Sustainability

2024

Jump to: 2023

9 pages, 397 KiB

Open AccessArticle

Assessment of the Quantities of Non-Targeted Materials (Impurities) in Recycled Plastic Packaging Waste to Comply with EU Regulations and Sustainable Waste Management

by Beata Waszczyłko-Miłkowska, Katarzyna Bernat and Krystian Szczepański

Sustainability 2024, 16(14), 6226; https://doi.org/10.3390/su16146226 - 21 Jul 2024

Viewed by 972

Abstract

Plastic packaging waste (PPW) can be considered as solid waste with harmful effects on the environment or as a material with recycling potential in terms of sustainable development in a circular economy. Knowing the amount of PPW generated is very important as it [...] Read more.

Plastic packaging waste (PPW) can be considered as solid waste with harmful effects on the environment or as a material with recycling potential in terms of sustainable development in a circular economy. Knowing the amount of PPW generated is very important as it is related to the availability of this material for recycling and determines the actual recycling rate (denominator of a fraction). PPW is very heterogeneous and contains a certain number of impurities (e.g., product residues, direct printing, glue, labels, plastic sleeves, cap, etc.). According to EU law, an annual report (for the data in 2021) on the masses of both the PPW actually recycled (PPW_R) (“targeted materials”) and impurities (“non-targeted materials”) must be prepared and submitted to the European Commission. The PPW_R is used for the calculation of the recycling rate (the numerator in a fraction). The impurities should be considered for the calculation of own resources (national contributions to the general EU budget based on the uniform call rate of 0.80/kg of non-recycled PPW). To date, the Council of the EU has not proposed a method for calculating these amounts, so they have only been estimated. The present study (the first of its kind in Poland) aimed to estimate the number of impurities in PPW and the actual amount of PPW_R at the calculation point using a method accepted by the EU. In the installations, PPW (plastic packaging (15 01 02), multi-material packaging (15 01 05) and mixed packaging waste (15 01 06)) is recycled together with other plastic waste (plastic (16 01 19), plastic (17 02 03), plastic and rubber (19 12 04), and plastics (20 01 39)). It was assumed that the proportions of the mass of individual types of PPW in the total mass of plastic waste processed in the installation were proportional to the mass of impurities in these individual types of PPW. It was found that the average percentage of impurities in PPW was 4.40–6.90%, which seems to be relatively low. However, this means that, when calculating the PPW_R, the mass of impurities should be subtracted from the mass of PPW entering the recycling process. As a result, the mass of PPW_R at the calculation point in 2021 in Poland was almost 30,000 tonnes lower than the original mass entering the installation. Thus, applying the uniform call rate to the weight of impurities in the PPW increases Poland’s own resources by approx. 24 million euros. Full article

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23 pages, 2273 KiB

Open AccessArticle

Barriers of and Possibilities for Recycling of Single-Use Take-Away Food and Beverage Packaging: Evidence from Lithuanian Market

by Valdonė Daugėlaitė and Jolita Kruopienė

Sustainability 2024, 16(13), 5732; https://doi.org/10.3390/su16135732 - 4 Jul 2024

Viewed by 949

Abstract

The use of single-use take-away packaging for food and beverages is steadily growing globally. The consumption habits of ordering food online and the very short time of use of single-use take-away packaging suggest that high amounts of potential resources are continuously being wasted. [...] Read more.

The use of single-use take-away packaging for food and beverages is steadily growing globally. The consumption habits of ordering food online and the very short time of use of single-use take-away packaging suggest that high amounts of potential resources are continuously being wasted. Since there is a lack of studies that could represent the status of packaging materials used within the take-away delivery industry, it is difficult to predict the potential for material recycling and reuse. This research aimed at identifying (1) the predominant packaging materials used by the take-away food and beverage industry according to the food category, (2) packaging weight in order to understand the potential for material recovery, (3) labelling in order to understand communication with consumers about what is relevant for choosing end-of-life scenarios, and (4) the residues of the food and beverage within packaging after use, which potentially affects the recyclability of packaging. The research identified at which stages of the value chain there was a potential for the better circulation of single-use packaging materials and provided insights for decision makers (businesses, institutions, etc.) to improve the sustainability of take-away packaging. Full article

