Waste management outlook for mountain regions: Sources and solutions

The use of artificial intelligence algorithms to detect macroplastics in aquatic environments: A critical review

The presence of macroplastic (MP) is having serious consequences on natural ecosystems, directly affecting biota and human wellbeing. Given this scenario, estimating MPs' abundance is crucial for assessing the issue and formulating effective waste management strategies. In this context, the main objective of this critical review is to analyze the use of machine learning (ML) techniques, with a particular interest in deep learning (DL) approaches, to detect, classify and quantify MPs in aquatic environments, supported by datasets such as satellite or aerial images and video recordings taken by unmanned aerial vehicles. This article provides a concise overview of artificial intelligence concepts, followed by a bibliometric analysis and a critical review. The search methodology aimed to categorize the scientific contributions through temporal and spatial criteria for bibliometric analysis, whereas the critical review was based on generating homogeneous groups according to the complexity of ML and DL methods, as well as the type of dataset. In light of the review carried out, classical ML techniques, such as random forest or support vector machines, showed robustness in MPs detection. However, it seems that achieving optimal efficiencies in multiclass classification is a limitation for these methods. Consequently, more advanced techniques such as DL approaches are taking the lead for the detection and multiclass classification of MPs. A series of architectures based on convolutional neural networks, and the use of complex pre-trained models through the transfer learning, are currently being explored (e.g., VGG16 and YOLO models), although currently the computational expense is high due to the need for processing large volumes of data. Additionally, there seems to be a trend towards detecting smaller plastic, which need higher resolution images. Finally, it is important to stress that since 2020 there has been a significant increase in scientific research focusing on transformer-based architectures for object detection. Although this can be considered the current state of the art, no studies have been identified that utilize these architectures for MP detection.

Overview of municipal solid waste management in sub-tropical climatic region of North Eastern India

Municipal solid waste management (MSWM) is perceived as a global issue regardless of the place of waste generation. The amount of unmanaged waste is increasing rapidly, along with its impact on the environment and human health. In hilly areas, specifically the North Eastern Region (NER) states of India, due to the unique topography coupled with socio-economic factors, there are inadequate waste management practices marked by insufficient infrastructure, minimal research studies, and limited data availability. This paper comprehensively reviews the existing status of MSWM practices and waste treatment technologies, identifies the challenges, and discusses the prospective approaches for MSWM in NER states of India. NER, is characterized by its hilly terrain and has the most diverse demographic profile in the country. The study highlights the notable increase in waste generation in the urban population in NER. The total amount of waste generated in NER is about 2907 tons per day, with a collection rate of 86.96%, treatment at 31.09%, and landfilling at 33.67%. The biodegradable fraction makes up the majority of waste composition (more than 50%) in NER, followed by recyclables and inert. The existing MSWM consists of waste collection, transportation, and disposal with limited source segregation and treatment. All the states of NER practice open dumping and burning as the primary waste treatment and disposal system. The study discusses the challenges and prospects to ensure effective MSWM in NER. This review is a region-specific study that considers cultural diversity, topography, and socio-economic dynamics. The outcome of this review will be helpful to the researchers and policymakers in making appropriate waste management plans and improve the MSWM system in NER.

Characterization for optimizing the integrated management of solid waste for energy recovery and circular economy

Municipal solid waste (MSW) management poses a significant environmental challenge in municipalities across developing nations worldwide. Our studies were focused on characterizing the waste and analyzing the chemical properties of mixed waste fractions to assess their potential for waste-to-energy conversion. The objective of our study was to scrutinize the existing state of the MSW management system and gauge its waste generation rates. Specific ASTM methods were employed to carry out both physical and chemical characterizations. The outcomes reveal that the city generates a daily volume of 1155 tons of domestic solid waste (DSW), translating to a generation rate of 0.51 kg-1 capita-1 day-1. When analyzed by source, organic matter emerged as the predominant constituent, accounting for 73.74% of the waste, followed by combustible content waste at 15.17%. The moisture content of MSW ranged between 26 and 58% throughout the seasons, while volatile solids varied from 22.35 to 99.74%. Among the components screened, carbon and oxygen stood out as the dominant elements. The calorific values encompassed a broad range, ranging from 14.87 MJ kg-1 for leather waste to a substantial 25,629.27 MJ kg-1 for organic waste. To alleviate the escalating burden of increasing solid waste generation, alternative treatment approaches were recommended. These include composting, biomethane plants, the establishment of recycling facilities, and the enhancement of existing landfill sites to scientifically designed landfills. In summary, the findings from this study provide valuable insights for regulatory bodies and municipal authorities. These insights can guide the formulation of policies concerning waste sampling, characterization, segregation, and the implementation of education and awareness campaigns.

Determinants of quantification of tourism waste in the hilly terrain of Himalayas: A spatial approach

The rapid economic development in environmentally sensitive zone of Himalayas resulted in the increased generation of tourism waste. However, the accounting methodology for accumulation of tourism waste in the hilly terrain was found to be missing. Accordingly, the socio-economic factors influencing the tourism waste generation were identified, and their correlation analysis was performed. The tourism waste generated within and outside an urban local body was quantified over a period of 12 years (2008-2019) using a novel methodology, considering the socioeconomic factors, such as economic significance, geographical terrain, location of tourist destinations and tourism-related activities. The spatial dependency of tourism waste accumulation in the Himalayan state of Himachal Pradesh, India was analyzed using the geographically weighted regression. Furthermore, the air pollutants' emission (PM_2.5, PM₁₀, CO, SO₂ and NO_x) from the open burning of neglected tourism waste were also quantified and compared with the existing literature.

