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Leachate from municipal solid waste landfills poses a significant threat to aquatic ecosystems due to poor management practices. This study evaluated thirty leachate samples from Iranian metropolises using the Leachate Pollution Index (LPI). Various parameters, including BOD₅, COD, TDS, pH, EC, heavy metals, turbidity, PAHs, phthalates, and humic acid, were analysed. The BOD₅ levels ranged from 350 to 20,000 mg/L, and the COD levels ranged from 2,000 to 90,000 mg/L. The TDS content varied between 14.7 and 67 g/L, while the turbidity ranged from 15 to 186 NTU. Heavy metals were present but within standard limits. The phthalate concentrations ranged from 6 to 150.8 mg/L, and the humic acid concentrations ranged from 135 to 2,200 mg/L. Naphthalene was the most frequent hydrocarbon detected. The LPIs were less than 30 for all the samples, with the highest in Ahvaz and the lowest in the treated samples from Tehran. This study highlights the presence of persistent organic and hazardous contaminants in Iran’s municipal landfills, emphasizing the need for effective leachate treatment and improved waste management practices. Enhanced final disposal methods, increased waste recovery, and improved solid residue separation are crucial for preventing further leachate production and environmental contamination.

The sustainable management of landfill leachates remains a matter of important concern in many countries. We used as case study a medium-sized Greek landfill, and we initially investigated the performance of the existing secondary leachate treatment system. The activated sludge process removed chemical oxygen demand (COD), biochemical oxygen demand (BOD), NH 4 -N, and PO 4 -P by 55%, 84%, 94%, and 14%, respectively, but the effluents did not meet the legislation requirements for discharge or reuse. Afterwards, different management options of these effluents (co-treatment with sewage in the centralized treatment plant, onsite tertiary treatment with reverse osmosis, granular activated carbon (GAC), ozonation, photo-Fenton, or constructed wetlands) were evaluated regarding their operational costs and environmental footprint. The use of constructed wetlands presented the lower operational cost, energy requirements, and greenhouse gas (GHG) emissions, not exceeding 21.5 kg CO 2eq /day. On the other hand, the power consumption and the GHG emissions of the other on-site technologies ranged from 0.37 kWh/m 3 and 5.56 kg CO 2eq /day (use of GAC) to 39.19 kWh/m 3 and 588.6 kg CO 2eq /day (use of ozonation), respectively. The co-treatment of the leachates with municipal wastewater required 0.6 kWh/m 3 and emitted 30.18 kg CO 2eq /day. For achieving zero-discharge of the treated leachates, a system consisting of constructed wetlands and evaporation ponds in series was designed.

This study investigated seasonal variations in the physico-chemical properties of leachate from the Kupferberg landfill site, examining the influence of landfill age and climatic factors. Data provided by the Windhoek Municipality during the years 2017 to 2022 facilitated the exploration of critical concerns related to groundwater protection and human health. Guided by two research questions and anchored in hypotheses tested at a 95% confidence level, the study employed Statistical Packages for Social Scientists (SPSS) for analysis. Significant temperature variations were observed across years [F (5, 21) = 4.493, p < 0.05], indicating a substantial relationship between landfill age and seasonal variations in leachate physico-chemical properties. Further ANOVA tests revealed temperature trends impacting leachate parameters, such as organic content and pH. While COD displayed a declining trend with landfill age, inorganic components like Cl - and alkalinity exhibited no distinct age-related pattern. Wet seasons demonstrated higher EC and Cl - - mean values than dry seasons, correlating with elevated COD levels. The study underscored the incremental rise in parameter values over time and during the rainy season, attributed to solid waste degradation and rainwater percolation. Notably, climatic conditions significantly influenced seasonal variations in leachate physico-chemical properties (p < 0.05). Based on this outcome, null hypothesis 1 was rejected. The second null hypothesis was also rejected because climatic conditions do influence the seasonal variations in physico-chemical properties. These findings are crucial for emphasizing the need for effective leachate management strategies and providing valuable insights for arid regions. Future research can expand on a national scale, employing one-way ANOVA tests on other landfills in Namibia, and engaging local communities for comprehensive data collection on cross-contamination.

The study was aimed at evaluating the influence of bioaugmentation on the limitation of the toxic impact of mature landfill leachate (MLL) in the co-digestion with sewage sludge (SS). The bioaugmenting mixture (BA) comprised wild-living microorganisms at the concentrations of 0.07 and 0.19 g kg-1VS. The study was conducted in semi-flow mesophilic digesters, using different SS:MLL:BA ratios of 90:5:5 and 87:4.3:8.7°%o v/v at related HRTs of 18.2 and 17.4 d, respectively. The control runs included the sole SS anaerobic digestion, and co-digestion of SS and MLL in a volumetric ratio of 95:5%. Using a sufficiently high BA dose and an adequate inoculum size, bioaugmentation improved the co-digestion efficiency. The methane yields were higher as compared to a non-bioaugmented co-digestion system, reaching 0.24 m3 kg-1VSadded and 0.17 m3 kg-1TSadded, and the difference was of statistical significance. The same tendency occurred regarding the VS removal. Bioaugmentation seemed to accelerate the metabolic transformations, which was confirmed by the enhanced values representing the rate constant of biogas production. Thus, a beneficial effect of overcoming the toxic impact of MLL on the efficiency of its co-digestion with SS was revealed using bioaugmentation.

Society needs sustainable methods for landfilling from an environmental perspective, but they have to be cost effective and affordable. Aftercare represents considerable costs within waste management system and costs can be expected to accrue over a long period of time showing the need to compare different management options. Direct-discharge limits for leachate COD and nitrogen are different in various (European) countries. When leachate COD or nitrogen has decreased at the latter part of the aftercare period, effluent limits 50 or 200 mg/l for COD and 10 or 70 mg/l for nitrogen have a considerable impact on period length. The objective of this paper is to discuss the effects of leachate discharge limits on landfill aftercare and leachate management costs in various conditions. Landfill simulator results and modelling are used to estimate leachate concentrations in three different scenarios. It is suggested that stricter discharge limits (shown before) impact on the costs of activated carbon filtration (1.4-fold) and biological treatment (1.1–1.24-fold). Stricter limits also extend the aftercare period length considerably, but with substantial water circulation the differences are clearly smaller. These results support the recent suggestion of aftercare incentives, and some details of applying these incentives in different conditions are discussed.

This study sought to predict leachate levels within a municipal solid waste landfill and evaluate design alternatives for landfill expansion using the U.S. Geological Survey modular flow model with new flow and contaminant transport packages (MODFLOW-SURFACT). This was used to overcome the drawbacks of the more widely used Hydrologic Evaluation of Landfill Performance (HELP) model in predicting leachate levels and movement within a landfill. The valley landfill in this study had two imminent issues regarding leachate management. One was its current high leachate levels, and the other was the selection of a design option for the bottom of the expanded landfill above it. According to the model calibration, relatively high leachate levels in the current landfill were attributed to unsatisfactory leachate removal efficiency by the leachate collection system. Additional leachate pumping was necessary to prevent possible leachate level increase after the landfill expansion over the current landfill. Based on numerical investigations of the design options of the expanded landfill bottom, the separation of leachate generated in the upper (expanded) landfill from the lower (existing) one is recommended, indicating that a low permeable layer such as a liner is an essential component. MODFLOW-SURFACT can be successfully used to calibrate landfill properties and predict hydraulic performance with given landfill conditions, particularly for a valley landfill.

The origin and fate of landfill leachate and gas constituents generated during the sequential phases of solid waste transformation and stabilization are emphasized within the perspective of the in situ processes of microbially mediated attenuation. The fundamental biochemical and physicochemical reaction mechanisms are presented in terms of their spatial and temporal dimensions and their significance for transformation of both nonhazardous and hazardous waste constituents. Supporting information from laboratory, pilot-scale and full-scale applications is used as a basis for interpretive analysis and for providing operational guidance and promoting future developments. The diversity, domains, and functional interdependence of the acidogenic, methanogenic, sulfate and nitrate reducing, nitrifying and denitrifying, and methanotrophic consortia are addressed in order to reveal opportunities for landfill process modifications and associated operational optimization. Controlled attenuation, linked with operational and regulatory realities, are used to suggest innovative landfill configurations involving prospective compartmentalization and integrated waste loading, dedicated treatment zones for in situ transformation of waste and leachate constituents with associated gas capture, control and utilization. Monitoring requirements are emphasized to provide guidance and feedback for operational control and environmental compliance. Finally, technology needs for establishing a more unified approach to the development and management of bioreactor landfills are presented.

In this project, the study of soil characteristics due to the municipal solid waste was carried out in a selected location around the recently closed Municipal Solid Waste (MSW) dumpsite located opposite to Periya Eri in Chromepet, Chennai. Soil samples were collected from the selected location, i.e. 2 sites within 1500m from the dumpsite and another 2 sites beyond 1500m from the dump yard. Total 12 soil samples from 4 sites were collected from a ground depth of 0-30cm, 30-60cm and 60-90cm below the surface. The collected soil samples have been analyzed for pH, moisture, total organic matter, ash content, total organic carbon, specific gravity, conductivity and bulk density and the result were compared with the standards. The study suggested, providing Permeable Reactive Barriers (PRBs) around the solid waste dump site/landfill for reducing the leachate concentration before entering to the soil and thus soil contamination can be minimized to some extent and this technology is cost-effective and eco-friendly since the materials used in the barriers are locally available and low-cost which is sustainable and protect human health, nature and the environment. This study indicated that soil properties did not reach high pollution levels, and therefore posed a low eco-risk potential in surface soil near the landfill.

Upgrading a crude dump site into a sanitary landfill is a very challenging task; Matuail landfill site in Dhaka posed just such a challenge. From the very beginning, the existing disposal site had been used for the crude dumping of solid wastes. All types of solid wastes were haphazardly disposed of all over the site. The existing drainage channels of the dumping ground were not operational due to blockage by indiscriminate waste dumping. A large amount of leachate oozing out from the waste mixed with storm water and made the site esthetically very displeasing and environmentally unsound. This adverse situation sometimes caused disruption of the waste vehicular movement. Step-by-step improvement measures have been taken in the open dump to make it controlled and sanitary by adopting simple and locally available materials, technical guidelines, and construction techniques.

The USA, China and India are the top three producers of municipal solid waste. The composition of solid wastes varies with income: low-to-middle-income population generates mainly organic wastes, whereas high-income population produces more waste paper, metals and glasses. Management of municipal solid waste includes recycling, incineration, waste-to-energy conversion, composting or landfilling. Landfilling for solid waste disposal is preferred in many municipalities globally. Landfill sites act as ecological reactors where wastes undergo physical, chemical and biological transformations. Hence, critical factors for sustainable landfilling are landfill liners, the thickness of the soil cover, leachate collection, landfill gas recovery and flaring facilities. Here, we review the impact of landfill conditions such as construction, geometry, weather, temperature, moisture, pH, biodegradable matter and hydrogeological parameters on the generation of landfill gases and leachate. Bioreactor landfills appear as the next-generation sanitary landfills, because they augment solid waste stabilization in a time-efficient manner, as a result of controlled recirculation of leachate and gases. We discuss volume reduction, resource recovery, valorization of dumped wastes, environmental protection and site reclamation toward urban development. We present the classifications and engineered iterations of landfills, operations, mechanisms and mining.