LIST OF ABBREVIATIONS AGRL Agricultural land AHP Analytical hierarchical process ANP Analytic network process Fuzzy AHP Fuzzy analytic hierarchy process GEOBIA Geographic object-based im
INTRODUCTION
Background of the study
The rapid pace of urbanization, population growth, and ongoing industrialization is placing significant pressure on the environment and is a major driving force behind the increasing generation of solid waste (Debrah et al., 2021; Nepal et al., 2022) Solid waste management (SWM) is recognized as a critical challenge in numerous countries, particularly within low- and middle-income economies (Abdel-Shafy & Mansour, 2018; Aparcana, 2017; Ziegler-Rodriguez et al., 2019) The environmental pollution situation has increasingly worsened due to the lack of sustainable solid waste management systems in these countries The growing “waste footprint” accelerates the spread of pollution, which not only directly affects the livelihoods and well-being of local communities but also exerts negative impacts on the natural environment and public health (Mostakim et al., 2021; Scarlat et al., 2015) Each year, humans generate between 2.1 and 2.3 billion tons of solid waste, and without timely intervention measures, this figure is projected to rise to 3.8 billion tons by 2050 (United Nation, 2024) The interplay between urbanisation, population growth, and industrial activities highlights the complexity of environmental challenges faced by the modern era Improper solid waste disposal can result in severe environmental consequences, causing not only ecosystem degradation but also adverse effects on human health
In particular, frontline workers at waste processing sites are exposed to higher risks due to frequent contact with pollutants and hazardous agents during waste handling, thereby prolonging and exacerbating these impacts (Shah et al., 2021; Siddiqua et al., 2022) Therefore, effective waste management, particularly the assessment and mitigation of negative impacts, is a prerequisite As the volume and diversity of waste continue to expand, treatment systems become increasingly complex, necessitating the simultaneous application of multiple approaches such as recycling, energy recovery through incineration, and safe landfill disposal (Amoah and Kursah, 2019) The sustainable development goals emphasize the importance of adopting sustainable waste treatment methods while promoting a transition towards a circular economy This shift aims to minimize negative environmental impacts and enhance human quality of life, not only in the present but also over the long term (United Nation, 2024) However, in the majority of low- and middle-income countries, solid waste collection and management systems remain suboptimal due to limitations in resources, infrastructure, and social awareness (Anuardo et al., 2022; Campitelli et al., 2022) The rapid increase in rural-to-urban migration driven by the pursuit of employment and improved living standards is exerting direct pressure on infrastructure systems while contributing to the growth of municipal solid waste generation (Wilson et al., 2013)
Numerous studies have identified various solid waste treatment methods, including composting, recycling, landfill disposal, and incineration Among these, sanitary landfilling remains a popular and effective option in low- and middle-income countries due to its feasibility and relatively low investment costs (Abdel-Shafy and Mansour, 2018; Mor and Ravindra, 2023) Effective management of waste landfill sites plays a crucial role in mitigating environmental pollution and protecting public health Traditionally, decision-making processes in waste management have often followed a top-down approach, where authorities make choices without adequately considering the perspectives of stakeholders such as businesses, communities, and non-governmental organizations (NGOs) Social acceptance is a key factor for sustainability in solid waste management planning Divergent interests among stakeholders frequently lead to conflicts in shaping management systems For instance, regulatory agencies may prioritize cost-saving solutions with minimal landfill volumes, while businesses aim to maximize profits and reduce operational costs
To manage solid waste effectively, it's important to find a middle ground between different interests by working together, especially including the community, since they are key to making sure waste management is truly sustainable Beyond social and economic challenges, technical considerations must also be accounted for It is important to note that solid waste landfilling must comply with regulations to ensure environmental safety Identifying suitable locations for landfill construction near waste generation sources remains a significant challenge (Mallick, 2021; Mvula et al., 2023) Moreover, a potential solid waste disposal area must consider multiple criteria, including hydrological, geographical, environmental resource, transportation, geomorphological, topographical, and settlement factors These considerations are essential for the rational management of solid waste and the minimisation of the impacts associated with waste disposal (Chandel et al., 2024).
Research rationale
• Scientific basis: This study contributes to improving approaches in geospatial data processing while analyzing socioeconomic factors, structural characteristics, morphology, and related activities to identify suitable locations for solid waste landfills The results of the research support the United Nations Sustainable Development Goal SGD-11.6.1, helping to improve solid waste management and planning in line with the development goals of Phu Yen province
• Practical basis: This study demonstrates the necessity of identifying appropriate landfill sites to enhance waste management efficiency in Phu Yen province Proper site selection contributes to minimizing environmental pollution and mitigating adverse impacts on human health and ecosystems The research employs an integrated method incorporating economic, environmental, topographical, and social factors to evaluate potential sites, ensuring a balanced consideration of elements influencing waste management processes This study provides a scientific foundation to support spatial organization and planning adjustments aligned with the province’s development goals, thereby contributing to the realization of sustainable development objectives in the region.
Research questions
This study aims to address the following questions:
• What factors contribute to increasing pressure on solid waste management systems in low- and middle-income countries?
• Which combined methods or models are suitable for comprehensively selecting solid waste landfill areas?
• How can geospatial technology be applied in landfill area selection to support solid waste management in Phu Yen Province and other low- and middle- income countries?
Research Aims and Objectives
• Objectives: To apply geospatial technology for selecting suitable areas for landfill activities supporting solid waste management in Phu Yen province, aiming to achieve the United Nations Sustainable Development Goal SDG-11.6.1
• Research aims: To fulfill the research objective, this thesis carries out the following main research tasks:
✓ Develop a theoretical framework on the application of geospatial technology in studying the impact of solid waste on the natural environment and human health;
✓ Investigate the scientific basis and select a comprehensive set of factors to evaluate potential solid waste landfill areas;
✓ Apply the multiple criteria decision analysis (MCDA) method combined with the fuzzy analytic hierarchy process (fuzzy AHP) to generate spatial distribution maps of suitable landfill areas;
✓ Analyze and assess potential landfill areas for sustainable waste management and development in Phu Yen Province, Vietnam, and other low- and middle-income countries.
Scope of this research
This thesis is limited to the following research scopes:
• Spatial scope: The empirical study is conducted in Phu Yen Province (Vietnam), covering mainland territory between the geographic coordinates of 12°42'36" to 13°41'28" North latitude and 108°40'40" to 109°27'47" East longitude, with a natural area of approximately 5,026 km²
• Temporal scope: Geospatial data were collected and used to develop spatial distribution maps of suitable landfill sites in Phu Yen Province for the period 2023-2024
• Scientific scope: The selection of appropriate solid waste landfill sites to replace outdated landfills is based on the analysis of economic, environmental, topographical, and social factors using geospatial technology as the primary research method.
