Landfill Site Research Articles

Biodegradable Waste Management in Georgia: Problems of the Composting System Introduction

Biodegradable waste management and, in particular, the introduction and implementation of composting systems are among the major problems for Georgia. An increase in the volume of municipal waste has been recorded in the country; therefore, the volume of generated biodegradable waste is also increasing. In accordance with the National Waste Management Strategy 2016-2030 of Georgia, the municipal waste generated in 2021 amounted to 1,104,952 tons. It is worth noting that the largest part of municipal waste is organic waste - 54.7%, while plastic waste is 13.8%, paper and cardboard - 10.6%, textiles - 4.1%, and other wastes. According to various studies, by 2030, waste generation is expected to increase from 0.6% to 1.2% annually, which should be the cause of significant challenges for national and local authorities, especially local municipalities, whose duties include municipal waste collection and transportation as well as the implementation of separate waste collection systems. Biodegradable waste management, including various composting systems, is of particular importance.The study shows that composting, as one of the best approaches for recycling biodegradable waste, is still not properly developed in Georgia. It is possible to name only a few successful experiences. Noteworthy among them is the Kutaisi Composting Center, which was established within the framework of the EU JOP “Black Sea Basin” in Kutaisi, Georgia. The Composting Center is designed for windrow composting of green waste (tree branches, leaves, grass). Its productivity is 2000 tons of compost annually. This Composting Center is one of the first in Georgia. It can bring very tangible benefits. In particular, the amount of municipal waste going to landfill sites was reduced by approximately 10%; the expenditures of the municipalities connected to the maintenance of green facilities (received compost is used) and so on have been reduced.Among the biodegradable waste composting approaches, it is recommended to use systems such as:Centralized composting,Community composting,Home (individual) composting.A centralized composting method can be used in municipalities where a large amount of biodegradable waste is generated. It is especially favorable in regions where the agricultural sector is developed and large amounts of green waste are generated. The Kutaisi Composting Center is a good example of the centralized composting system. As experience shows, such large-scale composting is particularly effective for green waste composting.It is promising for Georgia to introduce community composting approaches that offer an optimal scheme for communities to get the maximum benefits of their potential.Composting is an approach used in the field of biodegradable waste management that has the greatest potential in Georgia and can make a significant contribution to both economic development and the protection of the social and natural environment.

Dynamic changes in dissolved organic matter during transport of landfill leachate in porous medium.

The dynamic changes in dissolved organic matter (DOM) during the transport of landfill leachate (LL) in porous medium should be explored, considering the high levels of DOM in the LL of municipal solid waste. Column experiments were carried out at 25°C at a Darcy's flux of 0.29cm/h for 2722h to compare the transport of Cl-, ultraviolet absorbance at 254nm (UV254), chemical oxygen demand (COD), and dissolved organic carbon (DOC) in the simulated porous medium by using the CXTFIT2.1 code. Results showed that the convection-dispersion equation (CDE) could describe Cl- transport well. The high levels of λ and D could be highly correlated with the physicochemical properties of the porous medium. The transport of the studied DOM with evident aromatic character could be described appropriately by the CDE model with the first-order reaction assumption, considering the similar variation trends of UV254, COD, and DOC in the effluent during experiments. Specifically, the values of retardation factor (R) were in the following order: DOC > UV254 > COD, whereas the low values of the first-order decay coefficient (k1) for DOC and COD were still higher than that for UV254. High contents of humic-like substances in the DOM with complex toxic components resulted in the natural low removal efficiencies of COD, DOC, and UV254 (≤ 23%), which could be confirmed by the variations of fluorescence index (FI) and humification index (HIX) in the effluent. The results should be helpful in evaluating the environmental risk induced by the LL leakage in a landfill site.

Utilizing Industrial Sludge Ash in Brick Manufacturing and Quality Improvement.

