Abstract

Microplastics pose a severe threat to marine ecosystems; however, relevant mathematical modeling and analysis are lacking. This paper formulates two stoichiometric producer-grazer models to investigate the interactive effects of microplastics, nutrients, and light on population dynamics under different settings. One model incorporates optimal microplastic uptake and foraging behavior based on nutrient availability for natural settings, while the other model does not include foraging in laboratory settings. We establish the well-posedness of the models and examine their long-term behaviors. Our results reveal that in natural environments, producers and grazers exhibit higher sensitivity to microplastics, and the system may demonstrate bistability or tristability. Moreover, the influences of microplastics, nutrients, and light intensity are highly intertwined. The presence of microplastics amplifies the constraints on grazer growth related to food quality and quantity imposed by extreme light intensities, while elevated phosphorus input enhances the system’s resistance to intense light conditions. Furthermore, higher environmental microplastic levels do not always imply elevated microplastic body burdens in organisms, as organisms are also influenced by nutrients and light. We also find that grazers are more vulnerable to microplastics, compared to producers. If producers can utilize microplastics for growth, the system displays significantly greater resilience to microplastics.

Introduction

Plastic pollution has steadily increased due to widespread plastic use, insufficient disposal practices, and limited waste management capacity over decades. Plastic wastes discharged into terrestrial and aquatic habitats are considered a serious threat to biodiversity, due to their resistance to decomposition (Gall and Thompson, 2015, Carbery et al., 2018). The small plastic particles, ranging from 0.1 to 5 mm in size, are called microplastics (EFSA Panel on Contaminants in the Food Chain (CONTAM), 2016). Microplastics are observed almost in all aquatic habitats (Eerkes-Medrano et al., 2015, Peeken et al., 2018). Chronic exposure to microplastics presents several challenges for aquatic organisms (Cui et al., 2017, Duis and Coors, 2016, Nolte et al., 2017, Zhang et al., 2017, Khoironi et al., 2019, Sjollema et al., 2016, Besseling et al., 2014).

Studies have shown that microplastics can be absorbed, concentrated, and transported into various organisms, such as algae. This process significantly hampers algal growth, chlorophyll levels, and photosynthetic activity (Cao et al., 2022, Liu et al., 2019, Chae et al., 2019, Wu et al., 2021, Jiao et al., 2022, Gray and Weinstein, 2017, Zhang et al., 2017, Sjollema et al., 2016, Yang et al., 2020, Ferguson, 2011, Wang et al., 2020, Khoironi et al., 2019, Rodrigues et al., 2019, Salman et al., 2016). This inhibition may occur due to physical factors, such as the blockage of light and airflow (Bhattacharya et al., 2010, Wang et al., 2020, Salman et al., 2016, Bhattacharya et al., 2010), or interactions between microplastics and algae, including adsorption, aggregation (Zhang et al., 2017), and the destruction of algal cell walls through surface absorption (Liu et al., 2019). However, it is worth noting that some laboratory studies suggest that certain algae species may increase in the presence of smaller-sized microplastics, possibly because microplastic particles can be utilized as substrates for the growth of algae (Yokota et al., 2017, Mao et al., 2018, Jiao et al., 2022, Canniff and Hoang, 2018).

Discussion

Microplastics can be mistakenly ingested or adhere to the surfaces of marine organisms, resulting in significant adverse effects (Zhang et al., 2017, Liu et al., 2019, Sazli et al., 2023, Gregory, 1996, Derraik, 2002, Blarer and Burkhardt-Holm, 2016, Alomar et al., 2017). This paper presents two stoichiometric models to investigate population dynamics in the presence of microplastics in both field and laboratory settings. The interactive effects of light, nutrients, and microplastics on population dynamics have been rigorously studied.

For natural ecosystems, the OMUF model reveals complex dynamics. When the microplastic concentration is relatively low, the behavior of the system is strongly influenced by the initial conditions and can exhibit bistability or tristability. Conversely, when microplastics in the environment become excessively abundant, the only outcome is the extinction of grazers. Furthermore, the tolerance to microplastics of the producer-grazer system described in OMUF model (3.5) is significantly lower, compared to that of the system defined in NM model (2.11). This discrepancy potentially arises from the fact that in the natural ecosystem, grazers have to face more challenges and pay significant feeding costs, such as food scarcity, nutrient deficiencies, predation risk, multiple toxins, and human impact, making them more susceptible to microplastics.

