Multicriteria Model for Selection of Landfill Site for Solid Waste in the Municipality of Arbieto

1. Introduction

The final disposal of municipal solid waste (MSW) remains a major environmental and public health challenge in many rural and peri-urban areas of developing countries, where open dumpsites continue to be the only management solution. In Bolivia, this issue is evident in several municipalities that lack technical infrastructure and comprehensive planning for the safe treatment and elimination of waste [1,2]. The municipality of Arbieto, located in the department of Cochabamba, exemplifies this problem: it comprises 67 communities, yet only the central town in District 1 has a reconditioned dumpsite, which operates without proper control of leachate or gas emissions. The remaining communities lack collection systems and typically resort to burning or burying waste [3], practices that increase soil and water pollution and directly affect public health.

In response to this situation, it is crucial to implement a sustainable strategy for final disposal site selection that integrates environmental, social, legal, and technical criteria. Various international studies have demonstrated the effectiveness of Geographic Information Systems (GIS) and multi-criteria analysis (MCA) in identifying optimal locations for sanitary landfills. For example, Bera et al. [2] used spatial overlays of variables such as slope, geology, and land use in India; Ampofo et al. [3] applied GIS integrated with the Analytic Hierarchy Process (AHP) in Ghana to avoid social conflict zones; Barros et al. [1] utilized Boolean logic and map algebra in Brazil to comply with environmental legislation; similarly, Quinteros et al. [6] in Bolivia, Biazen Molla [7] in Ethiopia, and Arabeyyat et al. [8] in Jordan demonstrated the usefulness of GIS-based multicriteria evaluation for landfill siting in diverse environmental and social contexts.

In this context, the present study aims to determine the most suitable site for the final disposal of municipal solid waste in Arbieto by applying a spatial multi-criteria analysis using GIS and an optimization model with GAMS software. The working hypothesis is that the integrated use of these tools enables the identification of technically feasible, environmentally safe, and socially acceptable landfill sites, offering a replicable approach for other rural municipalities.

The results indicate that there are areas with high territorial suitability for constructing a sustainable sanitary landfill in Arbieto. This solution could significantly reduce soil and water contamination, improve public health, and align with sustainable development goals through an approach that combines technical, environmental, and social dimensions.

2. Materials and Methods

This study implemented a geospatial multicriteria decision-making (MCDM) methodology using ArcGIS to identify optimal locations for sanitary landfill siting in the municipality of Arbieto, Cochabamba, Bolivia. The method integrates environmental, technical, legal, and social criteria in a Boolean logic overlay model, ensuring equal weight for all variables.

2.1. Review of Technologies and Planning Approaches

To contextualize the proposed methodology, a literature review was conducted, focusing on best practices for siting landfills using Geographic Information Systems (GIS), multicriteria evaluation, and alternative disposal technologies. Key studies included landfill planning strategies using AHP and GIS (Barros et al. [1]), weighted overlay mapping (Bera et al. [2]), and multicriteria evaluation in African contexts (Ampofo et al. [3]). Additional examples of landfill siting using multicriteria methods in Bolivia and other developing countries were also reviewed (Quinteros et al. [6], Biazen Molla [7], Arabeyyat et al. [8]). Furthermore, recent advances in leachate treatment and waste valorization strategies were considered (Cheniti et al. [4], Kerboua et al. [5]).

2.2. Study Area and Data Collection

The municipality of Arbieto comprises seven districts and 67 communities. Data layers were acquired from the PTDI of Arbieto and the Instituto Geográfico Militar (IGM). The following shapefiles were used:

-

Digital Elevation Model (DEM)

-

Hydrography (rivers and water bodies)

-

Road network (secondary and tertiary)

-

Urban and rural population centers

-

Geological formations

-

Vegetation cover (classified from Landsat imagery)

Figure 1 shows the shapefile of the Map of the Municipality of Arbieto inserted into the ArcGIS software, as the starting point for adding the other shapefiles required for the multicriteria model for sanitary landfill site selection.

