A Review of Landfill Leachate

Over the years, the use of electrical resistance tomography (ERT) has expanded significantly in engineering applications owing to the competence of the programme involving project duration, cost and data limitation aspects. This investigations was particularly relevant for ERT to assess the level of pollution from waste dumps in Simpang Renggam, Johor, Malaysia. ERT conducted an in-depth investigation using ABEM Terrameter LS 2 devices and Schlumberger protocol configurations in the research area. Furthermore, seven (7) parameter parameters for characterization of leachate have been identified and evaluated for current leachate conditions such as chemical oxygen demand, biological oxygen demand, suspended solids, hydroelectric power, ammonia hydrocarbons, trium and biodegradability ratio. Furthermore, the study was able to determine the existence of chemicals in soils at a depth of 1.5–4.0 m, particularly at low resistivity of 1–10 m due to chemically apparent resistance. Based on the research conducted, the current characteristics of the Simpang Renggam gas station were 1 633.9 mg/L (chemical oxygen demand), 137.41 mg/L (biological oxygen demand), 359.8 mg/L (suspended solids), 7.61 (hydrogen output), 385.29 (hydrogen ammonia), 117.65 (turbidity), and 0.07 (biodegradability ratio), showing that other parameters beyond the value of the local standards set out in the Environmental Quality Leaching from the dump is thought to have been caused by system deficiency in controlling and managing waste, which have been intensified by the current excessive rainfall. In retrospect, the ERT results are workable for recognizing leachate and can therefore be used by the authorities to take instant action to end the ample water disruption in the studied region.

Indiscriminate disposal of solid wastes into the environment generates landfill gases and leachates. Leachate, a mixture of deleterious substances including metals, inorganic and organic compounds, particulate matters, radioactive elements, and microorganisms, contaminates soils and underground and surface water resources increasing risk to human and wildlife health. This study is a compendium of studies on the cytotoxic and genotoxic assessment of Olusosun landfill (the largest unregulated landfill in African). Leachates emitted from Olusosun solid waste landfill induced cytotoxicity and DNA damage via direct and indirect mechanisms. Different biomarkers of genotoxicity were used to evaluate the cytotoxic and genotoxic potentials of OSL leachates. Biomarkers of chromosome aberration, micronucleus assay, comet assay, sperm head abnormality test and toxicogenomic signatures, were assessed in somatic and germline cells of exposed organisms. The mechanisms of DNA damage include generation of free radicals and oxidative stress, inhibition of DNA repair process, alkylation on DNA molecules that may lead to chromosome breakage, down-regulation of transcriptional genes related to apoptotic expressions, and increased DNA fragmentation in cells and tissue. The damaged DNA can increase genome instability and genetic related diseases. Heavy metals, physico-chemicals and organic substances present in the leachates are known mutagens, genotoxin and carcinogens. It is suggested that proper landfill management be instituted in various countries to avert exposure to landfill emissions.

Landfilling is an engineered alternative for the safe disposal of municipal solid waste (MSW) and hazardous waste. To dispose of solid waste, most countries use the initial phase of landfilling in the form of open dumping. Landfill leachate, gas emissions, and odor control are presented as issues of designing and operating a landfill. In fact, leachate is considered highly contaminated wastewater because it contains dissolved organic compounds, inorganic macro compounds and heavy metals. Therefore, leachate characterization is a crucial step towards preventing pollution and evaluating the performance leachate treatment alternatives. Furthermore, it is important to discuss some challenges in landfill leachate management and treatment. Accordingly, this chapter will introduce and summarize different topics related to landfill leachate characterization, including physical/chemical characterization and leachate generation and composition factors. Finally, future trends in landfill Leachate Management that could improve leachate quality are further discussed.

Solid waste management is becoming more and more difficult. Finding a solution that is both affordable and environmentally friendly is a challenge for many nations. When water undergoes filtering downward through a landfill, it collects dissolved components from the decaying waste and creates leachate. The leachate may be either safe or extremely harmful depending on the properties of the landfill and the waste it houses. An initial aerobic phase, an anaerobic acid phase, an initial methanogenic phase, and a stable methanogenic phase are the minimum stages of decomposition that landfills go through. Leachates may contain considerable concentrations of heavy metals, inorganic salts, ammonia, halogenated hydrocarbons suspended solids, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), and organic pollutants in huge quantities. Also abundant in it are phenol, nitrogen, and phosphorus. Due to its propensity to seep into soils and subsoils and seriously pollute receiving waters, landfill leachate could be a significant cause of surface and groundwater contamination if it is not properly handled and disposed of. Therefore, throughout the past few decades, pollutant reduction from leachate treatment has gained substantial attention.