This research demonstrates changes in the behaviors and characteristics of sintered bricks while using industrial sludge ash (ISA) and waste glass (WG) as a replacement for clay in the brick manufacturing procedure. Owing to the limited amount of available land in Taiwan, it is becoming increasingly difficult to locate suitable sites for sanitary landfills, which is a common final disposal method for ash that is produced during thermal treatment in sludge factories. To meet the urgent need for land, the final waste disposal must convert this waste into a new resource. This research investigated the feasibility of using general industrial sludge ash waste, due to its abundance and high potential as a raw material in producing bricks. The result of this study shows that the bricks made from ISA and WG under a certain mixture proportion (ISA50%/WG40%/Clay10%) had excellent industrial potentials, such as compressive strength and water absorption rate. However, owing to the wide variety of components from different sources of ISA, the mixture proportion might vary accordingly. This study also analyzed the incineration index, proportion design, and process improvement, as well as investigating the possibility of increasing the total use of sludge ash as a resource. This study shows the potentials of utilizing wastes as raw materials in industrial manufacturing procedures. Therefore, more wastes can be tested and turned into resources in the future.

Long-Term Polyethylene (Bio)Degradation in Landfill: Environmental and Human Health Implications from Comprehensive Analysis.

This study investigates the process of long-term (bio)degradation of polyethylene (PE) in an old municipal waste landfill (MWL) and its implications for environmental and human health. Advanced techniques, such as ICP-ES/MS and IC-LC, were used to analyze heavy metals and anions/cations, demonstrating significant concentration deviations from control samples. The soil's chemical composition revealed numerous hazardous organic compounds, further indicating the migration of additives from PE to the soil. Toxicological assessments, including Phytotoxkit FTM, Microtox® bioassay, and Ostracodtoxkit®, demonstrated phytotoxicity, acute toxicity, and high mortality in living organisms (over 85% for Heterocypris Incongruens). An unusual concentration of contaminants in the MWL's middle layers, linked to Poland's economic changes during the 1980s and 1990s, suggests increased risks of pollutant migration, posing additional environmental and health threats. Moreover, the infiltration capability of microorganisms, including pathogens, into PE structures raises concerns about potential groundwater contamination through the landfill bottom. This research underscores the need for vigilant management and updated strategies to protect the environment and public health, particularly in older landfill sites.

Durability of Prestressed Piles in a Leachate Environment.

Prestressed pipe piles are common concrete components characterized by dense concrete structures and favorable mechanical properties, and thus, extensively used as coastal soft soil foundations. However, their durability in harsh environments has not been fully clarified. In this study, leachate from an actual landfill site was collected from the east coast of China as the corrosive medium, and the corrosion process was accelerated by electrifying prestressed pipe piles. The results demonstrated that the concentration of chloride ions in the concrete of the prestressed pile increased with the increase in corrosion time. Moreover, the experimental corrosion of these prestressed piles in the drying-wetting cycle proved to be the most severe. However, a protective layer of epoxy resin coating can effectively inhibit the diffusion of chloride ions into the interior of the piles. The final theoretical corrosion amounts of the piles were 1.55 kg, 1.20 kg, and 1.64 kg under immersion, epoxy resin protection, and a drying-wetting cycle environment. The application of epoxy resin reduced chloride penetration by 22.6%, and the drying-wetting cycle increased chloride penetration by 5.8%, respectively, with corresponding corrosion potentials following similar patterns. The actual corrosion depth of the welding seam was 3.20 mm, and there was a large corrosion allowance compared with the requirement (6.53 mm) for the ultimate bending moment. In summary, these prestressed piles exhibited good durability in a leachate environment.

Evaluation of the Activity of a Municipal Waste Landfill Site in the Operational and Non-Operational Sectors Based on Landfill Gas Productivity