Extreme light condition, either too low or too high, restricts the growth of grazers. When light intensity is excessively low, producers can only survive at low densities due to weakened photosynthesis, and grazers go extinct because of insufficient food. When light intensity is excessively high, the P:C ratio in producers becomes very low, and grazers go extinct due to nutrient deficiency. However, when light intensity falls within a moderate range, coexistence of both species may occur, and the system demonstrates a greater ability to withstand microplastics.

Abstract

Recycling of abandoned waste bottom ash has been a key issue in Republic of Korea in terms of environmental protection as well as economic concern. In this work, a method for recycling of abandoned bottom ash has been discussed based on the results from laboratory and industrial-scale experiments. Abandoned bottom ash was magnetically separated and properties of magnetically separated bottom ash samples as well as properties of mortar and masonry cement brick made of bottom ash were investigated. According to the experimental results, bulk and skeletal densities were ranked in the order of strongly magnetic > weakly magnetic > as-received > non-magnetic (from heavier to lighter) bottom ash. From laboratory-scale experiments, compressive strengths of mortars made of bottom ash samples (measured by ASTM C 109) were lower than that of mortar made of standard sand. Among bottom ash samples, mortar made of non-magnetic bottom ash (after removal of unburnt carbon) showed higher compressive strength with lower thermal conductivity (measured by ASTM C 1113) and weight than others. Masonry cement brick made of magnetic bottom ash showed lower weight and thermal conductivity than those made of standard sand, while meeting the KS strength guideline as a masonry cement brick. The results suggest the applicability of bottom ash as lightweight aggregate for production of masonry cement brick. However, considering the lower strength obtained from masonry cement brick made of as-received bottom ash (without removal of unburnt carbon), unburnt carbon content should be removed prior to its utilization as lightweight aggregate.

Introduction

Consumption of fossil fuels for operation of coal fired power plant has been consistently increasing all over the world (International Energy Agency, 2009; Korre et al., 2010; Leblond, 2006; Shafiee & Topal, 2008). Although reduction in CO2 emission is very critical issue in this industry (Hussain et al., 2022), recycling of waste by-products is as important issue as the reduction of CO2 emission in terms of environmental protection (Abbas et al., 2020; Bui et al., 2019; Lee et al., 2020; Meek et al., 2021; Oakes et al., 2019) considering the amount of waste that has been generated so far. Approximately 730 million tons of bottom ash (Abbas et al., 2020) and 600 million tons of fly ash (Çiçek & Çinçin, 2015; Nyale et al., 2013) are annually produced in the world. Although fly ash has been successfully utilized as a supplementary cementitious material due to its beneficial properties such as reduction in the heat of hydration (Atiş, 2002a, 2002b; Langan et al., 2002; Matos et al., 2020; Nocuń-Wczelik, 2001; Schindler & Folliard, 2005), improvement in workability (Atiş, 2002b; Leung et al., 2016; Nocuń-Wczelik, 2001; Uysal et al., 2012; Yao et al., 2015), and long-term strength and durability (Pala et al., 2007; Siddique, 2003; Tikalsky et al., 1988), most of the bottom ash has not been recycled and abandoned in the waste storage site.

The utilization of bottom ash as a supplementary cementitious material has been limited. The chemical compositions of bottom ash are similar to that of fly ash. However, the particle size is larger and the structure is more crystalline than fly ash. For this reason, the pozzolanic activity of bottom ash is very weak. The work of (Cheriaf et al., 1999) showed that bottom ash did not react with calcium hydroxide at early ages. The pozzolanic activity was very slow until 28 days, and became accelerated after 90 days. Jurič et al. (Jurič et al., 2006) recommended to replace up to 15 wt% of cement by bottom ash to use it as a supplementary cementitious material. Kula et al. (Kula et al., 2002) showed that bottom ash can be used as a supplementary cementitious material depending on its particle size distribution. Jaturapitakkul et al. (Jaturapitakkul & Cheerarot, 2003) observed a glassy aluminosilicate phase (diffused halo maxima) at 20–27° 2θ (Cheriaf et al., 1999; Chindaprasirt et al., 2009) that can be a source of pozzolanic reaction, but reported that the pozzolanic activity of bottom ash can be increased by grinding the particle size lower than 45 μm. According to the literature, pozzolanic activity of bottom ash was so slow or weak that it cannot be effectively utilized as a supplementary cementitious material without additional mechanical or chemical treatment (Filipponi et al., 2003; Liu et al., 2018; Mangi et al., 2018).