Table 1 presents the maps and shapefiles required to apply the Multicriteria Model for the selection of a final disposal site for municipal solid waste.

2.3. Multicriteria Criteria and Processing in ArcGIS

Six critical variables were defined: slope, distance to rivers, distance to roads, distance to settlements, geology, and vegetation cover. Each layer was standardized and reclassified into binary values: 1 = suitable, 0 = unsuitable. Suitability thresholds were defined based on Bolivian technical norms and international literature:

$C_1:$Slope: Areas with a slope between 4° and 15° were considered suitable.

$C_2:$Hydrology: A buffer of 500 m was applied to all surface water bodies to avoid contamination.

$C_3:$Road Access: Sites located more than 500 m from main roads were favored, balancing access and impact mitigation.

$C_4:$Proximity to Settlements: A minimum distance of 500 m from populated centers was established to prevent health risks.

$C_5:$Geology: Stable, low-permeability geological formations were preferred.

$C_6:$Land Cover: Areas without significant vegetation or agricultural activity were prioritized.

$$C_i(x,y)=\left\{\begin{array}{c}1ifcriterioniissatisfiedatlocation(x,y)\\ 0,ifnotsatisfied\end{array}\right.$$

where $C_i\left(x,y\right)$is the value of criterion i at the spatial point $(x,y)$

Table 2. Criteria for Sanitary Landfill Site Selection.

Criterion 1: Slope	Criterion 2: Hydrology	Criterion 3: Access Roads	Criterion 4: Population Centers	Criterion 5: Vegetation Cover	Criterion 6: Geology	Value
<15o	>500 m	>500 m	>500 m	Fam. Apacheta, Condorsinga, Cercapuquio, Volcanic Center, Antarazo, Subvolcanic Rocks, Andesite/Diabase, Dacite/Rhyodacite, Fam. Astobamba, Chambara, Sacsaquero, Castrovirreyna.	Area without vegetation, semi-humid scrubland, humid scrubland, grassland.	1
>15o	<500 m	<500 m	<500 m	Fam. Chulec-Pariatambo, Chayllacatana, Goyllarisquisga, Casapalca, Auquivilca, Caudalosa, Huando, Huichinga, Santa Barbara, Andesite/Diabase, Apacheta, Wetland Deposits, Glaciers, Urban Areas.	Urban areas, wetlands, agricultural cultivation areas, glaciers, lakes, rivers, forest plantations.	0

Source: Own elaboration based on GEO GISS [9].

Table 2. Criteria for Sanitary Landfill Site Selection.

Criterion 1: Slope	Criterion 2: Hydrology	Criterion 3: Access Roads	Criterion 4: Population Centers	Criterion 5: Vegetation Cover	Criterion 6: Geology	Value
<15o	>500 m	>500 m	>500 m	Fam. Apacheta, Condorsinga, Cercapuquio, Volcanic Center, Antarazo, Subvolcanic Rocks, Andesite/Diabase, Dacite/Rhyodacite, Fam. Astobamba, Chambara, Sacsaquero, Castrovirreyna.	Area without vegetation, semi-humid scrubland, humid scrubland, grassland.	1
>15o	<500 m	<500 m	<500 m	Fam. Chulec-Pariatambo, Chayllacatana, Goyllarisquisga, Casapalca, Auquivilca, Caudalosa, Huando, Huichinga, Santa Barbara, Andesite/Diabase, Apacheta, Wetland Deposits, Glaciers, Urban Areas.	Urban areas, wetlands, agricultural cultivation areas, glaciers, lakes, rivers, forest plantations.	0

Source: Own elaboration based on GEO GISS [9].