This research identifies the productivity of landfill gas actively captured at a municipal waste landfill site with a waste mass exceeding 1 million Mg from sectors in the operational and non-operational phases, considering meteorological conditions. Based on the analysis of landfill gas, including emissions and composition (CH4, CO2, O2, and other gases), the processes occurring demonstrate the impact of the decomposition of deposited waste on the activity of the deposit. With average monthly gas emissions exceeding 960,000 m3, the average content of CH4 (30–63%) and CO2 (18–42%) and the varied content of O2 (0.3–9.8%) in individual sectors of the landfill site were significant. The statistically significant relationship between CH4, CO2, and landfill gas emissions exhibited a noticeable decrease in methane content. Despite the abandonment of waste storage, a high correlation is present between the emission level and methane content (0.59) and carbon dioxide (0.50). In the operational part of the landfill, this relationship is also statistically significant but to a lesser extent; Spearman’s R-value was 0.42 for methane and 0.36 for carbon dioxide. The operational and post-operational phases of the municipal waste landfill demonstrated a noticeable impact from the amount of precipitation, relative humidity, and air temperature, on landfill gas productivity. The generally progressive decline in the activity of the waste deposit, which reflects a decreasing trend in the methane content of approximately 2% annually in the total composition of landfill gas, as well as the share below 50%, indicates the need only to utilise landfill without producing energy.

Environmental and Health Impact of Heavy Metal Accumulation in (Hair - Nails) of Scavenger Workers at Some Landfill Sites in Baghdad City-Iraq

Background: Heavy metals are considered one of the most dangerous environmental pollutants due to their high toxicity, even at low concentrations, and their accumulation in various body tissues. Landfills contain various wastes rich in heavy metals, such as batteries, paints, and household and hospital waste, making them a major source of air, soil, and groundwater pollution. Objective: To analyze the level of accumulation of heavy metals in hair and nail samples of waste collectors. Material and method: Five main landfill sites in the city of Baghdad were chosen to collect hair and nail samples from waste collectors of both sexes for the winter and summer seasons to analyze the levels of metal concentrations (lead, cadmium, nickel, zinc, and copper). And the use of atomic absorption spectrometry (AAS). Results: Higher concentrations of lead, copper, and nickel were found in nail samples during the summer compared to the winter, indicating an increased risk of exposure to them. While zinc accumulation was much greater in winter samples. Conclusions The results highlight the health risks faced by landfill workers. A need to develop tailored strategies to control exposure to these emissions based on weather conditions and priority metals of concern identified through regular biological monitoring.

Estimation of landfill gas emissions at the solid waste disposal site of low-population regions with LandGEM and tabasaran–rettenberger mathematical models

ABSTRACT In developing countries, solid waste most commonly ultimately ends up is landfill. Landfill sites release significant amounts of air pollutants, such as methane (CH4) and carbon dioxide. It is thus important to reduce, control, and recycle these gases. In this study, we aimed to calculate gas emissions and energy production from landfill sites serving low-population areas. Future landfill gas production was estimated using LandGEM and Tabasaran – Rettenberger models, based on population and waste volume predictions. In both models, total amount of landfill gas and CH4 produced reached their highest values in 2035. According to the LandGEM model, this will amount to 11,230 and 3,179 Mg/year, respectively, while the Tabasaran – Rettenberger model predicted 14,986 and 4,014 Mg/year, respectively. The volume of landfill gas calculated using the Tabasaran – Rettenberger model was 3.730 million m3/year for 2021, while this was 2.544 million m3/year using the LandGEM model. In 2021, 84007 Mg of waste was disposed of at the landfill site. According to data from the electricity generation plant at the site, the electrical energy generated in 2021 was 5,309 kWh. Comparing the results from these two models with actual landfill data, the Tabasaran – Rettenberger model came closest to the estimate. Therefore, the Tabasaran – Rettenberger model can be used to estimate the potential for gas production at landfill sites in cities with similar waste components.

Severe microplastic pollution risks in urban freshwater system post-landfill fire: A case study from Brahmapuram, India

To investigate the escalating issue of microplastic (MP), pollution in urban water bodies, this study focuses on the aftermath of the Brahmapuram landfill fire in Kochi, India, analyzing its impact on MP concentrations in nearby freshwater system. The study conducted sampling sessions at the landfill site immediately before and after the fire. Post-fire, findings demonstrated a substantial increase in MP concentrations in surface waters, with levels rising from an average 25793.33 to 44863.33 particles/m³, featuring a notable presence of larger, predominantly black MPs. Sediment samples showed no significant change in MP count, but there was a significant increase in mass concentration. SEM/EDS analysis revealed changes in surface morphology and elemental composition, suggesting thermal degradation. Risk assessment using the Microplastic Pollution Index (MPI) and Risk Quotient (RQ) methods indicated heightened MP pollution risk in surface water post-fire. Hierarchical cluster analysis revealed the landfill's proximity as a significant factor influencing MP characteristics in the aquatic system. The study highlights the escalated challenge of MP pollution in urban water bodies following environmental disasters like landfill fires, underscoring the urgent need for policy and environmental management strategies.