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20 pages, 15029 KiB

Open AccessArticle

Synthesis and Characterization of Biochars and Activated Carbons Derived from Various Biomasses

by Tuan-Dung Hoang, Yan Liu and Minh Thang Le

Sustainability 2024, 16(13), 5495; https://doi.org/10.3390/su16135495 - 27 Jun 2024

Cited by 2 | Viewed by 1248

Abstract

Reducing CO₂ emissions is urgently needed to slow down the impacts of climate change. CO₂ capture using an amine solution has been developed and implemented at pilot and commercial scales. However, amine scrubbing, in particular, produces a lot of degraded solvents [...] Read more.

Reducing CO₂ emissions is urgently needed to slow down the impacts of climate change. CO₂ capture using an amine solution has been developed and implemented at pilot and commercial scales. However, amine scrubbing, in particular, produces a lot of degraded solvents as waste and is energy intensive. Solid sorbents have been used to overcome these drawbacks. In this work, waste biomass-derived carbon materials were developed and characterized. Advanced thermal chemical processes, i.e., hydrothermal and pyrolysis processes, were applied to produce materials from agrifood waste, such as soybean and okara. It was found that functional groups (-C=O and -OH) appeared in the synthesized materials, implying the generation of surface oxygenated groups. Preliminary results showed that synthesized activated carbons were obtained with good yields and relatively high surface areas, which may be applied as CO₂ adsorption materials to solve CO₂ emission problems. Full article

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22 pages, 2419 KiB

Open AccessArticle

Assessing the Potential for Valorisation of a Pulp and Paper Industry Byproduct for the Construction of Unpaved Forest Roads: A Geotechnical Perspective

by David Miranda Carlos, Catarina Martins, Daniela Rodrigues, Joaquim Macedo and Margarida Pinho-Lopes

Sustainability 2024, 16(13), 5332; https://doi.org/10.3390/su16135332 - 22 Jun 2024

Viewed by 1089

Abstract

Integration of sustainability into industry has encouraged practices of circular economy, reusing and recycling resources. This paper studies alternative solutions to materials traditionally used for unpaved roads, with a byproduct of the pulp and paper industry (not pre-treated), and analyses its valorisation potential [...] Read more.

Integration of sustainability into industry has encouraged practices of circular economy, reusing and recycling resources. This paper studies alternative solutions to materials traditionally used for unpaved roads, with a byproduct of the pulp and paper industry (not pre-treated), and analyses its valorisation potential from a geotechnical perspective. Two approaches were adopted: (1) assessment of geotechnical properties of base materials (aggregate, local soil and byproduct) and mixtures (aggregate/local soil and byproduct, 3% or 6%); (2) design of the base layer (case study), considering different solutions for the material forming that layer, assessing its height and life cycle. The small incorporation percentages studied changed the geotechnical properties of aggregate and local soil, reducing sensitivity to water and increasing the water content for optimum compaction. The CBR of mixtures reduced with the incorporation of the byproduct. For the case study, incorporation of byproduct (6% maximum) in the local soil did not significantly affect the base layer height. Total replacement with the byproduct is mechanically possible. For the fixed height of the base layer, incorporating the byproduct in traditional materials reduced the unpaved road life cycle, reflecting CBR reductions. From a geotechnical perspective, the valorisation of this byproduct is promising, and from an industry point of view, its use (geotechnical valorisation) represents a way to promote circular economy and sustainability. Full article

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16 pages, 627 KiB

Open AccessArticle

Elevating Recycling Standards: Global Requirements for Plastic Traceability and Quality Testing

by Benjamin Gazeau, Roberto Minunno, Atiq Zaman and Faiz Shaikh

Sustainability 2024, 16(12), 5122; https://doi.org/10.3390/su16125122 - 16 Jun 2024

Viewed by 1885

Abstract

Globally, we produced 489 million tonnes of plastic in 2023 and we recycled only 8.17%. This study navigates the landscape of recycling practices, highlighting the imperative to reevaluate and upgrade industry-standard protocols. The central focus of this study is on integrating more robust [...] Read more.