The final suitability $S\left(x,y\right)$ is obtained through the logical intersection of all considered criteria. Each spatial layer was transformed into a binary map (1 = meets the criterion, 0 = does not meet the criterion) using ArcGIS tools such as Slope, Euclidean Distance, Reclassify, and Raster Calculator. Layers were combined using a Boolean overlay method The final suitability was calculated as:

$$S\left(x,y\right)=C_1\left(x,y\right)\wedge C_2\left(x,y\right)\wedge \dots \wedge C_n\left(x,y\right)$$

A final value of $S\left(x,y\right)=1$indicates that the location is suitable for final disposal according to all criteria, while a single value of 0 in any layer excludes the site.

where $S\left(x,y\right)$represents the final suitability at point $\left(x,y\right)$and Cᵢ are the binary criteria. Only cells with a value of 1 in all layers were considered suitable.

Table 3. Procedure for Sanitary Landfill Site Selection Using the Multicriteria Model.

Table 3. Procedure for Sanitary Landfill Site Selection Using the Multicriteria Model.

2.4. Model Workflow

Importation of shapefiles (DEM, roads, rivers, settlements, geology, vegetation)

Generation of slope layer (Slope tool)

Euclidean Distance for rivers, roads, and settlements

Reclassification into binary raster layers (Reclassify tool)

Raster overlay via Raster Calculator to generate final suitability map

Exportation of final map in raster and shapefile formats for validation and visualization.

2.5. Optimization with GAMS

To complement spatial analysis, the General Algebraic Modeling System (GAMS) was used to optimize transportation routes and costs from 20 waste generation sources. The optimization function minimized operational and environmental costs, facilitating efficient allocation of resources for future landfill management.

2.6. Validation

The methodology was validated based on prior applications in rural or peri-urban areas of Brazil [1], India [2], and Ghana [3], demonstrating replicability in contexts with limited access to high-resolution datasets.

2.7. Declaration of AI Use

No generative artificial intelligence (GenAI) was used in the generation of data, analysis, or interpretation. AI tools were used only for editing and proofreading support.

2.8. Data Availability

All spatial layers used in this study are publicly available through the PTDI of Arbieto and the Instituto Geográfico Militar (IGM). DEM data were obtained from ASTGTM2 tiles S18W066 and S18W067.

2.9. Ethical Considerations

This study did not involve human or animal subjects and therefore did not require ethical approval. The approach outlined ensures transparency, replicability, and adaptability to other municipalities with similar territorial and institutional constraints.

3. Results

This section presents the results of the multicriteria model developed for the sanitary landfill site selection in the Municipality of Arbieto, Cochabamba, using ArcGIS software.

3.1. Individual Criterion Mapping

The multicriteria analysis evaluated six critical factors: slope, proximity to rivers, proximity to roads, proximity to settlements, vegetation cover, and geological stability. Each factor was processed into binary suitability layers (1 = suitable; 0 = unsuitable) according to defined thresholds.

Table 4 summarizes the classification criteria for each variable.

Criterion 1. Slope: Areas with slopes <15° were classified as suitable (green, value = 1); areas >15° as unsuitable (red, value = 0).

Criterion 2. Distance to rivers: >500 m suitable (green); <500 m unsuitable (red).

Criterion 3. Distance to roads: >500 m suitable (green); <500 m unsuitable (red).

Criterion 4. Distance to settlements: >500 m suitable (green); <500 m unsuitable (red).

Criterion 5. Vegetation cover: disturbed land, shrublands, and grasslands considered suitable (green); forests and wetlands unsuitable (red).

Criterion 6. Geology: stable formations with low permeability were suitable (green); permeable or unstable formations were unsuitable (red).

3.2. Final Suitability Mapping

The final suitability map was obtained by applying a Boolean intersection of all criteria layers, These criteria were integrated into a single Boolean overlay model using the following equation, as described by Equation (1):

$$S\left(x,y\right)=C_1\left(x,y\right)\wedge C_2\left(x,y\right)\wedge \dots \wedge C_n\left(x,y\right)$$

where $S\left(x,y\right)$ represents the final suitability at location $\left(x,y\right)$ , and each $C_i$ is a binary criterion layer.