Identification of potential landfill site suitability for urban solid waste disposal of Balurghat Municipality of Dakshin Dinajpur District using GIS and multi-criteria decision-making approach

The production of urban solid waste is one of the most dangerous environmental health risks on the planet. By selecting suitable landfill sites, it is possible to resolve the issue of health risks and environmental pollution driven by the unscientific disposal of solid waste. The current research is centered on determining suitable landfill locations for solid waste disposal within the Balurghat municipality through the integration of Geographic Information System (GIS) and Multi-Criteria Decision-Making (MCDM) approach. Ten factors were taken into consideration according to their weightage including elevation (0.022), Lithology (0.027), Slope (0.032), Land use and land cover LULC (0.040), Depth of water (0.057), Population density (0.075), Distance from sensitive places (0.107), Distance from road (0.154), Distance from river (0.205) and Land value (0.282). After conducting thorough field visits, an analytical hierarchy process (AHP) under the MCDM approach using GIS reveals acceptable sites that were noted and referenced. Final results are validated through a receiver operating characteristic (ROC) curve using randomly selected 80 potential landfill-suitable site location points with higher accuracy, and a total of 93% of the area under the curve (AUC) has been found worthy to validate the spatial result. The present investigation revealed that only 0.65% of land is very highly suitable, 31.06% of land is highly suitable, 52.54% of land is moderately suitable and 14.74% of land is not suitable for landfilling in Balurghat Municipal area and surroundings respectively. The highly suitable site belongs to the Mamna, Katna, Kuaran, Amtali, Noksha, Bannapara, and Malancha villages of the study area which is a very negligible area. So, the planners should adopt alternative strategies like source minimization, composting, sanitary landfills and awareness programmes for sustainable solid waste management. Hence, the Balurghat Municipality administration, urban planners, and administrative authorities stand to gain valuable insights from the findings of this study as they endeavour to enhance the management of urban solid waste in the area.

A Foam Line Position Detection Algorithm for A/O Pool Based on YOLOv5

During the biochemical pretreatment process of leachate in urban landfill sites, if the foam in the A/O pool is not promptly addressed, it can lead to overflow, posing hazards to the surrounding environment and personnel. Therefore, a real-time foam line detection algorithm based on YOLOv5x was proposed, which enhances feature information and improves anchor box regression prediction to accurately detect the position of foam lines. Firstly, in the preprocessing stage, employing a rectangular box to simultaneously label the foam line and the edge of the A/O pool within the same region, enhances the feature information of the foam line. Then, the C3NAM module was proposed, which applies weight sparse penalties to attention modules in the feature extraction section, to enhance the capability of extracting foam line features. Subsequently, a B-SPPCSPC module was proposed to enhance the fusion of shallow and deep feature information, addressing the issue of susceptibility to background interference during foam line detection. Next, the Focal_EIOU was introduced to ameliorate the issue of class imbalance in detection, providing more accurate bounding box predictions. Lastly, optimizing the detection layer scale improves the detection performance for smaller targets. The experimental results demonstrate that the accuracy of this algorithm reaches 98.9%, and the recall reaches 88.1%, with a detection frame rate of 26.2 frames per second, which can meet the actual detection requirements of real-world application scenarios.