Significance of Thesis
• Scientific significance: The research results contribute a scientific foundation to support spatial organization and planning adjustments aligned with Phu Yen Province’s development orientation, thus promoting the realization of sustainable development goals in the region
• Practical significance: The experimental outcomes concretize the theory of applying geospatial technology in mapping the spatial distribution of landfill sites Additionally, the study offers practical value by optimizing solid waste management processes toward sustainable development.
Structure of Thesis
The thesis is organized into five chapters Chapter 1 Introduces the research background, scientific basis, research questions, objectives, content, scope, and structure of the thesis
Chapter 2 Provides the theoretical foundation related to the research topic, including concepts of solid waste, its origin and characteristics, storage and disposal methods, management and recycling functions, geospatial approaches in integrated solid waste management, and a review of previous empirical studies
Chapter 3 focuses on research methodology, including the study area, data sources, and the methodological framework applied in the study Chapter 4 Presents and analyzes research results, discussing key findings Finally, Chapter 5 Summarises the main results, proposes relevant recommendations, and outlines directions for future research.
LITERATURE REVIEW
Conceptual definitions of solid waste
Solid waste can be defined as anything that is no longer of use or is no longer desirable There are various types of solid waste, including waste generated from urban and rural areas, industrial activities, and hazardous sources Among these, municipal solid waste is the most common, originating from households, commercial establishments, and institutions Industrial waste may be produced by factories, construction sites, or mining operations Hazardous waste, on the other hand, includes materials that pose a risk to human health or the environment, such as toxic chemicals, batteries, and medical waste Effective waste management plays a crucial role in protecting public health and the environment According to the resource conservation and recovery act (RCRA), "solid waste" is defined as any discarded material, including sludge from wastewater treatment plants, air pollution control facilities, and waste generated from industrial, commercial, mining, agricultural, and community activities (US EPA, 2016) Nearly all human activities result in some form of solid waste This waste can originate from a wide range of sources, including daily household activities Based on their origin, composition, and specific characteristics, solid wastes are classified into several categories Such classification supports more effective collection, treatment, and recycling processes, helping to minimize negative environmental impacts
Figure 2.1 Major categories of solid waste based on sources of generation
• Municipal solid waste: Municipal solid waste includes the everyday garbage generated by individual households and residential areas This category comprises paper, plastics, food scraps, textiles, packaging materials, garden waste, as well as some hazardous items such as batteries and cleaning products (Amasuomo and Baird, 2016)
• Industrial solid waste: The rapid expansion of industrial sectors has led to a significant increase in solid waste generated from manufacturing processes and industrial activities at factories and enterprises This type of waste comprises metal scraps, chemicals, solvents, sludge, and various by-products that are not classified as hazardous waste or regulated industrial waste (Amasuomo and Baird, 2016)
• Hazardous solid waste: Hazardous waste refers to types of waste that pose substantial risks to public health and the environment due to their toxic, flammable, explosive, or highly infectious properties (Amasuomo and Baird, 2016) Such waste is generated from a wide range of sources, including medical waste (e.g., syringes, surgical tools, biological samples), industrial waste (e.g., toxic chemicals, lubricants, batteries), radioactive waste (from nuclear research and energy production), and electronic waste
• Agricultural solid waste: Agricultural solid waste includes crop residues, animal manure, pesticides, and other waste materials generated from agricultural production activities (Amasuomo and Baird, 2016) The composition of this waste may vary depending on the type of crops, livestock, and cultivation methods Therefore, appropriate disposal measures must be applied to minimize adverse impacts on ecosystems and reduce environmental pollution
• Construction and demolition solid waste: This category of solid waste is generated from construction, renovation, and demolition activities It consists of a wide range of materials such as concrete, wood, bricks, metals, gypsum, and asphalt (Amasuomo and Baird, 2016) Effective management of construction and demolition waste requires a strong emphasis on collection, sorting, and recycling practices to reduce environmental impacts and optimize the use of available resources
• Urban solid waste: Urban solid waste refers to waste that is collected and managed within urban areas (Aziz and Khodakarami, 2013) Its main sources include household waste, along with waste generated from commercial activities, offices, and other urban functions Due to its complex composition, diversity, and large volume, the management of urban solid waste demands efficient systems for collection, treatment, and recycling to mitigate environmental consequences and promote sustainable urban development Common treatment methods include recycling, biological processing, energy recovery, and controlled landfilling.
Sources, composition, and generation rate of solid waste
Population growth and increased access to energy are among the primary drivers of rising solid waste generation In the past, the amount of solid waste produced was relatively low due to limited material consumption and small-scale production activities (Nayanathara Thathsarani Pilapitiya and Ratnayake, 2024) However, the processes of urbanization and global trade have significantly contributed to the escalation of solid waste generation, both in terms of quantity and diversity over time This upward trend clearly reflects shifts in consumption patterns and lifestyles, with growing demand for industrial products, materials, and consumer goods (Alfaia et al., 2017; Awasthi et al., 2023)
The rapid increase in solid waste has emerged as a major global environmental management challenge In 2023, the volume of municipal solid waste (MSW) worldwide reached approximately 2.3 billion tons, and it is projected to rise to 3.8 billion tons by 2050 (United Nation, 2024) Moreover, changing shopping behaviors have led to a substantial increase in packaging-related waste, particularly plastics and paper The composition of urban solid waste is influenced by seasonal variations, economic conditions, living standards, and social activities These factors reflect the dynamics of consumer behavior and community development, thus necessitating effective waste management strategies to ensure sustainability One rapidly increasing type of solid waste in many developed countries is electronic waste (e- waste), which includes discarded devices such as computers, televisions, mobile phones, and other electronic products (Ankit et al., 2021; Jain et al., 2023; WHO,
2024) Concern over this issue has grown significantly due to the expansion of the semiconductor industry, especially given the presence of hazardous substances such as lead, mercury, and cadmium in electronic devices This situation poses considerable challenges for the management and treatment of solid waste, as each type of material requires specific handling and management methods to ensure environmental safety and treatment effectiveness.