Conclusion

In this work, magnetic separation was applied on bottom ash that was stored in the pond site of Hadong coal fired power plant. Properties of magnetically separated bottom ash were analyzed, mortar specimens as well as masonry cement brick samples were prepared, and compressive strength, water absorption, and thermal conductivity were measured. According to the results obtained from this work, following conclusions can be drawn.

1) Magnetic separation with 1000 and 3000 gauss magnet was effective for separating bottom ash samples that contains higher amount of magnetite. As a result, bulk and skeletal density of strongly magnetic bottom ash were higher than those of as-received bottom ash. Non-magnetic bottom ash showed the lowest bulk and skeletal density.

2) Pozzolanic activity of bottom ash was ranged 53 ~ 62% of fly ash that was stored at the same pond site. Considering the particle agglomeration observed from the fly ash, it is possible to evaluate the pozzolanic activity of bottom ash either as non-pozzolanic or as very weakly pozzolanic.

3) From laboratory scale experiments, non-magnetic bottom ash showed the better performance than strongly magnetic bottom ash in terms of compressive strength and thermal conductivity. Since large amount of unburnt carbon stayed together with non-magnetic bottom ash, removal of unburnt carbon is a key factor for successful utilization of non-magnetic bottom ash.

4) Masonry cement brick made of magnetic bottom ash showed 40% reduction in unit weight, 20% reduction in thermal conductivity. Utilization of non-magnetic bottom ash for masonry cement brick production after removal of unburnt carbon can also be a successful application, considering the results from laboratory-scale experiments (density and thermal conductivity was lower for non-magnetic bottom ash).

Abstract

     Globally, to ensure food security bio-based fertilizers must replace a percentage of chemical fertilizers. Such replacement must be deemed sustainable from agronomic and greenhouse gas (GHG) emission perspectives. For agronomic performance several controlled protocols are in place but not for testing GHG emissions. Herein, a pre-screening tool is presented to examine GHG emissions from bio-waste as fertilizers. The various treatments examined are as follows: soil with added mineral nitrogen (N, 140 kg N ha−1) fertilizer (MF), the same amount of MF combined with dairy processing sludge (DS), sludge-derived biochar produced at 450 °C (BC450) and 700 °C (BC700) and untreated control (CK). These treatments were combined with Danish (sandy loam) or Irish (clay loam) soils, with carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) emissions and soil inorganic-N contents measured on selected days. During the incubation, biochar mitigated N2O emissions by regulating denitrification. BC450 reduced N2O emissions from Danish soil by 95.5% and BC700 by 97.7% compared to emissions with the sludge application, and for Irish soil, the N2O reductions were 93.6% and 32.3%, respectively. For both soils, biochar reduced CO2 emissions by 50% as compared to the sludge. The lower N2O reduction potential of BC700 for Irish soil could be due to the high soil organic carbon and clay content and pyrolysis temperature. For the same reasons emissions of N2O and CO2 from Irish soil were significantly higher than from Danish soil. The temporal variation in N2O emissions was correlated with soil inorganic-N contents. The CH4 emissions across treatments were not significantly different. This study developed a simple and cost-effective pre-screening method to evaluate the GHG emission potential of new bio-waste before its field application and guide the development of national emission inventories, towards achieving the goals of circular economy and the European Green Deal.

Introduction

     Agricultural sources of greenhouse gas (GHG) emissions crucially influence climate change. During the period from 2007 to 2016, GHG emissions from agriculture, forestry and land use contributed about 23% of total net anthropogenic emissions, and emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) from agriculture accounted for 13%, 44% and 81% of the anthropogenic emissions, respectively (IPCC et al., 2019). In November 2016 the legally binding international treaty on climate change called the Paris Agreement was adopted by 195 Parties. The key messages of the Paris Agreement include 1) limiting global warming to well below 2 °C, preferably to 1.5 °C, compared to pre-industrial levels; 2) establishing climate resilience and mitigating GHG emissions without threatening food production; and 3) aligning financial flows with pathways for low GHG emissions and climate-resilient development (UNFCCC, 2015). Therefore, the reduction of GHG emissions from agricultural soils with new effective mitigation strategies within the framework of the Paris Agreement becomes vital for the achievement of global warming reduction goals.

