy and chemical efficiency in reducing environmental impacts. Future work should address scaling up, valorizing residual fractions, and expanding comparisons with alternative technologies to enhance sustainability and circularity. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

14 pages, 440 KiB

Open AccessArticle

Assessment of Sustainable Waste Management: A Case Study in Lithuania

by Renata Činčikaitė

Sustainability 2025, 17(1), 120; https://doi.org/10.3390/su17010120 - 27 Dec 2024

Viewed by 747

Abstract

Sustainable waste management is a very important issue that has received increasing attention in recent years due to its significant impact on the environment and human health. As the population and urbanization increase, more and more waste is generated, leading to problems such [...] Read more.

Sustainable waste management is a very important issue that has received increasing attention in recent years due to its significant impact on the environment and human health. As the population and urbanization increase, more and more waste is generated, leading to problems such as pollution, resource depletion, climate change, etc. Therefore, it is necessary to develop effective waste management strategies that are sustainable and do not harm the environment. The EU is making progress in sustainable waste management within the wider context of a circular economy, but challenges remain, particularly in reducing material consumption and effectively managing specific waste streams. The EU’s approach involves setting clear targets, monitoring progress in a comprehensive framework, and supporting Member States in achieving these targets. In 2019, Lithuanian companies invested about 40% more in environmental protection than in 2018. Notably, 15% of them are invested in waste management. An inhabitant throws out an average of 278 kilograms of mixed municipal waste per year. According to the global waste index in 2022, Lithuania ranked 16th (up from 23rd place), Latvia 37th (down from 35th place), and Estonia 32nd (down from 30th place). The purpose of this article is to identify the factors that determine sustainable waste management in cities and to predict the changes that will occur. Research methods: synthesis and comparison of concepts and methods in scientific literature, secondary data analysis, statistical data processing, and expert interview methods. Research results: It has been determined which factors and how they determine sustainable waste management in the country. The experts evaluated the alternatives—waste prevention, reuse, recycling, and optimization of landfills—according to the following criteria: economic, social, environmental protection, and technology. The most important criterion was determined to be the environmental protection criterion. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

15 pages, 2035 KiB

Open AccessEditor’s ChoiceArticle

Preliminary Analysis and Possibilities of Reducing the Carbon Footprint of Embedded Materials on the Example of Innovative Systemic Railway Stations (ISS)

by Marta Thomas, Maria Ratajczak and Agnieszka Ślosarczyk

Sustainability 2024, 16(23), 10345; https://doi.org/10.3390/su162310345 - 26 Nov 2024

Viewed by 686

Abstract

The paper presents a comprehensive analysis of the environmental impact of building materials used in the construction of railway stations. It analyses two examples of innovative railway stations built in Poland in recent years and examines the impact of the choice of building [...] Read more.

The paper presents a comprehensive analysis of the environmental impact of building materials used in the construction of railway stations. It analyses two examples of innovative railway stations built in Poland in recent years and examines the impact of the choice of building materials on the Global Warming Potential (GWP) of the stations. The analysis found significant differences in GWP between the two stations, with structural steel being the largest contributor for one station, accounting for 48% of the total GWP. Replacing traditional materials with low-emission alternatives was shown to reduce the total GWP for both stations by around 60%. The research highlights the importance of analysing the GWP of all building materials, even in small quantities, as some materials, such as high-pressure laminates, can have a disproportionate impact on carbon emissions. The study also shows that the correct use of low-carbon building materials in the construction of the station can lead to a significant reduction in the carbon footprint of the building. Collaboration between designers, investors and contractors is essential to achieve sustainable building designs that minimise the environmental impact of construction. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

22 pages, 3313 KiB

Open AccessArticle

Evaluation of Biogas Production from Anaerobic Digestion of Biopolymeric Films and Potential Environmental Implications

by Nicolò Montegiove, Roberto Petrucci, Leonardo Bacci, Giovanni Gigliotti, Debora Puglia, Luigi Torre and Daniela Pezzolla

Sustainability 2024, 16(22), 10146; https://doi.org/10.3390/su162210146 - 20 Nov 2024

Viewed by 865

Abstract

The increasing environmental pollution resulting from plastic waste and the need to reuse agro-industrial wastes as a source of discarding has led to the development of innovative biobased products. In the frame of this context, the use of neat polylactic acid (PLA) and [...] Read more.