Microplastic pollution in mountain terrains and foothills: A review on source, extraction, and distribution of microplastics in remote areas

Microplastic (MP) pollution is a critical environmental concern that exists within different mountain ecosystem compartments. This review paper highlights the source, sampling, distribution, and behavior of MPs in mountain terrains and foothills. Atmospheric transport and tourism are major sources of MP pollution in mountain ecosystems. Snow samples provide the maximum concentration of MPs compared to that of stream or ice core samples. Precipitation events considerably influence MP deposition and fallout in mountains and glaciers. PE, PP, PS, polyester, and PVC are common plastic polymers with diverse shapes, such as fibers, fragments, films, and pellets. Ecological concerns and stress due to MP accumulated in natural ecosystems have also been discussed, with considerable focus on MP transport and distribution dynamics at higher altitudes as prospects for future research. A remarkable knowledge gap was observed regarding the MP pathways in the mountainous ecosystems and the assessment of microplastic-associated additives, such as heavy metals and other toxic chemicals, including the evidence of nano-sized plastics. Furthermore, studies on the ecological and biological risks posed by MPs on remote mountains is severely limited with respect to global climate change, biodiversity loss, and influence on ecosystem services.

Factors of variability in the accumulation of waste in a mountain region of southern Poland

The analysis of change factors in waste management in the period from 2012 to 2015 in three municipalities in a mountainous region of southern Poland exhibited strong differentiation. This was recognised based on multiple indicators of waste accumulation. Such differences were investigated between two periods, which highlighted the effect of changes in waste management primarily resulting from Directive 2008/98/EC. These changes relate to the development of selective waste collection based on eight types of waste. On this basis, an increase was observed in the amount of waste collected in the communities. Particular attention was paid to the community with the highest number of tourists, the waste accumulation rate (452.74 kg per capita) and the cost per year. An increase in the number of tourists is an important factor in terms of waste accumulation, and other factors made it possible to recognise the direction of the changes taking place in waste management. In terms of changes in waste accumulation, the implementation of the European Union law into the national law in the field of waste management is a significant factor.

Role of Waste Collection Efficiency in Providing a Cleaner Rural Environment

The exposure of rural communities to illegal waste dumping practices associated with the lack of or poor waste collection schemes prior to the closure of rural dumpsites under EU regulations and the role of collection efficiency afterward in reducing this critical environmental threat constitutes a key issue in rural Romania. The present study reveals huge amounts of household uncollected waste released into the natural environment outside the official statistics of rural dumpsites. Despite the expansion of waste collection coverage towards rural areas since 2010, the problem of illegal dumping practice is difficult to solve. The improvement of collection efficiency, better law enforcement, and surveillance of environmental authorities coupled with educational and environmental awareness are necessary steps to combat this bad practice. A circular economy paradigm must be enacted in rural regions through separate collection schemes and to improve cost-efficient alternatives, such as home composting, and traditional and creative reuse practices, particularly in less developed regions.

Effective incineration of fuel-waste slurries from several related industries

This study is based on the analysis of a set of industrial sectors (coal processing, wood processing, transport, oil, and water treatment) in order to identify the amount and type of combustible waste suitable for incineration. The main ignition and combustion parameters of these wastes have been experimentally obtained from their direct individual incineration in the original form and as part of a slurry based on wastewater. It has been established that a set of parameters allow waste-derived fuel mixtures to compete with coal dust and fuel oil with an environmental advantage. In particular, the concentration of sulfur and nitrogen oxides in the combustion products of all the tested slurries is 1.5-3 times as low as that of coal dust. Most of the wastes in question do not provide such advantages when burnt individually. We have assessed the fire safety of fuel mixtures and analyzed the prospects of mass waste incineration technologies. The calculations show that about 14-20% of coal and oil can be saved annually by extensively involving industrial waste in the energy sector. The experimental results obtained are the basis for the development of useful technologies for the safe and efficient combustion of waste from different industries.

Rural plastic emissions into the largest mountain lake of the Eastern Carpathians

The lack of proper waste collection systems leads to plastic pollution in rivers in proximity to rural communities. This environmental threat is more widespread among mountain communities which are prone to frequent flash floods during the warm season. This paper estimates the amounts of plastic bottles dumped into the Izvoru Muntelui lake by upstream rural communities. The plastic pollution dimension between seasonal floods which affected the Bistrita catchment area during 2005-2012 is examined. The floods dumped over 290 tonnes of plastic bottles into the lake. Various scenarios are tested in order to explain each amount of plastic waste collected by local authorities during sanitation activities. The results show that rural municipalities are responsible for 85.51% of total plastic bottles collected during 2005-2010. The source of plastic pollution is mainly local. The major floods of July 2008 and June 2010 collected most of the plastic bottles scattered across the Bistrita river catchment (56 villages) and dumped them into the lake. These comparisons validate the proposed method as a reliable tool in the assessment process of river plastic pollution, which may also be applied in other geographical areas. Tourism and leisure activities are also found to be responsible for plastic pollution in the study area. A new regional integrated waste management system should improve the waste collection services across rural municipalities at the county level when it is fully operational. This paper demonstrates that rural communities are significant contributors of plastics into water bodies.