Conclusions

     Addition of biochar from pyrolysis of dairy sludge (DS) to soils together with mineral N fertilizer instead of directly adding DS, substantially reduced emissions of N2O to a level near that of untreated soil. Biochar pyrolyzed at 450 °C (BC450) reduced emissions of N2O by 95.5% and CO2 by 59.4% when applied to a Danish sandy loam soil (DA), and from an Irish clay loam soil (IR), emissions were reduced by 93.6% and 57.1%, respectively. Biochar from 700 °C pyrolysis (BC700) suppressed 97.7% and 49.7% of N2O and CO2 emissions from DA soil, and 32.3% and 62.4% from IR soil. Biochar shows no effect on CH4 emissions. Pyrolysis conditions and soil properties significantly affect the suppression of N2O emissions by biochar. This study provides a simple and cost-effective tool to examine the GHG emission potential of bio-waste before applying it in agricultural lands and helps in developing national emission inventories.

Abstract

     This work suggests an optimal strategy to sort and recycle plastic waste as a renewable energy resource with maximizing economic feasibility and mitigating environmental pollution. To derive the optimal sorting and recycling strategies of plastic waste, a novel optimization model is developed; it calculates the overall profit by subtracting the profit of recycling plastic from the total annualized cost. Then the model is used to identify the optimal strategy to sort and recycle plastic waste as a renewable energy resource in mixed-integer nonlinear programming that maximizes the overall profit. In the derived optimal sorting and recycling strategy, high-density polyethylene is recycled to produce downgrade plastic; low-density polyethylene, polypropylene, and polystyrene are recycled as pyrolysis oil; and polyethylene terephthalate is recycled to produce refuse plastic fuel. The derived optimal case can significantly increase the overall profit by about 3,137% (i.e., 35 US$/1 kg of recycled plastic), and 492% (i.e., 29 US$/1 kg of recycled plastic) compared to conventional case in South Korea and Japan respectively.

Introduction

     The demand for plastics has rapidly increased in many industries because of their versatility, and easy production. Consequently, plastic waste is discharged in massive quantities; estimates of plastic waste discharged into rivers, lakes, and seas is 9–23 million t per year globally (Borrelle et al., 2020; Masuda et al., 2001). Thus, the importance of plastic waste recycling is increasing (Shah et al., 2015; Zhang et al., 2020). Plastic waste is a mixture of different types, so it must be sorted into before it is recycled (Gundupalli et al., 2017; Hearn and Ballard, 2005; Lim and Cho, 2003). Economically-viable sorting and recycling of plastic will yield a cheap and abundant source of valuable chemicals and renewable energy (Gadaleta et al., 2020). However, current systems to sort and recycle plastic waste are not optimized, so their costs are high. Thus, only 27.2 wt% of plastic waste is recycled, whereas 36.4 wt% is landfilled, and 36.4 wt% is incinerated (Vieira et al., 2022). Therefore, the soil and air pollution according to the landfilled plastic and the significant amount of SOx, NOx, and CO2 emitted in the incineration of waste plastic is serious. The types of recycled plastic have different uses depending on the product (e.g., downgrade plastic, pyrolysis oil, and refuse plastic fuel) that is produced (Kim et al., 2020; Krauklis et al., 2021; Shaha et al., 2020; Yaqoob et al., 2021). Methods to recycle plastic waste are classified into material, chemical, and thermal types (Zhuo and Levendis, 2014). They have very different capital and operating costs according to the throughput of the plastic waste of each method (Huang et al., 2002). Therefore, to improve plastic waste recycling, it is crucial to derive optimal sorting and recycling strategy for plastic waste that indicate which plastics will be sorted to be recycled and how the plastic will be recycled according to each recycling method considering economic feasibility.

Conclusion

     This study found an optimal strategy to sort and recycle plastic waste as a renewable energy resource for maximizing economic feasibility and mitigation of environmental pollution caused by landfilled plastic and air pollutants according to incineration of plastic. This study makes two major contributions to the literature. First, to the best of the author’s knowledge, it is the first attempt to optimize the plastic waste sorting and recycling system by deriving an optimal sorting and recycling strategy to improve the recycling of for plastic waste as a renewable energy resource maximizing economic feasibility and mitigating of environmental pollution. Also, the results allow us to increase the recycling of plastic waste by maximizing the overall profit of the plastic waste sorting and recycling system. In the derived optimal sorting and recycling strategy, HDPE is recycled to produce downgrade plastic; LDPE, PP and PS are recycled as pyrolysis oil; and PET is recycled to produce refuse plastic fuel. The derived optimal case can increase overall profit by ∼ 3,137% compared to CCS, and 492% compared to CCJ, and also emission of air pollutants. Thus, this study provides valuable insight into the many recycling industries of waste plastics to achieve clean production, cost-effectiveness, and environmental protection. In many literatures, strategies such as operating condition optimization were proposed to reduce the cost of each sorting method. Thus, in further study, it is crucial to consider the detailed proposed strategies in deriving the optimal solution to maximize economic feasibility.