Globally, we produced 489 million tonnes of plastic in 2023 and we recycled only 8.17%. This study navigates the landscape of recycling practices, highlighting the imperative to reevaluate and upgrade industry-standard protocols. The central focus of this study is on integrating more robust traceability criteria and advanced quality testing methodologies to improve recycled plastics with intrinsic value, particularly in anticipation of future market applications. The investigation examines the prevailing industry standard traceability and quality framework. It then assesses the applicability of those standards using technical datasheets for recycled high-density polyethylene resin grades. This study proposes a paradigm shift toward a more sophisticated analytical approach. This comprehensive framework aims to transcend traditional quality and traceability evaluation. This paper employs a mixed methodological approach, including a thematic analysis of relevant industry standard regulations and an in-depth literature review, to address the need for an operational framework for recycling quality. This study highlights that recycling quality depends on technical attributes determining functionality and application suitability. While some properties are measured, the conventional framework does not address the degradation level of recycled plastic. This study concludes with broader considerations, emphasising the need for a traceability model to disclose material history and composition. This study advocates an industry-wide upgrade in recycling standards, prioritising traceability and quality testing. The proposed enhancements in testing grids and the improved understanding of recycling quality collectively contribute to a holistic framework, unlocking the intrinsic value of recycled plastics for future market applications. Full article

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9 pages, 472 KiB

Open AccessEditor’s ChoiceArticle

Using the Amount of Plastic Packaging Placed on the Market to Determine the Annual Amount of Plastic Packaging Waste Generated in Poland to Enable Sustainable Waste Management

by Beata Waszczyłko-Miłkowska and Katarzyna Bernat

Sustainability 2024, 16(12), 5048; https://doi.org/10.3390/su16125048 - 13 Jun 2024

Cited by 1 | Viewed by 977

Abstract

A new category of own resources based on national contributions, which are calculated on the basis of the amount of non-recycled plastic packaging waste (PPW) (EUR 0.80 per kilogram), was introduced in 2021 by the decision of the EU Council (EU, Euratom, 2020/2053). [...] Read more.

A new category of own resources based on national contributions, which are calculated on the basis of the amount of non-recycled plastic packaging waste (PPW) (EUR 0.80 per kilogram), was introduced in 2021 by the decision of the EU Council (EU, Euratom, 2020/2053). In accordance with the European strategy for plastics, the Union budget can contribute to reducing pollution from PPW, which is consistent with sustainable waste management. To calculate the own resource of plastics, it is necessary to determine the amount of non-recycled PPW by taking the difference between the amounts of generated and recycled PPW. Data on the amount of recycled PPW can be obtained from recycling facilities. The challenge, however, is to determine the actual amount of PPW generated in a given year. For this reason, the present study was undertaken to determine the amount of PPW generated annually, based on the amount of plastic packaging placed on the market (PPM) (i.e., with the use of the placed-on-the-market approach). To perform the calculations, the Polish entities that place products in plastic packaging on the market were identified. It was assumed that the amount of PPM was the sum of the amounts of packaging stated by producer responsibility organizations (PRO), as well as self-compliers (SC), private imports (I), and free-riders (FR), minus the amount of packaging privately exported (E). To obtain the relevant data from the records linked to the amounts of plastic packaging imported to and exported from Poland, a detailed methodology was developed. A complementary analysis was concurrently conducted to estimate the amount of plastic PPM by free-riders. The results of these analyses indicate that the amount of packaging transparently reported by the PRO accounted for almost 97% of the total amount of PPM. The analysis found 19,728 SC who placed 2.22% of the total plastic packaging on the market. The total amount of privately imported plastic packaging was 17,304,666 kg (1.37%). Plastic packaging placed on the market by FR is 24,788,196 kg (1.97%). However, the amount of plastic packaging privately exported was 30,571,691 kg (2.43%). Thus, in 2021, the amount of plastic packaging placed on the Polish market was 1,259,345,296 kg; this figure constitutes the basis for determining the own resources based on non-recycled PPW. It also indicates the potential of PPW to serve as a resource for the production of new products, which is in accordance with the principles of a circular economy. Full article

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30 pages, 3863 KiB

Open AccessReview

By-Product Valorization as a Means for the Brewing Industry to Move toward a Circular Bioeconomy

by Paul-Loup Pasquet, Maud Villain-Gambier and Dominique Trébouet

Sustainability 2024, 16(8), 3472; https://doi.org/10.3390/su16083472 - 21 Apr 2024

Cited by 1 | Viewed by 3795

Abstract

Beer production consumes significant amounts of water, energy, and raw materials, and results in the production of various by-products, including wastewater, brewers’ spent grain, yeast and hop. To lower its environmental footprint, by-products may be reclaimed or valorized in agro-food, cosmetic, material, chemical [...] Read more.

Beer production consumes significant amounts of water, energy, and raw materials, and results in the production of various by-products, including wastewater, brewers’ spent grain, yeast and hop. To lower its environmental footprint, by-products may be reclaimed or valorized in agro-food, cosmetic, material, chemical industries, etc. According to most recent research, breweries have the potential to become biorefineries, as they can extract diverse valuable plant-based compounds such as carbohydrates, proteins, lipids, phenolic compounds, platform chemicals, and biopolymers. These biomolecules possess bioactive and physicochemical properties, which can be enhanced through recovery processes. Brewery by-products may be utilized in various industries within the bioeconomy frame. In agro-food systems, extracts can increase final products’ techno-functionalities. Such additives can also help in creating marketing labels such as clean-label healthy, which can further attract potential customers. Businesses can gain economic and socio-environmental benefits by implementing sustainable practices, which can also improve their corporate image. This article outlines recent advancements in the processing and valorization of brewery by-products, ultimately defining an up-to-date, sustainable strategy for clean beer production. Full article

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20 pages, 368 KiB

Open AccessArticle

Intentions to Create Green Start-Ups for Collection of Unwanted Drugs: An Empirical Study

by Anuli Njoku, Kamel Mouloudj, Ahmed Chemseddine Bouarar, Marian A. Evans, Dachel Martínez Asanza, Smail Mouloudj and Achouak Bouarar

Sustainability 2024, 16(7), 2797; https://doi.org/10.3390/su16072797 - 27 Mar 2024

Cited by 3 | Viewed by 1391

Abstract

Drug waste poses a real threat to human health and the environment. Therefore, recycling and sustainability scholars have recently sought practical solutions to the drug waste problem. Furthermore, several governments have made significant efforts to reduce the negative effects of waste, such as [...] Read more.

Drug waste poses a real threat to human health and the environment. Therefore, recycling and sustainability scholars have recently sought practical solutions to the drug waste problem. Furthermore, several governments have made significant efforts to reduce the negative effects of waste, such as establishing programs to take back unwanted drugs (expired and unused) for recycling (i.e., drug reuse or drug redispersing). However, many of these programs have failed to achieve their goals. In this context, it is expected that creating green start-ups to collect unwanted drugs will contribute to solving this problem. Accordingly, this study aims to investigate the antecedents of intentions to create green start-ups for collecting unwanted drugs. To this end, the authors integrate start-up self-efficacy and drug waste collection-related knowledge constructs into the theory of planned behavior (TPB). Using a self-administered paper questionnaire and relying on a convenience sample, data were collected from 328 students in six Algerian universities. A hierarchical multiple regression was conducted to test the proposed study model. Theresults revealed that perceived behavioral control (PBC) (β = 0.187, p < 0.001), attitudes (β = 0.182, p = 0.002), start-up self-efficacy (β = 0.169, p = 0.001), drug waste collection-related knowledge (β = 0.161, p < 0.001), and subjective norms (β = 0.088, p < 0.05) have a positive significant effect on the intention to create a start-up to collect unwanted drugs. In conclusion, this paper contributes to reducing drug waste by investigating the drivers of intention to create green start-ups for collecting unwanted drugs. Therefore, our study is expected to provide valuable insights for hospitals, pharmacies, pharmaceutical manufacturers, environmental protection associations, and stakeholders interested in reverse logistics. Full article

2023

Jump to: 2024

21 pages, 11718 KiB

Open AccessReview

Biochar-Based Phosphorus Recovery from Different Waste Streams: Sources, Mechanisms, and Performance

by Hai Bang Truong, Thi Cuc Phuong Tran, Thi Phuong Nguyen, Thi Thao Nguyen Nguyen, Doan Thi Oanh, Duong Thi Thuy and Xuan Cuong Nguyen

Sustainability 2023, 15(21), 15376; https://doi.org/10.3390/su152115376 - 27 Oct 2023

Cited by 1 | Viewed by 2192

Abstract

Elevated phosphorus (P) levels in water sources can result in eutrophication, which in turn causes environmental pollution and adversely affects aquatic ecosystems. Additionally, there is a risk of P depletion due to intensive exploitation and utilization. Therefore, the sustainable and efficient use of [...] Read more.

Elevated phosphorus (P) levels in water sources can result in eutrophication, which in turn causes environmental pollution and adversely affects aquatic ecosystems. Additionally, there is a risk of P depletion due to intensive exploitation and utilization. Therefore, the sustainable and efficient use of P, waste reduction, and P recovery from waste sources have become urgent priorities. This article aims to provide the most current assessments of the P regeneration process and its origins within waste and wastewater. This work also evaluates P recovery, as to its mechanisms, influencing factors, and performance. Moreover, the review presents comprehensive results from pilot and full-scale applications of P recovery. Further perspectives are analyzed, including economic feasibility, potential environmental impacts, research needs, and opportunities for improving P recovery. Full article

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22 pages, 2807 KiB

Open AccessArticle

Management of Small WEEE: Future Directions for Australia

by Gimhan Jayasiri, Sunil Herat and Prasad Kaparaju

Sustainability 2023, 15(18), 13543; https://doi.org/10.3390/su151813543 - 11 Sep 2023

Cited by 1 | Viewed by 1715

Abstract

Globally, the generation of small Waste Electrical and Electronic Equipment (WEEE) is rapidly increasing and accounted for over 30% of total E-waste in 2019. Managing this critical waste stream has proven challenging in Australia due to diverse product categories, short lifespans, and high [...] Read more.

Globally, the generation of small Waste Electrical and Electronic Equipment (WEEE) is rapidly increasing and accounted for over 30% of total E-waste in 2019. Managing this critical waste stream has proven challenging in Australia due to diverse product categories, short lifespans, and high frequency of disposal. To address the issue, a Multivocal Literature Analysis was conducted to identify prevailing situations, barriers, and prospects for a practical management framework. Findings were thematically analysed based on sustainability and circular-economy principles. The study revealed several critical obstacles, including the lack of involvement by local governments, the mixing of small WEEE with municipal waste, the absence of an established repair and reuse culture, and the limited domestic application of recovered metals. To address these issues, the study identifies the need for a dedicated co-regulatory stewardship scheme based on extended producer responsibility with eco-modulated fees and realistic scheme targets. Additionally, to accommodate the high product diversity, the expansion of treatment infrastructure is suggested while encouraging responsible consumption among customers. The findings of this investigation hold substantial value for the regulatory bodies in developing and implementing small-WEEE management schemes for Australia. Full article

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18 pages, 15316 KiB

Open AccessArticle

Energy Efficiency and Environmental Benefits of Waste Heat Recovery Technologies in Fishmeal Production Plants: A Case Study in Vietnam

by Tra Van Tung, Nguyen Thi To Nga, Huu Tap Van, Tran Hai Vu, Ksawery Kuligowski, Adam Cenian, Nguyen Quang Tuan, Phuoc-Cuong Le and Quoc Ba Tran

Sustainability 2023, 15(17), 12712; https://doi.org/10.3390/su151712712 - 22 Aug 2023

Cited by 2 | Viewed by 2209

Abstract

The fishmeal production industry is essential for providing protein for animal feed in the aquaculture sector. However, the industry faces challenges related to energy consumption and environmental sustainability. This study evaluates the energy efficiency and environmental benefits of waste heat recovery (WHR) technologies [...] Read more.

The fishmeal production industry is essential for providing protein for animal feed in the aquaculture sector. However, the industry faces challenges related to energy consumption and environmental sustainability. This study evaluates the energy efficiency and environmental benefits of waste heat recovery (WHR) technologies in a fishmeal production plant in Vietnam. Data were collected from the plant between 2016 and 2022, and a specific energy consumption (SEC) indicator and a comprehensive methodology were utilized. Implementing an economizer as a WHR technology resulted in a 55.5% decrease in SEC compared to the state before installation. The enhanced energy efficiency also translated to reduced energy consumption per output unit. Moreover, the economizer contributed to annual energy savings of 4537.57 GJ/year and cost savings of USD 26,474.49. Additionally, carbon dioxide (CO₂) emissions associated with producing one ton of fishmeal decreased by 58.37%. These findings highlight the potential for WHR technologies to improve energy efficiency and reduce the environmental footprint of fishmeal production. The study’s results provide valuable insights for practitioners and policymakers in promoting energy efficiency practices and reducing environmental impact in this and similar industries. Full article

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22 pages, 5754 KiB

Open AccessArticle

Evaluation of Kitchen Waste Recycling as Organic N-Fertiliser for Sustainable Agriculture under Cool and Warm Seasons

by Ksawery Kuligowski, Izabela Konkol, Lesław Świerczek, Katarzyna Chojnacka, Adam Cenian and Szymon Szufa

Sustainability 2023, 15(10), 7997; https://doi.org/10.3390/su15107997 - 14 May 2023

Cited by 7 | Viewed by 6004

Abstract

Kitchen waste could be processed and recycled into safe fertilizers/soil improvers for sustainable agriculture through different methods: (1) Dried pellets from model kitchen waste treated with anaerobic effective microorganisms; and (2) Anaerobically digested kitchen waste. For comparison, a commercial mineral fertilizer was used. [...] Read more.

Kitchen waste could be processed and recycled into safe fertilizers/soil improvers for sustainable agriculture through different methods: (1) Dried pellets from model kitchen waste treated with anaerobic effective microorganisms; and (2) Anaerobically digested kitchen waste. For comparison, a commercial mineral fertilizer was used. These methods were applied in two separate glasshouse experiments: one under cool (mainly winter) conditions (X–IV) and one under warm (mainly summer) conditions (VI–X) consisting of 3–4 subsequent harvests in northern Poland. Comparing the food waste agronomic performance after anaerobic digestion and effective microorganism treatments, especially under different climatic conditions, is a novel approach. Kitchen waste served as a much better fertilizer than mineral fertilizer, but only during the cool season. In addition, it provided 20–40% more plant yields for dosages >120 kg N/ha and a similar N uptake. In the warm season, in comparison to effective microorganism-incubated kitchen waste, its anaerobic digestion improved the relative agronomic effectiveness twice after 30 days of growth (82% versus 43%). However, the total effectiveness for anaerobically digested kitchen waste versus pelleted and effective microorganism-incubated kitchen waste was 32% versus 27% (N utilization-wise) and 36% versus 21% (plant biomass yield-wise). The Monod kinetic model was applied for the internal efficiency of N utilization; for the best fitting procedure, R² > 0.96 for the cool season and R² > 0.92 for the warm season. Kitchen waste introduced to the soil provided better soil properties than mineral fertilizer. The study contributes to the biological systems for waste recycling in agriculture, bioproduction processes, and the global food chain. Full article

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21 pages, 1046 KiB

Open AccessArticle

Development of Sustainability Assessment Criteria in Selection of Municipal Solid Waste Treatment Technology in Developing Countries: A Case of Ho Chi Minh City, Vietnam

by Phuong Giang Le, Hung Anh Le, Xuan Thang Dinh and Kieu Lan Phuong Nguyen

Sustainability 2023, 15(10), 7917; https://doi.org/10.3390/su15107917 - 11 May 2023

Cited by 4 | Viewed by 2649

Abstract

Municipal solid waste (MSW) management is a significant problem for developing countries due to lack of sufficient infrastructure, poor management capacity, and low level of waste treatment technology. This study proposes three main groups of criteria, i.e., social, economic, and environmental, that can [...] Read more.

Municipal solid waste (MSW) management is a significant problem for developing countries due to lack of sufficient infrastructure, poor management capacity, and low level of waste treatment technology. This study proposes three main groups of criteria, i.e., social, economic, and environmental, that can be used as an effective tool to assess the sustainability of MSW treatment technologies, considering Ho Chi Minh City, Vietnam as a case study. The sustainability assessment criteria consist of a list of indicators which consider potential waste treatment plants. The indicators and technologies then undertake a selection process from identifying assessment goals and key aspects to data collection and consultation of experts. The findings from the previous phase will be used to select the most preferred waste technology through AHP and normalization approaches. As a result, 12 selected indicators are as follows: investment cost, treatment cost, operation and maintenance costs, revenue/benefits, job creation, community consensus, support policy, community health, air pollution, water pollution, greenhouse gas emissions, and land quota. Among three MSW facilities selected, i.e., landfill, compost, and waste-to-energy incineration, waste-to-energy is determined as the best alternative solution for Ho Chi Minh City in a given context of approximate 70% of landfilling being applied. The selection process and indicators found can guide decision-makers and policy on selecting MSW treatment technologies in developing countries. Additionally, Ho Chi Minh City’s governors benefit from finding the most appropriate waste technology. A technology adoption roadmap and its implementation plan should be thought thoroughly to address challenges in MSW management in the city. Full article

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16 pages, 6912 KiB

Open AccessArticle

Improving the Degradation Kinetics of Industrial Dyes with Chitosan/TiO₂/Glycerol Films for the Sustainable Recovery of Chitosan from Waste Streams

by Nhung T. Tuyet Hoang and D. Duc Nguyen

Sustainability 2023, 15(8), 6979; https://doi.org/10.3390/su15086979 - 21 Apr 2023

Cited by 2 | Viewed by 1829

Abstract

This study investigates the potential of a combined photocatalysis–adsorption approach to effectively degrade near wash yellow (NWY), a commonly used and highly persistent dye in the textile industry, notorious for its challenging treatment and removal from wastewater due to its colorfastness. A chitosan–glycerol [...] Read more.

This study investigates the potential of a combined photocatalysis–adsorption approach to effectively degrade near wash yellow (NWY), a commonly used and highly persistent dye in the textile industry, notorious for its challenging treatment and removal from wastewater due to its colorfastness. A chitosan–glycerol (CTiG) film combined with titanium dioxide was examined in both batch and continuous-flow experiments under visible solar irradiation. The results show that this combination was more effective than a pure chitosan film (60%) or chitosan–glycerol film (63%), with up to 83% degradation of NWY achieved in just 60 min of visible solar irradiation. The kinetics of the film were evaluated using both pseudo-first-order and Langmuir–Hinshelwood kinetic models. The rate constant values (k, min⁻¹) decreased with increasing NWY concentration from 20 to 80 mg/L, and k was found to be greater than twice as high under visible solar irradiation as it was in the dark. The Langmuir–Hinshelwood model’s K_LH (reaction rate constant) and K_L (adsorption coefficient) values were 0.029 mg/L·min and 0.019 L/mg, respectively. The optimal conditions for NWY degradation were found to be 4% TiO₂ to chitosan ratio, glycerol/chitosan ratio of 40%, and a pH of 7. In the continuous-flow model, the CTiG film was submerged in an 8 L NWY solution (80 mg/L) and degraded at a rate of 22.6 mg NWY/g film under natural sunlight. This study contributes to the development of effective and sustainable methods for the degradation of dyes from textile industry wastewater. Full article

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