Solid waste disposal
2.3.1 Methods of solid waste disposal
Common methods for solid waste disposal include recycling, composting, incineration, landfilling, and specialized disposal Among these, recycling involves the collection, sorting, and transformation of discarded materials such as paper, plastic, glass, metals, and electronic devices into new products These measures help conserve natural resources and reduce the volume of waste sent to landfills and save energy compared to producing from raw materials Composting is an effective biological decomposition method applied to organic waste, such as food scraps and yard waste, that produces nutrient-rich fertilizer that improves soil fertility Additionally, this method reduces methane emissions from landfills and decreases the demand for chemical fertilizers, contributing to more sustainable agriculture Incineration, or waste-to-energy conversion, uses high temperatures to decompose waste while generating energy in the form of heat or electricity This method significantly reduces waste volume, limits the need for landfilling, and maximizes resource utilization However, if not properly controlled, incineration may release toxic substances and air pollutants, adversely affecting the environment and human health Therefore, modern incineration technologies must be equipped with advanced gas filtration and emission control systems to ensure safe disposal processes and minimize atmospheric pollution Landfilling remains a widely used traditional disposal method, especially in low- and middle-income countries Nevertheless, this method requires careful management, particularly with regard to liner systems and the collection of leachate and methane gas to reduce the risk of groundwater contamination and environmental pollution (Suman Mor, 2024) Certain types of waste, especially hazardous waste and industrial by-products, require specialized disposal methods to neutralize or detoxify harmful components before disposal These methods may include chemical, physical, or biological processes, ensuring environmental safety and public health protection An effective solid waste management strategy must combine multiple methods, prioritizing waste reduction, reuse, and recycling whenever possible, to optimize resources and achieve sustainable development goals
According to the World Health Organization (WHO), inadequate solid waste disposal can lead to soil, water, and air pollution, seriously impacting public health, particularly for communities living near waste disposal sites Solid waste generation is an inevitable consequence of economic and social development, posing challenges not only to public health but also to environmental protection Therefore, solid waste management must be implemented through effective strategies to minimize negative impacts, protect living environments, and promote sustainable development
Waste management and disposal activities vary depending on the characteristics of each region, city, or country Despite differences in methods and scale, the solid waste management process generally follows three main stages: (i) sources of solid waste generation; (ii) collection, treatment, and transfer activities; and (iii) disposal, recycling, and final processing of solid waste Current technologies for converting solid waste into energy include thermochemical and biological methods, enabling the transformation of solid waste into solid, liquid, and gaseous fuels to meet the increasing energy demand (Alao et al., 2022; Kasiński and Dębowski, 2024; Shah et al., 2021) Among these waste-to-energy technologies, incineration is regarded as a widely applied and popular method It not only generates energy in the form of electricity, heat, and steam but also significantly reduces the mass and volume of waste Specifically, the incineration process can reduce the mass of waste by up to 80-85%, while volume reduction can reach 95-96%, playing a crucial role in minimizing the amount of solid waste requiring disposal and decreasing reliance on landfills (Tozlu et al., 2016)
In low-middle income countries, landfill sites often viewed as an organized and common method for disposing of solid waste Some landfill areas in these countries also serve as temporary storage facilities, incorporating collection and transfer stations to carry out processes such as sorting, recycling, and waste disposal (Mmereki et al., 2016; Idowu et al., 2019) These landfills occasionally serve as monitoring points for managing solid waste, aiding in the separation of recyclable materials before final treatment or disposal Though landfilling remains one of the most widely employed solid waste disposal methods, many large cities and low- middle income countries continue to face shortages of available space for new landfill sites due to the overwhelming volume of solid waste generated
Due to the demands of sustainable development, solid waste treatment technologies at landfill sites have been carefully reviewed to identify opportunities and challenges for improving management efficiency An effective solid waste management strategy requires a flexible integration of both traditional and modern treatment methods, prioritizing waste reduction, reuse, and recycling These efforts alleviate environmental pressures and aim to maximize the economic value extracted from solid waste, thereby contributing to the promotion of sustainable development
2.3.2 Challenges in solid waste management in low- and middle-income countries
Solid waste management is a complex issue that requires coordination across multiple factors, ranging from management policies to community actions Although local authorities hold primary responsibility, the cooperation of the public plays a crucial role in ensuring long-term effectiveness (Le et al., 2018; Salama et al., 2024; Zhang et al., 2024) Recent evidence indicates that individual behavior significantly impacts the success of waste management strategies Awareness of solid waste and its potential risks to health and the environment directly influences how individuals handle their waste (Raghu and Rodrigues, 2020; Salvia et al., 2021; Nguyen, 2023; Tosi Robinson et al., 2024) Factors such as disposal habits, waste handling frequency, use of waste bins, and participation in environmental protection activities all affect the success of the solid waste management system Therefore, any solution must consider the human factor, as community involvement determines the enforcement of management policies (Abdel-Shafy and Mansour, 2018; Alimoradiyan et al., 2024) The core of an effective waste management system depends on the government’s ability to implement policies, adjust factors to transition toward sustainable solutions, and enact new regulations that align with development trends
In low- and middle-income countries, solid waste management remains a pressing challenge, significantly impacting the natural environment and public health Waste treatment systems in many areas are still limited, resulting in soil, water, and air pollution, which increases the risk of disease outbreaks and degrades the quality of life (Zohoori and Ghani, 2017; Alimoradiyan et al., 2024) Practices such as indiscriminate dumping, open burning of waste, and ineffective leachate treatment at landfills contribute to heightened pollution of air, soil, and water sources, posing serious risks for the spread of infectious diseases A major challenge in these regions is the lack of infrastructure and financial resources, which hampers the effective implementation of waste management solutions The absence of an integrated collection and treatment system leads to uncontrolled waste discharge near water sources, causing severe contamination and adversely affecting community health This situation not only elevates the risk of respiratory and digestive diseases but also directly undermines the quality of life, especially for residents in suburban and rural areas
Not only low-income areas but even major cities face severe pollution problems due to ineffective solid waste management In Banjul (Gambia), residents struggle with air pollution from open-air landfill fires, especially during the rainy season when waste from these sites spills into surrounding water sources (E S Sanneh, 2011) In Phnom Penh (Cambodia), hundreds of thousands of tons of waste are burned or landfilled uncontrolled every year, causing serious harm to both the natural environment and local communities (Bandith Seng, 2018) Countries like Thailand, Nigeria, and Mozambique are also confronting similar challenges, as open dumpsites not only cause severe pollution but also directly threaten the sustainability of regional ecosystems (Ferronato and Torretta, 2019)
Meanwhile, in Vietnam, approximately 60,000 tons of municipal solid waste are generated daily, with around 60% originating from urban areas (Statistical Yearbook, 2021) According to statistics from the Ministry of Agriculture and Environment, over 70% of this waste is disposed of by landfilling, but less than 20% is treated properly to meet sanitary standards (General Statistics Office of Vietnam,
2024) Most unsanitary landfills severely affect soil, water, and air quality, especially in large urban centers Additionally, about 30% of waste is not landfilled properly, while two-thirds of the remainder is burned manually, contributing significantly to air pollution from smoke and dust, negatively impacting human health and ecosystems (General Statistics Office of Vietnam, 2024)
The Seventeen Sustainable Development Goals (17 SDGs) play a pivotal role in promoting comprehensive and long-term global development Several of these goals directly address waste management, with the aim of enhancing environmental quality and improving human well-being These goals not only focus on reducing waste and increasing recycling but also encourage sustainable resource use, ecosystem protection, and safeguarding public health By 2030, establishing a modern and environmentally friendly waste management system is a critical target to minimize the negative impacts of waste on ecosystems and public health To achieve this, low- and middle-income countries must adopt a comprehensive approach that combines investment in advanced infrastructure, raising public awareness, and implementing sustainable policies More importantly, close cooperation among governments, international organizations, and communities is essential to building a waste management system that is not only efficient but also delivers long-term benefits, steering toward a sustainable future
2.4 Management and recycling of solid waste
2.4.1 Solid waste management in developed countries
Solid waste remains a serious challenge for developed economies such as France, Germany, the United States, and many other countries worldwide The increase in solid waste generation is closely linked to rapid population growth, strong economic development, and rising living standards (Carol Emilly Hoareau, 2021; Mmereki et al., 2016) In the United States, waste management is carried out through various methods including landfilling, incineration with or without energy recovery, recycling, and composting (US EPA, 2013) The choice of treatment method depends largely on the waste composition For example, waste with a high organic content is typically prioritized for composting to produce beneficial products, while the proportions of paper and plastics in the waste stream determine the feasibility of recycling or incineration for energy recovery
