Solid waste management is much more than the simple disposal of urban detritus. It embodies an essential aspect of urban life, reflecting consumption patterns, economic activities, and lifestyles within a community (Das et al., 2019). Effective management involves an integrated, scientific approach to all phases, from collection to recycling, supported by comprehensive evaluation (Debrah et al., 2021; Nanda & Berruti, 2021). This crucial dimension actively contributes to sustainable development and requires meticulous attention in modern urban planning (Prajapati et al., 2021; Simatele et al., 2017). Over the last few decades, the growth in the world's population and rapid urbanization have led to a significant increase in solid waste production, reaching 2.24 billion tons in 2020, with a projection of 3.4 billion in 2050 (Kulleh & Manaf, 2023; Marshall & Farahbakhsh, 2013). This increase underlines the urgency of global concerns about household waste management (Azevedo et al., 2019).
Household waste arising from the daily activities of households, institutions and businesses represents a major challenge on a global scale (Durlević et al., 2023; Mallick, 2021; Zewdie & Yeshanew, 2023). The diversity of this waste, which varies considerably from region to region, encompasses organic and inorganic components and biodegradable and non-biodegradable fractions, ranging from food waste to packaging materials, glass, plastic and much more…. Inadequate management of these materials can lead to a range of environmental problems, including pollution and depletion of natural resources (Bilgilioglu et al., 2022; Chabuk et al., 2016; Kazuva et al., 2021). To mitigate these issues, sustainable waste management adopts the "waste management hierarchy" as a guiding framework, emphasizing source reduction, recycling and the use of waste for energy generation, before resorting to disposal methods (Eskandari et al., 2016). However, despite this approach, a significant proportion of solid waste still ends up in landfill, underlining the pressing need to rethink and strengthen waste management strategies for greater sustainability. Landfill is the imperative and final step in the waste management hierarchy (Asefi et al., 2020; Eskandari et al., 2016). According to Nanda & Berruti, (2021), only 25% of the municipal solid waste collected is diverted to waste management options such as recycling and composting, the rest is landfilled.
A landfill is a necessity in modern waste management, despite techniques used for recovery (recycling, sorting, etc.) and elimination (incineration), there will always be some residue, whether final or not, to bury (Kontos et al., 2005). So landfilling remains a common practice for waste disposal. In developed countries, landfill represents an organized and widespread method to dispose of municipal solid waste (Ali & Ahmad, 2020; Rahmat et al., 2017). Conversely, in developing countries, this practice remains a major concern, reflecting the persistent challenges posed by rapid population growth and changing lifestyles within societies (Abderrahmane & Hassiba, 2014b). Algeria offers a striking example of this reality, facing a major challenge in the sustainable management of household waste (Abdelli et al., 2017; Abderrahmane & Hassiba, 2014a). Over the decades, the quantity of waste has increased considerably, and the composition of waste has evolved from an organic profile (food waste) to complex materials, generating significant risks for the environment and public health (Amina et al., 2020; Bendjoudi et al., 2009; Naghel et al., 2022). Currently, the predominant method of disposal remains open dumping, representing an alarming 87%. According to a survey carried out by the Ministry of Spatial Planning and Environment (MATE), more than 3,000 illegal dumps sites covering a surface area of 4,552.5 hectares have been identified in all provinces, and the restrictions imposed by environmental agencies being ignored, as are the rules and techniques for managing landfills (Naghel et al., 2022). This finding underlines the urgent need to explore sustainable solutions and appropriate planning of landfill sites for responsible waste management, contributing to environmental sustainability and improving the living environment of local populations.
