Decreasing Greenhouse Gas Emissions from the Municipal Solid Waste Sector in Chinese Cites.

Municipal solid waste (MSW) management systems play a crucial role in greenhouse gas (GHG) emissions in China. Although the government has implemented many policies to improve the MSW management system, the impact of these improvements on city-level GHG emission reduction remains largely unexplored. This study conducted a comprehensive analysis of both direct and downstream GHG emissions from the MSW sector, encompassing sanitary landfill, dump, incineration, and biological treatment, across 352 Chinese cities from 2001 to 2021 by adopting inventory methods recommended by the Intergovernmental Panel on Climate Change (IPCC). The results reveal that (1) GHG emissions from the MSW sector in China peaked at 70.6 Tg of CO2 equiv in 2018, followed by a significant decline to 47.6 Tg of CO2 equiv in 2021, (2) cities with the highest GHG emission reduction benefits in the MSW sector were historical emission hotspots over the past 2 decades, and (3) with the potential achievement of zero-landfilling policy by 2030, an additional reduction of 203.7 Tg of CO2 equiv is projected, with the emission reduction focus toward cities in South China (21.9%), Northeast China (17.8%), and Southwest China (17.3%). This study highlights that, even without explicit emission reduction targets for the MSW sector, the improvements of this sector have significantly reduced GHG emissions in China.

Mini-Open Dumps in the Paraná River Floodplain: Local Problems with Global Effects.

The growing production of urban solid waste is a structural problem faced by most cities around the world. The proliferation of mini-open dumps (MOD; small spontaneous open-air waste dumps formed in urban and peri-urban areas) on the banks of the Paraná River is particularly evident. During the historical drought (June-December 2021), we carried out sampling campaigns identifying MODs of the Santa Fe River, a secondary channel of the Paraná River. MOD were geolocated, measured, described and classified by origin. The distance to the river and other sensitive places was considered (houses-schools-health facilities). Our results suggested a serious environmental issue associated with poor waste management. MOD were extremely abundant in the study area, being mostly composed of domestic litter. Plastics clearly dominated the MOD composition. Burning was frequently observed as a method to reduce the volume of MOD. We concluded that the proliferation of MOD is a multi-causal problem associated with a failure of public policies and a lack of environmental education.

New insight into the spatio-temporal patterns of functional groups of hotspot inside the composting aggregates by synchrotron-based FTIR in hyperthermophilic composting.

Hyperthermophilic composting (HTC) is a recently developed and highly promising organic fraction of municipal solid waste (OFMSW) treatment technology. Investigation of organic matter (OM) dynamics in compost particle is thus crucial for the understanding of humification of HTC process. Herein, this work aimed to study the chemical and structural changes of OM at the molecular level during HTC of OFMSW using EEM and SR-FTIR analyses. Additionally, two-dimensional correlation spectroscopy (2D-COS) was also utilized to probe and identify the changes in chemical constituents and functional groups of organic compounds on the surface of compost particles during different composting periods. Results show that SR-FTIR can detect fine-scale (~µm) changes in functional groups from the edges to the interior of compost particles during different composting periods by mapping the particles in situ. In the hyperthermophilic stage (day 9), the extracted µ-FTIR spectrum reveals a distinct boundary between anaerobic and aerobic regions within the compost particle, with a thickness of anaerobic zone (1460 cm-1) of approximately 30 µm inside the particle's core. This provides direct evidence of anaerobic trends at compost microscales level within compost particles. 2D-COS analysis indicated that organic functional groups gradually agglomerated in the order of 1330 > 2930 > 3320 > 1600 > 1030 > 895 cm-1 to the core skeleton of cellulose degradation residues, forming compost aggregates with well physicochemical properties. Overall, the first combination of SR-FTIR and EEM provides complementary explanations for the humification mechanism of HTC, potentially introducing a novel methodology for investigating the environmental behaviors and fates of various organic contaminants associated with OM during the in-situ composting biochemical process.

Enhanced thermophilic high-solids anaerobic digestion of organic fraction of municipal solid waste with spatial separation from conductive materials in a single reactor volume.