The study examined to identify, characterize, and quantify microplastics in Groundwater samples around the municipal solid waste dumpsites, namely Vellalore dump yard, Coimbatore Corporation in South India. We have collected groundwater samples from bore well (15 nos) in 1-L Silanized amber glass bottles with Teflon-lined caps within 2 km distance from the municipal solid waste disposal sites during the post-monsoon season (November 2019) in South India. To evaluate the identification and quantification of microplastic abundance, characteristics (composite, size, colour, shape and surface morphology), and distribution of groundwater performed using LABOMED zoom stereo microscope, Fourier Transform Infrared Spectroscopy (ATR-FTIR) fitted with Complete Attenuated Reflectance and Scanning electron microscope (SEM) fitted with an energy dispersive X-ray (EDX) analyser. The total amount of microplastic particles was found to contain freshwater sources among the groundwater samples (n = 15) ranging from 6 and 80 items/L. Vellalore dump yard sampling sites dominant-coloured particles included white (18%), black (32%), red (19%), blue (16%), green (10%), and yellow (5%) respectively. Also, a Polymer type occurs in the following order nylon (70%), pellets (18%), foam (6%), fragments (3%) fibers/PVC (2%) and polythene (1%). The study confirmed the microplastic tracers in groundwater contamination near dump yards. In Vellalore dump yard sampling sites, 90% of microplastics were derived from the fragmentation of the buried waste of the plastics predominantly polypropylene (PP), polystyrene (PS) was presented. These methods for identifying and quantifying microplastics in groundwater is likely to provide a scope for further research into the pathways by which microplastic enter the environment.

The most widely utilized method of solid waste disposal around the world is the use of Municipal Solid waste (MSW) landfills. Upto 95% of the waste collected worldwide is disposed off in landfills. The main issues related with the landfills are the production of methane gas and liquid leachate. Among these issues, generation of leachate is of growing concern. In developing countries landfilling is the commonly used method and most of the landfills do not have any liners at the base or proper top covers, which as a result of leachate generation from solid waste results in the potential problems of ground water/surface water contamination. Besides landfilling is considered the most economical method of waste disposal, in recent decades several problems of social and environmental attention are associated with landfills. Amongst the environmental problems related to MSW landfilling, ground water contamination is the most prominent. From physical, chemical, and biological point of view the leachate generated from MSW disposal sites is considered as one of the highly contaminated resources. Sanitary landfill that is present in urban areas is often related to potential environmental pollution of ground water and surface water. Landfills pose potential risk to human health as well due to the toxic impacts caused by the leachates when released into the environment and the potential of landfills to generate leachates even after 100 years of closure. It has been reported earlier that even small amounts of leachate can pollute large volume of groundwater that can make them unusable for domestic and many other purposes. In this chapter authors have reviewed the leachate composition from MSW landfills, contamination of ground and surface water sources by different pollutants present in the leachates. The effect of depth of water source and its distance from landfill along with other factors affecting the contamination of water sources is also reviewed. Authors have suggested remedial measures and that proper management of solid waste can help to decrease the contamination of through leachate production.

Leachate is wastewater generated in sanitary landfills, resulting from the degradation of solid waste, with a high polluting potential for water bodies. The ecotoxicological assessment of this effluent is essential to determine the impact of its pollutants on the aquatic ecosystem. In this context, the objective of this study was to evaluate the acute toxic effects caused by some pollutants measured by the parameters total ammonia nitrogen (TAN), total alkalinity, humic substances (HS), and chloride present in the leachates from different landfills in Rio de Janeiro State (Brazil). The test organisms evaluated represented different trophic levels of the food chain: Vibrio fischeri, Danio rerio, Daphnia similis, activated sludge microorganisms and Artemia sp. Ecotoxicity results for the selective removal of pollutants from the leachate, such as air-stripping and membrane filtration experiments, are presented. The obtained data were evaluated by principal components analysis methodology. This study highlights the importance of toxicity assessment for landfill leachates and choosing suitable test organisms.