Solid waste management in the United States is primarily driven by a free- market system, where economic incentives play a key role Currently, many waste treatment facilities are highly automated, operating at large capacities with efficient sorting capabilities However, there is no nationwide mandatory recycling law in the U.S.; instead, regulations vary by state Some states have enacted specific recycling laws, but overall uniformity remains lacking The increasing recycling rates reflect strong community support for recycling activities, while also revealing differing opinions on waste-to-energy methods (Nussbaum, 2008) The U.S government has implemented various measures to promote recycling, including facilitating businesses, providing financial incentives, and raising public awareness through educational programs Additionally, Asian markets, with their high demand for recycled materials, receive a portion of the recycled waste, especially paper and plastics However, recently, some importing countries have tightened quality standards on recyclable waste, forcing the U.S to adjust its waste management strategies to ensure long- term sustainability
Waste reduction policies in Europe aim to generate positive impacts on both the environment and society The European "zero waste" strategy focuses on transforming solid waste into valuable resources, which requires waste treatment facilities to implement effective systems for sorting recyclable materials, conducting necessary recycling processes, alongside composting and waste incineration operations (Fudala-Ksiazek et al., 2016; Almansour and Akrami, 2024) In the European Union (EU), the total amount of solid waste generated has slightly decreased recently, from 521 kg per person in 2020 to 527 kg per person in 2021, and further down to 513 kg per person in 2022 This trend indicates a continuing need for more decisive actions to enhance recycling efficiency and promote sustainable waste management in the future (European Union, 2024; United Nation, 2024) Recently, landfill mining has attracted growing attention across the EU, largely driven by rising commodity prices and the increasing demand for maximizing resource recovery Extracting recyclable materials from landfills not only alleviates environmental pressure but also generates significant revenue Additionally, this process facilitates energy recovery from waste, contributing to renewable energy production This emerging trend reflects a paradigm shift in waste management toward resource optimization and building a more sustainable system overall
Although numerous studies have provided clear estimates of the costs associated with landfill mining, several technical, economic, and environmental challenges still require careful consideration In particular, analyses of energy efficiency and risk assessments related to landfill mining remain insufficiently explored, mainly due to the lack of large-scale field studies Expanding research and practical implementation will be key to determining the feasibility and long-term impacts of this approach
2.4.2 Solid waste management in low- and middle-income countries
Geospatial techniques in solid waste management
2.5.1 Remote sensing and geographic information systems in solid waste disposal
In recent decades, the application of geospatial technologies including remote sensing (RS) and geographic information systems (GIS) in solid waste management has become increasingly widespread across many cities worldwide, ranging from developed countries such as the United States, Germany, and Croatia to developing nations like Thailand, China, and Vietnam Notably, the use of GIS is not limited to waste management; both RS and GIS technologies are widely employed in various fields, including agriculture, natural resource management, urban and economic planning, disaster risk reduction, and public health (Pham et al., 2021) In the context of solid waste management, the primary objective of utilizing GIS is to optimize costs and time while enabling policymakers to make more accurate and effective decisions
RS and GIS offer powerful tools for analyzing and managing spatial data, which support planning for waste treatment facilities, monitoring operational processes, and optimizing waste collection routes As a result, waste management systems can operate more efficiently, reduce resource wastage, and improve service quality
Planning for sustainable waste management is a complex and time-consuming process that requires careful consideration Decision-makers are often confronted with conflicting factors, including economic pressures, environmental requirements, and the need for social consensus (World Bank, 2021) According to the United Nations, sustainable solid waste management goes beyond waste disposal, emphasizing the integration of waste governance at both national and local levels through a life-cycle approach (United Nation, 2024) This involves strategies such as waste minimization, reuse, recycling, and resource recovery, to enhance resource efficiency and ensure environmentally sound waste management To be effective, sustainable waste management solutions must not only be economically feasible but also socially acceptable and environmentally beneficial when implemented (Kharat et al., 2016; Awadh and Mallick, 2024; Alimoradiyan et al., 2024) If properly applied, these measures can reduce pollution and extend the lifespan of natural resources Therefore, a sustainable waste management strategy must strike a balance between economic, environmental, and social interests to ensure long-term efficiency in resource use and environmental protection
Figure 2.2 Illustration of monitoring of Tho Vuc solid waste landfill,
The application of remote sensing and GIS technologies can significantly optimize and streamline the implementation of sustainable solid waste management
By integrating geospatial technologies, researchers are able to combine accurate data on waste generation rates, composition, and treatment locations to optimize management processes However, the adoption of remote sensing and GIS remains in its early stages and faces numerous limitations in many developing regions, particularly across Asia (Sk et al., 2020) The use of these technologies in solid waste management not only brings technical advancements but also helps bridge the gap toward achieving sustainable development goals Numerous studies have identified technology as a critical factor in promoting sustainability across various sectors, including waste management (Prajapati et al., 2021) Such evidence underscores the potential of remote sensing and GIS in addressing waste management challenges not only in developed countries but also in developing nations, where waste systems are often underdeveloped and fragmented Nevertheless, the lack of research related to the use of remote sensing and GIS in solid waste management is more pronounced in low- and middle-income countries compared to economically stable regions elsewhere This emphasizes the impending need to enhance research and practical application of these technologies in the field of solid waste management The primary objective of applying remote sensing and GIS in this context is to minimize both the cost and time of transporting waste to landfills These technologies can improve waste collection processes, especially in countries with poorly planned collection systems Additionally, they support the implementation of sustainable waste management strategies by identifying suitable locations for disposal and recycling facilities The integration of remote sensing, GIS, stakeholder engagement, and an effective regulatory framework is essential for ensuring proper solid waste management
2.5.2 Multiple criteria decision analysis techniques in solid waste disposal
Effective solid waste management largely depends on the types of waste generated by a community, which are influenced by various factors such as socio- economic conditions, household size, and even seasonal variations (Otumawu- Apreku, 2020) The continuous changes in both the composition and volume of solid waste present serious obstacles to economically and environmentally sound treatment and disposal Therefore, clearly and accurately defining the problem is a crucial first step in developing decision-making processes that lead to practical and sustainable waste management solutions To identify the most effective waste treatment options, it is essential to consider local demographic characteristics and development strategies (United Nation, 2024) This enables decision-makers to establish appropriate scenarios and make context-based recommendations Community health and well-being can be impacted differently depending on the waste management approach, as each option involves varying costs and potentially conflicting objectives Importantly, a waste management model that proves effective in one area may not be suitable in another, due to local differences in waste characteristics Consequently, authorities need fast and efficient tools to simulate a nd assess various options, thereby identifying the most appropriate solutions for specific local conditions
During the previous three decades, solid waste management strategies have been continuously improved through the application of multiple criteria decision analysis (MCDA) This approach provides a spatial framework for managing diverse conditions and integrating multiple factors from fields such as environmental science, topography, society, culture, human behavior, and economics, while taking into account stakeholder priorities MCDA within a GIS environment is considered an optimal modeling approach in spatial sciences, offering a means to address the challenges of quantifying non-monetary values (Doboch Wanore et al., 2023; Molla, 2024; Roy et al., 2022) Recent studies have widely applied MCDA in solid waste management, enabling decisions based on a range of factors such as social impact, environmental concerns, resource use, land availability, and recycling potential The strength of MCDA lies in its flexibility, allowing for the assessment of qualitative factors without requiring their conversion into monetary values Such an approach ensures a more accurate reflection of influential factors and is particularly helpful in addressing trade-offs between conflicting factors
Moreover, MCDA can integrate both quantitative and qualitative data, facilitating more effective analysis of complex information that traditional methods may struggle to process Advanced techniques such as fuzzy set theory can also be incorporated to handle uncertainty and imprecision in data (Kharat et al., 2016).Thus, applying MCDA in a GIS-based environment is a widely adopted approach for addressing complex and conflicting factors in solid waste management For this reason, the present thesis employs the integrated GIS–MCDA approach to analyze and identify suitable sites for solid waste landfill in the study area.