The increasing environmental pollution resulting from plastic waste and the need to reuse agro-industrial wastes as a source of discarding has led to the development of innovative biobased products. In the frame of this context, the use of neat polylactic acid (PLA) and its blend with polybutylene succinate (PBS) with or without cellulose nanocrystals (CNCs) extracted from hemp fibers is explored here. This study aimed to assess the biogas production of different biopolymeric films. In parallel, life cycle assessment (LCA) analysis was performed on the same films, focusing on their production phase and potential end-of-life scenarios, regardless of film durability (i.e., single-use packaging) and barrier performance, to counteract possible soil health threats. Specifically, this study considered three specific systems: PLA, PLA_PBS (PLA/PBS blend 80:20 w/w), and PLA_PBS_3CNC (PLA/PBS blend + 3% CNCs) films. The assessment involved a batch anaerobic digestion (AD) process at 52 °C, using digestate obtained from the anaerobic treatment of municipal waste as the inoculum and cellulose as a reference material. The AD process was monitored over about 30 days, revealing that reactors containing cellulose showed inherent biodegradability and enhanced biogas production. On the other hand, biopolymeric films based on PLA and its blends with PBS and CNCs exhibited an inhibitory effect, likely due to their recalcitrant nature, which can limit or delay microbial activity toward biomass degradation and methanogenesis. LCA analysis was performed taking into consideration the complex environmental implications of both including biopolymers in the production of renewable energy and the use of post-composting digestate as an organic fertilizer. Remarkably, the PLA_PBS_3CNC formulation revealed slightly superior performance in terms of biodegradability and biogas production, mainly correlated to the presence of CNCs in the blend. The observed enhanced biodegradability and biogas yield, coupled with the reduced environmental impact, confirm the key role of optimized biopolymeric formulations in mitigating inhibitory effects on AD processes while maximizing, at the same time, the utilization of naturally derived energy sources. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

20 pages, 5243 KiB

Open AccessArticle

CFD Simulation of Moving-Bed Pyrolizer for Sewage Sludge Considering Gas and Tar Behavior

by Mayu Hamazaki, Shan Miao, Mitsuo Kameyama, Hisashi Kamiuchi and Kiyoshi Dowaki

Sustainability 2024, 16(22), 10119; https://doi.org/10.3390/su162210119 - 20 Nov 2024

Viewed by 694

Abstract

This study focused on the small-scale dual fluidized-bed gasifier for hydrogen (H₂) production from sewage sludge. One of the current problems with the pyrolizer is tar condensation. Tar could reduce the efficiency of the H₂ yield by adhering and condensing [...] Read more.

This study focused on the small-scale dual fluidized-bed gasifier for hydrogen (H₂) production from sewage sludge. One of the current problems with the pyrolizer is tar condensation. Tar could reduce the efficiency of the H₂ yield by adhering and condensing on walls and pipes. It was revealed that more tar can be decomposed with higher reaction temperatures. Therefore, this study aimed to increase the tar decomposition efficiency with raising the heat carriers’ (HCs) temperature and analyzing the temperature distribution in the furnaces using a CFD simulation. The tar decomposition rate in the pyrolizer was +34.4%pt. by 100 °C of the HCs’ temperature rising. It is implied that less tar trouble and a longer lifetime of the H₂ production plant could be expected by raising the HCs’ temperature. However, comparing the heat transfer efficiency of the whole system, the lower HC inlet temperature of +7.4%pt., because of the hot gas, which supplies heat to the HCs, required more heat, making the thermal efficiency poorer. In addition, the environmental impact of the AGM was increased by 27.2% with the HCs’ temperature rising to 100 °C. Thus, the heat exchange efficiency of the preheater needs to be improved to raise the HCs’ inlet temperature and reduce the amount of hot gas required. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

18 pages, 2935 KiB

Open AccessArticle

Mapping the Sustainability of Waste-to-Energy Processes for Food Loss and Waste in Mexico—Part 2: Environmental and Economic Analysis

by Alonso Albalate-Ramírez, Alejandro Padilla-Rivera, Juan Felipe Rueda-Avellaneda, Brenda Nelly López-Hernández, Luis Ramiro Miramontes-Martínez, Alejandro Estrada-Baltazar and Pasiano Rivas-García

Sustainability 2024, 16(22), 9774; https://doi.org/10.3390/su16229774 - 8 Nov 2024

Viewed by 1117

Abstract

Mexico generated 8.9 million tons of food loss and waste (FLW) in the year 2022, which was primarily managed through linear economy schemes where final disposal sites are predominant, leading to significant contributions to climate change and economic losses. This study, as a [...] Read more.