Landfill leachate occurs as one of the by-products of waste deterioration. It is the mineralization of pollutants within the waste stream which gives rise to a very concentrated, dark and toxic chemical mix, depending on the type of waste disposed, age of dumpsite and climatic conditions of the site. Leachate is generally collected at the bottom of the landfills, in unlined landfills, leachate usually migrates through the underground strata and may travel down to the groundwater table. Some lateral migration of the leachate is also possible depending on the surface and subsurface geology. The migrating leachate can dissolve soluble chemicals, many with toxic constituents that may result in soil and water resources pollution. Hence proper leachate management procedures should be developed and incorporated into the design of landfills.

Accurate landfill leachate and biogas production estimation is essential for effective waste management and environmental protection. In this study, we look at the range of techniques available for estimating landfill leachate and biogas production, considering various influencing factors such as waste composition, environmental conditions, and landfill design. Through the practical application of these estimation methods to the Oum Azza landfill, we discovered valuable information about the dynamics of leachate and biogas production at this specific landfill. In particular, our research identified the water balance method as the most accurate and suitable approach for estimating leachate quantities. In contrast, the LandGEM multiphase method was optimal for estimating biogas. The implications of our results go far beyond the scope of this study, as they highlight the profound importance of accurate estimation in the development of sustainable waste management strategies. The insights gained from this research pave the way for designing and implementing waste management practices that are both environmentally friendly and economically viable, thus contributing to a more sustainable and ecologically harmonious future.

Nowadays, the average generation of global municipal solid waste (MSW) is about 2.00 billion tons, and is anticipated to reach 3.40 billion tons by 2050 due to urbanization and increase in population. Landfill is the most popular method due to cost-effectiveness, and about 90% of global MSW is landfilled, producing massive landfill leachate. Landfill leachate includes various pollutants, such as organic compounds, heavy metals, ammonia, and inorganic salts, leading to serious pollution to the surrounding environment. In this work, the traditional methods for treating landfill leachate, and recovery technologies of nutrients (N and P), inorganic salts, bioenergy, and humic substances from landfill leachate are summarized, and the corresponding progress and bottlenecks of these technologies are identified. Among these resources recovery, nutrients (N and P) are extracted by struvite precipitation, adsorption, ammonium stripping, and membrane filtrations. The extraction of metals from landfill leachate is summarized. In terms of energy recovery, methane production, hydrogen production, and cultivating microalgae are included and discussed. In addition, humic substances as liquid fertilizer are recovered by using membrane technologies, adsorption, and other technologies are identified. Finally, the challenges, and prospects of traditional methods and resource recovery are discussed. Overall, this work can provide insights into resources recovery from landfill leachate, facilitating the sustainable development of landfill leachate disposal.

The production of solid waste, which is increasing on a global scale, presents considerable impacts linked to the environment. The storage of this waste in anaerobic conditions makes it possible to produce a large volume of leachate, which is harmful to the environment. This study concerns the sizing and design of a system for treating leachate (young and stabilized) by nitrification–denitrification, coagulation-flocculation followed by filtration on materials. The results showed that the optimal concentrations of FeCl₃ used as a coagulant vary between 6–8 and 4–6 for young and stabilized leachates for a pH of around 8.5. This work constitutes an interesting case study, making it possible to reduce leachate pollution produced by a public landfill using a simple technology. This work includes an interesting case study, making it possible to minimize leachate pollution produced by a public landfill using a simple technology. The results obtained in the laboratory on a pilot scale showed that the proposed steps are complementary and make it possible to reduce pollution effectively. However, using the treatment plan to discharge leachate stored in Basin 3 is more enjoyable, which presents a reduced pollutant load compared to the quality of raw leachate received by Basin 1. The sector's design based on the determined optimal conditions makes it possible to minimize pollution considerably. Furthermore, calculating the sector's costs remains moderate, which could encourage establishing the industry in development.

While meeting environmental waste disposal requirements, landfills introduce new environmental and public health hazards, including potential operational lapses and conflicts with local communities. 92 municipalities in Rio de Janeiro send waste to 19 sanitary landfills, accounting for 96.94% of the total daily MSW generation in the state. The 19 licensed and operational landfills in Rio de Janeiro are overseen by 16 operators: 10 private entities, two inter-municipal consortia, and four municipal governments. Private operators manage approximately 17,061 tons/day, consortia around 598 tons/day, and municipalities around 259 tons/day. Ciclus Ambiental oversees 8933 tons/day, and Orizon Valorizacao de Residuos manages 6094 tons/day, collectively managing around 15,027 tons/day, representing roughly 80% of the daily waste generation in Rio de Janeiro.