Study on hydraulic conductivity of dredged sediment-attapulgite vertical cutoff walls under confining pressure

Landfills require effective containment systems to prevent the leakage of leachate into the underground environment. Cutoff walls are commonly employed for this purpose, with options including rigid and flexible designs. In areas where structural strength is not a primary concern, flexible cutoff walls offer lower permeability and environmental benefits due to their lack of cement content, thereby reducing CO2 emissions. This study investigates the use of dredged sediment and attapulgite as materials for flexible cutoff walls. Through analyses of bound water content, free water content, hydraulic conductivity, and scanning electron microscopy, we explore the impact of confining pressures on cutoff wall permeability.Our findings reveal that the consolidation induced by confining pressure does not significantly alter the bound water content within the cutoff wall. Instead, changes in water content are predominantly attributed to variations in free water content. Under identical confining pressures, we observe a positive correlation between permeability and hydraulic gradient, with permeability increasing as the hydraulic gradient rises, and anti-permeability decreasing accordingly. Additionally, when holding the hydraulic gradient constant, increasing confining pressure leads to a continuous decrease in permeability. Microscopic analyses highlight that high confining pressure not only compresses pore diameter but also alters pore morphology, thereby influencing permeability.This study contributes to the understanding of cutoff wall behavior under different conditions. Our results demonstrate that increasing confining pressure during soil consolidation effectively reduces cutoff wall permeability to meet design standards. However, the influence of high leachate head on permeability should also be considered. These findings provide a more environmentally friendly and lower permeability option for landfill sites, which is significant for the design and enhancement of containment systems in landfill sites.

Hydrogeological assessment and contaminant transport modelling of Enyimba landfill site in Aba, Nigeria

ABSTRACT Commercial and industrial growth in cities generates hazardous waste, often disposed of in open dump sites, contaminating groundwater. Understanding pollutant movement and numerical models are crucial for effective water resource management. This study assessed hydrogeological dynamics and pollutant transfer in the Enyimba landfill site, Nigeria, using field surveys and contaminant modelling to understand groundwater quality and arsenic contamination spread. The research technique included field and laboratory experiments, as well as water sampling during both dry and wet seasons, to evaluate groundwater quality. The geochemical examination of groundwater samples revealed the amounts of several metals using atomic absorption spectrophotometry. The study used contaminant transport modelling with Visual MODFLOW Flex 6.1 and MT3DMS software to simulate groundwater flow and solute transport within the aquifer layers. Predictive simulations over a 20-year timeframe demonstrated the progressive spread of arsenic pollution from the landfill, resulting in an ellipsoid-shaped plume stretching from its source. Arsenic levels have gradually increased, posing a serious threat to groundwater quality and human health. The research highlights the need for remedial measures to reduce groundwater pollution, including waste recovery and recycling facilities and geo-membrane use. It emphasizes proactive actions to protect groundwater supplies and promote environmental sustainability in the Enyimba landfill site.

Tracking bioaerosol exposure among municipal solid waste workers using hematological and inflammatory biomarkers

High levels of bioaerosols may exist in the air of municipal solid waste (MSW) management facilities, constituting a significant occupational hazard for workers. In this study, we investigated the potential association between exposure to bioaerosols and inflammatory biomarkers among municipal solid waste workers (MSWWs) at both the landfill site and the municipal solid waste transfer station (MSWTS), in comparison to a control group without exposure. Air sampling was conducted at six points around the landfill, two points at the MSWTS, and one point in a public park (as a control area) during the spring and summer of 2019. The results of our study revealed that airborne pathogens were highly prevalent at the sampling points, especially in the active zone and leachate collection pond. Aspergillus species were the predominant fungal species detected in this study, with the highest occurrence observed for Aspergillus flavus (83.3%), Aspergillus niger, and Aspergillus fumigatus (75.0%). Furthermore, Staphylococcus species accounted for over 75% of the total bacterial bioaerosols detected across all study areas. The blood test results of workers revealed a significant increase in platelets (PLT), immunoglobulin G (IgG), white blood cells (WBC), neutrophils, basophils, and high-sensitivity C-reactive protein (hs-CRP) compared to the control group. Conversely, platelet distribution width (PDW), mean platelet volume (MPV), and platelet-large cell ratio (P-LCR) in the exposed subjects exhibited a decreasing trend compared to the control group. These findings suggest a potential association between exposure to bioaerosols, particularly in the vicinity of open dumpsites, and elevated levels of hematologic and inflammatory markers in circulation. Furthermore, the influence of smoking status and confounding factors appears to be significant in both the control and exposure groups.