METHODOLOGY
Description of the study area
Phu Yen Province is located in the south central coastal region of Vietnam, with a total natural area of approximately 502,596 hectares It is a coastal province, with its mainland territory stretching from 12°42'36" to 13°41'28" North latitude and from 108°40'40" to 109°27'47" East longitude Phu Yen borders Binh Dinh Province to the north, Khanh Hoa Province to the south, Dak Lak and Gia Lai Provinces to the west, and the East Sea to the east (Figure 3.1) Administratively, the province is divided into nine units, including one city (Tuy Hoa), two towns (Song Cau and Dong Hoa), and six districts (Phu Hoa, Tuy An, Tay Hoa, Dong Xuan, Son Hoa, and Song Hinh)
Figure 3.1 Location of Phu Yen province in Vietnam (Landsat satellite image) The rapid pace of urbanization, coupled with the expansion of infrastructure and the strong development of the tourism sector in Phu Yen Province, has led to a significant increase in solid waste generation (Tosi Robinson et al., 2024) Urban sprawl and population growth have resulted in rising demand for housing, commercial spaces, and public services, which in turn have driven up the volumes of construction waste and consumption-related refuse Additionally, the flourishing tourism industry, particularly in coastal areas, has contributed a substantial amount of waste, mainly from short-term visitors This surge in waste generation has overburdened existing landfills, with many sites struggling to handle the increasing waste load (Figure 3.2) The limited capacity of current disposal facilities has resulted in environmental degradation and demonstrates the importance of finding more effective waste management solutions
Figure 3.2 Photos taken on December 13, 2022 and July 31, 2023: Examples of some landfills in Phu Yen province, (A) spontaneous landfill near the sea in Tuy An district, (B) and (D) leachate from a landfill flowing near a rice field in Dong Hoa district, (C) birds foraging at an open-air landfill near agricultural land in Tuy An district, and (E) an open-air landfill near a plantation forest in Tay Hoa district Currently, solid waste management (SWM) in Phu Yen Province primarily relies on uncontrolled open dumping at unregulated disposal sites It is estimated that the province generates approximately 500 tons of municipal solid waste daily Of this amount, around 85% is systematically collected by designated waste management units (collection here is understood as transporting solid waste to landfills and not treating it), while the remainder is either self-managed by residents or remains uncollected due to logistical constraints Across the province, more than 40 organizations and individuals actively participate in collecting household waste from residential areas However, many rural communities, especially those near lagoons and bays, have yet to establish effective waste collection and management systems Consequently, residents in these areas often resort to informal disposal methods or directly discharge waste into the surrounding environment, resulting in significant ecological risks
At present, Phu Yen has approximately 20 planned landfill sites, whereas several localities still depend on temporary dumpsites, which are not designed to meet long-term waste management needs (People's Committee of Phu Yen province,
2023) In such cases, waste is often handled by manual burning, a practice that poses serious risks to air quality and public health Moreover, although waste management is a critical issue, investments in collection, transportation, and disposal of household waste in rural areas remain insufficient to meet actual demand Infrastructure limitations mainly stem from severe financial shortages, creating significant environmental challenges, especially in densely populated areas with high waste generation rates This budget deficit not only exacerbates the existing waste management crisis but also poses multiple threats to public health and ecosystem balance
3.1.2 Characteristics of natural and socio-economic factors
The terrain of Phu Yen Province is quite diverse, with most of the area consisting of high and medium mountains, tending to slope downward from west to east In addition, the province also has hilly areas and low coastal plains The land of Phu Yen mainly lies in areas with steep slopes, with more than 50% of the natural area having slopes of 20° or greater The terrain surface is strongly dissected and is divided into five main regions: (i) The high mountainous region accounts for the majority of the province's area, including Dong Xuan, Song Hinh, Son Hoa districts, along with parts of Dong Hoa district and Tay Hoa district The three sides of the province are bordered by mountains, including the Cu Mong range in the north, the Deo Ca range in the south, and the eastern edge of the Truong Son range in the west These mountain ranges form an arc surrounding the province, extending from Cu Mong Pass, along the western border, and ending at Deo Ca Pass; (ii) The low mountainous and coastal hilly region serves as a transition between the high mountainous area and the coastal plain; (iii) The coastal plain region has relatively flat terrain, mainly concentrated in Tuy An, Phu Hoa, Tay Hoa districts, Dong Hoa district, and Tuy Hoa city, located in the lower basins of the Da Rang and Ban Thach rivers; (iv) The low plains and coastal dunes region adjacent to the coastal plain includes most of the sand dunes and beaches in Tuy An district, Song Cau and Dong Hoa district, and Tuy Hoa city; and (v) The highland region includes the Van Hoa plateau, located at about 400 meters elevation, in Son Xuan, Son Long, and Son Dinh communes
• Climate characteristics and hydrological system
The climate of Phu Yen province features a tropical monsoon oceanic climate, with an average annual temperature ranging from 25.3 to 27.1°C, showing clear differentiation according to terrain Due to the terrain gradually lowering from west to east, the climate is distinct and divided into three characteristic zones: (i) The high mountain climate zone in the west and northwest: This area has a highland climate with average rainfall from 1,700 to 2,000 mm The rainy season arrives early and lasts about two months longer than the plains The average temperature is below 25°C, and in the highlands below 23°C The maximum temperature does not exceed 35°C and is not affected by dry hot western winds; (ii) The mountain climate zone in the south and southwest: Stretching from Hoa Thinh commune (Tay Hoa district) to
Ea Ba commune (Song Hinh district), bordering M’Drak district (Dak Lak province), located in the northern region of the Vong Phu - Deo Ca Mountains range This area experiences high rainfall, from 260 to 2,400 mm, with about 130 rainy days per year The rainy season arrives early, and the average temperature is relatively low; (iii) The low mountain, gentle hill, and coastal plain climate zone: Characterized by average rainfall below 1,700 mm, with about 100 rainy days annually The average air temperature is relatively high, from 25 to 26.4°C Rivers in Phu Yen are relatively evenly distributed throughout the province and share common characteristics: they originate from the eastern Truong Son Mountains range, flowing through mountainous, midland, and plain areas before emptying into the sea Except for the
Ba River and Ky Lo River, most other rivers have basins mainly within the province, characterized by short, steep courses, river mouths often shifted to the north, prone to silting and influenced by tidal regimes Riverbeds are unstable, with many sections along the banks frequently experiencing erosion The main flow directions of the rivers are northwest, southeast or west-east
• Land use characteristics and development orientation of Phu Yen Province