Only cells satisfying all criteria (value = 1) were selected as suitable landfill sites.

Figure 2. Final suitability map identifying optimal landfill locations (ArcGIS raster output). Source: Author’s elaboration.

Figure 2. Final suitability map identifying optimal landfill locations (ArcGIS raster output). Source: Author’s elaboration.

In Figure 3, the results of the final solid waste disposal site selection are presented using a satellite map. This visual representation illustrates the optimal zones identified through the multicriteria model, highlighting suitable areas for the future sanitary landfill in the municipality of Arbieto.

3.3. Site Alternatives Identified

Three candidate sites were identified as suitable for sanitary landfill development:

Table 5. Landfill Site Alternatives Identified.

Site	Easting (m)	Northing (m)	Area (m²)	Area (m²)
Site 1	812367.00	8061779.00	149,795.25	14.98
Site 2	810050.00	8060550.00	13,274.12	1.33
Site 3	812364.00	8063307.00	132,105.58	13.21

Source: Author’s elaboration.

Table 5. Landfill Site Alternatives Identified.

Site	Easting (m)	Northing (m)	Area (m²)	Area (m²)
Site 1	812367.00	8061779.00	149,795.25	14.98
Site 2	810050.00	8060550.00	13,274.12	1.33
Site 3	812364.00	8063307.00	132,105.58	13.21

Source: Author’s elaboration.

All identified sites are located in District 5, within the communities of Olimpo and Tackoloma, in the Municipality of Arbieto.

3.5. Interpretation

The findings confirm that, despite the municipality's challenging topography and environmental constraints, there are viable sites for the establishment of a sanitary landfill. Specifically, Site 1, with an area of 14.98 ha, presents the most favorable conditions due to its sufficient distance from water bodies, urban areas, and its stable geological features.

The application of a Boolean logic multicriteria model ensures transparency, objectivity, and replicability, providing a robust decision-making tool for future waste management planning in Arbieto.

The Municipality of Arbieto covers a total area of 15,967.75 hectares. Based on the multicriteria spatial analysis, three potential sites were identified as optimal locations for a future sanitary landfill. Among them, Site 1 (14.98 ha) and Site 3 (13.21 ha) present the most favorable areas for future waste disposal infrastructure, while Site 2 (1.33 ha) offers a smaller but technically suitable alternative.

These results provide a technically grounded foundation for advancing towards the planning, design, and implementation of a sanitary landfill system, ensuring environmental protection, public health, and compliance with international standards.

4. Discussion

The selection of the optimal site for the final disposal of solid waste in the municipality of Arbieto was carried out by applying a multicriteria analysis model within a GIS environment, where each variable was reclassified into a binary format (value 1 if the criterion was met, value 0 if not). The criteria included slopes lower than 15°, distances greater than 500 meters from rivers, roads, and population centers, the presence of stable geological formations, and areas with minimal or no vegetation cover. Subsequently, a Boolean overlay technique was applied in ArcGIS by multiplying all the layers that simultaneously met the defined criteria. Thus, only the areas with a value of 1 across all layers were identified as potentially suitable zones for the construction of a sanitary landfill.

The results demonstrated that the optimal location for the future sanitary landfill is concentrated in the northern part of the municipality, specifically in District 5, within the communities of Olimpo and Tackoloma, at UTM coordinates 812367.00 m E, 8061779.00 m N. These findings confirm the working hypothesis that a multicriteria analysis methodology within a GIS environment would allow the identification of technically, environmentally, and socially appropriate areas for final waste disposal in rural contexts such as Arbieto.

When compared with international studies, the results are consistent with those reported by Bera et al. [2] in India, Ampofo et al. [3] in Ghana, and Barros et al. [1] in Brazil, where Boolean and multicriteria overlay models were also applied for landfill siting in rural or peri-urban territories. Similar to those studies, the use of GIS tools enabled the efficient management of multiple technical, environmental, and social criteria, contributing to a more objective and replicable planning process.