Abstract

This study aims to examine the effect of the environmental accounting strategy on sustainability performance and explore waste management as a mediation between environmental accounting strategy and the sustainability performance of Micro, Small and Medium Enterprises (MSMEs). Research data was collected from 194 MSMEs in East Java Indonesia through online and offline questionnaires. The data analysis is performed with PLS-SEM. The results of the study found that the MSME’s environmental accounting strategy had an effect on sustainability performance, and it was proven that MSME’s waste management mediated the effect of environmental accounting strategy on MSME sustainability performance. The originality of this research is the development of research instruments, which combine from various sources from previous researchers, GRI standards and Indonesian Government Regulations so that they can contribute Environmental Management Accounting literature and practical contributions to MSMEs and related institutions in determining sustainability performance strategies. This research implication supports the goals of the Indonesian Government’s Sustainability Development Goals (SDGs) regarding SDGs Goal number 12 Responsible consumption and production. The government needs to establish a waste management policy to improve environmental problems. The implications of future research can collect larger data and can compare the MSMEs between emerging countries. Also, MSMEs need to establish strategic Environmental Accounting so that it has an impact on sustainability performance.

Introduction

Companies produce goods or services using raw materials and other materials in the production process. As a result, it impacts material waste, product, and packaging waste. The impact on economic sustainability can reduce sales and operating profits because consumers prefer environmentally friendly products. The impact on environmental sustainability not only can reduce environmental damage such as soil and water pollution and increased global warming but also decrease in employee welfare along with a decrease in operating profit.

Moreover, management’s understanding and knowledge of environmental accounting strategies and waste management are essential in achieving business sustainability in companies, including Micro, Small, and Medium Enterprises (MSMEs). The negative impacts of MSMEs include environmental pollution from production waste. As many as five industries are the biggest producers of B3 (Toxic Hazardous Materials) waste in Indonesia, namely: the metal, chemical, electricity, sugar, and paper industries. As stated by the Deputy Chairperson of Investment in East Java, Turino Junaidi, said that the amount of MSME waste is large, but the level of investment for the waste treatment industry is still small (www.kompasiana.com). For example, from 71 SMEs making tofu in Jombang, almost all of the soybean waste is disposed of together on village roads before finally being dumped into the river. As a result, it polluted the environment in three villages and even polluted surface water and well water. (www.jatim.kompas.tv/article/126221). Therefore, the environmental problems are mostly caused by the impact of economic and social activities of companies, including Micro, Small Medium Enterprises (MSMEs). Polluted water sources, polluted air, deforested forests, and global warming have damaged the environment. People’s awareness demands the importance of protecting environmentally friendly production processes and being concerned with business continuity than the short-term goal of profit.

Conclusion and implication of the research

Indonesia is concerned with Green Accounting because MSMEs waste is quite high and poor waste management. The East Java government has the second largest MSMEs in Indonesia and has a problem with industrial waste. However, it does not take maximum responsibility for product waste and an impact on low sustainability performance. This indicates the need for an Environmental Accounting strategy to support policies to minimize environmental costs related to environmental prevention costs for waste reduction employee training, environmental prevention costs for waste recycling training, environmental detection costs for environmentally friendly product inspection, internal failure costs for waste treatment and failure costs. external for cleaning polluted environment. This research implication supports the goals of the Indonesian Government’s Sustainability Development Goals (SDGs) regarding SDGs Goal number 12 Responsible consumption and production. The government needs to establish a waste management policy to improve environmental problems. Therefore all parties, namely: entrepreneurs including MSMEs, government, private sector, communities including financial institutions have the same responsibility to carry out activities and run a business with due regard to production that is responsible for the environment and society.

Abstract

     Circular economy approaches are commonly depicted by two cycles, where the biological cycle is associated with regeneration in the biosphere and the technical cycle with reuse, refurbishment, and recycling to maintain value and maximize material recovery. This work, instead, presents an alternative vision to the management of carbon-based materials that integrates the two cycles and enables the phasing-out of fossil carbon from the material system. The aim is to investigate the benefits and global potential of a co-recycling system, as an alternative to conventional recycling systems that separate biomass-based materials (e.g., wood, paper) from fossil-based materials (e.g., plastics). Thermochemical recycling technologies enable the conversion of carbon-based waste materials into high-quality synthetic products, promoting circularity and avoiding carbon losses such as carbon emissions and waste accumulation in landfills and nature. Here, the construction and analysis of co-recycling scenarios show how the deployment of thermochemical recycling technologies can decouple the material system from fossil resource extraction. Furthermore, energy use is reduced if pyrolysis and/or gasification are included in the portfolio of recycling technologies. In a decarbonized energy system, deployment of co-recycling can lead to near-zero carbon emissions, while in more carbon-intensive energy systems the choice of thermochemical recycling route is key to limiting carbon emissions.