Phu Yen Province has a total natural area of approximately 5,045 km², of which agricultural land accounts for a large proportion with 428,211 ha (85.2% of the total provincial area) Most of this area is forest land, while agricultural production land only accounts for 164,629 ha, mainly dedicated to short-term crops such as rice, cassava, and sugarcane Although perennial crops currently have a low proportion, the trend of restructuring crop composition toward sustainability and the application of scientific and technical advancements are contributing to improved land use efficiency For non-agricultural land, the current area is 56,637 ha (11.27%), but the utilization efficiency remains low
Notably, residential land and commercial service land in urban centers have not been optimized in terms of space and building height, leading to land resource waste Meanwhile, unused land accounts for about 17,747 ha (3.53%) and is scattered mainly in hilly areas and regions with complex terrain If properly planned, this area has potential for exploitation for both agricultural and non-agricultural purposes Overall, agricultural land is mainly concentrated in coastal plains and areas suitable for agricultural production, while non-agricultural land is distributed in urban centers such as Tuy Hoa, Song Cau, and in industrial and service zones With a considerable area of unused land remaining, land planning and optimization will play a crucial role in the province's development orientation in the future Currently, migration phenomena, particularly out-migration, significantly affect the population of Phu Yen province, with an average annual rate of 0.6-0.7% Most migrants are in the working- age group (15–50 years old), with a higher proportion of females migrating compared to males Although the population growth rate of the province is not as high as in other localities, Phu Yen still faces overloading issues at the solid waste landfill sites The main cause is the increase in solid waste volume, stemming from consumption demand and the urbanization rate in urban areas, despite the slow population growth Solid waste landfills not only cause land waste but also pose serious environmental pollution risks Therefore, restructuring and upgrading the waste disposal system has become necessary An effective solution is to apply advanced waste treatment technologies to minimize negative environmental impacts and optimize land use for other development purposes
In the near future, Phu Yen Province aims to develop sustainably by maximizing land potential to serve socio-economic objectives Land use planning will focus on converting part of the agricultural land to industrial, service, and tourism purposes to meet economic development needs Coastal areas will be prioritized for ecotourism and resort development, while mountainous regions will be exploited for production forests along with renewable energy projects, especially wind and solar power Additionally, the province emphasizes the construction of synchronous infrastructure, especially key industrial zones and economic clusters, to attract investment and strengthen regional linkage capacity Land use planning not only targets economic development but must also ensure sustainability through environmental protection measures, climate change adaptation, and improved efficiency in managing land resources Thus, based on satellite data, auxiliary data, and field-collected data as well as analyses of natural condition characteristics, this thesis has compiled and classified the land use/land cover (LULC) objects of Phu Yen Province, presented in detail in Table 3.1 This table not only clarifies the distribution and characteristics of each land use type but also effectively supports the selection of training sample sets for the machine learning classification model of LULC as well as the accuracy verification of the classification results
Table 3.1 Types of land use/land cover in Phu Yen Province
Includes all artificial surface covers, such as areas with high population density featuring buildings, commercial activities, industrial zones, or transportation infrastructure, as well as residential areas mixed with green spaces Human settlements are not densely packed These areas are organized according to specific spatial patterns
Land used for cultivation purposes, including seasonal cropland (e.g., paddy fields) and fallow agricultural land during the land preparation phase, with sparse vegetation patches or mats
Natural forests, plantations, restored forests, or nature conservation areas, including primary forest cover, artificially planted forests for ecological restoration, or protected areas aimed at maintaining biodiversity and natural ecosystems
Lakes, rivers, streams, canals, and artificial water bodies representing open water areas with diverse shapes, often irregular and varying across regions
Areas dominated by barren or shrubs land, typically found on dry, nutrient-poor, or degraded lands These areas have low tree canopy coverage, mainly consisting of small, hardy plant species such as grasses and shrubs adapted to harsh conditions
• Socio-economic conditions of Phu Yen Province
Phu Yen Province has a population of 872,964 people, ranking 47th nationwide Within the North Central Coast and South Central Coast regions, it ranks 12th out of 14 provinces, positioned above Quang Tri and Ninh Thuan Provinces The population distribution by administrative units is as follows: Tuy Hoa city (155,920 people), Tuy An district (133,000 people), Tay Hoa district (127,000 people), Song Cau town (120,780 people), Dong Hoa town (119,921 people), Phu Hoa district (113,850 people), Dong Xuan district (65,300 people), Son Hoa district
Materials
3.2.1 Multispectral satellite imagery and GIS datasets
Multispectral satellite images from Landsat-8 OLI and Landsat-9 OLI-2, acquired during 2023 and 2024 with cloud cover below 10%, were freely accessed via the USGS Earth Explorer platform (https://earthexplorer.usgs.gov) The imagery underwent preprocessing to mitigate noise through atmospheric and topographic corrections using the ATCOR algorithm (Atmospheric and Topographic Correction), incorporated within the Catalyst Professional software suite (https://catalyst.earth/) The preprocessing process includes the following steps: (i) Correcting peak atmospheric reflection (TOA Reflectance); (ii) Remove haze noise on the image (Haze removal) and (iii) Convert radiation value to surface reflectance value (Ground Reflectance)
Subsequently, The Landsat data were converted to the VN-2000/UTM zone 49N coordinate system The GIS database was obtained from the Department of Natural Resources and Environment of Phu Yen Province, and the geological maps were sourced from the Vietnam Geology Department (see Table 3.2) Additionally, statistical data pertaining to land prices, tourist attractions, population demographics, and per capita income were gathered from diverse governmental and non- governmental sources
Table 3.2 Sensor characteristics of Landsat-8/9 OLI images and ancillary data
Acquisition date Type of data used Spectral mode Spectral resolution Spatial resolution/Scale
Landsat 8 OLI Landsat 9 OLI-2 Multispectral
The study conducted field surveys within Phu Yen province, engaging with specialized departments at district levels and relevant provincial agencies to collect documents, statistical data, planning schemes, and development orientations This process aimed to validate land use/land cover (LULC) classification results and supplement information on natural conditions as well as socio-economic characteristics The LULC dataset comprised a total of 1,000 samples selected for use in training, validation, and accuracy assessment of classification results derived from Landsat-8/9 OLI satellite imagery Data on the locations of existing and planned solid waste landfill sites were obtained from the Phu Yen Provincial Planning Department to support the research.