The identification of suitable areas in Arbieto highlights the importance of proactively planning the integrated management of solid waste by prioritizing the acquisition and protection of suitable land for sanitary landfills. Therefore, it is essential for the Autonomous Municipal Government of Arbieto to manage the legalization of the selected plots, prevent future illegal settlements, and guarantee their exclusive use for technical waste disposal. Additionally, it will be crucial to implement socialization processes with local communities to ensure social acceptance of the project and strengthen participatory governance.

Finally, for future research directions, it is recommended to incorporate dynamic scenario analyses of urban growth and population expansion, as well as to evaluate complementary alternatives such as transfer stations, waste valorization facilities, and waste generation minimization strategies. Furthermore, the model could be enhanced by integrating multicriteria weighting methods like the Analytic Hierarchy Process (AHP) for more complex scenarios or by including more detailed environmental impact simulations based on pollutant dispersion models.

5. Conclusions

The methodology applied through the use of ArcGIS software and the review of relevant literature enabled the selection of suitable sites for the final disposal of municipal solid waste in the municipality of Arbieto. By applying defined selection criteria, it was possible to identify specific areas that should be protected from illegal settlements to ensure proper integrated solid waste management.

Historically, the final disposal of waste in Arbieto has been conducted through open dumps, burning, or burial of waste across all districts, leading to serious social issues, environmental contamination, and public health risks. If no corrective measures are taken, these problems will intensify in the short term due to population growth and urban expansion.

The diagnostic process, based on GIS data and maps obtained from the PTDI of Arbieto and processed through ArcGIS, provided a clear identification of zones suitable for final waste disposal. The analysis of shapefiles related to topography, hydrography, road networks, population centers, geology, and vegetation cover allowed the pinpointing of the most appropriate locations for establishing a sanitary landfill.

Urban sprawl and informal settlements have placed increasing pressure on the local environment, causing significant land-use changes and generating further risks to public health. Soil contamination from improperly managed solid waste remains a critical issue in the municipality, underscoring the urgent need for an integrated waste management system beginning with the selection of an appropriate final disposal site.

Moreover, community education and environmental awareness campaigns conducted alongside the technical work constitute a key contribution. In the short to medium term, these actions are expected to foster concrete environmental protection measures and promote sustainable practices among the local population.

6. Patents

No patents have resulted from the work reported in this manuscript.

Appendix A.1. Procedure for Multicriteria Analysis in ArcGIS

The step-by-step procedure for performing the multicriteria analysis for sanitary landfill site selection in ArcGIS is presented below:

Table A1. Procedure for Multicriteria Analysis in ArcGIS.