Ground Tire Rubber as a Sustainable Additive: Transforming Desert Sand Behavior

Managing waste tires presents a significant challenge globally, particularly in regions experiencing high temperatures and shortage of landfill sites. This issue is affecting countries like Kuwait, where the abundance of waste tires is a major source of environmental and safety risks, particularly during the intensely hot summer months. This extreme heat has sparked numerous fires, leading to substantial air pollution due to thick black smoke. Given the limited disposal options, recycling waste tires and finding practical applications for ground tire rubber (GTR) is essential. To address the challenge, a comprehensive laboratory testing program was conducted, using locally produced rubber aggregates as an additive to Kuwait's local surface sands. Two new variables were examined namely the size and gradation of the GTR, and the density of the compacted mixes. For this purpose, two different sizes of rubber aggregates, fine and coarse produced locally, were utilized, and the impact of relative compaction on the strength and compressibility of the mixtures was investigated by testing samples compacted to the maximum density and to 95% of the maximum density. The results suggest that combining local surface sands with rubber tire additives results in a lighter, more permeable, and compressible material, contributing significantly to sustainable waste management. With 20% rubber additive the maximum dry density decreased by nearly 20%, and the permeability increased by 1.74–3.11 times and the compression index increased by 6.15 and 3.8 times with fine and coarse rubber respectively. The angle of friction remained unchanged at 36° with the addition of coarse rubber and decreased by 3°–4° with fine rubber. The change in behavior although not an increase in the strength and stiffness, offers a range of suitable practical applications in civil engineering and environmental management, including use as a drainage layer, embankment construction on soft ground, earth fill around retaining walls, an additive in asphalt mixes, and in manufacturing compressible tiles for sports facilities.

Assessing Water Quality Index in Kani-Qirzhala Area, Erbil City, Kurdistan Region of Iraq

Groundwater is an essential water source in many areas in the Kurdistan Region of Iraq (KRI). The groundwater can be used for many purposes such as municipal, agricultural, and domestic. The objective of this study is to assess the quality of groundwater in the Kani-Qirzhala area. The study area covers 60 km2, and includes twenty-seven water wells, which have been selected and used to study the water quality parameters in such area. Canadian Council of Ministers for the Environment Water Quality Index method was used to evaluate Water Quality Index and SPSS software version 25 even to study the correlation between Water Quality Index and water quality parameters. The results indicated that the quality of water in most of the wells is fair, except the quality of water in wells 19, 24, and 27 is found to be poor. Well19 is located close to the Erbil landfill site (Kani-Qirzhala) and this poor quality is due to the effect of Landfill site leachate. The Well 24 is in the Erbil store area where the leachate of landfill is discharged to this surrounding area. The quality of water in well 27, on the other hand, was marginal and existed on the eastern side of the study area. The significant correlation revealed a good correlation between WQI and water quality parameters such as (pH, EC, TDS, Ca2+ Na1+, Mg2+, NO3-1, K1+, SO42-, Cl1-, Hardness, Alkalinity, Iron, and Copper).

Comparative life cycle assessment of landfill gas utilization in South Korea with parametric uncertainties

Landfill gas, a major contributor to global CH4 emissions, which have a much greater impact on global warming than CO2 does, is inevitable as a waste derivative. Upcycling landfill gas into value-added products is a powerful strategy to reduce greenhouse gas emissions and to use materials in a circular system. This study presents a full life cycle assessment of electricity produced using landfill gas at the Sudokwon landfill site, the largest case of landfill gas upcycling in South Korea. To ensure the representativeness of the results, we used statistical data to capture the technical and regional characteristics of the national market share as primary data. In addition, a parametric uncertainty analysis integrated with data quality assessment was conducted to reflect the temporal dynamics of landfills and enhance the reliability of this study. Our findings demonstrate that upcycling landfill gas into electricity is environmentally beneficial across sixteen impact categories compared with two baseline scenarios that do not involve landfill gas upcycling. The methodological approaches presented herein can address multifunctional challenges in waste treatment systems and improve the reliability of life cycle inventories.