In this context, optimizing landfill site selection requires a comprehensive approach that takes into account environmental and socio-economic factors (Bilgilioglu et al., 2022). Such a complex balance requires interdisciplinary collaboration involving experts in geomorphology, geology, hydrology, environment, urban planning and community stakeholders. Following our extensive literature review, various approaches and methodologies were employed to address the issue of landfill site selection (Özkan et al., 2019). Among the methods, that use artificial intelligence and machine learning, such as GBT (Gradient Boosting Trees), DT (Decision Trees), SVM (Support Vector Machines), and RF (Random Forest) (Al-Ruzouq et al., 2022; Mohsin et al., 2022), these approaches rely on algorithms to extract patterns from large datasets. However, it is crucial to note that their implementation requires in-depth expertise, substantial resources for data processing, specific software and strict input parameters, underlining the complexity and requirements inherent in these advanced methods, this considerably limits their application in landfill site selection. In addition, over the past two decades, a remarkable number of scientific publications have included Geographic Information System (GIS) based Multiple-Criteria Decision-Making (MCDM) modeling (Bilgilioglu et al., 2022; Kazuva et al., 2021; Zewdie & Yeshanew, 2023). Indeed, the use of GIS technology facilitates decision-making by identifying the most appropriate sites to minimize environmental and social risks, and offers the possibility of assessing potential impacts on natural resources (Bilgilioglu et al., 2022; Longley, 2005). On the other hand, the MCDM approach encompasses a wide range of methods (Rezaeisabzevar et al., 2020), such as the TOPOSIS (Technique for Order Preference by Similarity to Ideal Solution) method, which requires high-quality data and complex modelling, thus imposing constraints on its applicability (Beskese et al., 2015); The VIKOR (VIseKriterijumska Optimizacija I Kompromisno Resenje) method (Liu et al., 2014) which focuses on ranking and selecting from a set of alternatives and determining compromise solutions for a problem with conflicting criteria, this method can be sensitive to outliers or extreme data points, which can distort the analysis results (Papathanasiou, 2021); and some Fuzzy logic methods like FAHP (Mallick, 2021; Mohsin et al., 2022) and fuzzy TOPSIS (Sagnak et al., 2021), these methods rely on data that is either imprecise or challenging to precisely quantify (Madi et al., 2016).
Among the most widely used Multi-Criteria Decision-Making (MCDM) methods within the scientific community, the Analytic Hierarchy Process (AHP) holds significant importance (Saaty, 1980). This method has demonstrated its relevance across various domains, including environmental impact assessment (Lu et al., 2017; Singh et al., 2023), renewable energy development (Ghimire & Kim, 2018), forest fire risk mapping (Lamat et al., 2021), geo-hazard susceptibility assessment (Goumrasa et al., 2021; Mokadem et al., 2024; Souissi et al., 2020), and landfill site selection (Abdo et al., 2023; Elhamdouni et al., 2017; Eskandari et al., 2016; Makonyo & Msabi, 2022; Rahmat et al., 2017). Its importance arises from its ability to hierarchically structure complex decisions, enabling decision-makers to systematically compare and evaluate multiple criteria and alternatives, thereby providing a structured approach to decision-making (Özkan et al., 2019). In landfill site selection, the use of GIS-AHP method provide a systematic framework for evaluating environmental criteria involved in the decision-making process by identifying and evaluating the study area’s characteristics relevant to landfill site selection, such as Socio-economic, geomorphic, hydrologic, and climatic factors (Mallick, 2021; Rahmat et al., 2017).
In Bejaia province, Algeria, waste management presents a multitude of challenges, notably the absence of controlled and engineered landfill sites, difficulties in effectively monitoring and controlling authorized landfill efficiency, low levels of recycling, and limited capacity of authorized landfills, often situated in inappropriate locations. According to the environmental department and National Waste Agency (AND), the province hosts approximately 40 open dumps generating around 294 405 tons of waste annually. These landfills lack integrated systems and continuous environmental safety monitoring, leading to waste volume reduction through incineration, which often causes atmospheric and visual pollution. Household waste is indiscriminately dumped with no control or technology, and landfill sites are chosen without adequate study or supervision. Additionally, the majority of these dumps are predominantly situated near the Soummam River valley, leading to pollution and water contamination issues. Concurrently, the proliferation of illegal dumpsites due to population growth, coupled with ineffective and inefficient waste management practices, contributes to environmental degradation and the depletion of natural resources. This situation exposes the population to significant environmental and health risks.
In the present work, a GIS-MCDM approach is conducted in order to identify the best viable location for landfilling sites by integrating various environmental and socio-economic factors characterizing the southwest part of Bejaia. The selection of the study area was influenced by several pivotal factors: Firstly, the absence of existing landfill facilities in the region necessitated a focus on waste management practices. Secondly, the complex physical, environmental, and socio-economic characteristics of the area played a crucial role in its selection. Notably, the presence of the Soummam River Valley, one of Algeria's largest rivers, introduced additional intricacies to the environmental dynamic. This highlights the necessity of adopting waste management strategies that consider the potential impact on this vital natural resource. Additionally, this area has never been the subject of similar work, while the methodology adopted, integrating freely available geospatial data, constitutes a cost-effective means for assessing and selecting optimal landfill sites, saving both time and money.