Despite benefits such as lower water and working volume requirements, thermophilic high solids anaerobic digestion (THSAD) often fails due to the rapid build-up of volatile fatty acids (VFAs) and the associated drop in pH. Use of conductive materials (CM) can promote THSAD through stimulation of direct interspecies electron transfer (DIET), while the need for their constant dosing due to poor separation from effluent impairs economic feasibility. This study used an approach of spatially separating magnetite and granular activated carbon (GAC) from the organic fraction of municipal solid waste (OFMSW) in a single reactor for THSAD. GAC and magnetite addition could both mitigate the severe inhibition of methanogenesis after VFAs build-up to ∼28-30 g/L, while negligible methane production was observed in the control group. The highest methane yield (286 mL CH4/g volatile solids (VS)) was achieved in magnetite-added reactors, while the highest maximum CH4 production rates (26.38 mL CH4/g VS/d) and lowest lag-phase (2.83 days) were obtained in GAC-added reactors. The enrichment of GAC and magnetite biofilms with various syntrophic and potentially electroactive microbial groups (Ruminiclostridium 1, Clostridia MBA03, Defluviitoga, Lentimicrobiaceae) in different relative abundances indicates the existence of specific preferences of these groups for the nature of CM. According to predicted basic metabolic functions, CM can enhance cellular processes and signals, lipid transport and metabolism, and methane metabolism, resulting in improved methane production. Rearrangement of metabolic pathways, formation of pili-like structures, enrichment of biofilms with electroactive groups and a significant improvement in THSAD performance was attributed to the enhancement of the DIET pathway. Promising results obtained in this work due to the spatial separation of the bulk OFMSW and CM can be useful for modeling larger-scale THSAD systems with better recovery of CM and cost-effectiveness.

[Effects of food waste biogas residue composting on soil aggregates and its organic matter content in relocation site]. / åŽ¨ä½™åžƒåœ¾æ²¼æ¸£å †è‚¥å¯¹æ¬è¿åœ°åœŸå£¤å›¢èšä½“åŠå ¶æœ‰æœºè´¨å«é‡çš„å½±å“.

Understanding the effects of food waste biogas residue composting and chemical amendments on soil aggregates composition of different particle sizes, stability, and organic matter distribution in relocation sites could provide primary data for improving soil quality and land utilization of food waste biogas residue composting. We analyzed the characteristics of soil aggregates distribution, stability of aggregates, and organic matter content in different particle sizes under treatments with different application amounts of food waste biogas residue composting, chemical amendments (ß-cyclodextrin, calcium sulfate and ferric oxide were mixed at a mass ratio of 1:1:1), and control (100% soil). The results showed that 20% (soil: biogas residue composting=8:2) and 30% (soil: biogas residue composting =7:3) biogas residue composting significantly decreased the micro-aggregates content with the particle size of <0.106 mm and increased the large aggregates content with the particle size of 0.5-1.0 mm. All treatments significantly increased large aggregates content with the particle size of ≥2.0 mm, soil aggregate structure content, and mean weight diameter, but reduced the percentage of aggregate destruction. Among all the treatments, the effect of mixes application of 20% biogas residue composting and chemical amendments was the best. Biogas residue composting treatments significantly affected the distribution of organic matter in soil aggregates, with the strongest effect under 30% biogas residue composting treatment. Biogas residue composting treatments significantly increased soil organic matter content in all aggregates, with the maximal increase of organic matter content in soil micro-aggregates with the particle size of 0.106-0.25 mm. In conclusion, biogas residue composting could increase organic matter content of soil aggregates in different particle sizes, promote the formation of large soil aggregates, and improve the stability of aggregation. Specifically, the mixed application of biogas residue composting and chemical amendments performed better on soil improvement in relocation site.

[Effects of Fly Ash on the Efficiency and Bacterial Community Structure of Urban Multi-source Organic Solid Waste].

