Characterization of Landfill Leachates and Sediments in Major Cities of Indochina Peninsular Countries—Heavy Metal Partitioning in Municipal Solid Waste Leachate

Landfill leachate a potential challenge towards sustainable environmental management

The increasing amount of waste globally has led to a rise in the use of landfills, causing more pollutants to be released through landfill leachate. This leachate is a harmful mix formed from various types of waste at a specific site, and careful disposal is crucial to prevent harm to the environment. Understanding the physical and chemical properties, age differences, and types of landfills is essential to grasp how landfill leachate behaves in the environment. The use of Sustainable Development Goals (SDGs) in managing leachate is noticeable, as applying these goals directly is crucial in reducing the negative effects of landfill leachate. This detailed review explores the origin of landfill leachate, its characteristics, global classification by age, composition analysis, consequences of mismanagement, and the important role of SDGs in achieving sustainable landfill leachate management. The aim is to provide a perspective on the various aspects of landfill leachate, covering its origin, key features, global distribution, environmental impacts from poor management, and importance of SDGs which can guide for sustainable mitigation within a concise framework.

Utilization of microbial fuel cells as a dual approach for landfill leachate treatment and power production: a review

Landfill leachate, which is a complicated organic sewage water, presents substantial dangers to human health and the environment if not properly handled. Electrochemical technology has arisen as a promising strategy for effectively mitigating contaminants in landfill leachate. In this comprehensive review, we explore various theoretical and practical aspects of methods for treating landfill leachate. This exploration includes examining their performance, mechanisms, applications, associated challenges, existing issues, and potential strategies for enhancement, particularly in terms of cost-effectiveness. In addition, this critique provides a comparative investigation between these treatment approaches and the utilization of diverse kinds of microbial fuel cells (MFCs) in terms of their effectiveness in treating landfill leachate and generating power. The examination of these technologies also extends to their use in diverse global contexts, providing insights into operational parameters and regional variations. This extensive assessment serves the primary goal of assisting researchers in understanding the optimal methods for treating landfill leachate and comparing them to different types of MFCs. It offers a valuable resource for the large-scale design and implementation of processes that ensure both the safe treatment of landfill leachate and the generation of electricity. The review not only provides an overview of the current state of landfill leachate treatment but also identifies key challenges and sets the stage for future research directions, ultimately contributing to more sustainable and effective solutions in the management of this critical environmental issue.

Citizens' perception towards landfill exposure and its associated health effects: a PLS-SEM based modeling approach

Around 90% of municipal solid waste in India is treated improperly at open dumps and landfills, posing a severe threat to public health. Landfills are an annoyance whose presence causes uncertainty, stress, and dissatisfaction in neighboring residential areas. This research investigates the perceived impact of exposure to landfills on health in terms of environmental quality, general living status, and defensiveness. To meet the current study's objective, "Case of exposed population" to landfill, i.e., 384 participants dwelling near 1 km of the dump site in Siliguri municipality, West Bengal, India, were considered using a purposive sample approach. The present study adopted Partial Least Square-Structural Equation Modeling (PLS-SEM) approach to prove the hypothesis related to the residential perception of landfills and their impact on health. The findings reveal that all three constructs, namely environmental quality (β = .997, t = 19.607, and ρ < 0.001), general life status (β = .116, t = 2.475 and ρ < 0.05), and people's defensive attitude (β = .150, t = 2.526 and ρ < 0.001), significantly affect the health condition of those exposed to a landfill site. The results suggest that by understanding the impact of landfills on resident health, policymakers and bureaucrats can promote reliable and effective measures linked to sustainable solid waste disposal facilities. The administration must create a policy to protect citizens who live near landfills by improving the ambient environment, establishing health management facilities, and raising awareness through public participation.

Optimization of multi-frequency electromagnetic surveying for investigating waste characteristics in an open dumpsite

Implications: Open dump mining (ODM) is now applied as a sustainable approach to combat improper waste disposal and reduce municipal solid waste (MSW) in the open dumpsite. To implement ODM for producing RDF, business developers must know the amount and composition of waste that can be converted into RDF before mining. This study used multi-frequency EM surveys with frequencies of 5,000, 11,000, and 15,000 Hz. This multi-frequency method effectively determined the waste composition and identified potential excavation points in the open dumpsite prior to ODM. This method can mitigate the limitations of traditional surveying, due to its improved mobility, lower time consumption, and reduced labor needs.

Progress and prospects in mitigation of landfill leachate pollution: Risk, pollution potential, treatment and challenges

The escalating loads of municipal solid waste (MSW) end up in open dumps and landfills, producing continuous flows of landfill leachate. The risk of incorporating highly toxic landfill leachate into environment is important to be evaluated and measured in order to facilitate decision making for landfill leachate management and treatment. Leachate pollution index (LPI) provides quantitative measures of the potential environmental pollution by landfill leachate and information about the environmental quality adjacent to a particular landfill. According to LPI values, most developing countries show high pollution potentials from leachate, mainly due to high organic waste composition and low level of waste management techniques. A special focus on leachate characterization studies with LPI and its integration to treatment, which has not been focused in previous reviews on landfill leachate, is given here. Further, the current review provides a summary related to leachate generation, composition, characterization, risk assessment and treatment together with challenges and perspectives in the sector with its focus to developing nations. Potential commercial and industrial applications of landfill leachate is discussed in the study to provide insights into its sustainable management which is original for the study.