Mexico generated 8.9 million tons of food loss and waste (FLW) in the year 2022, which was primarily managed through linear economy schemes where final disposal sites are predominant, leading to significant contributions to climate change and economic losses. This study, as a continuation of a prior work (Part 1), aims to evaluate the economic and environmental feasibility of implementing waste-to-energy anaerobic digestion (WtE-AD) plants for FLW management across Mexico, identifying the key factors that influence the competitiveness of these systems compared to conventional waste management practices. Using the outcomes of an energy feasibility analysis (Part 1), alongside life cycle assessment (LCA), geographic information systems, and cost engineering, this research analyzes the eco-efficiency and viability of WtE-AD for FLW valorization throughout the Mexican territory. The results indicate that, with a conventional waste management fee of USD 35.4 t⁻¹, only the largest WtE-AD plant in the State of Mexico (treatment capacity of 2536.8 t FLW d⁻¹) achieved a positive net present value (NPV) of USD 70.1 million, while all the other plants remained economically unviable. Conversely, under an optimistic scenario with a fee of USD 139 t⁻¹, plants processing over 50 t FLW d⁻¹ achieved profitability, with the largest plant reaching an NPV of USD 1.15 billion. The environmental assessment showed that larger plants effectively act as carbon sinks, with the largest plant reducing emissions by up to −89.8 kg CO₂ eq t⁻¹ of FLW. These findings emphasize the need for appropriate waste management fees and governmental incentives to ensure the economic viability of WtE-AD plants. This study provides valuable insights for policymakers, highlighting the potential of WtE-AD technologies to contribute to Mexico’s energy transition and the shift toward a circular economy. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

30 pages, 11305 KiB

Open AccessArticle

Optimisation and Composition of the Recycled Cold Mix with a High Content of Waste Materials

by Przemysław Buczyński and Jakub Krasowski

Sustainability 2024, 16(22), 9624; https://doi.org/10.3390/su16229624 - 5 Nov 2024

Viewed by 833

Abstract

This research focuses on a mineral–cement mixture containing bitumen emulsion, designed for cold recycling procedures, the formulation of which includes 80% (m/m) of waste material. Deep cold recycling technology from the MCE mixture guarantees the implementation of a sustainable development policy in the [...] Read more.

This research focuses on a mineral–cement mixture containing bitumen emulsion, designed for cold recycling procedures, the formulation of which includes 80% (m/m) of waste material. Deep cold recycling technology from the MCE mixture guarantees the implementation of a sustainable development policy in the field of road construction. The utilised waste materials include 50% (m/m) reclaimed asphalt pavement (RAP) from damaged asphalt layers and 30% (m/m) recycled aggregate (RA) sourced from the substructure. In order to assess the possibility of using a significant amount of waste materials in the composition of the mineral–cement–emulsion (MCE) mixture, it is necessary to optimise the MCE mix. Optimisation was carried out with respect to the quantity and type of binding agents, such as Portland cement (CEM), bitumen emulsion (EMU), and redispersible polymer powder (RPP). The examination of the impact of the binding agents on the physico-mechanical characteristics of the MCE blend was performed using a Box–Behnken trivalent fractional design. This method has not been used before to optimise MCE mixture composition. This is a novelty in predicting MCE mixture properties. Examinations of the physical properties, mechanical properties, resistance to the effects of climatic factors, and stiffness modulus were conducted on Marshall samples prepared in laboratory settings. Mathematical models determining the variability of the attributes under analysis in correlation with the quantity of the binding agents were determined for the properties under investigation. The MCE mixture composition was optimised through the acquired mathematical models describing the physico-mechanical characteristics, resistance to climatic factors, and rigidity modulus. The optimisation was carried out through the generalised utility function U^III. The optimisation resulted in indicating the proportional percentages of the binders, enabling the assurance of the required properties of the cold recycled mix while utilising the maximum quantity of waste materials. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

21 pages, 4806 KiB

Open AccessArticle

Adsorption of Phosphate from Aqueous Solution Using Hydrochar Produced from Agricultural Wastes

by Esha Shrestha, Ashish Manandhar and Ajay Shah

Sustainability 2024, 16(21), 9259; https://doi.org/10.3390/su16219259 - 25 Oct 2024

Viewed by 961

Abstract

Excess phosphorus (P) in agricultural runoff can cause eutrophication in nearby waterbodies. Therefore, it is crucial to remove P from agricultural runoff before it reaches aquatic environments. This study evaluated the P adsorption potential of adsorbents prepared via co-hydrothermal carbonization of multiple agricultural [...] Read more.