Introduction

     Carbon-based fuels (mainly fossil fuels but also biomass) account for about 90% of the current global primary energy supply. Carbon is also a building block in a wide range of materials (carbon-based materials; C-materials) used in society. While fossil fuel use is the main cause of anthropogenic greenhouse gas (GHG) emissions, and a transition away from the use of such fuels is essential to limit the global temperature increase to 1.5 °C (IPCC et al., 2018), the production and use of materials such as plastics, cement and steel entail significant GHG emissions (IEA, 2018; Jambeck et al., 2015). The use of biomass-based products can effectively reduce the use of fossil fuels and GHG-intensive materials. There is also scope for substituting existing biobased products with more benign products. For example, cellulose-based textiles can replace cotton which is associated with soil and water depletion, as well as harmful impacts on human health and biodiversity due to excessive use of pesticides and fertilizers (IPCC et al., 2019c; Niinimäki et al., 2020). However, the biomass supply potential is limited by resource constraints (Gerten, 2018) and implications of expanded biomass use for mitigation and other objectives depend on many factors, including soil and climate conditions, biomass type, land management system, scale and pace of deployment, and influence on land use (Calvin et al., 2021). For instance, cropland expansion for energy crop production may cause deforestation, with consequent GHG emissions and negative impacts on biodiversity (IPCC et al., 2019b).

Conclusion

     A co-recycling scenario utilizing advanced thermochemical recycling is proposed and analyzed. The results show that such a scenario can combine natural and synthetic C-materials in the same recycling scheme and that enables to decoupling of the Carbon Material System from the extraction of fossil resources, as well as minimizing waste generation. Advanced thermochemical recycling enables the recovery of any carbon flow (CO2, natural or synthetic, losses, etc.) and the production of high-quality products. A focus on carbon recycling, instead of material recycling, can improve C-materials (wood, paper, plastics, and textiles) resource management, by increasing the resource utilization from 0.7 to 1.1 tC-material/tCRtM, i.e., producing more C-materials than resources used, as well as reducing the CMS losses by half.

Highlights

Abstract

Keywords

1. Introduction

2. Procedures and methods

3. Results

4. Discussion

5. Conclusion

Funding

Declaration of Interests

Acknowledgments

References

Abstract

Waste education modules were designed to tackle waste production. Knowledge acquisition, the promotion of individual sustainable attitudes combined with technology and science motivation are supposed the key players in achieving science citizenship. We assessed the identified parameters by monitoring the learning effect of fifth-graders, the Two Major Environmental Value scale (2-MEV), the Science Motivation scale (SMOT) as well as the Technology Questionnaire (TQ). Preservation correlated positively with knowledge acquisition, while Utilization correlated negatively. Moreover, intrinsic motivation correlated positively with pre-knowledge levels. Male students preferred the social implications of technology, as well as self-efficacy. Female students focused on appreciation of nature.

1. Introduction

In the wake of global environmental protection efforts, various waste management initiatives should help promote sustainability and tackle excessive waste production. The involvement of the younger generation is, thereby, crucial since individual waste management is believed to be based on social norms and self-perception [1,2]. Thus, education about the impact of waste on the environment and health at school is important [3], while initiatives that focus on public involvement in creating feasible solutions further contribute to overall sustainable waste management [4,5]. Students who took part in educational programs on waste management could share their expertise with families and friends [6], [7], [8]. Therein presented recent findings in science and technology [9] could be combined with environmental protection to highlight its timeliness and relevance while motivating students. This leads to the question as to how the motivation to learn natural sciences is connected to enthusiasm for technologies and the environment and if this connection expands to knowledge acquisition in environmental sciences in combination with topics such as waste recovery. The UNESCO’s charter on environmental education [10] highlighted awareness, attitudes, skills, and content knowledge as key components of individual environmental competences. In consequence, many instruments have been developed to investigate these predicted interrelationships. The refined instruments were used in this study and are described below.