Characterization and differentiation of dissolved organic matter in leachate derived from an old Japanese landfill site through Orbitrap mass spectrometry

Elucidating the characteristics of dissolved organic matter (DOM) is crucial to assessing its impact on the bioavailability and mobility of pollutants in landfill leachate. This study reports a comprehensive 5–month investigation into the characteristics of DOM in leachate from an old Japanese landfill, collected at six different sampling points. The molecular composition, chemical properties, and structural characteristics of DOM were assessed using Orbitrap mass spectrometry and spectral analysis. The leachate DOM mainly consisted of CHO-containing molecules (58.5–88.9%), low-oxygen unsaturated phenolic compounds (40.5–54.0%), and aliphatic compounds (19.4–47.3%), with slight variation among sampling points. A significant portion of the nominal oxidation state of carbon was in the reduced zone (76.2–95.4%). The results underscore the distinct molecular composition of DOM in mature Japanese landfill leachate compared to young and mature leachates from other countries. Two of six sampling points, with notable differences in molecular characteristics, were compared and elucidated. The composition of landfill waste, rather than landfill age, was the main factor affecting the characteristics and differentiation of leachate DOM.

A comprehensive review on the integration of geographic information systems and artificial intelligence for landfill site selection: A systematic mapping perspective.

Properly selecting landfill sites for waste disposal is crucial for mitigating environmental and public health risks. Geographic Information Systems (GISs) and Artificial Intelligence (AI) techniques have emerged as valuable tools for identifying suitable landfill locations. This study presents a systematic mapping study (SMS) that investigates the usage of GIS and AI in landfill site selection. We searched six databases (IEEE Xplore, ACM Digital Library, Science Direct, Emerald Insight, Taylor & Francis Online and Web of Science) using predefined keywords related to landfills, GIS and AI. From 858 initially retrieved articles, we selected 48 relevant articles for in-depth analysis. Our research aimed to answer various questions, such as publication trends, the geographic distribution of case studies, criteria for assessing landfill suitability, tools and techniques employed, preliminary site screening methods, decision-making processes, limitations and future research directions. We used bubble charts, bar charts and tables to visualize the results. The findings of our study highlight the growing interest in using GIS and AI for landfill site selection and emphasize the importance of incorporating multi-criteria decision-making techniques. Furthermore, the results reveal the need for developing more advanced AI models, addressing the limitations of current approaches and exploring novel visualization techniques for enhancing landfill site selection processes. This study provides valuable insights for researchers and practitioners in waste management, environmental science and geoinformatics. It sets the groundwork for future research on improving GIS- and AI-based landfill site selection methodologies.

Economic and environmental benefit of informal waste scavenging at landfill sites: A case study at Bukit Gemuk, Tawau, Sabah, Malaysia

Recycling is an important part of the solid waste management system. However, community engagement in this activity remains relatively low. The presence of a group of individuals engaged in collecting recyclable materials at landfill sites has contributed to improving solid waste management performance. This paper aims to identify the background and activities of scavengers in collecting recyclable items at landfills, as well as the environmental impact of the scavenging activity. This study was based on questionnaires distributed to 46 scavengers in the study area. The Life Cycle Assessment (LCA) method was used to assess the environmental impact of using recyclable materials in manufacturing products. The LCA analysis could identify the contribution of recycled materials to the total savings of carbon dioxide (CO2), methane (CH4), and nitrogen dioxide (N20) by using recycled materials in the production of a new product. According to the study, the majority of those involved in the scavenging activity are immigrants from Indonesia and the Philippines. Despite safety and health concerns, their efforts to earn a living through waste scavenging are extremely valuable. Furthermore, the findings show that their contribution to the collection of recyclable materials cannot be denied. It is because the presence of this group is essential in a country where recycling awareness is low. Furthermore, the indirect contribution to the environment is important, particularly in reducing the use of natural materials in producing new materials. As a result, the government must devise a more effective strategy for recycling programs by involving all stakeholders.