Effect of chloride ions on the simultaneous electrodialysis and electrochemical oxidation of mature landfill leachate

An attempt has been made to improve the treatment efficiency of mature landfill leachate prior to the existing biological treatment. In this study, electrochemical oxidation (EO) was applied as a pre-treatment to remove organic contaminants and was simultaneously combined with electrodialysis (ED) to remove ionic constituents, such as ammonium and phosphate. A laboratory-scale electrochemical reactor was designed by utilizing a carbon graphite anode and a stainless steel cathode and separated by an anion exchange membrane (AEM) and cation exchange membrane (CEM), creating a three-compartment reactor. The oxidation of the organic pollutant would occur in the anodic compartment, while the targeted ammonium and phosphate ions would be migrated and accumulated in the central compartment. The treatment process was performed in a batch recirculation time of 12 h at a constant supplied current of 0.25 A and evaluated by means of the initial leachate pH (i.e., original pH value of 7.85; adjusted pH value of 5.50 and 8.50) and three different initial chloride concentrations. The higher the chloride concentration in the leachate, the higher the removal efficiency, except for total phosphate. The highest chemical oxidation demand (COD) removal was 86.2% (0.88 g W^-1 h^-1), at an initial leachate pH value of 7.85 with the addition of 2 g L^-1 of NaCl. Furthermore, under the same conditions, the ammonium, total phosphate, and chloride removals were 85% (0.44 g W^-1 h^-1), 89% (0.08 g W^-1 h^-1), and 83% (0.69 g W^-1 h^-1), respectively. Also, the concentrated ionic compounds in the central compartment can lower the energy consumption and can possibly be further treated or managed.

Analysis of the possibility of conducting a comprehensive assessment of landfill leachate contamination using physicochemical indicators and toxicity test

The inevitable consequence of the operation of landfills is the emission of leachate, which is considered to be one of the main polluters of the ground and water environment. The leachate contains soluble organic compounds, inorganic contaminants, suspended solids, heavy metals and dangerous substances. The selection of the leachate disposal method requires a comprehensive assessment of its properties. Therefore, the physicochemical parameters and toxicity tests were chosen for a comprehensive assessment of the properties of leachate. Four municipal waste landfills (operational and non-operational) were selected for the study, for which multidimensional statistical analyses were carried out. The study was conducted between the period of April 2018 and December 2019. The comprehensive assessment showed that pollutants in leachate from the analyzed landfills remained at a level which did not allow them to be discharged to water or soil. The presence of substances particularly harmful to the aquatic environment (e.g AN, chromium, copper) may hinder their treatment together with household sewage, as it involves obtaining a permit required under laws. Toxicity of leachate may also be a problem, as it may persist after the treatment process is completed. The values of pH, EC and the concentrations of ON, TDS, TSS, chloride, iron and manganese had the strongest influence on the properties of leachate from all landfills. For operational landfills, these were also calcium concentrations, for non-operational ones COD, TU and the concentrations of TKN, AN, TS, sodium, potassium and magnesium. The mentioned parameters also showed strong correlation with other physicochemical properties of the leachate, which indicate their suitability for the monitoring of leachate and the aquatic environment in the vicinity of municipal waste landfills.

Impact of landfill leachate contamination on surface and groundwater of Bangladesh: a systematic review and possible public health risks assessment

Dumping of solid waste in the non-engineered landfill is very common in the developing countries. Among the different disadvantages of this kind of landfilling, leachate is the major concern to public health, which is a toxic byproduct generated from the landfill; and can percolate to the ground water and consequently migrate in surface water. Using systematic review on published data, the present study endeavors to compare the leachate contamination potential of four major landfills of Bangladesh, named Amin Bazar, Matuail, Mogla Bazar and Rowfabad; which are situated in 3 of the 6 big mega cities of Bangladesh and assessed the effects of leachate leakage on surrounding water body as well as on human health. This study, for the first time calculated the leachate pollution index (LPI) for the landfill sites of Bangladesh and found that the LPI of Matuail landfill site (19.81) is much higher which is comparable to some polluted landfill sites of India and Malaysia. The concentrations of several potentially toxic metals found in the surface and ground water in the vicinity of the landfill sites were above the maximum permissible limit values of department of Environment, Bangladesh and World Health Organization (WHO). The human health risk index for toxic heavy metals in different vegetables and rice grain showed high health risk potential for Pb, Cd, Ni, and Mn. The total carcinogenic risk for Ni and Pb are found very high in the edible plants near those landfill sites, suggesting the risk of Ni and Pb induced carcinogenesis by the consumption of those plants. The present conditions of surface, ground water and agriculture products near the landfill sites of Bangladesh are much frightening to the biota and local inhabitants.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13201-021-01431-3.