The methodology framework used in the study
The study adopts an integrated approach based on a methodological framework that incorporates remote sensing (RS), geographic information systems (GIS), and multiple criteria decision analysis (MCDA) for identifying potential landfill sites in Phu Yen province, as illustrated in Figure 3.3 This process includes the following main steps: (i) the processing of multispectral satellite images and ancillary data for LULC classification, (ii) identifying the main factors and sub- factors related to selecting potential solid waste landfills, (iii) developing potential solid waste landfill index using fuzzy AHP, and (iv) a final assessment of landfill potential for waste management in Phu Yen Province, Vietnam Details of each step are presented in the sections below:
Figure 3.3 Flowchart of selecting potential landfill areas for solid waste disposal workflow using geospatial technologies.
3.3.1 Processing of multispectral satellite images and ancillary data for land cover and land use classification
Geographic object-based satellite image analysis (GEOBIA) was applied for land use/land cover (LULC) classification in Phu Yen Province Unlike traditional pixel-based approaches that focus on a single pixel as the analysis source, GEOBIA relies on scale, shape, and compactness parameters to segment satellite images (Blaschke et al., 2014; Do et al., 2023; Nguyen et al., 2024; Pham et al., 2019) GEOBIA integrates spatial features and remote sensing results into a GIS to evaluate the characteristics of land-use types This classification method avoids overlapping errors because objects are extracted directly from the images (Mhanna et al., 2023; Pham et al., 2021; Saralioglu and Vatandaslar, 2022) The object-based LULC classification process was implemented in Catalyst professional focus software and consists of four main steps:
• Image segmentation: The segmentation parameters including scale (15), shape (0.8), and compactness (0.65) were selected through multiple iterations using different parameter sets The segmentation process was performed based on the Blue, Green, Red, and Near Infrared spectral bands to optimize classification performance
• Training model and validation: This stage involved the development of a rule-based classification system for LULC The initial step included a detailed analysis of LULC object characteristics on the segmented image a critical phase for defining classification thresholds for each class Each object derived from the imagery carries a set of attribute information, including spectral values, brightness, shape, spatial location, structure, area, and distance to image boundaries To build the classification rule set, the analyst must have comprehensive knowledge of: (i) image channel characteristics, (ii) spectral reflectance properties of the LULC classes, (iii) the geographic context of the study area, and (iv) relationships between various LULC categories In this study, five primary LULC classes were identified for Phu Yen Province: Open water bodies (OWB), Residential area (REA), Forest area (FRS), Agricultural land (AGRL), and Shrubs/barren land (SBL) A total of 1,000 ground- truth samples were used for model training and validation, of which 750 samples (70%) were used for training and 250 samples (30%) for validation and classification accuracy assessment
• Classification: The GEOBIA-based classification approach allows for the integration of several algorithms, including, Decision Tree (DT), K-Nearest Neighbors (K-NN), Random Forest (RF), and Support Vector Machine (SVM), to support LULC classification Among these, SVM has demonstrated superior classification performance in prior studies, particularly for medium- and high- resolution satellite imagery The SVM algorithm is grounded in statistical learning theory, which maps two-class datasets into n points in a d-dimensional space, where each point belongs to a class labeled as ±1 The goal is to construct an optimal hyperplane that maximally separates the classes The training dataset is defined as{(x₁,y₁), (x₂,y₂), (x₃,y₃), (x₄,y₄),…, (xₙ,yₙ)}, with xᵢ belonging to Rd and yᵢ ∈ {±1} The SVM algorithm seeks to maximize the margin between two LULC classes while minimizing classification errors The performance of SVM is influenced by the selection of the kernel function, which may include linear, polynomial, radial, and sigmoid kernels In this study, the SVM classifier was applied using a radial basis function (RBF) kernel and standardized data to identify and classify the five LULC classes in Phu Yen Province: OWB, REA, FRS, AGRL, and SBL
• Classification accuracy assessment: The initial classification results were refined through manual inspection to ensure the correct assignment of LULC categories, particularly OWB, REA, FRS, AGRL, and SBL Accuracy assessment was conducted using the final composite LULC classification layers Two commonly used statistical metrics, Overall Accuracy and the Kappa Coefficient, were employed to evaluate the performance of the classification results
3.3.2 Identifying main factors and sub-factors related to selecting potential solid waste landfills
Solid waste management (SWM) in low- and middle-income countries faces numerous limitations and challenges, which significantly hinder operational efficiency (Zohoori and Ghani, 2017) The selection of landfill sites must satisfy essential conditions to minimize adverse impacts on the natural environment and public health Moreover, the selection criteria must align with local land use regulations, national standards, previous research, and the availability of relevant spatial data in the study area The choice and prioritization of factors directly affect the suitability of selected locations for landfill construction This suitability is determined based on previous literature and under the guidance of environmental experts However, landfill site selection should not rely solely on the linear application of factors; instead, a flexible, context-specific approach is required to accommodate local conditions In practice, it is rarely feasible to meet all factors simultaneously Therefore, identifying and prioritizing the most critical factors plays a pivotal role in the decision-making process The assignment of weights is essential to effectively manage trade-offs between different factors The initial step of this study involved identifying relevant criteria that should be considered
Based on a synthesis of prior studies on potential landfill site selection in low- and middle-income countries, and taking into account the natural, economic, and socio-cultural characteristics of Phu Yen Province, this research grouped the factors into four main categories: economic factors (A), environmental factors (B), topographic factors (C), and social factors (D), to evaluate the suitability of solid waste landfill sites The results of this analysis are presented as a spatial “suitability map” for each area All factors were converted into raster format with a spatial resolution of 30 meters (Figure 3.4) and processed in the ArcGIS environment to analyze potential landfill sites in Phu Yen Province The detailed description of groups A, B, C, and D will be provided in the following sections:
Land price (A1, unit: $/m 2 ) : A1 influences both the initial investment and long-term operational costs, making it a critical factor in economic feasibility High land prices compel authorities to consider sites farther from residential areas or with smaller land In contrast, lower land costs can significantly reduce land acquisition expenses, enabling more flexible and efficient landfill designs and lowering the frequency of site expansion Affordable land also facilitates the adoption of advanced technologies such as waste-to-energy conversion or recycling, thereby enhancing the sustainability of the landfill High land prices also increase the cost of developing infrastructure such as roads, drainage systems, and leachate disposal facilities This can lead to compromises in infrastructure quality or scale, raising the risk of environmental pollution and public health hazards Conversely, lower land prices alleviate financial pressure, allowing for the development of high-quality infrastructure that ensures waste containment, leachate management, and gas disposal systems meet regulatory standards This contributes to safer and more sustainable landfill operations The sustainability of a landfill project is closely tied to the affordability of land Reasonable land prices allow for the acquisition of larger areas, provide flexibility in design, and accommodate future expansions to handle increasing waste volumes without the need for frequent site changes Therefore, land price is a key consideration in selecting solid waste landfill sites, as it directly impacts land acquisition costs, infrastructure development, and the overall sustainability of the project Thorough assessment of these aspects ensures that landfill projects are not only financially viable but also environmentally and socially responsible