Excess phosphorus (P) in agricultural runoff can cause eutrophication in nearby waterbodies. Therefore, it is crucial to remove P from agricultural runoff before it reaches aquatic environments. This study evaluated the P adsorption potential of adsorbents prepared via co-hydrothermal carbonization of multiple agricultural wastes, including dairy manure (DM), corn stover (CS), and eggshell (ES), followed by thermal activation. The performance of the prepared adsorbents was investigated by both batch and column experiments. The activated hydrochar (AHC) with a DM/CS/ES ratio of 1:0:1 showed the highest P adsorption capacity of 209 ± 0.6 and 65.97 ± 9.04 mg/g in batch and column experiments, respectively. The P adsorption mechanism was well described by the Langmuir isotherm model (R² > 0.8802) and the pseudo-second-order kinetics model (R² > 0.8989). The adsorbent indicated the longest breakthrough and exhaust time of 210 and 540 min, respectively, with an adsorbent dose of 1 g and an initial concentration of 25 mg P/L. The breakthrough curve was well described by the Thomas model (R² > 0.971). Thus, this study indicates that AHC with eggshell has high potential for use as an adsorbent for P removal from agricultural runoff. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

16 pages, 4502 KiB

Open AccessArticle

The Basic Properties of Lightweight Artificial Aggregates Made with Recycled Concrete Fines

by Edyta Gosk, Katarzyna Kalinowska-Wichrowska, Marta Kosior-Kazberuk, Magdalena Joka Yildiz, Łukasz Derpeński, Przemysław Zamojski and Paweł Lipowicz

Sustainability 2024, 16(20), 9134; https://doi.org/10.3390/su16209134 - 21 Oct 2024

Viewed by 1168

Abstract

The production of lightweight aggregate based on waste is an important step towards sustainable and ecological construction. It contributes to reducing the negative impact of the construction sector on the environment by reducing the consumption of natural raw materials and reducing waste of [...] Read more.

The production of lightweight aggregate based on waste is an important step towards sustainable and ecological construction. It contributes to reducing the negative impact of the construction sector on the environment by reducing the consumption of natural raw materials and reducing waste of various origins, including rubble concrete. The physical and mechanical properties, including grain shape index, water absorption, bulk density, resistance to crushing, frost resistance, leachability of heavy metals, and porosity of lightweight artificial aggregate made from rubble concrete waste (KRC) were presented in the paper. The obtained test results prove that the proposed artificial aggregate has similar water absorption and bulk density and even better frost and crushing resistance than artificial aggregates available on the market. Due to its properties, it can be used for lightweight concrete, gardening, or as a separating layer in home sewage treatment plants. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

21 pages, 7944 KiB

Open AccessArticle

Analysis of the Prices of Recycling Byproducts Obtained from Mechanical–Biological Treatment Plants in the Valencian Community (Spain)

by Javier Rodrigo-Ilarri and María-Elena Rodrigo-Clavero

Sustainability 2024, 16(16), 6714; https://doi.org/10.3390/su16166714 - 6 Aug 2024

Viewed by 1398

Abstract

Municipal solid waste (MSW) management in Spain, particularly in the Valencian Community, heavily relies on mechanical–biological treatment (MBT) plants followed by landfill disposal. These MBT facilities utilize mechanical processes like shredding, screening, and sorting to segregate recyclables (metals, plastics, paper) from organic material [...] Read more.