Step	Procedure Description	Tool Used	ArcGIS Menu
1	Load the georeferenced map of Arbieto municipality	Add Data	Shapefile Distri_oficial
2	Load the Digital Elevation Model (DEM)	Add Data	DEM ASTGTM2_S18W066, DEM ASTGTM2_S18W067
3	Generate the slope map from DEM	Slope	ArcToolbox > Spatial Analyst Tools > Surface > Slope
4	Reclassify slope map (0–15% = 1; >15% = 0)	Reclassify	ArcToolbox > Spatial Analyst Tools > Reclassify
5	Load rivers shapefile	Add Data	Shapefile Rivers
6	Create Euclidean distance map from rivers	Euclidean Distance	ArcToolbox > Spatial Analyst Tools > Distance > Euclidean Distance
7	Reclassify distance to rivers (>500m = 1; ≤500m = 0)	Reclassify	ArcToolbox > Spatial Analyst Tools > Reclassify
8	Load road network shapefile	Add Data	Shapefile Local Roads
9	Create Euclidean distance map from roads	Euclidean Distance	ArcToolbox > Spatial Analyst Tools > Distance > Euclidean Distance
10	Reclassify distance to roads (>500m = 1; ≤500m = 0)	Reclassify	ArcToolbox > Spatial Analyst Tools > Reclassify
11	Load population centers shapefile	Add Data	Shapefile Localities
12	Create Euclidean distance map from population centers	Euclidean Distance	ArcToolbox > Spatial Analyst Tools > Distance > Euclidean Distance
13	Reclassify distance to population centers (>500m = 1; ≤500m = 0)	Reclassify	ArcToolbox > Spatial Analyst Tools > Reclassify
14	Load vegetation cover shapefile	Add Data	Shapefile Native Vegetation
15	Reclassify vegetation cover (no vegetation, grasslands, shrublands = 1; forests = 0)	Reclassify	ArcToolbox > Spatial Analyst Tools > Reclassify
16	Load geology shapefile	Add Data	Shapefile Geology
17	Reclassify geological formations (stable formations = 1; unstable formations = 0)	Reclassify	ArcToolbox > Spatial Analyst Tools > Reclassify
18	Perform raster overlay (logical intersection)	Raster Calculator	ArcToolbox > Spatial Analyst Tools > Map Algebra > Raster Calculator
19	Generate final suitability map	Raster Overlay	Result of logical AND operation
20	Export final map in raster and shapefile formats	Export Data	ArcGIS Output Options

Table A1. Procedure for Multicriteria Analysis in ArcGIS.

Step	Procedure Description	Tool Used	ArcGIS Menu
1	Load the georeferenced map of Arbieto municipality	Add Data	Shapefile Distri_oficial
2	Load the Digital Elevation Model (DEM)	Add Data	DEM ASTGTM2_S18W066, DEM ASTGTM2_S18W067
3	Generate the slope map from DEM	Slope	ArcToolbox > Spatial Analyst Tools > Surface > Slope
4	Reclassify slope map (0–15% = 1; >15% = 0)	Reclassify	ArcToolbox > Spatial Analyst Tools > Reclassify
5	Load rivers shapefile	Add Data	Shapefile Rivers
6	Create Euclidean distance map from rivers	Euclidean Distance	ArcToolbox > Spatial Analyst Tools > Distance > Euclidean Distance
7	Reclassify distance to rivers (>500m = 1; ≤500m = 0)	Reclassify	ArcToolbox > Spatial Analyst Tools > Reclassify
8	Load road network shapefile	Add Data	Shapefile Local Roads
9	Create Euclidean distance map from roads	Euclidean Distance	ArcToolbox > Spatial Analyst Tools > Distance > Euclidean Distance
10	Reclassify distance to roads (>500m = 1; ≤500m = 0)	Reclassify	ArcToolbox > Spatial Analyst Tools > Reclassify
11	Load population centers shapefile	Add Data	Shapefile Localities
12	Create Euclidean distance map from population centers	Euclidean Distance	ArcToolbox > Spatial Analyst Tools > Distance > Euclidean Distance
13	Reclassify distance to population centers (>500m = 1; ≤500m = 0)	Reclassify	ArcToolbox > Spatial Analyst Tools > Reclassify
14	Load vegetation cover shapefile	Add Data	Shapefile Native Vegetation
15	Reclassify vegetation cover (no vegetation, grasslands, shrublands = 1; forests = 0)	Reclassify	ArcToolbox > Spatial Analyst Tools > Reclassify
16	Load geology shapefile	Add Data	Shapefile Geology
17	Reclassify geological formations (stable formations = 1; unstable formations = 0)	Reclassify	ArcToolbox > Spatial Analyst Tools > Reclassify
18	Perform raster overlay (logical intersection)	Raster Calculator	ArcToolbox > Spatial Analyst Tools > Map Algebra > Raster Calculator
19	Generate final suitability map	Raster Overlay	Result of logical AND operation
20	Export final map in raster and shapefile formats	Export Data	ArcGIS Output Options