Potassium Ferrate (VI) as the Multifunctional Agent in the Treatment of Landfill Leachate

Possible use of potassium ferrate (VI) (K₂FeO₄) for the treatment of landfill leachate (pH = 8.9, Chemical Oxygen Demand (COD) 770 mg O₂/L, Total Organic Carbon (TOC) 230 mg/L, Total Nitrogen (Total N) 120 mg/L, Total Phosphorus (Total P) 12 mg/L, Total Coli Count (TCC) 6.8 log CFU/mL (Colony-Forming Unit/mL), Most Probable Number (MPN) of fecal enterococci 4.0 log/100 mL, Total Proteolytic Count (TPC) 4.4 log CFU/mL) to remove COD was investigated. Central Composite Design (CCD) and Response Surface Methodology (RSM) were applied for modelling and optimizing the purification process. Conformity of experimental and predicted data (R² = 0.8477, R_adj² = 0.7462) were verified using Analysis of Variance (ANOVA). Application of K₂FeO₄ using CCD/RSM allowed to decrease COD, TOC, Total N, Total P, TCC, MPN of fecal enterococci and TPC by 76.2%, 82.6%, 68.3%, 91.6%, 99.0%, 95.8% and 99.3%, respectively, by using K₂FeO₄ 0.390 g/L, at pH = 2.3 within 25 min. Application of equivalent amount of iron (as FeSO₄ × 7H₂O and FeCl₃ × 6H₂O) under the same conditions allowed to diminish COD, TOC, Total N, Total P, TCC, MPN of fecal enterococci and TPC only by 38.1%, 37.0%, 20.8%, 95.8%, 94.4%, 58.2%, 90.8% and 41.6%, 45.7%, 29.2%, 95.8%, 92.1%, 58.2%, 90.0%, respectively. Thus, K₂FeO₄ could be applied as an environmentally friendly reagent for landfill leachate treatment.

The Potential Health Risk Associated with Edible Vegetables Grown on Cr(VI) Polluted Soils

This study reports on the assessment of the growth potential of five edible vegetables, which were grown in Cr(VI) spiked soils. The vegetable plants that were used in this study were Vigna angularis, Cicer arietinum, Spinacia oleracea, Amaranthus dubius Thell and Phaseolus vulgaris. Dried ground samples from roots, stems and leaves were analysed for various oxidation states of Cr. The daily intake of chromium, hazard quotient (HQ) and hazard index (HI) methods were employed to assess the potential human health risks posed by these Cr oxidation states through vegetable consumption. The results showed that Vigna angularis was the only vegetable that germinated in highly concentrated Cr(VI) in the simulated soil (456 mg/kg). The highest total chromium (Ch_T) bioaccumulated in the roots was found in Phaseolus vulgaris at 0.8. The highest Ch_T translocation factor in the stem was that of Cicer arietinum and Vigna angularis at 0.30. The same plants translocated the highest Ch_T to the leaf at 0.7. A child or an adult consuming such contaminated Cicer arietinum vegetables were likely to take in between 508 and 785 mg/day of Ch_T, which are above the World Health Organisation guidelines of 220 and 340 mg/day, respectively. The highest HQ was found in Cicer arietinum at 8.7 and 13.4 for adults and children, respectively. The same species of plants also had high HI at 17.4 and 27.2 for adults and children, respectively. This indicated that consumers of the edible vegetables grown in Cr(VI) rich soils may be exposed to health risks, and the children were more likely to be vulnerable to these adverse effects than the adults.

Characterization of mercury-reducing potential bacteria isolated from Keputih non-active sanitary landfill leachate, Surabaya, Indonesia under different saline conditions

The objectives of this research were to identify the capability of bacteria isolated from a non-active sanitary landfill to remove mercury under different saline conditions and to understand the removal kinetics. The mercury concentrations used in the minimum inhibitory concentration (MIC) test were 0, 5, 10, 15 and 20 mg/L. The capability of one selected bacterium from the MIC test to remove mercury under different saline conditions (0, 10, 20, and 30‰) was also tested. Five indigenous bacteria were isolated from the Keputih non-active sanitary landfill, Surabaya, Indonesia. The MICs of mercury for FA-1, FA-2, FA-3, FA-4, and FA-5 were 5, 10, 5, 5, and 5 mg/L, respectively. Based on biochemical characterization, FA-2 was identified as Pseudomonas aeruginosa. The isolate of P. aeruginosa was capable of removing Hg under different saline conditions. The optimum saline condition for P. aeruginosa to remove Hg was 10‰, with a removal percentage of 99.7 ± 0.18% following pseudo-second-order kinetics (R² = 0.9939) with k₂ = 2.0059 mg substrate/g adsorbent/hr. Hence, isolated P. aeruginosa showed potential for the bioremediation of mercury-contaminated areas.

Preface: Special Issue on Environmental Toxicology of Trace Metals

Trace metals (TMs) have a central role in the functioning of aquatic and terrestrial ecosystems. [...]