Municipal solid waste (MSW) management in Spain, particularly in the Valencian Community, heavily relies on mechanical–biological treatment (MBT) plants followed by landfill disposal. These MBT facilities utilize mechanical processes like shredding, screening, and sorting to segregate recyclables (metals, plastics, paper) from organic material and other nonrecyclables. While public funding supports these plants, private entities manage them through complex, long-term concession contracts. This structure restricts access to crucial data on the sale prices of the byproducts generated during MBT. Publicly available information on relevant company and administration websites is typically absent, hindering transparency surrounding byproduct revenue. This study addresses this gap by analyzing 2012’s available data on revenues obtained from byproduct sales following mechanical treatment at MBT plants within the Valencian Community and comparing them with Spanish national data. This research revealed a significant finding—the statistical distribution of average prices obtained from Ecoembes auctions in the Valencian Community mirrored the corresponding distribution for prices calculated from auctions conducted in other Spanish regions. This suggests a potential uniformity in byproduct pricing across the country. It has also been found that none of the analyzed price distributions exhibited a normal (Gaussian) distribution. The findings also highlight the need for alternative pricing models that move beyond simple averages and account for regional variations and outliers. As actual prices are not available after 2012, this lack of transparency poses a challenge in comprehensively evaluating the economic viability of MBT plants. Furthermore, it raises concerns regarding whether the revenue generated from byproduct sales reflects fair market value. Limited public access to this information can potentially indicate conflicts of interest or inefficiencies within the waste management system. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

17 pages, 6413 KiB

Open AccessArticle

Performance of a Diesel Engine Fueled by Blends of Diesel Fuel and Synthetic Fuel Derived from Waste Car Tires

by Mirosław Jakubowski, Artur Jaworski, Hubert Kuszewski and Krzysztof Balawender

Sustainability 2024, 16(15), 6404; https://doi.org/10.3390/su16156404 - 26 Jul 2024

Viewed by 1214

Abstract

Waste car tires are a significant burden on the environment. One way to manage them is through energy recovery by burning them in the furnaces of combined heat and power plants or cement plants, which from an environmental point of view is not [...] Read more.

Waste car tires are a significant burden on the environment. One way to manage them is through energy recovery by burning them in the furnaces of combined heat and power plants or cement plants, which from an environmental point of view is not a favorable solution. Another way to use waste tires is to produce liquid fuels, which can be used as pure fuels or components added to conventional fuels. Therefore, it is necessary to conduct research aimed at evaluating the physical and chemical properties of tire-derived fuels relative to conventional fuels. It is also important to determine the impact of feeding engines with synthetic fuels, regarding their operational and environmental performance. In this article, the physicochemical properties of typical diesel fuel, synthetic fuel derived from waste tires (WT) and its blends with diesel fuel (DF) in shares of 5, 10, 15, 20 and 25% v/v were studied. Tests were also conducted on an internal combustion engine with a common rail injection system (CR IC) engine to determine operational and emission parameters. The results showed, among other things, a deterioration relative to diesel fuel of such parameters as cold filter plugin point (CFPP) and flash point (FP). At the same time, a favorable effect of synthetic fuel addition was noted on hydrocarbon (HC) and nitrogen oxide (NOx) emissions. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

19 pages, 10150 KiB

Open AccessArticle

Enhancing the Properties of Cement Composites Using Granulated Hemp Shive Aggregates

by Katarzyna Kalinowska-Wichrowska, Magdalena Joka Yildiz, Edyta Pawluczuk, Izabela Zgłobicka, Małgorzata Franus, Wojciech Nietupski and Magdalena Pantoł

Sustainability 2024, 16(14), 6142; https://doi.org/10.3390/su16146142 - 18 Jul 2024

Cited by 2 | Viewed by 1068

Abstract

In recent years, civil engineers have been exploring innovative methods of constructing buildings using environmentally friendly materials. The beneficial properties of hemp harl, an agricultural waste that is gaining popularity in construction, prompted the idea of strengthening its properties through the granulation process [...] Read more.