1.1. Review on technology and environmental attitudes

Highlights

Abstract

Graphical abstract

Keywords

1. Introduction

2. Materials and methods

3. Results and discussions

4. Conclusion

Author contribution

Declaration of competing interest

Acknowledgement

Appendix A. Supplementary data

References

Abstract

During the Covid-19 pandemic, personal protection equipment (PPE) was widely used to control the virus further spared. In this study, the presence of PPE wastes along the coastline of Bushehr port, the Persian Gulf from nine stations was investigated (4 times during 40 days), and their potential for microplastics (MPs) creation was preliminarily assessed. In total, more than 2380 PPE were collected in the study area. No significant differences were found between various beaches regarding their types and common activities. In addition, the estimated disposal rate of PPE per day and year is 350 and 127,750 items, respectively. More than 10% of the collected PPE from Bushehr’s coastal areas on each sampling day were damaged. Based on the microscopic analysis, the left surgical masks and torn plastic gloves in the coastal regions are emerging sources of secondary microfibers and MP particles (mostly fragments and films) in the marine environments, respectively.

1. Introduction

During the last year, human beings have faced deadly infectious disease, and since March 2020, Covid-19 was declared as a pandemic by the World Health Organization (WHO) (Ducharme, 2020). Then, different measures have been used in different parts of the world, such as staying at home (lockdown), travel restriction, social distancing, washing of hands, surface disinfection, and isolation (Aragaw, 2020; Fadare and Okoffo, 2020; Rhee, 2020). Moreover, various personal protective equipment (PPE-i.e., face masks, gloves, face shields, alcohol spray) was used in different countries in order to control the virus further spared (De-la-Torre and Aragaw, 2021; Nowakowski et al., 2020). It is estimated that more than 129 billion face masks and 65 billion gloves have been used monthly all around the world (Prata et al., 2020). Discarded only 1% of these PPE exceeds ten million items (Celis et al., 2021) and can cause an environmental crisis.

Single-use face masks, N95 masks, gloves, and face shields are mainly produced from plastic polymers such as polypropylene, polystyrene, polyacrylonitrile, polyester, and polyurethane (Aragaw, 2020; Ardusso et al., 2021; Potluri and Needham, 2005; Sangkham, 2020). Most of the surgical masks have three layers: 1) an inner layer with soft fibers, 2) a middle layer with melt-gusted filter, and 3) an outer layer with nonwoven fibers which are usually colored and water-resistant (Aragaw, 2020; Fadare and Okoffo, 2020). Approximately the weight of polypropylene (PP) in a single N95 mask and surgical mask is 11 and 4.5 g, respectively (Abbasi et al., 2020; Liebsch, 2020). In addition, the most commonly single-use gloves are made of polyethylene (PE), latex, and nitrile (Nowakowski et al., 2020). Although these types of plastics can easily be recycled, they are usually mixed with other wastes or left in the environment (i.e., parks, beaches, forests) (Nowakowski et al., 2020).

Abstract

Keywords

1. Introduction

2. Framework and model formation

3. Computational experiments

3.1. Experimental data design

3.2. Results and discussion

4. Conclusion

Declaration of Competing Interest

Acknowledgements

References

Abstract

Generally, the activities of post-disaster waste management usually produce high carbon emissions, which can cause damage to the environment. However, the issue of carbon emissions in the post-disaster waste supply chain is neglected. Hence, this paper aims to propose a mixed-integer linear programming model to address the post-disaster waste processing supply chain network design problem with the consideration of a carbon tax policy. The proposed model is developed based on the concept of a mixed strategy of waste separation to reduce carbon emissions. Not only the carbon emission perspective but also the financial perspective for post-disaster waste supply chain management is determined in the objective function. The proposed model was verified and validated by employing a numerical example based on realistic data. Based on the numerical example, the results show that the implementation of a carbon tax policy with the mixed strategy for waste separation can reduce carbon emissions in the post-disaster waste supply chain efficiently.