To achieve efficient resource utilization of fly ash and multi-source organic waste, a composting experiment was carried out to investigate the effects of fly ash on co-aerobic composting using kitchens, chicken manure, and sawdust (15:5:2). The effects of different application doses (5 % and 10 %, calculated in total wet weight of organic solid waste) of fly ash on physical and chemical properties, nutrient elements, and bacterial community structure during co-composting were evaluated. The results showed that the addition dose of 5 % and 10 % fly ash significantly increased the highest temperature (56.6 ℃ and 56.9 ℃) and extended the thermophilic period to nine days. Compared with that in the control, the total nutrient content of compost products in the treatments of 5 % FA and 10 % FA was increased by 4.09 % and 13.55 %, respectively. The bacterial community structure changed greatly throughout the composting, and the bacterial diversity of all treatments increased obviously. In the initial stage of composting, Proteobacteria was the dominant phylum of bacteria, with a relative abundance ranging from 35.26 % to 39.40 %. In the thermophilic period, Firmicutes dominated; its relative abundance peaked at 52.46 % in the 5 % FA treatment and 67.72 % in the 10 % FA treatment. Bacillus and Thermobifida were the predominant groups in the thermophilic period of composting. The relative abundance of Bacillus and Thermobifida in the 5 % FA and 10 % FA treatments were 33.41 % and 62.89 %(Bacillus) and 33.06 % and 12.23 %(Thermobifida), respectively. The results of the redundancy analysis (RDA) revealed that different physicochemical indicators had varying degrees of influence on bacteria, with organic matter, pH, available phosphorus, and available potassium being the main environmental factors influencing bacterial community structure. In summary, the addition of fly ash promoted the harmlessness and maturation of co- aerobic composting of urban multi-source organic waste, while optimizing microbial community structure and improving the quality and efficiency of composting.

Evolution of physicochemical and leaching characteristics of municipal solid waste incineration fly ash in China under ultra-low emission standard.

The physical and chemical characteristics of fly ash has changed significantly under ultra-low emission system and the current leaching system is no longer suitable for high alkalinity fly ash. This work investigated the pH values and evolution of physical and chemical characteristics of fly ash from 24 typical municipal solid waste incineration plants in China. The pH value of the leaching solution obtained by HJ/T 300-2007 presented two different acid and alkali characteristics, where high and low alkalinity fly ash accounted for 54.17% and 45.83%, respectively. The alkali content in fly ash increased significantly after ultra-low emission standard, increasing by 18.24% compared with before the implementation of GB 18485-2014. The leaching behavior of high alkalinity fly ash showed the illusion that they could enter the landfill only by the addition of a small amount of chelating agent or even without stabilization treatment, and its long-term landfill risk is significant. The phase change of high alkalinity fly ash and pH value change of the leaching solution after carbonation were the key factors for the leaching concentration change of heavy metals. Therefore, it is recommended to improve the existing leaching system or conduct accelerated carbonization experiments to scientifically evaluate the long-term leaching characteristics of high alkalinity fly ash, and to reduce the risk of heavy metal release from high alkalinity FA after entering the landfill site.

An overview of waste management practices of street vendors in sub-saharan africa: A meta-analysis.

Many low-income developing countries struggle with waste collection and the development of disposal facilities, leading to issues such as illegal dumping and poor enforcement of waste management regulations. The pollution caused by street vendors' waste is particularly evident in the central business districts of cities in developing nations. The informal economy, which includes activities such as street vending has become prevalent in developing countries, particularly in Sub-Saharan African (SSA) nations. This study aims to conduct a systematic review and meta-analysis of existing literature on street vendors' waste management practices in the region, with a focus on understanding the factors influencing waste mismanagement and identifying integrated strategies employed across SSA. In most SSA areas, research is conducted to evaluate food vendor hygienic practices (33%), however the waste management component, which is crucial to hygiene, makes up just 15%, which is twice as small as the research that focused on hygienic practices. As a result, street vendors in the majority of sub-Saharan nations have little interest in waste management procedures. Many street vendors in the region resort to informal waste disposal methods because of no access to formal waste management infrastructure since they are not recognised as formal businesses. The study acknowledges the street vendors' contribution to food security in developing Sub Saharan Africa, as well as the significance of comprehending their waste management practices. Despite their prevalence in urban areas, these informal businesses still face a lack of recognition and inclusion from governing bodies. Therefore, the study emphasises the necessity of incorporating street vendors into formal municipal waste management systems and providing them with enhanced infrastructure and services. Given that the lack of recognition subsequently make it challenging to integrate vendors into formal waste management systems. Subsequently this has a negative cumulative impact on developing and enforcing clear regulations that specify the responsibilities of street vendors in waste management. Thus, leading to the absence of comprehensive by laws regulations governing waste management for street vendors within Sub-Saharan Africa.