In recent years, civil engineers have been exploring innovative methods of constructing buildings using environmentally friendly materials. The beneficial properties of hemp harl, an agricultural waste that is gaining popularity in construction, prompted the idea of strengthening its properties through the granulation process and using it as an aggregate in cement composites. This work aimed to investigate whether the use of hemp husk in the form of granules would have a positive effect on the properties of cement composites compared to their traditional form (stems). Potato starch was introduced as an additional factor in the granulation process to improve the material. Experimental tests were carried out on organic fillers, fresh mixtures, and hardened composites. Physical, mechanical, and structural tests (SEM imaging) were carried out. The highest strength was demonstrated by samples containing hemp shive aggregate (1.186 MPa), while the use of hemp shives in the form of granules had a positive effect on the consistency and density, and it also reduced water absorption by 30% during the production of the composite. The apparent density of composites with hemp shives in the form of hemp pellets was higher (1042 ÷ 1506 kg/m³) than in the case of composites with shives in the form of harl (727 ÷ 1160 kg/m³). Nevertheless, hemp shive in both forms can be used as a natural aggregate in cement composites. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

18 pages, 3268 KiB

Open AccessArticle

Mapping the Sustainability of Waste-to-Energy Processes for Food Loss and Waste in Mexico—Part 1: Energy Feasibility Study

by Alonso Albalate-Ramírez, Alejandro Padilla-Rivera, Juan Felipe Rueda-Avellaneda, Brenda Nelly López-Hernández, José Julián Cano-Gómez and Pasiano Rivas-García

Sustainability 2024, 16(14), 6111; https://doi.org/10.3390/su16146111 - 17 Jul 2024

Cited by 1 | Viewed by 1876

Abstract

Mexico generated 8.9 Mt of food loss and waste (FLW) at food distribution and retail centers in the year 2022. Traditional management methods in Latin America primarily involve final disposal sites, contributing to national greenhouse gas emissions of 0.22 Mt CO₂ eq [...] Read more.

Mexico generated 8.9 Mt of food loss and waste (FLW) at food distribution and retail centers in the year 2022. Traditional management methods in Latin America primarily involve final disposal sites, contributing to national greenhouse gas emissions of 0.22 Mt CO₂ eq y⁻¹. This creates an urgent need for sustainable valorization strategies for FLW to mitigate environmental impacts. This comprehensive study analyzes the geographical distribution of FLW generation and proposes a valorization approach using WtE-AD plants. Geographic information systems were employed for geographical analysis, life cycle assessment was used for environmental evaluation, and circular economy business models were applied for sustainability assessment. The primary objective of this first part of the contribution is to evaluate the technical feasibility of implementing waste-to-energy anaerobic digestion (WtE-AD) plants for FLW management in Mexico considering their geographical locations. The results demonstrate that WtE-AD plants with treatment capacities exceeding 8 t d⁻¹ can achieve positive energy balances and significantly reduce greenhouse gas emissions. Specific findings indicate that these plants are viable for large-scale implementation, with larger plants showing resilience to increased transport distances while maintaining energy efficiency. The results highlight the critical influence of methane yields and transport distances on plant energy performance. This study underscores the importance of strategically placing and scaling WtE-AD plants to optimize resource efficiency and environmental sustainability. These findings provide essential insights for policymakers and stakeholders advocating for the transition of Mexico’s food supply chain toward a circular economy. Future parts of this study will explore detailed economic analyses and the policy frameworks necessary for the large-scale implementation of WtE-AD plants in Mexico. Further research should continue to develop innovative strategies to enhance the techno-economic and environmental performance of WtE-AD processes, ensuring sustainable FLW management and energy recovery. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

19 pages, 2614 KiB

Open AccessArticle

Kinetic Modeling of Co-Pyrogasification in Municipal Solid Waste (MSW) Management: Towards Sustainable Resource Recovery and Energy Generation

by Anabel Fernandez, Daniela Zalazar-García, Carla Lorenzo-Doncel, Diego Mauricio Yepes Maya, Electo Eduardo Silva Lora, Rosa Rodriguez and Germán Mazza

Sustainability 2024, 16(10), 4056; https://doi.org/10.3390/su16104056 - 13 May 2024

Cited by 4 | Viewed by 1875

Abstract

This study addresses the co-pyrogasification of municipal solid waste (MSW) from the Environmental Technology Park, San Juan, Argentina. This process involves heating waste at high temperatures in a low-oxygen or oxygen-free atmosphere as a sustainable strategy for waste management and energy generation. The [...] Read more.