1. Introduction

In a large-scale disaster, thousands of tonnes of mixed wastes are generated. The mixed waste is usually composed of building rubble, household materials, electrical appliances, a small amount of concrete, wood chips, plastics, glass, soil, sand, and so on [1]. The mixed waste is removed and disposed of after the disaster. Normally, the activities of mixed waste management involve waste collection, transfer, recycling, and disposal, all of which can produce CO2, causing damage to the environment, and can threaten the health of the disaster victims and workers in the affected area [2], [3]. According to Ritchie and Roser [4], the average annual growth rate of CO2 emissions was 30.36 billion tonnes from 1950 to 2017. In 2017, the world emitted 36.15 billion tonnes of CO2, while in 2000 the figure was 11.59 billion tonnes. Due to the issue of carbon emissions, CO2 emissions reduction has become an effective way to reduce the pressure on many countries [5]. Nowadays, several policies have been proposed to reduce CO2 emissions, such as carbon taxes, carbon caps, cap and trade, and so on [6], [7]. The Energy Information Administration stated that “the real constraint lies not in our ability to develop the necessary technologies but in our political will to deploy them” [8]. Nowadays, low-carbon supply chains are becoming more and more popular in many organizations. Many organizations usually apply carbon tax policies because this policy has been successful in many countries. However, consideration of a carbon tax policy in the post-disaster waste supply chain is still neglected. Most policymakers pay attention to the cost or time only [2], [9].

To reduce carbon emissions, the carbon tax policy in the post-disaster waste supply chain should be determined. Therefore, this paper aims to propose a mathematical model for post-disaster waste management with consideration of a carbon tax policy. The proposed mathematical model is developed based on the concept of a mixed strategy of waste separation (on-site and off-site separation) to reduce carbon emissions. Not only the carbon emissions but also the total cost for the post-disaster waste supply chain management is determined in the proposed model.

Highlights

Abstract

Graphical abstract

Keywords

1. Introduction

2. Methods used to conduct the mini-review

3. Composition of healthcare waste

4. Persistence rate of COVID-19 virus and its possible transmission through healthcare solid waste

5. Waste management strategies during the COVID-19 pandemic

6. Challenges

7. Potential for healthcare solid waste management strategies

8. Conclusions

Funding

Ethical approval

CRediT authorship contribution statement

Declaration of competing interest

Acknowledgments

References

Abstract

Healthcare waste comprises the waste generated by healthcare facilities, medical laboratories and biomedical research facilities. Improper treatment of this waste poses serious risks of disease transmission to waste pickers, waste workers, health workers, patients, and the community in general through exposure to infectious agents. Poor management of the waste emits harmful and deleterious contaminants into society. However, contamination of highly contagious agents such as the COVID-19 virus has created enormous instability in healthcare waste handling and subsequent recycling because of the volume of the waste generated and its contagious nature. Several countries have adopted safety measures to combat this contamination and manage healthcare waste; however, these measures are insufficient and vary depending on the context of the country. In addition, the WHO has set out guidelines for management of healthcare waste. These guidelines are helping to manage the highly contagious healthcare waste resulting from the current pandemic. Proper healthcare waste management may add value by reducing the spread of the COVID-19 virus and increasing the recyclability of materials instead of sending them to landfill. Disinfecting and sorting out healthcare waste facilitates sustainable management and allows their utilization for valuable purposes. This review discusses the different healthcare solid waste management strategies practiced in different countries, the challenges faced during this management, and the possible solutions for overcoming these challenges. It also provides useful insights into healthcare solid waste management scenarios during the COVID-19 pandemic and a possible way forward.

1. Introduction

After radiation waste, healthcare waste is considered the second most hazardous waste globally. It includes various forms of waste, both hazardous and non-hazardous, such as sharps, human body parts, blood, chemical waste, pharmaceutical waste, and medical devices (Rodriguez-Morales, 2013). All of this waste is produced mainly by hospitals, primary care facilities, laboratories, mortuaries, autopsy centers, laboratories, blood banks, nursing homes, and other medical locations (Pepin et al., 2014). It is generated during diagnosis, treatment, immunization of humans or animals, research, or the production or testing of biologicals. If not properly handled, it can have devastating effects on human health (Johannessen et al., 2000). During any infectious disease outbreak, the waste generated from healthcare facilities increases exponentially; as a result, special care must be taken by management in order to avoid troubling impacts (Ramteke and Sahu, 2020).

The outbreak of coronavirus disease 2019 (COVID-19) has arisen from the SARS-CoV-2 virus, which causes an acute respiratory disease (Mol and Caldas, 2020; WHO, 2019; WHO, 2020b); it was first reported in Wuhan, China (Wang et al., 2020) in December 2019. It has been acknowledged as a Public Health Emergency of International Concern (PHEIC) (Wilder-Smith and Osman, 2020), and the virus has spread to almost all countries across the globe. The pandemic continues to be a significant public health threat worldwide. The rapid increase in the number of COVID-19 infected patients and the highly transmissible nature of the disease have led to a high number of hospitalizations.