Distance to traffic (A2, units: m) directly influences both operational efficiency and waste management costs To optimize operations, access roads to the landfill must be of high quality and capable of supporting the heavy load and frequency of waste trucks Proximity to major roads helps reduce traffic congestion, saves time and fuel, and minimizes emissions and noise pollution factors especially important in urban areas If a landfill is far from main transportation networks, initial investment costs increase due to the need for constructing or upgrading roads, along with potential legal and social challenges The quality of the access roads also affects operational efficiency; substandard roads may hinder truck movement, raise accident risks, and increase maintenance expenses Poor road conditions also reduce transportation efficiency, require more trips, and result in higher emissions Investing in high-quality transportation infrastructure helps maintain safety, facilitates monitoring and emergency response, extends the landfill’s operational life, and reduces long-term maintenance costs These factors collectively ensure the long-term sustainability and efficiency of waste treatment projects
Per capita income (A3, units: $/person/year): A3 reflects the living standards and economic development of the community This indicator not only helps assess the community’s financial capacity to support landfill operations but also indicates their expectations regarding waste management services Communities with higher incomes often demand stricter environmental and health protection standards, as well as advanced waste management solutions They are more likely to call for strict regulations and compliance with aesthetic standards to minimize the landfill’s impact Understanding the per capita income allows prediction of the level of community engagement and the likelihood of opposition or legal challenges if the project fails to meet expectations Furthermore, this criterion supports the development of effective communication strategies tailored to the socioeconomic characteristics of the local population For instance, in high-income areas, communication can emphasize advanced technologies and stringent environmental control, whereas in lower-income areas, it may focus on job creation and economic development opportunities Considering per capita income enables waste management authorities to formulate sustainable plans aligned with community needs, ensuring economic viability, social equity, and environmental protection during landfill site selection
Distance to open water bodies (B1, units: m) : B1 is crucial for minimizing the risk of water pollution and safeguarding public health Landfills located near water bodies such as rivers, lakes, or reservoirs pose a high risk of contamination from leachate, which contains hazardous chemicals, heavy metals, and microorganisms that can severely affect both human health and aquatic ecosystems Heavy rainfall or flooding can exacerbate this risk, especially in areas with a high groundwater table Maintaining adequate distance from water sources helps ensure regulatory compliance, avoid legal penalties, and maintain public trust Locating landfills far from water bodies reduces disaster-related risks, lowers the cost of technical mitigation measures, and supports long-term sustainability Appropriate distance also enhances community acceptance of landfill projects by reducing pollution concerns and encouraging public participation in decision-making processes Additionally, distancing landfills from water bodies can reduce operational costs, promote sustainable waste management practices such as recycling and composting, and protect the environment while supporting socio-economic development Such distance ensures that landfills contribute positively to the overall development of the communities they serve while preserving ecological integrity
Distance to shrubs/barren land (B2, units: m) : provides multiple ecological benefits, including habitat for rare plant and animal species, conservation of biodiversity, and maintenance of ecosystem balance Locating a landfill near shrubland can help minimize adverse environmental impacts These areas help stabilize soil, reduce erosion, and improve soil quality, while also acting as buffers that filter pollutants and regulate the local microclimate In addition to ecological advantages, siting landfills near barren or shrub-covered areas is economically beneficial since such lands are typically low in value and underutilized Utilizing degraded land for landfill purposes can reduce land acquisition costs and protect high-value land such as agricultural fields or residential areas However, it is important to carefully assess site characteristics, including soil type, vegetation density, and proximity to sensitive habitats, to avoid unintended negative impacts on the ecosystem
Distance to forest (B3, units: m) : B3 is a critical factor in landfill site selection because forests provide essential ecosystem services such as carbon sequestration, oxygen production, and habitat protection Land degradation or deforestation caused by landfill operations can hinder forest regeneration, cause soil erosion, degrade water quality, and contribute to climate change, thereby affecting both plant and animal life Forests are particularly sensitive to pollution from leachate and heavy metals, which can reduce plant health, decrease biodiversity, and encourage the spread of invasive species, resulting in ecosystem degradation Additionally, clearing forest land for landfill construction reduces the area's carbon storage capacity, further contributing to climate change Forests are also vital resources and sources of livelihood for many local communities Landfills near forests may disrupt timber harvesting, non-timber product collection, and cultural practices, potentially resulting in income loss and social conflict Maintaining a safe distance between landfills and forests is therefore essential to minimize environmental and social impacts and promote sustainable development for both ecosystems and communities
Distance to agricultural land (B4, units: m) : B4 is a key factor as it directly affects environmental quality and agricultural productivity Locating landfills near farmlands can lead to soil contamination, especially if waste is improperly managed Leachate may contain heavy metals and toxic chemicals that can infiltrate farmland, degrade soil quality, and negatively affect crops, leading to reduced yield and food quality These contaminants can enter the food chain, posing serious health risks to both humans and animals, including neurological, respiratory, and carcinogenic effects In addition to environmental and health concerns, siting landfills near agricultural areas also has economic consequences Agriculture is the primary income source for many communities, and degraded soil conditions can directly impact farmers' livelihoods Crop contamination may lower market value or cause harvest failure, resulting in financial hardship and disruptions in the food supply chain Maintaining an appropriate distance from agricultural land helps protect soil resources, supports sustainable land use practices, and safeguards vital ecosystem services such as carbon storage, water filtration, and wildlife habitat This not only protects the environment but also fosters community trust and acceptance of waste management projects Public opposition due to pollution concerns can delay or derail landfill development efforts