This study addresses the co-pyrogasification of municipal solid waste (MSW) from the Environmental Technology Park, San Juan, Argentina. This process involves heating waste at high temperatures in a low-oxygen or oxygen-free atmosphere as a sustainable strategy for waste management and energy generation. The principal objective is to focus on understanding the MSW co-pyrogasification kinetics to enhance performance in reactor design. A representative sample of MSW collected over a month was analyzed, focusing on the variation in mass proportions of plastic, organic matter, and paper. The empirical methodology included the deconvolution of macro-TGA curves and deep learning algorithms to predict and validate macro-TG data during co-pyrogasification. The findings reveal that MSW is a solid matrix more easily treated on thermochemical platforms, with kinetic and thermodynamic parameters favoring its processing. This approach suggests that MSW co-pyrogasification may represent a feasible alternative for resource recovery and bioenergy production, supporting the policies for the transition to a cleaner future and a circular economy. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

Review

Jump to: Research

26 pages, 1696 KiB

Open AccessReview

Heavy Metal and Antimicrobial Residue Levels in Various Types of Digestate from Biogas Plants—A Review

by Małgorzata Czatzkowska, Damian Rolbiecki, Ewa Korzeniewska and Monika Harnisz

Sustainability 2025, 17(2), 416; https://doi.org/10.3390/su17020416 - 8 Jan 2025

Viewed by 1178

Abstract

Global population growth generates problems relating to increasing demand for sustainable energy and waste treatment. Proper solid waste management promotes material reuse, maximizes recovery and reduces anthropological pressure on natural resources. Anaerobic digestion (AD) is an alternative method of stabilizing organic substrates and [...] Read more.

Global population growth generates problems relating to increasing demand for sustainable energy and waste treatment. Proper solid waste management promotes material reuse, maximizes recovery and reduces anthropological pressure on natural resources. Anaerobic digestion (AD) is an alternative method of stabilizing organic substrates and generating biogas as a source of environmentally friendly energy. In addition, digestate is not only a waste product of that process but also a renewable resource with many potential applications. The circular economy concept encourages the use of digestate as a source of nutrients that promotes plant growth and improves soil properties. However, the stabilized substrates often contain various contaminants, including heavy metals (HMs) and antibiotics that are also detected in digestate. Therefore, the agricultural use of digestate obtained by AD could increase the pool of these pollutants in soil and water environments and contribute to their circulation in these ecosystems. Moreover, digestate may also increase the co-selection of genes determining resistance to HMs and antibiotics in environmental microorganisms. This article comprehensively reviews published data on the residues of various HMs and antimicrobial substances in different digestates around the world and maps the scope of the problem. Moreover, the potential risk of residual levels of these contaminants in digestate has also been evaluated. The review highlights the lack of legal standards regulating the concentrations of drugs introduced into the soil with digestate. The results of the ecological risk assessment indicate that the presence of medically important antimicrobials in digestate products, especially those used in agriculture, should be limited. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

27 pages, 2001 KiB

Open AccessReview

Upcycling of Food By-Products and Waste: Nonthermal Green Extractions and Life Cycle Assessment Approach

by Marinela Nutrizio, Josipa Dukić, Iva Sabljak, Aleksandra Samardžija, Vedran Biondić Fučkar, Ilija Djekić and Anet Režek Jambrak

Sustainability 2024, 16(21), 9143; https://doi.org/10.3390/su16219143 - 22 Oct 2024

Cited by 1 | Viewed by 3531

Abstract

Food loss and waste constitute a substantial threat to global food system sustainability, representing 38% of energy consumption in the supply chain. The 2030 Agenda for Sustainable Development highlights a vision integrating social, economic, and environmental pillars. Addressing environmental impact requires recycling (destruction [...] Read more.

Food loss and waste constitute a substantial threat to global food system sustainability, representing 38% of energy consumption in the supply chain. The 2030 Agenda for Sustainable Development highlights a vision integrating social, economic, and environmental pillars. Addressing environmental impact requires recycling (destruction for new creations) and upcycling (converting waste into valuable products). This review highlights nonthermal green extractions and sustainable techniques in upcycling raw materials such as olives, red beetroot, sugar beet, and coffee, which are widely used in the food industry. Nonthermal processing efficiently extracts bioactive compounds and utilizes waste. Key approaches for its valorization include life cycle assessment, environmental footprint analysis, energy efficiency strategies, digitalization, and sustainability considerations. However, challenges remain in calculating their environmental impact. Waste and by-product valorization from raw materials address disposal issues, offering economic and environmental benefits. Nonthermal techniques show optimistic opportunities in green extraction and sustainable upcycling. The focus is on raw materials including olives, red beetroot, sugar beet, and coffee byproducts, and possible product development. There are powerful connections offering industry tools for impactful sustainability management and guiding decisions on waste-to-value or ‘upcycling’ products. The review contributes to filling the gap in usage of nonthermal processing in upcycling of waste and by-products. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