Public awareness, knowledge, and attitude regarding proper disposal of unused medicines and associated factors in Gondar city, northwest Ethiopia.

Background: Proper disposal of unwanted medicines, in addition to reducing wastage, has a positive impact on the environment and public health. Improper disposal of medications increases the risk of accidental poisonings, particularly among children. This study aimed to assess the level of knowledge, attitudes, and awareness regarding the proper disposal of unused medicines in Gondar city, northwest Ethiopia. Method: From 30 July to 30 August 2023, a community-based cross-sectional study was conducted among the public in Gondar city. The data were gathered using the Kobo toolbox, exported into an Excel sheet, and then analyzed using SPSS version 27. Multivariate and bivariate binary logistic regressions were performed. A p-value of 0.05 with a 95% confidence interval (CI) was used to determine statistical significance. Result: From 786 study participants, the overall knowledge and attitude of the community toward the proper disposal of unused medicines were 42.6 and 42.9%, respectively. Factors identified in this study included ages between 19 and 25 [AOR = 6.91, 95% CI: (3.45, 13.84); education level: secondary [AOR = 11.82, 95% CI: (1.01, 3.29)] and college and above [AOR = 5.68, 95% CI: (2.25, 14.30)]; prior information [AOR = 6.41; 95% CI: (4.02, 10.22)]; and good attitudes [AOR = 2.11; 95% CI: (1.47, 3.02)]] as factors associated with good knowledge toward proper disposal of unused medicines. In addition, receiving information [AOR = 1.86 95% CI: (1.22, 2.86)], taking medication in the past 6 months [AOR = 1.61, 95% CI: (1.09, 2.38)], and being knowledgeable [AOR = 2.07 95% CI: (1.46, 2.94)] were factors contributing to positive attitudes toward the disposal of unused medicines among the general public. Furthermore, approximately 369 participants (46.9%) in our study lacked awareness about the harmful effects of disposing of unused medicine in regular waste. Conclusion: A relatively low level of knowledge and attitudes about the proper disposal of unused medications is present in the community. In this regard, a well-coordinated and methodical public awareness campaign is recommended to disseminate information and promote the appropriate disposal of unused medications.

Combustion characteristics and gasification kinetics of Brazilian municipal solid waste subjected to different atmospheres by thermogravimetric analysis.

This study examines the gasification kinetics of Brazilian municipal solid waste (MSW) and its components under air, CO2, and air/CO2 (70/30 vol%) atmospheres. The ignition indices of paper and plastic are 6 and 3 times that of food waste, which are 38.6 × 10-3 %/min3 and 19.6 × 10-3 %/min3, respectively, implying a faster separation of volatile compounds from the paper and plastic. The minimum Eα values of 132 kJ/mol and 140 kJ/mol have been obtained for paper waste under air and air/CO2, respectively. On CO2 condition, MSW has an average Ea value of 96 kJ/mol. Under an air/CO2 atmosphere, a high synergistic ΔW of -4.7 wt% has been identified between individual components. The presence of air and CO2 improves the oxidation and char gasification process, thus resulting in better combustion. Hence, the gasification of MSW under an air/CO2 atmosphere would improve the waste-to-energy plant's performance and minimize the CO2 emission.

Evaluating factors promoting waste scavenging and its implications in a growing urban environ in Nigeria.

Despite the inherent risks associated with waste scavenging, it is surprising to note the age group involved in this activity. This study aimed to assess the motivating factors driving teenagers and youths to participate in waste scavenging, using a sample of 247 scavengers. The data underwent analysis using frequency counts, percentages, and factor analysis techniques. The findings revealed that all respondents were male and aged between 12 and 45 years. The primary sources of waste were dumpsites (61%), roadsides, and gutters (26%). Participants predominantly cited lack of formal education requirements and financial gain (93%) as key motivators for their involvement in waste scavenging. Additionally, 96% of scavengers were from northern Nigeria, with the remaining 4% from southern Nigeria. The factor analysis yielded significant results with a Kaiser-Meyer-Olkin (KMO) measure and Bartlett's test value of 67.770%, significant at p < 0.05. Four distinct factors emerged as significant motivators: (i) Lack of formal education (31.784%), (ii) Financial incentives (22.912%), (iii) Availability of wastes (14.297%), and (iv) Industrial demand for wastes (13.495%), in descending order of influence. Together, these factors accounted for 82.487% of the motivating factors behind youth engagement in waste scavenging in the study area. This outcome highlights potential challenges for the prospects of young individuals involved in scavenging unless substantial interventions are implemented. It is recommended that policies be developed to discourage scavenging activities while simultaneously promoting access to education and social welfare for this demographic. Such initiatives are crucial for redirecting young people away from scavenging and toward more sustainable livelihood options, ensuring a brighter future for them and contributing to overall societal development.

Landfill-mined soil-like fraction (LMSF) use in biopolymer composting: Material pre-treatment, bioaugmentation and agricultural prospects.

Polylactic Acid (PLA) based compostable bioplastic films degrade under thermophilic composting conditions. The purpose of our study was to understand whether sample pre-treatment along with bioaugmentation of the degradation matrix could reduce the biodegradation time under a simulated composting environment. Sepcifically, we also explored whether the commercial composts could be replaced by landfill-mined soil-like fraction (LMSF) for the said application. The effect of pre-treatment on the material was analysed by tests like tensile strength analysis, hydrophobicity analysis, morphological analysis, thermal degradation profiling, etc. Subsequently, the degradation experiment was performed in a simulated composting environment following the ASTM D5338 standard, along with bioaugmentation in selected experimental setups. When the novel approach of material pre-treatment and bioaugmentation were applied in combination, the time necessary for 90% degradation was reduced by 27% using compost and by 23% using LMSF. Beyond the improvement in degradation rate, the water holding capacity increased significantly for the degradation matrices. With pH, C: N ratio and microbial diversity tested to be favourable through 16s metabarcoding studies, material pre-treatment and bioaugmentation allow LMSF to not only replace commercial compost in polymer degradation but also find immense application in the agricultural sector of drought-affected areas (for better water retention) after it has been used for PLA degradation.

High-efficient stabilization and solidification of municipal solid waste incineration fly ash by synergy of alkali treatment and supersulfated cement.

Municipal solid waste incineration fly ash (IFA) designated as hazardous waste poses risks to environment and human health. This study introduces a novel approach for the stabilization and solidification (S/S) of IFA: a combined approach involving alkali treatment and immobilization in low-carbon supersulfated cement (SSC). The impact of varying temperatures of alkali solution on the chemical and mineralogical compositions, as well as the pozzolanic reactivity of IFA, and the removal efficiency of heavy metals and metallic aluminum (Al) were examined. The physical characteristics, hydration kinetics and effectiveness of SSC in immobilizing IFA were also analyzed. Results showed that alkali treatment at 25 °C effectively eliminated heavy metals like manganese (Mn), barium (Ba), nickel (Ni), and chromium (Cr) to safe levels and totally removed the metallic Al, while enhancing the pozzolanic reactivity of IFA. By incorporating the alkali-treated IFA and filtrate, the density, compressive strength and hydration reaction of SSC were improved, resulting in higher hydration degree, finer pore structure, and denser microstructure compared to untreated IFA. The rich presence of calcium-aluminosilicate-hydrate (C-(A)-S-H) and ettringite (AFt) in SSC facilitated the efficient stabilization and solidification of heavy metals, leading to a significant decrease in their leaching potential. The use of SSC for treating Ca(OH)2- and 25°C-treated IFA could achieve high strength and high-efficient immobilization.

Biohydrogen production by lactate-driven dark fermentation of real organic wastes derived from solid waste treatment plants.

This study evaluated the hydrogen production potential through lactate-driven dark fermentation (LD-DF) of organic wastes from solid waste treatment plants, including the organic fraction of municipal solid waste (OFMSW), mixed sewage sludge, and two OFMSW leachates. In initial batch fermentations, only OFMSW supported a significant hydrogen yield (70.1 ± 7.7 NmL-H2/g-VS added) among the tested feedstocks. Lactate acted as an important hydrogen precursor, requiring the presence of carbohydrates for sequential two-step lactate-type fermentation. The impact of operational pH (5.5-6.5) and initial total solids (TS) concentration (5-12.5 % w/w) was also evaluated using OFMSW as substrate, obtaining hydrogen yields ranging from 6.6 to 55.9 NmL-H2/g-VSadded. The highest yield occurred at 6.5 pH and 7.5 % TS. The LD-DF pathway was indicated to be present under diverse pH and TS conditions, supported by employing a specialized microbial consortium capable of performing LD-DF, along with the observed changes in lactate levels during fermentation.

Plasticizers inhibit food waste anaerobic digestion performance by affecting microbial succession and metabolism.

The widely existed plastic additives plasticizers in organic wastes possibly pose negative influences on anaerobic digestion (AD) performance, the direct evidence about the effects of plasticizers on AD performance is still lacking. This study evaluated the influencing mechanism of two typical plasticizers bisphenol A (BPA) and dioctyl phthalate on the whole AD process. Results indicated that plasticizers addition inhibited methane production, and the inhibiting effects were reinforced with the increase of concentration. By contrast, 50 mg/L BPA exhibited the strongest inhibition on methane production. Physicochemical analysis showed plasticizers inhibited the metabolism efficiency of soluble polysaccharide and volatile fatty acids. Microbial communities analyses suggested that plasticizers inhibited the direct interspecies electron transfer participators of methanogenic archaea (especially Methanosarcina) and syntrophic bacteria. Furthermore, plasticizers inhibited the methane metabolisms, key coenzymes (CoB, CoM, CoF420 and methanofuran) biosynthesis and the metabolisms of major organic matters. This study shed light on the effects of plasticizers on AD performance and provided new insights for assessing the influences of plasticizers or plastic additives on the disposal of organic wastes.

Revealing mechanisms of NH3 and N2O emissions reduction in the rapid bio-drying of food waste: Insights from organic nitrogen composition and microbial activity.

Inevitably, aerobic biological treatment processes generate emissions of ammonia (NH3) and greenhouse gas (GHGs) emissions, especially nitrous oxide (N2O). The rapid bio-drying process (RBD) for food waste (FW) alleviates issues arising from its substantial growth. However, its emissions of NH3 and N2O remain unknown, and the correlation with nitrogen components in the substrate remains unclear, significantly impeding its widespread adoption. Here, the nitrogen loss and its mechanisms in RBD were investigated, and the results are as follows: The total emission of NH3 and N2O were1.42 and 1.16 mg/kg FW (fresh weight), respectively, achieving a 98 % reduction compared to prior studies. Structural equation modeling demonstrates that acid ammonium nitrogen (AN) decomposition chiefly generates NH3 in compost (p < 0.001). Strong correlation (p < 0.001) exists between amino acid nitrogen (AAN) and AN. In-depth analysis of microbial succession during the process reveals that the enrichment of Brevibacterium, Corynebacterium, Dietzia, Fastidiosipila, Lactobacillus, Mycobacterium, Peptoniphilus, and Truepera, are conducive to reducing the accumulation of AN and AAN in the substrate, minimizing NH3 emissions (p < 0.05). While Pseudomonas, Denitrobacterium, Nitrospira, and Bacillus are identified as key species contributing to N2O emissions during the process. Correlation analysis between physicochemical conditions and microbial succession in the system indicates that the moisture content and NO3- levels during the composting process provide suitable conditions for the growth of bacteria that contribute to NH3 and N2O emissions reduction, these enrichment in RBD process minimizing NH3 and N2O emissions. This study can offer crucial theoretical and data support for the resource utilization process of perishable organic solid waste, mitigating NH3 and GHGs emissions.

Social competition drives collective action to reduce informal waste burning in Uganda.

Improving urban air quality is a pressing challenge in the Global South. A key source of air pollution is the informal burning of household waste. Reducing informal burning requires governments to develop formal systems for waste disposal and for residents to adopt new disposal behaviors. Using a randomized experiment, we show that social competitions between pairs of neighborhoods in Nansana municipality, Uganda, galvanized leadership and inspired collective action to reduce informal burning. All 44 neighborhoods in the study received a public health campaign, while 22 treated neighborhoods were paired and competed to reduce waste burning over an 8-mo period. Treated neighborhoods showed a 24 percent reduction (95% CI: 11 to 35 percent) in waste burning relative to control neighborhoods at the end of the competition period. There is no evidence that treated neighborhoods experienced a rebound in waste burning several months after the competitions. Community leaders reported greater effort in coordinating residents and more pride in their neighborhood when assigned to the competition treatment. These results suggest that creating focal points for leadership and collective action can be an effective and low-cost strategy to address policy problems that require broad participation and costly behavior change.

Integrating advanced techniques and machine learning for landfill leachate treatment: Addressing limitations and environmental concerns.

This review article explores the challenges associated with landfill leachate resulting from the increasing disposal of municipal solid waste in landfills and open areas. The composition of landfill leachate includes antibiotics (0.001-100 µg), heavy metals (0.001-1.4 g/L), dissolved organic and inorganic components, and xenobiotics including polyaromatic hydrocarbons (10-25 µg/L). Conventional treatment methods, such as biological (microbial and phytoremediation) and physicochemical (electrochemical and membrane-based) techniques, are available but face limitations in terms of cost, accuracy, and environmental risks. To surmount these challenges, this study advocates for the integration of artificial intelligence (AI) and machine learning (ML) to strengthen treatment efficacy through predictive analytics and optimized operational parameters. It critically evaluates the risks posed by recalcitrant leachate components and appraises the performance of various treatment modalities, both independently and in tandem with biological and physicochemical processes. Notably, physicochemical treatments have demonstrated pollutant removal rates of up to 90% for various contaminants, while integrated biological approaches have achieved over 95% removal efficiency. However, the heterogeneous nature of solid waste composition further complicates treatment methodologies. Consequently, the integration of advanced ML algorithms such as Support Vector Regression, Artificial Neural Networks, and Genetic Algorithms is proposed to refine leachate treatment processes. This review provides valuable insights for different stakeholders specifically researchers, policymakers and practitioners, seeking to fortify waste disposal infrastructure and foster sustainable landfill leachate management practices. By leveraging AI and ML tools in conjunction with a nuanced understanding of leachate complexities, a promising pathway emerges towards effectively addressing this environmental challenge while mitigating potential adverse impacts.

Integrating fuzzy-AHP and GIS for solid waste disposal site selection in Kenitra province, NW Morocco.

Selecting an optimal solid waste disposal site is one of the decisive waste management issues because unsuitable sites cause serious environmental and public health problems. In Kenitra province, northwest Morocco, sustainable disposal sites have become a major challenge due to rapid urbanization and population growth. In addition, the existing disposal sites are traditional and inappropriate. The objective of this study is to suggest potential suitable disposal sites using fuzzy logic and analytical hierarchy process (fuzzy-AHP) method integrated with geographic information system (GIS) techniques. For this purpose, thirteen factors affecting the selection process were involved. The results showed that 5% of the studied area is considered extremely suitable and scattered in the central-eastern parts, while 9% is considered almost unsuitable and distributed in the northern and southern parts. Thereafter, these results were validated using the area under the curve (AUC) of the receiver operating characteristics (ROC). The AUC found was 57.1%, which is a moderate prediction's accuracy because the existing sites used in the validation's process were randomly selected. These results can assist relevant authorities and stakeholders for setting new solid waste disposal sites in Kenitra province.