18 pages, 1352 KiB

Open AccessReview

Unraveling the Valorization Potential of Pineapple Waste to Obtain Value-Added Products towards a Sustainable Circular Bioeconomy

by Sarah L. Paz-Arteaga, Edith Cadena-Chamorro, Ricardo Goméz-García, Liliana Serna-Cock, Cristóbal N. Aguilar and Cristian Torres-León

Sustainability 2024, 16(16), 7236; https://doi.org/10.3390/su16167236 - 22 Aug 2024

Cited by 1 | Viewed by 3871

Abstract

The pineapple (Ananas comosus) is one of the most commercialized tropical fruits worldwide. Its high processing and consumption generate huge quantities of organic waste and severe economic and environmental issues. Embracing the circular bioeconomy concept, this fruit waste can be applied [...] Read more.

The pineapple (Ananas comosus) is one of the most commercialized tropical fruits worldwide. Its high processing and consumption generate huge quantities of organic waste and severe economic and environmental issues. Embracing the circular bioeconomy concept, this fruit waste can be applied as a bioresource (raw material) for the obtention of a wide range of high-valued biocompounds by applying innovative and ecofriendly technologies. In this paper, we critically describe pineapple-derived waste, from their chemical composition to their functional and biological properties, as well as the latest advances on valorization technologies, particular solid and submerged fermentations. Notably, this article highlights the possibility of using pineapple waste to obtain bioactive compounds such as bromelain, phenolic compounds, and dietary fiber, which have important biological properties such as antioxidant, anticancer, antimicrobial, and prebiotic capacities. Indeed, pineapple wastes can become valued materials by using green and biotechnological technologies that allow us to maximize their potential and might avoid wastage and environmental issues. Nevertheless, it is necessary to further investigate the biomolecules present in the waste derived from different pineapple varieties and their health beneficial effects as well as emerging technologies in order to obtain a full spectrum of natural value-added compounds that industries and society demand today. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Graphical abstract

24 pages, 5573 KiB

Open AccessReview

Waste Management of Wind Turbine Blades: A Comprehensive Review on Available Recycling Technologies with A Focus on Overcoming Potential Environmental Hazards Caused by Microplastic Production

by Sara Taherinezhad Tayebi, Matteo Sambucci and Marco Valente

Sustainability 2024, 16(11), 4517; https://doi.org/10.3390/su16114517 - 26 May 2024

Cited by 5 | Viewed by 3972

Abstract

The 2020 targets for sustainable development and circular economy encourage global leaders and countries to legislate laws and policies on several critical hot topics to prevent further global warming: (1) the increased utilization of renewable electrical power (wind turbine implants, as an example); [...] Read more.

The 2020 targets for sustainable development and circular economy encourage global leaders and countries to legislate laws and policies on several critical hot topics to prevent further global warming: (1) the increased utilization of renewable electrical power (wind turbine implants, as an example); (2) waste transformation into high-added-value materials based on the European Green Deal for energy transition; and (3) material and energy recovery and circularity. Accordingly, scholars and researchers have predicted that, hopefully, installed wind power capacity is going to increase dramatically by 2050. However, our ecosystem will have to face and deal with an enormous amount of decommissioned turbine blades. The disposal of these wastes via conventional methods could not only raise the possibility of microplastic formation, but could also boost the probability of environmental issues such as air pollution, soil, water contamination, etc. Moreover, these hazards will endanger wildlife and humans. As a result, the waste management of these retired blades composed of multi-lateral composite materials through a sustainable, effective, and feasible single/or hybrid process is necessary. This review aims to summarize all of the information about turbines, introduce all the various recycling pathways used for their blades, and provide a comparative analysis of these methods as well. In addition, the paper defines the possibility of microplastic formation from this waste (especially end-of-life turbine blade scraps), points out potential risks for the Earth, and suggests actions to inhibit their build-up and to keep the environment safe. Full article

(This article belongs to the Special Issue Research Progress and Evaluation Challenges of By-Product and Waste Valorization)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Research Progress and Evaluation Challenges of By-Product and Waste Valorization

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (20 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI