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Municipal Solid Waste Biochar for Prevention of Pollution From Landfill Leachate
Abstract
Municipal solid waste (MSW) is produced at an alarming rate, which may have a negative impact on the environment and on human health, if not properly managed. Open landfills are the most common way of disposing of MSW in the developing world. Landfill leachates generated from such open dump sites are directed to surface water bodies with no treatment in most places. Organic and inorganic compounds including organic acids, pesticides, volatile organic compounds, pharmaceuticals, heavy metals, and nutrients in the landfill leachates are extremely important substances to manage. Many different methods are currently in use to treat and fill leachates, such as aerobic biological treatment, anaerobic treatment, physiochemical treatment, coagulation, adsorption, and ion exchange. Among them, carbon adsorption is commonly used method for the remediation of organic and inorganic contaminants. Biochar (BC), a carbonaceous material produced by the pyrolysis of biomass under limited or no oxygen, is an efficient emerging substitute for activated carbon. Biochar from agricultural waste has exceptional capacity for the removal of many different pollutants. Similarly, BC can be potentially produced from the organic materials of the MSW itself, so that it may have a possibility for resource reuse. Hence, this chapter discusses the potential of BC from MSW and its applications to remediate different pollutants in MSW leachate as well as its ability to be used as a landfill cover and as a reactive barrier material.
... The use of MSW biochar as leachate treatment in landfills stems from its high adsorption, high surface area and microporous nature. Studies have shown that MSW biochar effectively removes numerous toxic heavy metals and NH3-N (Jayawardhana et al., 2016). The high surface area and adsorption capacity of MWS biochar also provide a huge opportunity for improving the functionality of landfill capping materials. ...
... The high surface area and adsorption capacity of MWS biochar also provide a huge opportunity for improving the functionality of landfill capping materials. Using MSW biochar in landfill capping materials improves removal rates of CH4 by between 60% and 90% (Gunarathne et al., 2019;Jayawardhana et al., 2016). In addition, MWS biochar enhances the performance of vegetation-based landfill cover due to its improvement of soil's physical and chemical properties. ...
... The range of feedstocks includes food wastes, crop straws, sewage sludge, woody residues, animal manures, shells (Camellia oleifera Abel.), chitin, etc. (Gao et al., 2021a;Gao et al., 2021b;Ge et al., 2020;Ge et al., 2021;Wang et al., 2020;Zheng et al., 2021;Zuo and Liu, 2021). As discussed, pyrolytic degradation of organic materials into biochar has emerged as an effective technique in which limited oxygen supply assists the full-fledged prevention of combustion and thus leads to ash production (Cao et al., 2014;Jayawardhana et al., 2016;Xing et al., 2021). Moreover, other thermochemical processes such as microwave-mediated pyrolysis, hydrothermal carbonization, torrefaction, and gasification have also been developed for biochar production (He et al., 2020;Kambo et al., 2015;Vithanage et al., 2017). ...
... Biochars are also recognized to stimulate the rate of nitrogen fixation and nitrogen mineralization as many biochar varieties contain a high hydrogen/carbon ratio which actively decomposes the mineral pool of soil and releases nitrogen for the plant uptake (Dai et al., 2016). Moreover, by controlling some species of autotrophic microbes, biochar efficiently retains the soil micronutrients preventing them from oxidation and mineralization by increasing soil pH (Jayawardhana et al., 2016). Biochar is strongly associated with inducing precipitation reactions in soil and facilitates the conversion of minerals into insoluble pools which in turn interact with other minerals, alter and absorb the into its surface and thereby, helps increase the nutrient uptake of plants (DeLuca et al., 2015;Jin et al., 2016). ...
In a desperate attempt to find organic alternatives to synthetic fertilizers, agricultural scientists are increasingly using biochar as a soil amendment. Using chemical fertilizers results in enormous financial burdens and chronic health problems for plants and soils. Global concerns have also increased over the prolonged consumption of foods grown with artificial fertilizers and growth promotors. This adversely affects the environment and the welfare of humans, animals, and other living organisms. This way, organic biofertilizers have established a sustainable farming system. In such a context, biochar is gaining much attention among scientists as it may improve the overall performance of plants; in particular, crops have been optimistically cultivated with the addition of various sources. Field experiments have been conducted with multiple plant-based biochars and animal manure-based biochar. Plants receive different essential nutrients from biochar due to their physicochemical properties. Despite extensive research on biochar's effects on plant growth, yield, and development, it is still unknown how biochar promotes such benefits. Plant performance is affected by many factors in response to biochar amendment, but biochar's effect on nutrient uptake is not widely investigated. We attempted this review by examining how biochar affects nutrient uptake in various crop plants based on its amendment, nutrient composition, and physicochemical and biological properties. A greater understanding and optimization of biochar-plant nutrient interactions will be possible due to this study.
... Some of the MSW disposal techniques that are frequently used include composting, sanitary landfilling, pyrolysis, recycling, and reuse (Talalaj and Biedka 2016). Jayawardhana et al. (2016) investigated on MSW biochar for preventing pollution from landfill leachate. The immediate input of (primarily human) waste materials into the environment is usually connected with conventional or classic pollutants. ...
... In addition, elevated levels of suspended solids silt up waterways and channels of navigation, necessitating frequent dredging. For drinking and crop irrigation, excess dissolved solids render the water undesirable (Jayawardhana et al. 2016). ...
Landfilling is one of the most common waste management methods employed in all countries alike, irrespective of their developmental status. The most commonly used types of landfills are (a) municipal solid waste landfill, (b) industrial waste landfill, and (c) hazardous waste landfill. There is, also, an emerging landfill type called “green waste landfill” that is, occasionally, being used. Most landfills, including those discussed in this review article, are controlled and engineered establishments, wherein the waste ought to abide with certain regulations regarding their quality and quantity. However, illegal and uncontrolled “landfills” (mostly known as open dumpsites) are, unfortunately, prevalent in many developing countries. Due to the widespread use of landfilling, even as of today, it is imperative to examine any environmental- and/or health-related issues that have emerged. The present study seeks to determine the environmental pollution and health effects associated with waste landfilling by adopting a desk review design. It is revealed that landfilling is associated with various environmental pollution problems, namely, (a) underground water pollution due to the leaching of organic, inorganic, and various other substances of concern (SoC) contained in the waste, (b) air pollution due to suspension of particles, (c) odor pollution from the deposition of municipal solid waste (MSW), and (d) even marine pollution from any potential run-offs. Furthermore, health impacts may occur through the pollution of the underground water and the emissions of gases, leading to carcinogenic and non-carcinogenic effects of the exposed population living in their vicinity.
Graphical abstract
... Various waste management methods must be incorporated into and appropriately managed by poultry owners. Proper waste management is a crucial concern for sustainability, as it can have a negative impact on the ecological aspect and human health (Baconguis, 2007;Jayawardhana et al., 2016). This study aims to discover the waste management challenges confronting poultry owners in San Jose, Batangas, and to assess their effort to protect the environment's safety and health. ...
... In today's generation, technology plays a significant role in reducing environmental impacts, but the expense of these technologies would be an issue because not all poultry owners are financially capable of shifting in using machinery. (Gerber, Opio, & Steinfeld, 2007). The global interest in the poultry sector generates severe concerns about animal welfare, feed efficiency, and reducing environmental footprint. ...
The poultry industry produces a lot of waste, and environmental issues grow as the egg industry expands. Poultry owners in the Philippines, notably in San Jose, Batangas, face numerous waste management concerns. This study examined these issues as well as their environmental safety policies. San Jose, in Batangas province, is renowned as "The Egg Basket of the Philippines" for its large-scale egg production. This study collected data using qualitative descriptive analysis. The poultry farms in the municipality were about 376 as of 2021, but with no definite total number of poultry owners. Interviews with the municipal agriculturist and ten poultry owners was utilized. The study revealed substantial waste management difficulties such as manure disposal, water and air pollution, odor disturbance and insects, weather conditions, and virus outbreaks (bird flu). The study's concerning SDGs were 6 (Clean Water and Sanitation) and 12 (Responsible Consumption and Production). Waste disposal over the past decades still poses a threat to the environment. The local government adopted poultry ordinances/resolutions: Resolution 164 of 2008, Resolution 341 of 2016, and Resolution 348 of 2016/Ordinance 007 series of 2016. These policies and initiatives were concluded to be environmentally friendly, but most poultry owners lack awareness of the said policies. Awareness is vital for better policy responses, and the municipality needs to develop its information dissemination. It is essential to improve waste management policies and farm monitoring methods. The local government should implement concrete socioeconomic and environmental programs to empower residents and poultry owners, especially the younger generation, and improve the municipality's knowledge of waste management techniques.
... The change in consumption patterns in urban societies resulted in an upsurge of heterogeneous consumption patterns, causing an extensive increase in the generation of solid hazardous waste (Buenrostro and Bocco 2003;Jayawardhana et al. 2016). Landfilling is the most common practice for the disposal of waste since it is the most cost-effective option. ...
... The generation of leachate is due to the existing liquid in the waste and from water present outside including rainwater. Various factors govern the concentration and quantity of leachate, which includes (1) the characteristics and quantity of waste discharged, (2) climatic conditions, (3) disposal area, (4) operational techniques functional at the landfill, (5) hydrogeology of the area, and (6) age of the waste heap (Armstrong and Rowe 1999;Jayawardhana et al. 2016). Table 5.1 summarizes various sources, permissible limit, and toxicity by various heavy metals present in groundwater. ...
Water is one of the fundamental needs for the life on earth. However, the wastewater released from the industries consists of dyes and other organic molecules, which become the serious issue for the water pollution. Among all water remediation techniques, heterogeneous photocatalysis has gained scientific attention for the water purification in terms of degradation of dyes and other organic pollutants. Heterogeneous photocatalysis is a very robust, low cost method and can provide complete mineralization of the pollutants. In this context, this chapter deals with the basic principle and mechanism of heterogeneous photocatalysis; and the parameters affecting the degradation kinetics. Furthermore, the different functional photocatalyst material, their limitation and the modification in the structure of semiconductor catalyst to absorb visible light are discussed in this chapter.
... The problems caused by environmental pollution are increasing due to the effects on the quality of life, from the discomfort caused by odors and unpleasant appearances caused by the waste dumped in landfills to the endangerment of human health induced by chemical compounds formed by partial decomposition or degradation of waste resulting from household and vegetable sources [1,2]. Leachate resulting from waste decomposition is a source of pollutants such as dissolved organics, inorganic macrocomponents, heavy metals, and xenobiotic organic compounds that can spread in the environment, affect the ecosystem, enter the food chain, and impact human health [3,4]. The environmental pollution induced by landfills into underground and surface water, including the ocean, and also in the atmosphere due to the suspension of particles and outdoor pollution has been studied due to its carcinogenic and non-carcinogenic effects on the exposed population living in their vicinity [5][6][7][8]. ...
Influences of landfills on the surrounding waters have been studied in the neighbourhood of an urban area. Analytical and spectroscopic methods were used to investigate the waters of a canal situated in the neighbourhood of the landfill. Dangerous chemical compounds have been identified in the water as pollutants resulting from the physico-chemical processes of degradation of landfill waste. The quick method with gas sensor detection and colorimetric ion identification using a commercial Quantofix kit, as well as precipitation with AgNO3, offered preliminary information completed by Fourier Transform Infrared Spectroscopy (FTIR). Pollutants that reached the canal waters either by air (evaporation) or by discharges or through rainwater were analysed from the point of view of the degree of danger, sources of waste materials, as well as their circuit in the environment. Hydrogen cyanide, nitrites, nitro compounds, sulfites and sulphates, sulfonic tension-active compounds, peroxydes and hyperoxydes, azo-compounds, organic and inorganic acids of high corrosive potential, and Fe ions were generally the detected pollutants, each of them with specific harmful potential contributing as well in a cumulative effect to endangering human health directly or indirectly as environmental circulating contaminants.
... Es por esto por lo que los propios lixiviados son considerados un contaminante altamente peligroso y tóxico, ya que son producto de la degradación de la materia orgánica biodegradable presente en los residuos sólidos urbanos. Tiene las características de sales, nitrógeno amoniacal, metales pesados, sales inorgánicas, etc. (Jayawardhana et al., 2016). ...
Esta investigación propuso determinar la cinética de metales tóxicos del lixiviado de la infraestructura de tratamiento y disposición final de residuos sólidos de Cajamarca al entrar en contacto con el suelo. El estudio se ejecutó a nivel de laboratorio; se colocó en un recipiente de 150 L, 100 kg de suelo y un volumen de 60 L de lixiviado para generar el contacto de ambos, el experimento duró 60 días y se muestreo cada 10 días en los siguientes lapsos de 0, 10, 20, 30, 40 y 50 días para luego ser recirculado. El lixiviado no aporta contaminantes al suelo, el suelo se comporta con un adsorbente puesto que el arsénico, el cadmio, el cromo, el hierro, el plomo y el zinc, son metales retenidos o adsorbidos en adición, el cobre y el mercurio son metales que el suelo no retiene. Con respecto a la cinética, se demostró que la velocidad de reacción del hierro es mayor a los demás con 0,012 mg/días y una adecuación promedio de todos los metales al modelo de pseudo segundo orden del 99,58%. Se concluye que los metales tóxicos del lixiviado tienen una baja velocidad de reacción en el suelo.
... Minerals 2023, 13, 873 2 of 21 waste being deposited at the landfill and the climate, among other things [5]. The mobility of the heavy metals found in leachate allows them to migrate away from the landfill site to other sites and water reserves, posing a major health risk for surrounding communities [6]. ...
Landfill sites open and close frequently throughout the world, taking over a significant amount of land and leaving it contaminated and unavailable to the surrounding population for use. Different forms of remediation methods have been employed to rehabilitate contaminated land to a state that poses less of a threat to the environment. Phytoremediation is one of the remediation techniques that has proven to be effective, economical and easier to implement compared to other methods. The main aim of this study was to explore the potential use of Lolium perenne L. to remediate and restore metal-contaminated landfill soil and determine its stress tolerance mechanism(s). The metal uptake, determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and inductively coupled plasma-mass spectroscopy (ICP-MS), revealed that Lolium perenne accumulate a higher amount of metals in the roots than in leaves, which was further confirmed by the translocation factor (TF) values of all of the metals that were below 1, ranging between 0.2 and 0.8, while Cu, Cr and Pb had a bioaccumulation factor (BCF) > 1. This confirms that L. perenne is capable of absorbing metals into the root matrix but might restrict further movement into other parts of the plant as a defense mechanism against metal toxicity. In response to metal-induced stress, L. perenne displayed an increase in enzyme activity of superoxide dismutase, glutathione S-transferase, peroxidase and amylases in plants grown in landfill soil. Peroxidases displayed the highest level of enzyme activity, while total amylolytic activity had the most significant increase in activity over time. Although not a hyperaccumulator, L. perenne is a potential candidate for the phytoremediation of landfill soil and the phytostabilization of Cu, Cr and Pb.
... Solid waste affects the environment and is a significant environmental concern worldwide and exerts immense pressure on public health and the environment [12][13][14][15][16]. It includes harmful algal blooms, surface, and groundwater quality degradation, soil quality degradation, widespread anoxia, agricultural plant species diversity, and impacts the native vegetation [17,18]. ...
Background and aim:
The improper handling of poultry litter and waste poses risks to humans and environment by introducing certain compounds, elements, and pathogenic microorganisms into the surrounding environment and food chain. However, understanding the farmers' knowledge, attitude, and practices (KAP) could provide insights into the constraints that hinder the appropriate adoption of waste management. Therefore, this study aimed to assess poultry farmers' KAP regarding waste management issues.
Materials and methods:
A cross-sectional KAP study was conducted with native poultry keepers and small-scale commercial poultry farmers in seven districts of Bangladesh. In the survey, 385 poultry producers were interviewed using validated structured questionnaires through face-to-face interviews to collect the quantitative data in their domiciles.
Results:
The overall KAP of farmers regarding poultry waste management issues demonstrated a low level of KAP (p = 0.001). The analysis shows that roughly 5% of farmers have a high level of knowledge of poultry waste management issues, followed by around one-third of respondents having a moderate level of knowledge. Considering the attitude domain, more than one-fifth of native poultry keepers and nearly two-thirds of commercial producers demonstrated a low level of attitude toward poultry waste management. Considering the overall analysis, roughly half of the respondents found a high level of attitude, and over half of the farmers showed a moderate level of attitude toward poultry waste management issues. The analysis showed that the level of good practices for native and commercial poultry production systems is estimated at 77.3% versus 45.9%, respectively, despite the farmers' lesser knowledge and attitudes toward poultry waste management systems. Overall, analysis showed that nearly 60% and 40% of poultry producers had high and moderate levels, respectively, of good practices in poultry waste management issues.
Conclusion:
Analysis of the KAP data shows that farmers had a low level of KAP toward poultry waste management. The result of this study will assist in formulating appropriate strategies and to adopt poultry waste management solutions by poultry farmers to reduce environmental degradation.
... One of the main issues caused by unsorted municipal waste is the generation of landfill leachate (LL), a liquid resulting from the degradation of organic waste, and its percolation via rainwater/groundwater to water bodies or other exposed-to-environment places. Transferred pollutants are mostly inorganic ions, dissolved organic compounds and heavy metals, and ammonia [6]. Moreover, the presence of emerging pollutants like sulfamethoxazole (SMX) [7], bisphenol A [8], acetaminophen [9], carbamazepine [10], ibuprofen [11], and caffeine [7] in the LL has been previously reported. ...
In this study, UVA and goethite activated persulfate oxidation was applied to treat a synthetic (SLL) and a real landfill leachate (RLL) spiked with sulfamethoxazole (SMX). Initially, SLL was used to find the optimum landfill leachate (LL) treatment conditions in terms of total organic carbon (TOC) and SMX removal. The screening experiments were conducted using a two-level, four-factor Plackett-Burman design (PBD) to investigate the effects of UVA irradiation, time, concentrations of persulfate (PS) and goethite, on the removal of TOC and SMX. Dark experiments (PS/Goethite) yielded only a 2% TOC removal. Therefore, further experiments were conducted under UVA (365 nm) using a three-factor Box-Behnken design (BBD) in conjunction with response surface methodology (RSM). Analysis of variance (ANOVA) indicated high regression coefficients for the BBD-RSM model in the case of TOC removal (R2 = 0.9755, adjusted R2 = 0.9314 and predicted R2 = 0.7956). In the case of SLL, RSM predicted an 84.4% TOC removal at the reaction time of 5.33 h, PS concentration of 477.4 mM, and goethite dosage of 755 mg/L under UVA. Experimentally, an 81.8% TOC removal and 100% removal of SMX were obtained under these conditions. Finally, the obtained optimum conditions were recalculated using RLL from the local municipal solid waste landfill, and 87% TOC and 100% SMX removals were obtained for PS concentration of 419.3 mM and goethite dosage of 663 mg/L after 4.68 h under UVA irradiation. Air stripping of RLL at pH 11 was complementarily applied to completely remove ammonia nitrogen after 3 hours. The results demonstrated the efficiency of the UVA/PS/Goethite system for the removal of organic matter from the LL for the first time.
... Wang et al., 2017). Leachate from landfills is a severely polluted liquid containing significant levels of inorganic ions, organic molecules, and other harmful substances, including toxic substances and ammonia (Jayawardhana et al., 2016). ...
Researchers have documented the negative effects of refractory chemicals and emergent pollutants in landfill leachate (LL) that cannot be degraded using conventional methods. The propagation, invasion, and deleterious effects of several LL hazards affect aquatic species, the environment, and food outlets, causing significant safety issues. These include cancer risks, chronic exposure, and reproductive consequences. Alternatively, solar energy is a sustainable solution for treating landfill leachate to benefit humans and the environment. In this work, a thorough bibliometric and systematic analysis of studies that employed solar energy for landfill leachate remediation over the past decade was conducted in order to determine trends, and future research areas. In addition to the energy demand, the economic aspect and the advantages of using solar power to treat landfill leachate were discussed. Additionally, the study gives specific suggestions for future research purposes and important problems. The reviewed literature revealed that combining solar-based physical-chemical and biological processes has proven to be the most efficient method for landfill leachate degradation. It also appears from the bibliometric study that more collaboration and contribution are needed to develop solar-based landfill leachate treatment. This study concludes that solar-powered landfill leachate remediation techniques would considerably increase the effectiveness of treated leachate reutilization, advancing the cause of environmental sustainability.
... El lixiviado ha sido reportado como la fuente más importante de contaminación de rellenos sanitarios; puede migrar vertical y horizontalmente por advección, dispersión y dilución(Chakraborty & Kumar, 2016;Xie et al., 2016). Los lixiviados son un líquido altamente contaminado por ser una mezcla de elevadas cantidades de iones inorgánicos, compuestos orgánicos y otros elementos tóxicos como metales pesados, arsénico y nutrientes(Jayawardhana et al., 2016;Mishra et al., 2019; ...
El impacto ambiental, originado por el crecimiento y concentración de la población, afecta de manera directa la cantidad de desechos sólidos urbanos que se generan, convirtiéndose en uno de los desafíos que enfrenta el mundo. Un relleno sanitario es una obra de infraestructura que involucra
métodos de ingeniería para la disposición final de los RSU y de manejo especial, con el fin de controlar, a través de la compactación e infraestructura adicionales, los impactos ambientales. Sin embargo, se ha observado que muchos de ellos funcionan como sitios controlados, causando una grave contaminación al agua subterránea por la fuga de lixiviados, producto de complejos proceso biológicos y fisicoquímicos que
ocurren durante su almacenamiento y degradación. Este estudio analizó artículos científicos de diferentes países. En los fin de controlar, a través de la compactación e infraestructura adicionales, los impactos ambientales. Sin embargo, se ha observado que muchos de ellos funcionan como sitios controlados, causando una grave contaminación al agua subterránea por la fuga de lixiviados, producto de complejos proceso biológicos y fisicoquímicos que ocurren durante su almacenamiento y degradación. Este estudio analizó artículos científicos de diferentes países. En los diversos estudios se han detectado numerosos contaminantes del agua subterránea, así como indicadores de materia orgánica. Generalmente, se ha citado que la contaminación del agua subterránea aparece
en la etapa inicial del relleno sanitario después de cinco años y alcanza su punto máximo de contaminación. Las concentraciones de los contaminantes provenientes de rellenos sanitarios disminuyeron exponencialmente a medida que aumentaba la distancia a las fuentes de agua. Por lo tanto, la contaminación del agua subterránea aparece principalmente a distancias cortas de un relleno sanitario. En este documento se describen las
concentraciones máximas de los contaminantes que se han reportado, además de su impacto a la salud y ambiente.
... Among all the processing and disposal technologies, RDF manufacturing is considered the most efficient technique for handling MSW and substitutes conventional fossil fuels (Reza et al. 2013;Jayawardhana et al. 2016). Refuse Derived Fuel (RDF) is an alternate fuel that helps eliminate the non-combustible fraction, moisture content, that could be traded and co-processed in the industries for power generation. ...
With scarce land availability and ever-soaring quantity of municipal solid waste (MSW), recovery and recycling of the waste stream can only be the savior. An integrated system that facilitates recovery in the form of nutrients, materials, and energy is the need of the hour. Conventional energy sources are getting scarcer with aggressive consumption in industries such as thermal power plants, metal and cement industries etc. While the combustible fraction of MSW colloquially known as refuse-derived fuel (RDF) can supplement the demand up to a considerable extent. Additionally, the application of RDF significantly lowers the operational expenditure and carbon footprint. Source-specific characterization, quality assessment, and promotion of RDF as a promising fuel for cement manufacturing plants were the primary objectives of the study. The investigation revealed the waste characteristics have been significantly varied between the source of generation, transfer station, and the MSW processing and disposal facility. The calorific value (CV) and moisture content (MC) of the mixed RDF consortium were the primary parameters of interest. CV and MC delineated an inversely proportional correlation. The CV value of 3200 cal/gm at source depleted to 1300 cal/gm in segregated combustible fraction, while the MC value has elevated from 14% to 33%. The findings direct better source segregation and transport of combustible fraction can enhance the RDF quality and encourage cement industries for better adaptation of RDF as a potential alternate.
... Among all the processing and disposal technologies, RDF manufacturing is considered the most efficient technique for handling MSW and substitutes conventional fossil fuels (Reza et al. 2013;Jayawardhana et al. 2016). Refuse Derived Fuel (RDF) is an alternate fuel that helps eliminate the non-combustible fraction, moisture content, that could be traded and co-processed in the industries for power generation. ...
The generation of solid waste (SW) has a direct connection with the monetary status of individuals and shows in terms of gross domestic product (GDP)/gross national income (GNI). The high-income countries (HICs) have shown a lingering generation of solid waste, mainly municipal solid waste (MSW). The MSW of HICs include organic biodegradable, paper, plastic metal, glass, and other inert waste and reported higher for the United States of America (50.70%), Canada (47%), Germany (22%), Canada (13%), Germany (12%), and Hungary (35%). The solid waste generation (kg/capita/day) was reported remarkably higher in Italy (59.83), followed by Australia (8.47), Switzerland (8.08), Hong Kong (7.18), Denmark, Singapore, and Lithuania. The treatment processes such as composting, landfilling or controlled dumping, recycling, and incineration were commonly followed by the HICs. The HICs are spending 82–250 USD/ton, 70–200 USD/ton, 65–150 USD/ton, 40–100 USD/ton, and 35–90 USD/ton for waste collection, waste to energy conversation, anaerobic digestion, sanitary landfill, and composting, respectively. The HICs such as the USA, Canada, Scotland, UK, Northern Ireland, and European Union have strict guidelines and rules for landfilling. The US Environmental Protection Agency has restricted the open dumping process by enforcing laws, administrative actions, and punishments with penalties. The strict restrictions are also effected to dispose bio-hazardous materials and substances generated from demolition/renovation of the building. Other side, adoption of emerging techniques plays significant role in circular economy for high-income countries.
... Leachate is defined as the hazardous substances produced in the landfill due to the process of decomposing of solid waste [1]. As of being labeled hazardous, leachate contains various heavy metals, organic compounds and ammonia nitrogen which can potentially bring harms and pollution towards environmental [2]. ...
Landfill leachate is considered dangerous as it contains countless pollutants. Untreated landfill leachate will damage groundwater resources, the environment and human health. An appropriate treatment is necessary to treat leachate to prevent harm to the environment and humans. The objective in this research is to determine the optimum aerated electrocoagulation under the influence of current density, pH of leachate and aeration rate for ammonia nitrogen and colour removal. The efficiency of removal ammonia nitrogen and colour were compared with Environmental Quality (Control of pollution from solid wastewater transfer station and landfill) Regulation 2009. This research used leachate from Simpang Renggam Sanitary Landfill. In this experiment two electrodes of aluminium and ferum at anode and cathode respectively were used. The highest removal percentage were obtained at 84.93% and 58.82% for the colour and ammonia nitrogen at 200 A/m2 of current density, 1.0 L/min of aeration rate and pH 5. The removal value was still insufficient to fit the environment quality standard. However, to meet the environmental quality standard, integration with other treatments method is suggested.
... Citing the statistics, it is evident that the majority of the MSW is simply gets dumped on the low laying grounds located somewhere on the outskirts of the cities. The precipitation, infiltration, surface water runoff, bird menace, rodent interference etc. triggers the vulnerability of waste and leads to mal odor, ground and surface water contamination, human and environmental health deterioration (Jayawardhana et al., 2016). Further, the perseverance of the inorganic and inert fractions leads to soil contamination, poses a fire threat, and also may incur carcinogenicity and acute toxicity among the animals (Mir et al., 2021). ...
The quantity of municipal solid waste (MSW) generation is escalating at an alarming rate with every passing year alongside the modernization of our economy. Unfortunately, the majority of this waste remains uncollected or ends up in open dumping and followed by uncontrolled burning. Citing the deep-rooted consequences, open dumping should be absolutely abandoned and scientific interventions should be aggressively exercised to reclaim the municipal brownfields. The present research work undertook the judicial task of assessing the comparative feasibility of biomining and scientific capping as a technology selection for reclamation of about a decade old 120 million tons of waste chunk laying at Jawahar Nagar dump yard. Primary dump samples were collected from various locations, considering depth as a variable. While leachate and groundwater samples were collected from Malkaram lake and preinstalled borewells receptively. Additionally, the ambient air quality and noise level also been ascertained within the buffer zone. The blended representative solid sample was segregated using a 70 mm mesh size trommel into organic and inorganic fractions. The organic fraction was composted using a lab-scale aerobic static pile composting (ASPC) while the trommel reject was processed as refuse derived fuel (RDF). Evidently, the compost lagged quality and depicted nutrient deficiency. While the burning of RDF produced siloxane gas, significantly due to elevated silicon level in the primary waste. Furthermore, due to the prolonged leaching tenure and seasonal dilution, the concentration of legacy leachate was relatively weaker. Borewell samples collected from a depth of 20 feet also portrayed minor contamination up to 500 meters horizontal radius. The issue of leachability can solely be resolved with the capping of the existing dump and the end product quality derived from the biomining process is highly questionable. Thus, handling such large quantity capping is a befitting option over biomining for Jawahar Nagar dumpsite. INTRODUCTION Presently, in India due to rapid urbanization and industrialization, the generation of MSW has been increasing tremendously and also expected to continue a similar trend in the future (Scott, 1995; Bhat et al., 2017; Sethurajan et al., 2018; Sharma et al., 2018). Annually, the comprehensive urban MSW generation in India is more than 62 million tons. Metro cities are the mammoth contributor of the entire chunk and waste production had already reached an alarming figure of 50,000 tonnes/day. While the waste generation from the tier 2 cities is also rigorously escalating and presently contribute up to 20,000 tones/day (Sharma et al., 2018). A study conducted by the central pollution control board (CPCB) revealed MSW generation in India is increasing at a distressing rate of 5 % per annum with a sharp escalation in the quantities of domestic hazardous waste (Sharma et al., 2018). With major financial constraints, inefficacy of collection, treatment, and disposal incurs further reasons to worry. So far India has miserably failed to set up wholesome source segregation and collection method. Presently, the country spends more than 60% of its annual waste management budget only in collection. Besides, only 20% or less of the collected materials are scientifically handled and treated. Citing the statistics, it is evident that the majority of the MSW is simply gets dumped on the low laying grounds located somewhere on the outskirts of the cities. The precipitation, infiltration, surface water runoff, bird menace, rodent interference etc. triggers the vulnerability of waste and leads to mal odor, ground and surface water contamination, human and environmental health deterioration (Jayawardhana et al., 2016). Further, the perseverance of the inorganic and inert fractions leads to soil contamination, poses a fire threat, and also may incur carcinogenicity and acute toxicity among the animals (Mir et al., 2021). There are numerous techniques for the reclamation and remediation of the dumpsites, includes processes such as capping and closure, in-situ vitrification, sub-surface cut-off walls, and waste biomining (Chakrabarti and Dubey, 2015; Thakare and Nandi, 2016). Waste biomining is a stable way to get rid of the entire range of problems associated with open dumping and reclaim valuable land (Kaksonen et al., 2017). There are several instances including reclamation of Mumbai Gorai dump yard by IL & FS Environment, 70 – 80 years old 12,00,000 tons of dump clearance by Nagar Nigam Indore within a minute span of 3 years and many more. But the process of biomining is highly sensitive and case-specific. The success of the process solely depends on factors such as characteristics of the waste, efficacy of the effective microorganism culture, acceptability of the processed end product at the local market etc. (Jerez, 2017; Banerjee et al., 2017; Venkiteela, 2020). Contrarily, though the scientific capping is not an end-to-end solution but still advisable in the cases where the quantity of waste is gigantic, land scarcity is prevalent, no nearby industries to consume the end products etc. Mehta et al. (2018) have also supported the above claim based on the assessment of locations specific MSW dump reclamation case studies. While in another Nagpur-based case study conducted by Ashootosh et al. (2020) reported the superiority of the biominingprocess over simple land capping due to the favorability of the local conditions. Capping eliminates the environmental interference and thereby reduces biosphere contamination and leachate generation. Further, it captivates rodent and vector breeding and thereby curtails the spreading of communicable diseases and improves aesthetics. But right consolidation through compaction and execution is utmost necessary in the above case. As non-compaction and faulty sloping will easily lead to heavy settlement and slope failure (Berkun et al., 2005; Al-Ghouti et al., 2021). The present study has been pursued with the primary objective to run a techno-commercial assessment between scientific capping and biomining. While the secondary objective was to ascertain the level of contamination and propose mitigative measures. MATERIALS AND METHOD
Study Area Spanning over 350 acres of a precious piece of land at the outskirts of Hyderabad city, Jawahar Nagar dumping yard was brutally utilized by the Greater Hyderabad Municipal Corporation (GHMC) for open dumping for a prolonged tenure of 10 years. It housed nearly 12 lakh metric tons of heterogeneous solid and domestic hazardous waste and continues polluting until 2015, until the Ramky group was offered to cap the legacy dumping and scientifically handle the site. The present study has been facilitated at Hyderabad Municipal Solid Waste Limited, formerly known as Jawahar Nagar dump yard to analyze and assess the feasibility of bio-mining as handling and management alternate to the existing practice of scientific capping. The epicenter of processing and disposal facility is lying approximately on the cross-section of 17°31'24.45"N and 78°35'23.37"E. As per the contract, the comprehensive legacy dumping to be capped in three phases over about 150 acres of area and Ramky has significantly entered the phase two of the operation only within a span of five years by successfully capping more than half of the legacy footprint. Sampling Methodology The waste pile was divided into three layers namely, base, middle, and top. A uniform amount of sample was collected from the successive layers of all five different corners which cover north, south, east, west, and central of the garbage pile. Sampling inspections were performed using a manual auger besides large samples were collected using a JCB excavator. The top six-inch layer of the pile was removed to avoid any contamination while collecting the samples and 5-10 kg of sample was collected from each of the locations. Further, intermediate and bottom layer samples were collected by digging a 500 mm diameter hole through the heap. A composite was prepared by a homogenized blending of all the fifteen grub samples. The blend was distributed into four equal quadrants and the top and bottom quadrants were eliminated diagonally while the left-over quadrants were mixed thoroughly. This process was repeated until a sample of the required bulk of 20 kg is obtained. Surface and subsurface water samples from borewell were collected in and around the facility. Piezometric monitoring borewells located near the landfills were utilized for the subsurface sample collection. While a rainwater pond turned leachate lake named Malkaram was determined as the primary source for leachate collection. Buffer samples were collected from Ambedkar Nagar, the nearby colony exiting at a distance of only 300 meters. Lab-scale Experimentation The representative sample was characterized for composition and further screened through a 70 mm mesh size trommel. The trommel permeate was considered as the organic fraction while the reject was mostly inorganics and inert. The organics were subjected to ASPC. The quantity of the air required is arrived using the method delineated below (Figure 1). MSW Pile size: 2m x 0.5m x 0.5m Volume of pile: 0.5 m3 Average Density of MSW: 620 Kg/m3 Weight of pile: 310 Kg Nitrogen required for matured compost: 9300 mg/kg dry : 9300 X 310 mg : 2.88 x 106 mg : 2.88 Kg Total air required: 2.88 x 100/76 [as Nitrogen in air is 76% by weight] : 3.79 Kg of dry air : 3.79/1.225 m3 [@ 15 deg C density of air 1.225 kg/m3] : 3.1 m3 This air is to be supplied for 100 min / day for 0.5 m pile Air flow rate required: 3.1 x 60/100 = 1.86 m3/h (for practical purpose a flowrate of 2 m3/h was maintained). The maturation period was considered as 28 days and post-maturation, the stabilized material was further cured for 24 hours and screened using 12 mm and 4 mm trommel respectively to obtain the desired product quality and particle size. Whereas, the trommel reject was evenly spreader on the copper trays and dried in an oven at 1050C for 2 hours. The dried material was micronized to the size of 50 mm or below using a scissor and inert such as glass, sand, stone etc. were segregated manually (Mohan and Joseph, 2020). Concurrently, a bench-scale capped landfill prototype was built using the below-mentioned procedure to evaluate the factors such as settlement and slope stability. A 30 mm thick low permeable soil was laid on the top of the waste, followed by a 60 mm layer of compacted clay liner (CCL). Each join between successive liner material was closely monitored. A 1.5 mm thick HDPE liner was placed on the top of the CCL. A 285 GSM geotextile membrane was placed as the successive above layer followed by a 15 mm thick drainage media layer. A further layer of geotextile membrane was placed on top of the drainage media for better stabilization, grip, and strength. The top vegetative soil layer of 45 mm thickness was laid off on top of the geotextile media and St. Augustine grass was rooted (Cortellazzo et al., 2020; Ashford et al., 2000). 2.4 Sample Analysis pH, Electrical Conductivity (EC) and Turbidity of the samples were analyzed using pH, EC-TDS, and Nephelometer of Mettler Toledo. The pH meter was calibrated with the buffer solution of 4.0, 7.0 & 9.12 at a controlled temperature. EC-TDS meter was calibrated with 0.1 M KCL having 12.8 mS/cm of conductivity. Nephelometer was calibrated with Formazine solution of 10 & 100 NTU. Total Dissolved Solids (TDS), (mg/L) was performed using the gravimetric method at 1800C in the oven. Titrimetric parameters such as Total Alkalinity as CaCO3 (mg/L), Total Hardness as CaCO3 (mg/L), Chloride as Cl- (mg/L), Calcium as Ca2+ (mg/L), Residual Free Chlorine (RFC), (mg/L) were analyzed using APHA (American Public Health Associations) method, 23rd Edition, 2017. Total Kjeldahl Nitrogen (mg/L) and Ammonical Nitrogen (mg/L) were performed through distillation followed by titration with H2SO4 as a titrant. Sulphide as S2- was done with the Iodometric method after distillation. Each titrimetric parameter was analyzed in triplicate after standardizing the titrant with required reagents and crossed checked by keeping a check standard. Sodium as Na (mg/L) and Potassium as K (mg/L) were performed using Flame Photometer. The photometer was calibrated with different standards from 10 to 100 (mg/L) standard solutions. The leachate sample was diluted enough to get the value within the standard range and cross-checked with check standards at the same time. Chemical Oxygen Demand (COD), (mg/L) was performed using the open reflux method for 2 hours at 1500C in COD Digestor. Biochemical Oxygen Demand (BOD), (mg/L) was performed using the alkali iodide azide method for 3 days. The samples were kept in a BOD incubator at 270C for 3 days. It was kept in duplicate to have a check on quality control. Sulphate was analyzed by the gravimetric method instead of turbidimetric or through UV-Visible spectrophotometer as its concentration was found more than 40 mg/L. Nitrate as NO3- was analyzed after filtration at 220-275 nm, while Hexavalent Chromium as Cr6+ was analyzed at 540 nm in the UV-Vis. Parameters like Cyanide as CN-, Fluoride as F-, and Phenolic Compounds were gone through a distillation process followed by UV-Vis. The distillation process ensures the removal of interferences presents either positive or negative. For the parameters like Total Iron or Ferric Iron, the samples were digested properly with the required reagents on the hot plate before analyzing in UV-Vis. For the metal analysis the water samples were digested at a temperature of 1000C using aqua regia as a media. The samples were digested to one-fourth of the volume on a hot plate. The recommended wavelengths as per APHA 3120 B were selected for each of the metals. The standard graph was plotted for each of the metals before analysis and crossed checked with the check standard at the same time. Parameters such as bulk density and particle size were performed through the certified beaker and sieve. The percentage of moisture content was estimated using the oven by keeping the compost sample for 2 hours at 1050C. C/N ratio was estimated through CHNS analyzer keeping sulfanilamide as a check standard. The analysis was performed by extracting the desired component in the desired solution prescribed in the method followed by converting the same from mg/L to mg/Kg. RESULTS AND DISCUSSION An exhaustive bench-study has been pursued and real-time samples were collected and analyzed for all possible parameters to determine the pros and cons attributed to both processes. The investigation begins by collecting the samples and concluded by impact assessment studies inclusive of the buffer zone. Both solid, liquid, and gaseous samples were precisely investigated to opt for the best solution. A detailed finding of the investigation is summarized below. Primarily, the representative solid sample was characterized through a manual separation process and the results are portrayed in Figure 1. Compost Characterization ASPC of the organic fraction has resulted in a recovery of 46.7% of the initial load. While 53.3% of the influent mass were inert and barely degradable fraction contributes to reject, the rest 4.1% is miscellaneous process loss. The processed compost was extensively analyzed including for metal contamination and the same is tabulated in Table 1. The value of C/N ratio, OC, TN, K2O, P2O5, and NPK evidently portrays the shortcoming in terms of nutrient availability. Though it is highly enriched in organic carbon and thus the same can be effectively utilized as a soil preconditioner. Ayilara et al. (2020) also reported a similar finding, where the city compost sourced from MSW lagged major plant nutrients. RDF Characterization Processed trommel rejects constitute cloth, rexine, leather, jute, paper, plastics, coir and other inert contributed to RDF. The fraction of inert was as high as 37.2% of the overall RDF mass and it mostly constituted glass and sand. The combined weight of sand and glass fragments contributed 73.5% of the total inert, while the rest was stone and small brickbats. The higher level of silicon associated with the presence of glass and sand yielded siloxane and triggered the possibility of kiln corrosion. A detailed RDF analysis report is enclosed in Table 2. The values explicitly portray the quality of RDF is moderately lower and higher salts concentration is extremely prevalent. With relatively lower NCV and such high salt concentration, the above specimen will certainly pose a corrosion threat to the kiln and shall be either neglected as kiln feed or can be utilized after dilution with Grade III RDF quality. Further, such high ash generation will also induct high transportation and landfill charges. Leachate Characterization The Malkaram leachate lake is the end result of prolonged, slow, and steady mixing of the legacy leachate through the existing fissure cracks in the sheath rock bottom profile. Apparently, the concentration of leachate is significantly lower due to the dilution. Samples were analyzed in triplicates and the mean value is tabulated here in Table 3. The metal concertation and rest of the parameter values are well within the secondary treatment influent range, except for TDS. Thus, a modular aerobic biological treatment unit such as moving bed biofilm bioreactor (MBBR) or membrane bioreactor (MBR) would be a well-suited pick. However, a reverse osmosis (RO) system needs to be installed to get rid of the high TDS content. The permeate of RO can be reused back into the system. Whereas, the reject can be converted into dried powder through forced evaporation mechanisms. The higher concentration of salts in RDF collaterally justifies the elevated TDS level in leachate. In a leachate impact assessment study performed by El-Salam and Abu-Zuid (2015) the reported BOD/COD ratio of 0.69 is greater than double the value of 0.301 reported in Table 3. Though the difference in both the values are quite high, it is relatable and justifiable by the huge age difference of the source waste. The primarily characterized data is of a fresh leachate generated from regular MSW, while the later one is from a decade old waste that barely has any unstabilized organic content. Groundwater Contamination The obvious reason for downward leachate infiltration and osmotic movement facilitates groundwater contamination. Both surface and subsurface water samples were collected within the dump yard and the buffer zone and analyzed using the standard methods. The results are portrayed in Table 4. The slightly alkaline pH of the borewell sample is an indication of the ongoing anaerobic process. The dissolved oxygen value of 3.5 mg/L further validates the correlation. Higher TDS and hardness values are self-indicative of elevated salt concentration in source waste. Eventually, the same interfered with the RDF quality. Positively in the case of all the parameters, a successive decrement in pollution concentration has been spotted from dump ground towards the buffer zone. In a similar study conducted by Singh et al. (2016) at Varanasi, Uttar Pradesh the reported concentration of the parameters is significantly higher than reported in Table 4. The basic reason behind variation is the dissimilarities of the local soil profile. The sandy and clay loam soil profile of Varanasi allows a greater rate of percolation and infiltration. While the bottom sheath rock profile at Jawahar Nagar permits the only a minute to little percolation rate. The difference in percolation rate is directly correlated to the concentration levels in this case. Contrarily, Kurakalva et al. (2016) have reported much-elevated pollutant concertation both in ground and surface water for a study conducted at the same site in 2016. The higher concentration is relatable to the fact of the non-closure of the open dump back then. Capping activity had at Jawahar Nagar gained its pace 2018 onwards and capping for the primary section of 70 acres got concluded only during mid of 2019. Due to the decrement in runoff and percolation, the quality of both surface and subsurface water has improved drastically. Impact Assessment The odor and groundwater contamination are two of the primary issues that triggered a massive public agitation initially. The root causes of both the issues are identified as rainwater percolation and anaerobic digestion respectively. Eventually, the completion of the capping process would resolve both the problems effectively. Other non-tangential impacts include nausea; headache; irritation of the eye, nasal cavity, and throat; diarrhoeal diseases; vector-borne disease, cattle toxicity etc. Scientific capping can easily cater as the wholesome solution for all (Cortellazzo et al., 2020). Yu et al. (2018) had performed an extensive study to comprehend the relativity of respiratory sickness and MSW borne air pollution. The study made a couple of dreadful revelations such as gases released due to the anaerobic digestion of MSW such as methane, hydrogen sulphide, and ammonia incur detrimental impact on Lysozyme and secretory immunoglobulin A (SIgA). While SO2 was reported as the lung capacity and functionality reducer. Further, a gender-specific study executed by the same research group revealed, air pollution impacts more severely on male children than the female and retards immune functions. Presently, the area of 351 acres has been developed as Asia’s one of the largest state of the art municipal solid waste processing and disposal facility by Ramky Enviro Engineers Limited. This ensured zero dumping and no further environmental interventions. As legal compliance, the facility monitors the quality of groundwater and ambient air quality in and around the facility on monthly basis to assure the biosafety. The variation in concentration of various monitoring parameters between 2012 to 2020 is summarized in Figure 2. The concentration of each of the parameters are showcased in ppm and a standard equipment error was settled at 3% for respirable dust sampler and multi-gas analyzer (Taheri et al., 2014). Despite all parameter values have gradually increased except for methane, the facility still managed to maintain them well under the regulatory limits. The decrement in methane concentration is directly correlated to the practice of aerobic composting and aeration-based secondary treatment that prevented the formation of the anaerobic atmosphere and henceforth methane generation. While for the rest of the parameters the increment in values is quite substantial and predictable due to the sudden escalation in MSW generation in the past decade in correlation with Gross domestic product (GDP) enhancement. The observed and interpreted impacts due to the elevated pollutant level are in-line with the georeferenced findings reported by Deshmukh and Aher (2016) based on a study conducted at Sangamner, Maharashtra. CONCLUSION The study critically analyzed and investigated every techno-environmental and socio-economic aspect correlated to open dumping. The bench-scale experimentation revealed the efficiency of the single liner scientific capping is fair enough to eliminate any further rainwater infiltration, however, it has no control over the generation of leachate due to the inherent moisture. Internal moisture related issue was anyhow compensated with pertinent compaction prior to dispose of the waste. Contrarily, both the products derived through the biomining process namely, compost and RDF lagged quality due to scantier nutrient content and higher salt and silicon content respectively. Besides, impact assessment studies concede the pollutant concentration in groundwater in and around the plant has drastically diminished post-July 2019 due to the partial completion of waste capping. It also abetted lowering the dust and odor issues relatively in the surrounding. ACKNOWLEDGMENT The authors would like to sincerely acknowledge GHMC, Hyderabad Integrated Municipal Solid Waste Limited, and Ramky Enviro Engineers Limited for enabling us to pursue the sample collection and other necessary onsite activities. Further, the authors would like to register profound acknowledgment to EPTRI for supporting us with the essential experimental facilities. REFERENCES Sharma, A., Gupta, A.K., Ganguly, R. (2018), Impact of open dumping of municipal solid waste on soil properties in mountainous region. 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... Positive and negative effects of biochar on plant growth performance have been discussed in literature by many researchers (Namgay et al., 2010;Younis et al., 2020;Alaboudi et al., 2019). The use of non-lignocellulosic material-derived biochar has been reported by various investigators with a pronounced effect on plant growth (Jayawardhana et al. 2016) and Pandey et al. (2020) noted that lignocellulosic feedstockderived biochar is suitable and safer for agriculture purposes compared to non-lignocellulosic feedstock. ...
Synergistic effect of biochar and microbes in soil enhances performance of plants. Hazardous tannery solid waste can be reduced by one-third in volume by conversion to biochar. A greenhouse trial was set up with soil having different doses of metal resistant microbe-impregnated biochar (MIBC) prepared from tannery solid waste. Consortia of autochthonous strains of Trichoderma and Bacillus were inoculated on BC and the behavior and fate of metals were evaluated for their bioavailability to sunflower. Sunflower was grown in pots for 80 days having six different amendments of tannery solid waste biochar (0–10% w/w) with and without Trichoderma and Bacillus consortia and its morphological and biochemical attributes as well as metal uptake were observed. The results illustrated that application of BC at 2% rate without inoculation increased the shoot length and dry biomass by 19.8% and 77.4%, respectively, while plant growth and performance were reduced at higher amendments of BC. However, application of MIBC with Trichoderma or/and Bacillus consortium significantly improved the plant attributes at all levels of amendment. The results indicated that MIBC having Trichoderma and Bacillus consortia at 10% rate increased shoot length and dry biomass by 65.3% and 516% compared to control without BC. Application of BC without inoculation reduced the uptake of Cu, Fe, and Ni and increased the mobilization of all other metals for uptake in sunflower. Mobilization and uptake of Cd, Cr, Cu, Ni, Pb, and Zn decreased with MIBC having Trichoderma and Bacillus consortia whereas that of Fe and Mg were noted. A considerable decrease in proline and total phenolic content was demonstrated by MIBC-grown sunflower. The data of metal fractionation in BC also supported the above findings. Therefore, MIBC can be used as a promising option for enhancing growth performance and ensuring the physiological safety of sunflower as an energy crop.
... Morita et al. [7] estimate that open dumpsites will account for 10% of global greenhouse gas emissions by 2025. Municipal solid waste, when disposed of, produces leachate, which is a highly contaminated liquid containing high amounts of inorganic ions, organic compounds, and other toxic elements such as heavy metals and ammonia [8,9]. In unplanned landfills, leachate is commonly mobilised to the surrounding environment (soils, surface, and groundwater), causing contamination [10]. ...
The contamination of areas around solid urban waste dumps is a global challenge for the maintenance of environmental quality in large urban centres in developing countries. This study applied a geophysical method (electrical resistivity) to identify leachate contamination plumes in the subsoil and groundwater, as well as to describe their temporal dynamics (2020 and 2021) in the surroundings of the Hulene-B waste dump, Maputo, Mozambique. Eight 400 m electrical resistivity profiles were performed, four profiles in January 2020 and four profiles in May 2021 overlapped, and the data were inverted with RES2D software. The electrical resistivity models predominantly indicate an E-W movement of large contamination plumes that are successively diluted with saturated media and groundwater, creating zones of less resistive anomalies (<4.2–< 8.5 Ω·m) possibly contaminated at the two analysed seasons, between 2020–2021. The thickness of the contamination plumes was higher in summer (2020) for profiles 1 and 2, and we associate it with the production and migration mechanisms of leachate that are intense in the hot and rainy season. Southwest of the dump, profile 4b showed the propagation of anomalous areas on the surface and at depth, which are associated with the production of leachate resulting from the continuous decomposition of waste that is continuously deposited in a new area southwest of the dump, thus generating a slow and continuous migration of leachate at depth, mainly in winter (2021). The spatial distribution of contamination plumes during both seasons was reduced significantly farther away from the waste deposit, revealing the attenuating effect of groundwater and lithological substrate (Profile 3).
... Morita et al. [7] estimate that open dumpsites will account for 10% of global greenhouse gas emissions by 2025. Municipal solid waste when disposed of produces leachate, which is a highly contaminated liquid containing high amounts of inorganic ions, organic compounds, and other toxic elements such as heavy metals and ammonia [8,9]. In unplanned landfills, leachate is likely to be mobilised to the surrounding environment (soils, surface, and groundwater) causing contamination [10]. ...
The contamination of areas around solid urban waste dumps is a global challenge for the maintenance of environmental quality in large urban centres in developing countries. This study applied geophysical methods (electrical resistivity) to identify leachate contamina-tion plumes in the subsoil and groundwater, as well as to describe their temporal (2020 and 2021) dynamics in the lithology and groundwater around the Hulene - B waste dump, Maputo, Mozambique. Geophysical methods (electrical resistivity) were applied to identify possible groundwater contamination plumes, their dynamics, mechanisms of their enrichment and dispersion. Eight 400 m electrical resistivity profiles were performed, four profiles in January 2020 and four profiles in May 2021, overlapped, and the data were inverted with RES2D software. The electrical resistivity models indicate an E - W move-ment of large contamination plumes that dilute superficially into the natural surface wa-ter receiving basin and groundwater, creating zones of resistive anomalies. The thickness of the plumes in the subsurface environment was shown to be extensive in summer for profiles 1a and 2b and we associate it with the higher leachate production and migration mechanisms, which are intense in the hot and rainy season. Profile 4b showed the prop-agation of anomalous surface and subsurface areas, which was associated with higher leachate production and migration process in the new deposition zone (west). The spatial distribution of contamination plumes at both stations reduced significantly as we moved further away from the waste deposit, revealing the attenuating effect of groundwater and lithological substrate (Profile 3 a, b, and fig.7).
... Leachate is a liquid that percolated through the solid waste in landfills. It is generated from liquids present in the waste and from outside water, including rainwater [1]. Leachates composition consisted of various types of chemicals. ...
The tropical climate condition and high moisture of solid waste characteristic in Malaysia led to the increase of leachate generation from landfill. Current leachate treatment showed less efficient to treat leachate due to various refractory pollutants in the leachate. This study employed electrocoagulation (EC) to investigate the effects of electrode material, current density and initial pH condition in reducing total suspended solid (TSS), chemical oxygen demand (COD), biological oxygen demand (BOD 5 ), ammonia-nitrogen and colour from the leachate. The result showed that aluminium electrode was able to remove all the parameters more effectively as compared to iron electrode. The optimum current density and pH condition were found to be 100 mA/cm ² and at pH 7, respectively. The COD in the leachate was predominantly exist as particulate matter and it was removed in the form of suspended solids. Although all the pollutant parameters still exceeded the standard discharge limit after the treatment, the electrocoagulation is proposed to act as pretreatment prior to biological treatment in sanitary landfill. The electrocoagulation also can treat leachate from open dumping landfill sites in order to reduce the leachate contamination into the environment.
... ere are solid waste landfills that are well managed and designed as part of the integrated waste management system and protect the environment from contaminants that may be present in the solid waste stream; however, that is not always the case. Most landfills still contribute to many environmental issues including groundwater contamination from leachate generation and emission of greenhouse gases from landfill gas (LFG) generation [7]. Landfills can also render surrounding soil and land unusable. ...
Totaling at 7.4 billion people, the world’s population is rapidly growing, bringing along with it an increase in waste generation. The impact of this exponential increase in waste generation has resulted in the increased formation and utilization of landfills. In the present day, landfills are utilized to dispose of chemical, hazardous, municipal, and electronic wastes. However, despite their convenience, most landfills are improperly managed and face constant changes from the surrounding environment that interfere with their internal landfill processes. The objectives of this mixed review are to highlight the negative impacts landfills have on the environment and public health as well as outline the need for proper management practices to mitigate these effects. Inadequate management of landfills leads to issues concerning leachate collection and landfill gas (LFG) generation, which give rise to groundwater contamination and air pollution. This paper recognizes the disadvantages of utilizing landfills as the main disposal method by focusing on these two primary effects that improper management of landfills has on the environment and human health. Many experts have also reported that communities within close proximity to improperly managed landfills have an increased risk of health issues. Apart from implementing proper landfill management practices, it is important to develop solutions to reduce waste generation altogether. This review discusses some of the innovative methods implemented by other countries to reduce landfill waste and the production of greenhouse gases as well as possible steps individuals can take to minimize their ecological footprints.
... Leachate is the fluid percolating through the landfills. It is generated from liquids present in the waste and outside water, including rainwater, seeping through the trash, and taking up organic and inorganic products from both physical extraction and hydrolytic and fermentation processes (Jayawardhana et al., 2016). Rainfall, microbial action, and organic matter in solid waste generated loads of leachate. ...
This study was carried out to characterize the biogeochemical and physicochemical properties of landfill leachate from Matuail Sanitary landfill site, Dhaka, Bangladesh. In addition, the study also aimed to identify the photodegradation of landfill leachate under natural sunlight. The leachate pH was slightly alkaline (7.87-8.07) with a minimum level of dissolved oxygen, and low BOD5/COD ratio that are indicators of the matured methanogenic phase. Ca, Fe, Br, Rb, Cu was present in a considerable amount. A trace amount of Sr, Co, As, Pb, Cr was found in the leachate sample. Fourier Transform - infrared (FTIR) spectra of all three samples had five major peak regions notably at 3440-3450 cm−1 (O–H groups of water), 1638 cm−1 ( C==O Amide I, carboxylates C=C, aromatic ring modes, or alkenes), 1385-1390 cm−1 (deformation of the C–H bond in CH2 and CH3, or the asymmetric stretching of COO¯), 1115 cm−1 (stretching of the C–O bond in phenol ethers and phenols) and 605 cm−1 (S–O bends of sulfates). In addition to the appearance of new peak, peak shifting on the 2nd-day and 5th-day phototreatment are in compliance with the 34% TOC reduction. From analyzing three-dimensional excitation/emission (3D-EEM) spectra of the raw sample pyrene-like or humic-like peak A (Ex 255/Em 465), soil fulvic-like peak Mp (Ex 315/Em 450), and humic-like peak C (Ex 370/455) was found indicating more humified characteristics of the mature landfill site. From 1-hour to 6-hours phototreatment, all three substances slightly lost fluorescence intensity. From the 2nd day to the 5th day of photo-treatment, two unknown photo-product was identified within Ex 210.0/ Em 457.0 and Ex 205.0/Em 408.0 at peak A region. Fluorescence intensity lost was 65% for peak A and 44% for peak C. Soil fulvic-like peak Mp was absent on the 5th day of photo-treatment.
... 152 The composition of leachate typically depends on the composition of the waste, moisture content, compaction degree, and weather conditions. 153 In general, the leachate is characterized by strong odors and coloration along with high pH, nitrogen compounds, heavy metals, chemical oxygen demand, and biological oxygen demand. 154,155 Over time, the formed leachates seep toxic chemicals and pollutants into surface water and groundwater, which could contaminate water and surrounding soils. ...
The paper presents an overview of the status, challenges, and prospects of current and emerging trends for the sustainable treatment and valorisation technologies of plastic wastes. The proliferation is ascribed to the growing population, living standards, and use of low cost, unbiodegradable, and chemically resistant plastic wastes in Nigeria. This scenario is exacerbated by the lack of comprehensive strategies for the collection, transport, segregation, and management of plastic wastes. Currently, plastic wastes treatment is accomplished by open‐air burning, dumping, and landfilling. More advanced technologies such as thermal (incineration, gasification), chemical (catalytic cracking and selective dissolution), and biological (microbial degradation) methods are also utilised for treatment and valorisation. However, these high costs, obsolete, and inefficient technologies result in GHG emissions, toxic fumes, toxins and leachates. Hence, novel technologies for the reuse, recycling, reduction, and valorisation of plastic waste must emphasize energy, materials, and resource recovery. The paper proposes the upcycling of plastic wastes into carbon nanomaterials (CMSs, CNFs, graphene flakes, CNTs), polymeric composite materials (WPCs, WFRPs), biocrude/bio‐oil, fuels, chemicals, and char through solvent/solvothermal treatment and plasma conversion. Solvent/solvothermal treatment can effectively treat and upcycle plastic wastes along with the removal of toxic, recalcitrant and bio‐accumulative pollutants such as brominated flame retardants and organophosphorus flame retardants. However, the study identified numerous challenges that currently hamper plastic wastes disposal, management, and valorisation. Hence, sustainable and socially friendly approaches for plastic waste management and valorisation are required to address their short and long‐term impacts on human health, safety and the environment in Nigeria. This article is protected by copyright. All rights reserved.
... Although various methods of composting are popular in India, a major fraction of the degradable MSW ends up in open dumpsites or unscientific landfills leading to environmental and human health hazards (Dutta and Jinsart, 2020). Leachates from municipal solid waste materials in landfill sites pollute the surface water and ground water with organic and inorganic constituents migrating downward until it reaches the saturated zone (Jayawardhana et al., 2016;Naveen et al., 2018;Youcai, 2018;Vallero and Blight, 2019). Aerobic and anaerobic composting though popular in the country, are slow processes taking two to three months for the completion of one cycle https://doi.org/10.1016/j.wasman.2021.01.002 0956-053X/Ó 2021 Elsevier Ltd. ...
Thermochemical digestion is a rapid technology of biowaste management resulting in the instant production of organic fertilizer. Characterization and assessment of its suitability as an organic fertilizer is essential for recommendation for crop application. Biowaste and the thermochemical digestate were subjected to physicochemical and biochemical characterization and the compost maturity parameters assessed. The product integrated with inorganic fertilizers was tested in an Ultisol grown with banana in comparison with farmyard manure based fertilizers. Temporal variation in soil reaction, water holding capacity, carbon dynamics, dehydrogenase activity and plant biomass were determined. The thermochemical digestate fertilizer had a bulk density (0.76 Mg m⁻³), pH (neutral), C:N ratio (16.26), CEC (85.70 cmol(+) kg⁻¹), CEC/ TOC ratio (3.99), Fertilizing index (4.7) and a Clean index (5.0). Field evaluation revealed enhanced water holding capacity (38.75–83.17%). Total carbon increased with consistently high labile (R² = 0.9551) and non labile carbon fractions and the lowest average lability index (0.78). Dehydrogenase activity at harvest enhanced by 72.81%. An even biomass allocation resulted in 38.84% more biomass production in the fruit over farmyard manure based treatments. In addition to ensuring the safety of the environmental ecosystem, the thermochemical digestate conformed to be a quality resource favoring microbial proliferation and carbon sequestration, thereby restraining carbon dioxide emission. The thermochemical digestate fertilizer based nutrition serves the key deliverables of natural resource management, ecofriendly rapid disposal of biowaste and quality organic fertilizer for banana in Ultisols.
... Because of the fact that sewage sludge contains a considerable amount of phosphorous, nitrogen, micronutrients, and organic matter, it may have a positive effect on soil properties [37]. On the other hand, in many parts of the world, the question of what type of organic waste can be used as biochar-making material is also closely related to the massive occurrence of them that concerns governments and public authorities for the treatment and recycling of these wastes [38,39]. In this sense, olive oil solid waste, poultry manure, and sewage sludge are three important waste biomasses that occurred in huge amounts during agricultural and municipal waste treatment activities [40][41][42], and they may have big potentials for biochar production and agricultural utilization in countries such as Turkey. ...
A short-term incubation study was carried out to investigate the effects of different biochar (pyrochar and hydrochar) amendments on soil properties. Pyrochars and hydrochars derived from sewage sludge (PSS and HSS), poultry manure (PPM and HPM), and olive oil solid waste (POW and HOW) through slow pyrolysis and hydrothermal carbonization (HTC) were mixed with soil in three different doses (1, 2, and 4%) and subjected to a 120 day incubation period. Selected soil physical (water-stable aggregate [WSA]) and chemical (pH, EC [Electrical conductivity], CaCO3, total N, soil organic matter [SOM], C:N ratio, and available P) were investigated at the end of incubation, while soil biological properties (urease [UR], alkaline phosphatase [ALP] and β-glucosidase [βG] enzyme activities) were evaluated in a time-course sampling, at 1, 60, and 120 days of the incubation. The results generally indicated that total N and soil available P contents were more responsive to pyrochars and hydrochars produced from different biomass wastes. All pyrochars showed significantly higher total N and available P over hydrochars depending on the application doses and only HOW showed a prominent enhancement in SOM over POW. In general, soil ALP activity did not show distinct changes in pyrochar amended conditions, whereas it seemed to increase significantly by the amendments of hydrochars, especially HSS (p < 0.05), over the control and application dose. The βG activity displayed a similar pattern with that of ALP activity in that increasing additions of hydrochars produced from all three waste biomasses significantly stimulated (p < 0.05) βG activity over those of their corresponding pyrochars. Unlike from ALP and βG activities, UR tended to decrease significantly (p < 0.05) in all pyrochar added treatments but depending on the waste biomass type and application dose; it showed different change patterns under hydrochar treatments. Overall, the results showed that the hydrochar obtained from HTC is more effective on the biological properties of soil compared to the biochar obtained by pyrolysis. On the other hand, it is possible to conclude that pyrochar was a very stable and recalcitrant C source than hydrochar according to microbial activities and could be an efficient, long-term strategy to sequester C in soils.
... A novel microbial nitrogen extraction process called anaerobic ammonium oxidation (anammox) has been reported over the past decade, which is capable of oxidizing ammonium into nitrogen gas under anaerobic nitrite as the electron acceptor ( Van de Graff et al., 1995;Phan et al., 2017;Wu et al., 2018;Lin et al., 2011). On the other hand, Municipal Solid Waste Biochar (MSW-BC) has received recent attention for its ability on volume reduction of waste and adsorbing nutrients (Ghezzehei et al., 2014;Jayawardhana et al., 2016;Gunarathne et al., 2018). A few studies have shown that the MSW-BC could be used effectively to mitigate contamination such as heavy metals and dyes (Agraioti et al., 2014;Parshetti et al., 2014;Li et al., 2015). ...
... When the process is not managed well and the wood or wood waste gets into contact with water leachate is generated. Leachate is produced when liquid percolates through solid material (Cheremisinoff, 1997;Jayawardhana et al., 2016). During this process, compounds leached from the solid material and when toxic affect aquatic organisms when released into water bodies. ...
Ghana has a long history as a major supplier of high-value hardwood timber and wood products to many countries. The research seeks to assess the effects of tropical wood leachates to aquatic organisms. Hence, five wood samples were selected; Mahogany (Khaya ivorensis), Cedrela (Cedrela odorata), Emire (Terminalia ivorensis), Wawa (Triplochiton scleroxylon) and Ceiba (Ceiba pendandra) from Oboyow forest reserve in Eastern Region- Ghana to assess their toxicity to aquatic organisms. Toxicity tests: Algal (Desmodesmus subspicatus) Duckweed (Lemna minor) and crustacean (Daphnia magna) were carried out using exposures to concentrations of 20, 30, 45, 67 and 100% v/v wood leachate in control media. The high levels of phenols measured in the various wood leachates was the main cause of toxicity. The percentage median Inhibition Concentration (%IC50) of the various wood leachate, ranged from 21.5 - 55.6% with mahogany exhibiting the highest toxicity and wawa the lowest. All the wood leachates were toxic to the aquatic organisms. The %IC50 showed both confirmed and potential toxicity among the various wood leachates and established that there was significant difference between various wood leachate toxicity.
... A group [41] prepared biochar from MSW by using pyrolysis in a custom-designed packed bed reactor at 400-800 °C, which was further used to remove the azo dye. In another report [48], researchers used MSW biochar for the prevention of pollution from landfill leachate. Similarly, the effect of MSW biochar on the removal of aqueous arsenic (V) from wastewater was studied [42]. ...
Interest in biochar production from organic waste has been growing in recent years due to its broad applicability, availability, and smoother production. Biochar production techniques are being continuously modernized to improve the production rate and quality. Though numerous methods have been reported in the recent past, a systematic classification of the same is yet to be explored. Based on the advancement of the techniques being employed for biochar production and modification of conventional methods, we have categorized all major techniques of biochar production into two primary classes. In the traditional approach, ancient methods and conventional pyrolysis techniques (Slow and Fast pyrolysis) are included, whereas, in modern approaches, several advanced technologies such as Gasification, Torrefaction, Hydrothermal carbonization, Electro-modification, along with modified traditional methods (Flash pyrolysis, Vacuum pyrolysis, and Microwave pyrolysis) are comprised. Further, the systematic review was intended to evaluate various types of feedstocks (agricultural biomass, forest/woody biomass, aquatic biomass, urban waste, and paper waste) with their potential to produce biochar. It was observed that the feedstock containing high cellulose was found to be helpful in improving the overall properties of biochar, including enhanced adsorptive action and retention of nutrients.
... However, several environmental problems resulted from landfill leachate have been reported (Agamuthu and Fauziah 2008). Leachate is usually generated when water passes across the solid waste resulted from different disposed materials (Jayawardhana et al. 2016). It is normally identified as a turbid dark brown colour with high pollutants concentrations. ...
Landfills are the main option for waste disposal all over the world. Most of the landfill sites across the world are old and are not engineered well to prevent contamination of the underlying soil and groundwater by the toxic leachate. The present study examines the potential use of raw zeolite and heated activated zeolite in the reduction of COD, NH3-N, and colour from leachate. Zeolite was activated using different temperatures at 150 °C, 200 °C, and 250 °C for 3 h. General characterization was conducted for raw zeolite and heat-activated zeolite to investigate the influence of temperature on zeolite properties. Batch experiments were conducted at the optimum dosage of zeolite and pH. Results demonstrated that the optimum dosage of raw zeolite was 10 g with 53.1%, 22.5% and 46% reduction of NH3-N, COD, and colour, respectively. The optimum pH for NH3-N was 7 with a percentage removal of 55.8% while better reduction of COD and colour was obtained at pH 4 with a percentage removal of 24.3% and 73.8%, respectively. Also, the optimum temperature tested was at 150 °C, where the optimum dosage using activated zeolite heated at 150 °C was 10 g, resulted in the maximum reduction of NH3-N, COD, and colour of 45.1%, 11.8% and 43.7%, respectively. The optimum dosage of activated zeolite heated at 200 °C and 250 °C, which was 25 g. This indicates that the use of the activated zeolite heated at 150 °C can achieve the optimum removal at a lower cost which is applicable for a larger scale of wastewater treatment. In addition, it was found that the capacity of the zeolite before and after heat activation was 41.30 cmol/kg and 181.90 cmol/kg, respectively. The adsorption isotherm analysis reveals that both Freundlich and Langmuir isotherms were in agreement with experimental data. However, the Freundlich isotherm model was more favourable than Langmuir isotherm to evaluate the adsorption equilibrium of the three pollutants as verified by the high R2 values.
... According to Oonk and Boom as cited by Jayawardhana et al. [12], the increasing amount of solid waste and its corresponding amount of emission when degraded can be simultaneously addressed by converting municipal solid waste into biochar. It is a carbon-rich product of pyrolysis which can be utilized both in the production of energy and of adsorbents according to Bernardo et al. as cited by Jin et al. [13]. ...
Nitrate is considered as a major groundwater pollutant causing serious health and environmental effects. In this study, the removal of nitrate from aqueous solutions using municipal solid waste-derived activated biochar (MSWAB) via adsorption was explored. Initially, municipal solid waste (MSW), another prominent source of environmental pollution, was used as feedstock to produce biochar, which was chemically activated using potassium hydroxide, producing MSWAB. Activation of MSWAB resulted to an increase in surface area from 2.5 to 6.5 m ² /g. The effect of initial nitrate concentration (A), pH (B), and adsorbent dosage (C) on nitrate removal were then evaluated using a 2k factorial experimental design. Results show that initial nitrate concentration, pH, and two-way interactions AB and AC have significant effects on % nitrate removal. Nitrate removal was found to increase as the initial nitrate concentration and pH decreases. Using Response Surface Methodology (RSM), the local optimum conditions for maximum nitrate removal of 66.97 % were determined to be at 30 mg/L initial nitrate concentration and pH 2 at 10 mg/mL adsorbent dosage. The appropriate isotherm for nitrate adsorption onto MSWAB was the Freundlich isotherm. Comparison with commercial activated carbon (CAC) in terms of nitrate removal efficiency at local optimum conditions showed that MSWAB is inferior to CAC. However, it is still notable that MSWAB was able to reduce the nitrate concentration from 30 mg/L to 11.27 mg/L which satisfies the 14 mg/L DENR effluent standard for Class C water bodies, showing its potential as an alternative adsorbent for treatment of nitrate-laden wastewaters.
... The liquid generated from anaerobic decomposition of solid waste, in landfills, represent a challenge for the solid waste management in developed countries. This liquid is called leachate, composed by a misture of different substances, such as humidity from the waste and rain, that percolates through the landfill cells (Castrill on et al., 2010;Jayawardhana et al., 2016;El-Gohary and Kamel, 2016). ...
The disposal of municipal solid waste (MSW) in landfills generates leachate, a highly polluting liquid to the aquatic environment. Leachate composition become a challenge to choose the best treatment process. Then, detailed techniques to determine the organic content, in terms of refractability, composition, sources and biodegradability in landfill leachate can help to choose the appropriate treatment and improve landfill management. In this sense, the aim of this study is to apply conventional and non-conventional parameters through inert chemical oxygen demand (COD) analyses and spectroscopic techniques of fluorescence and UV–vis absorbance for the characterization of municipal landfill leachate. Results indicated that physicochemical characterization cannot provided enough detailed information about leachate composition, which becomes the treatment process fragile. Inert COD, besides have high time to execution (∼30 days), presented additional information on potential of biological treatability in anaerobic conditions. Dissolved organic matter (DOM) characterization showed transitions between labile and refractory organic matter compounds. Moreover, the cost estimated showed that non-conventional parameters analysis have lower investment than conventional, being their implementation feasible. In conclusion, the synergy between conventional and non-conventional parameters, and the detailed information provided by inert COD and DOM characterization, shown a useful tool to the landfill management and, consequently, improving treatment process and its efficiency.
... The water retention during drought is important for plant growth and survival. Many researchers from agriculture and soil science have extensively investigated physical and chemical properties of biochars, which are produced from different feedstocks (such as plant-based (wheat, maize and corn) and animal-based (poultry litter, PM etc)) and also varying pyrolysis conditions (temperature, rate of heating, nitrogen flow, water content) (Gaskin et al. 2008;Sohi et al. 2010;Laird et al. 2010;Jayawardhana et al. 2016;Gunarathne et al. 2018). As per their studies, biochars produced from different feedstock possesses distinct physical and chemical properties, which may further influence soil properties. ...
Purpose
Biochars produced from different feedstocks (such as wood, pig manure) possess varying physical and chemical properties, which have influence on crack and evaporation rate of biochar-amended soil (BAS). Furthermore, influence of compaction state and drying-wetting cycles on evaporation rate and cracking of BAS has not been investigated comprehensively. The objective of this study was to investigate the effects of biochar types, compaction state of BAS, and drying-wetting cycles on crack propagation and retained water (or evaporation rate).
Material and methods
An animal and plant feedstock-based biochars were produced in-house from pig manure (PM) and wood (W), respectively. In addition, nano structured chalk and wheat biochar (CWB) were also produced. Soil amended with individual biochars was compacted in petri-glass discs at two densities. Disc specimens were subjected to multiple drying-wetting cycles, and evaporation rate of specimens and crack area were monitored throughout the experimental period (70 days). Images were captured after every 24 h and processed using image processing technique to obtain the crack intensity factor (CIF).
Results and discussion
The results show that plant-based W BAS showed the high water retention, i.e., low evaporation rate and low CIF. Furthermore, the crack potential of CW BAS was seen to be higher. In dense compacted soil, maximum CIF% can be reduced from 3.9 to 0.4% for W BAS, from 3.9 to 1.7% for PM BAS, and from 3.9 to 1.6% for CW BAS.
Conclusion
WB was able to resist cracking more efficiently than other types of biochar. Evaporation was found to be minimal for plant-based W BAS at 10% biochar percentage. Higher biochar content in soil was seen to increase the water retention of BAS significantly. Dense state of BAS at high biochar content (i.e., 10%) was effective in reducing evaporation rate and crack progression.
... These degraded microplastics enter the surrounding environments via air-born pathway (Rillig, 2012) and leachates Praagh et al., 2018;Su et al., 2019). Leachates are "the fluid percolating through the landfills and are generated from liquids present in the waste and from outside water, including rainwater, percolating though the waste" (Jayawardhana et al., 2016). Not only do untreated leachates contain higher microplastics than treated leachates , but they are also vectors of heavy metals and organic contaminants (Sui et al., 2017). ...
Plastic fabrication is increasing worldwide in response to daily human demands. This mass production is linked to the immense plastic marine litter found all around the world: each synthetic material is meant to find its way back into the aquatic systems. Anthropogenic pressure and the immense human population, the lack of appropriate plastic treatment process and the growing industrial activities advocate their presence in the aquatic environments. These plastics are then found in the form of microplastics (microscopic particle with a size < 5 mm) observed in the water, in the sediments and are prone to be ingested by various marine organisms along the trophic chain. This thesis focuses on (1) assessing microplastics sources and input into the aquatic environment and their occurrence in biota, and (2) to test the feasibility of using transplanted organisms (caging) for monitoring microplastics pollution in the marine coastal environment. Two coastal areas highly impacted by anthropogenic pressures were studied: Le Havre in France and the Lebanese coast. For the former, the role of a municipal wastewater treatment plant (WWTP) effluent and an abandoned coastal landfill as pathways for microplastics (MPs) input into the marine environment was assessed. MPs were first analyzed in raw sewage influent, sludge and effluent samples, and their fate was studied along a distance gradient from the WWTP in three matrices: surface water, sediments and wild mussels (Mytilus spp). MPs were found in all matrices with a decreasing abundance from the effluent. Strong MPs abundances (higher than those found near the WWTP effluent) were observed in the vicinity of the coastal landfill suggesting its importance as a MPs entry route into the marine coastal environment. Whereas for the Lebanese coast, we evaluated for the first time the MPs pollution in the seawater, sediments and two important seafood species (one pelagic fish: Engraulis encrasicolus and one bivalve: Spondylus spinosus). Results showed different patterns of MPs concentration in the analyzed matrices. The occurrence of MPs in the biota was high (83.4% and 86.3% in anchovies and spiny oysters, respectively). These results highlighted the high MPs pollution found in the Levantine Basin in comparison to other Western Mediterranean regions. In addition, the obtained results indicate the potential contribution of coastal landfills to this pollution. Most often microplastics studies involve collection of organisms’ samples from natural populations. In this thesis, we tested the feasibility of using transplanted organisms (caging) for monitoring microplastics’ pollution in the marine coastal environment. We developed caging experiments with juvenile European Flounder, Platichthys flesus, in estuarine nursery grounds and blue mussels, Mytilus edulis, in coastal marine environment. For each species, the abundance and characteristics (shape, size, color and type of polymers) of MPs ingested by caged individuals are compared with those ingested by wild individuals collected at the same site and with those found in their surrounding environment (surface water and sediments). Our results suggest that transplanted organisms (caging) may be a promising tool for MPs biomonitoring making monitoring more reliable with an accurate assessment of the biological effects of MPs over a predetermined exposure period.
... Owing to its large specific surface area, high density of negative surface charges, surface functional groups, adoption of biochar to remove or reduce organic, and inorganic contaminants from water/wastewater, including ammonium has been reported [8]. The molecular structure and the pore size distribution of the produced biochars depend majorly on two factors: (a) the type of feedstock (such as plant-based (wheat, wood, corn, straw, etc.) and animal based (poultry litter, pig manure, etc.)) and (b) pyrolysis conditions (i.e., temperature, heating rate, N flow, and water content) [12][13][14][15]. During the process of pyrolysis, biomass undergoes a variety of physical, chemical, and molecular changes which consequently contribute to the adsorption and immobilization of the target contaminant. ...
Previous studies for removal of ammonium from wastewater were mainly conducted
using biochars produced from agricultural residue. Feedstock type (agricultural residue, wood,
animal waste, and aquatic waste), as well as pyrolysis temperature, can significantly influence
biochar properties and hence its adsorption capacity. Such studies are useful in decision making for
selecting biochar depending on feedstock availability and pyrolysis temperature. This study aims to
explore the e�ects of di�erent types of biochar (laboratory prepared novel water hyacinth and algae
biochar, conventional cedar wood, rice straw, and pig manure biochar) on the adsorption kinetics
for ammonium removal from wastewater. The adsorption kinetics of biochars were compared to
that of commercially available clinoptilolite and interpreted with their respective physicochemical
properties (SEM, FTIR, XRD). Batch tests were performed to evaluate the e�ects of biochars on
adsorption of ammonium nitrogen at di�erent concentrations (10 mg/L and 100 mg/L). The tests
reveal that clinoptilolite has the highest adsorption capacity. Among biochars, pig manure (animal
based) biochar has a higher adsorption capacity in comparison to conventional agricultural residues
based biochars. The capacity of pig manure biochar under highly concentrated ammonium solution
(100 mg/L) is merely 20% lower than that of clinoptilolite. Both water hyacinth and algae biochar
produced at higher temperature (600 �C) show higher sorption rate and capacity (depending on
the initial concentration of ammonium) for ammonium in comparison to that produced at a lower
temperature (300 �C). This is likely due to an increase in porosity at higher temperatures of pyrolysis.
... However, the development of standard functioning sewer networks cannot match the speed of urban expansion, especially in low-income cities. Moreover, the recognition that vital resources from FS, such as organic matter and nutrients, can be used for soil amendment in agriculture has led to the development of resource-oriented sanitation approaches (Jayawardhana et al. 2016, Jepsen et al. 1997, Kah et al. 2016, Lau et al. 2017. FS can be managed more effi ciently through a resource-oriented sanitation approach that can recover organic matter and nutrients available in FS to be utilized in agriculture and close the loop in the nutrient cycle (Schönning et al. 2002). ...
Recent studies have shown that over half of the world’s population lives in urban areas, with the number of people living in slums growing by over 20 million per year and people living in urban areas lacking access to adequate sanitation. This study presents a review of the challenges facing fecal sludge management (FSM). A globally relevant issue in developing urban centers, especially in selected developing countries in West Africa was discussed. Some key findings of the review are that effective sanitation in developing areas depends on the chain of services and that one of the largest problems in sanitation is FSM. This study presents the initial steps toward understanding the main issues involving FSM in developing cities of West Africa. Results are intended to be used as a support for decisions on policies, strategies for FSM, and investments for improved treatment facilities in the region. The study suggests that governments and private sector organizations should develop adequate measures for handling fecal sludge
... No substantial removal of DOC or UVA 254 seems to occur at the doses of BC and PAC above 30 g/L and 2 g/L, respectively (Fig. S5). Although the optimized dose was much higher for BC (30 g/L) than for PAC (2 g/L), it can be argued that BC is a favorable adsorbent competitive enough with PAC because of its extra-benefits for environmental sustainability, e.g., low cost, alternative fertilizer, carbon sequestering function, and so on (Jayawardhana et al., 2016). ...
Forward osmosis (FO) has been adopted to treat complex wastewater such as landfill leachate due to its high rejection of organics. In this study, the in-line adsorptive process using biochar (BC) or powdered activated carbon (PAC) was applied to a cross flow FO system to enhance the mitigation of the FO membrane fouling from landfill leachate. The changes in the leachate composition along the treatments were tracked by excitation emission matrix-parallel factor analysis (EEM-PARAFAC) to identify tryptophan-like (C1), fulvic-like (C2), and humic-like (C3) components. After a single operation of FO, the C1 was found to be the main constituent responsible for membrane fouling irrespective of varying operation conditions regarding draw solute concentrations and flow rates. Both sorbents (i.e., BC and PAC) exhibited the preferential removal behavior towards C1 > C2 > C3, which was well supported by their individual adsorption isotherm model parameters. The addition of in-line adsorption treatment to FO resulted in substantial improvements in the filtered volume (>57%) and the flux recovery (>80%) compared to the single FO operation. Without chemical cleaning of membrane, the flux was fully recovered at a dose of 10 g/L BC or 0.3 g/L of PAC. A significant and negative correlation was found between the flux recovery and the C1 of the feed leachate or the corresponding spectral peak intensity (p < 0.05) for the integrated FO system, suggesting the potential of using on-line fluorescence monitoring for the performance of the integrated system in terms of fouling mitigation. This study provided a new insight into the effectiveness of BC or PAC adsorption as the in-line integration with an FO system for the targeted removal of FO membrane foulants in landfill leachate.
... However, not all local soils are suitable for fast vegetation growth and the soil is susceptible to erosion loss at their early plant establishment period (Schmidt et al., 2001). Biochar amended soil (BAS) has been advocated for use in such landfill systems in the recent past (Reddy et al., 2015;Jayawardhana et al., 2016;Ni et al., 2018;Weber and Quicker, 2018). Biochar is a carbon rich porous material, which is produced by heating any organic biomass in an oxygen free environment by a process called pyrolysis (Sohi et al., 2010;Kookana et al., 2011). ...
Biochar amended soil (BAS) has been explored as a cover material for geo-environmental applications such as landfill cover due to its vegetation potential. Soil erosion in these infrastructures can progressively lead to failure and hamper the workability of the system. BAS is compacted for geo-environmental applications, unlike agricultural soil, which are loose in nature. Furthermore, the love-hate relationship of biochar with water can potentially affect the functioning of compacted cover system. Thus, the performance of compacted BAS in the context of erosion potential is not well understood. The major objective of this technical note was to explore the erosion potential of compacted BAS sourced from four distinct biochars. Biochar were produced in-house and mixed with soil at 5% and 10% by weight. In total, 81 pinhole erosion tests were performed to gauge the erosion rate of bare soil and BAS at three different compaction states at same compaction energy. It was revealed that the erosion rate decreased with gradual increment in water content for BAS, which was mainly attributed to the change of particle orientation from flocculated to dispersed along the compaction curve. Addition of biochar to soil resulted in decrease of erosion along the dry state whereas the opposite was observed for wet state. This was attributed to the surface functional groups as well as particle gradation of biochar. Erodibility coefficient and critical shear stress plot of soil and BAS revealed that addition of biochar had minimal effect on erosion of compacted silty sand.
Aims:
Leachate comprises a solid waste decomposition product found fresh in collection trucks or as an effluent in landfills. This study aimed to assess the occurrence, concentrations, and genetic diversity of intact rotavirus species A (RVA) in solid waste leachate.
Methods and results:
Leachate samples were concentrated by ultracentrifugation, treated with propidium monoazide (PMA), and exposed to LED photolysis. Treated and untread samples were extracted using the QIAamp Fast DNA Stool mini kit and nucleic acids were screened for rotavirus species A (RVA) employing a Taqman® Real-time PCR. The PMA RT-qPCR method detected RVA in eight out of nine truck samples and in 15.40% (2/13) of the landfill leachate samples. The RVA concentrations in the PMA-treated samples ranged from 4.57 × 103 to 2.15 × 107 genomic copies (GC) 100 mL-1 in truck leachate and from 7.83 × 103 to 1.42 × 104 GC 100 mL-1 in landfill samples. Six truck leachate samples were characterized as RVA VP6 genogroup I2 by partial nucleotide sequencing.
Conclusions:
The high intact RVA detection rates and concentrations in truck leachate samples indicate potential infectivity and comprise a warning for solid waste collectors concerning hand-to-mouth contact and the splash route.
Over the past few decades, inefficient waste management has caused environmental problems, such as leachate leakage, high pollution in the surface and groundwater, and soil contamination. In this regard, it is essential to adopt proper pre-discharge leachate management and treatment in the case of municipal waste. This study proposes a novel sustainable network design model by determining the optimal combination of transfer stations and separation units equipped with waste compaction and leachate treatment technologies, waste treatment facilities with different efficiencies, and optimal waste and leachate flow allocation along with waste separation at the source for municipal solid waste (MSW) systems. The uncertainty in the generated amount of waste is also considered in different urban areas. Therefore, a two-stage stochastic programming has been developed to minimize the total cost and the leachate pollution potential of MSW network systems, considering leachate types, collection and garbage-bin-cleaning truck types, and recyclable waste quality. Furthermore, the social objective is to maximize the number of job opportunities. The sample average approximation approach and the augmented ε-constraint method have been implemented to address the model uncertainty and solve the proposed multi-objective model, respectively. The results have indicated that considering the leachate treatment in the MSW network and waste separation at the source, despite increasing the total cost, has decreased leachate pollution potential by 41.3% and has created the number of job opportunities by 29.2% compared to the current situation in Tehran as a case study. Moreover, complete waste separation at the source in the proposed model has shown that it can have a positive effect on decreasing the total cost and leachate pollution potential.
Biochar is carbonaceous material prepared from thermo-chemical conversion of biomass-based raw materials. These include agro-waste, forestry waste, animal manure, sewage sludge, and municipal waste. Different pyrolysis conditions and raw materials alter the properties of biochar such as pH, surface area, porosity, cation exchange capacity, nutrient availability, and water holding capacity. These physico-chemical properties further influence the functional properties of biochar for its different applications. In the present chapter, role of different raw materials used for the preparation of biochar, their effects on the properties, and characterization of biochar are discussed.KeywordsBiocharPyrolysisCation exchange capacityPore structureHydrothermal carbonization
The landfill leachate concentrate is a kind of waste water containing salt and refractory organics produced by the membrane bioreactor-nanofiltration/reverse osmosis process. In the present work, three integrated processes of electrocoagulation (EC)-direct contact membrane distillation (DCMD), electrooxidation (EO)-DCMD and EC-EO-DCMD were used to treat the leachate concentrate. The results show that the total organic carbon (TOC), Ca²⁺ and Mg²⁺ removal rates of the EC process were 40.52%, 98.03% and 88.84%, respectively, under the optimal operating conditions. The TOC removal rate of the EO process was 64.62% under the optimal operating conditions. The removal rates of TOC, Ca²⁺ and Mg²⁺ by combined EC-EO process were 82.16%, 99.04% and 94.22%, respectively. When the MD was applied together with the EC and EO steps, the flux improved 23%∼42%, which was confirmed by the SEM-EDS, FTIR and XRD analysis that only quite a small amount of humic acid and fulvic acid substances was observed to be randomly deposited on the membrane surface. During 72 h operation, the permeate had a lower conductivity than 15 μS/cm, and only a small amount of organic (TOC < 9.6 mg/L) was detected. These results clearly demonstrated that the EC and EO processes can effectively reduce the refractory organics and scaling inorganics, and coupled with MD can synergistically to remove the pollutant that providing a better choice for the treatment of leachate concentrate.
The effectiveness of earthen liners in preventing the migration of heavy metals (HM) from the landfill requires the study of the transport parameters of HM and the determination of the optimum thickness of the earthen liners that can effectively retain the HM within their permissible concentrations during the lifetime of a landfill. The aim of this study is to investigate the transport behavior of four HM (cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn)) through an earthen liner via physical and numerical modeling. Subsequently, the optimum thickness of earthen liners required to prevent the breakthrough of HM for different assumed landfill life expectancies was assessed from the long-term migration profiles of HM. In general, the extent of HM migration in two types of compacted residual soil liners, which were clayey sand and silty sand, followed the sequence of Zn < Cd < Cu < Pb. It is observed that the extent of HM migration was greater in the compacted silty sand sample attributed to its higher porosity and lower HM adsorption capacities. The numerical simulations results further revealed that the optimum thickness required for compacted clayey and silty sand liners to retain the four studied HM within their regulatory threshold values for a period of 100 years were 1 m and 1.9 m, respectively. Considering the higher mobility and more stringent allowable concentration of Cd, Cd can serve as a key indicator of early HM contamination caused by leachate migration from Malaysian municipal solid waste landfills.
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, was 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.
The biochar is a solid carbon-rich, porous material produced by the thermochemical conversion of a diverse range of biomass feedstocks under an inert atmosphere (i.e., in the absence of oxygen). We can produce the biochar at all likely scales, ranging from the industrial to the domestic level and even at individual farms, thus, the biochar industry is leading as a most appropriate at different socioeconomic settings. The possibility of sustainable biochar production practices and multi-functionality features make it a promising candidate to fulfill an increasing demand in the fields of soil amendment, agricultural sustainability, environmental protection, cutting-edge materials, and to achieve circular bioeconomy and mitigation of climate change. An available fraction of waste biomass (agroforestry waste, biomass crops, agricultural residues, mill residues, and animal manure, and many more) can be used efficiently in pyrolysis and converted into desired biochar materials, besides this alternative energy products, such as syngas, bio-oil, electricity generation, and process heat. This report emphasizes the fate of biomass composition, pyrolysis mechanisms, and applications of modern analytical and characterization techniques that are being adopted, applied, and standardized to improve understandings of molecular, structural, and surface properties characteristics of biochar. To achieve precisely designed biochar, there is a need to understand the latest advances in biochar materialization mechanisms and structure-application relationships to speed up their agronomic applications and to achieve a zero-waste dream. This report also summarizes a wide range of literature published on feedstocks, pyrolysis, and biochar and suggests several practical recommendations appropriate to implement and bring together specific details on the thermochemical conversion of biomass, desired biochar properties, organic and inorganic phases, and the significance to the agronomic applications.
Leachates generated from the landfills are considered as one of the major source of groundwater contamination and surrounding geoenvironment. An efficient engineered liner for the landfills assists to mitigate the groundwater contaminants by acting as an effective hydro-chemical barrier for the leachate. For geomaterials used in liners, it is important to determine the appropriate range of compaction parameters that would ensure hydraulic conductivity and mitigation of the groundwater contaminants within safe limits. Fly ash based liner materials can be much effective as it not only will solve the problem of proper and safe disposing of fly ash but also will be better liner material in comparison to sand bentonite mixes. The addition of cohesionless fly ash would improve the strength and reduce the shrinkage behavior of bentonite but at the same time might increase the hydraulic conductivity. Hence, it is important to determine the ranges of water content and dry unit weight for different bentonite–fly ash mixes that would satisfy the desired ranges of hydraulic conductivity and strength. The objective for the present chapter is to identify the bentonite–fly ash mix that enables maximum use of fly ash, for the hydraulic conductivity and mitigation of the groundwater contaminants. Various literatures have reported the potential valorization of a bentonite–fly ash mix as a compacted landfill liner compacted at optimum moisture content, satisfying the regulatory requirements of landfill liners. In addition, the groundwater contaminants retention characteristics of fly ash–bentonite mixes were also reported. Hence, the laboratory results discussed in this chapter would be quite handy for deciding the appropriate bentonite–fly ash mix to be evaluated at field scale.
Rising solid waste production has caused high levels of environmental pollution. Population growth, economic patterns, and lifestyle patterns are major factors that have led to the alarming rate of solid waste production. Generally, solid wastes such as paper, wood, and plastic are disposed into landfills due to its low operation and maintenance costs. However, leachate discharged from landfills could be a problem in surfaces and groundwater if not adequately treated. This study investigated the patterns of the water quality index (WQI) and polycyclic aromatic hydrocarbons (PAH) along Johan River in Perak, Malaysia, which received treated leachate from a nearby landfill. An artificial neural network (ANN) was also applied to predict WQI and PAH concentration of the river. Seven sampling stations were chosen along the river. The stations represented the upstream of leachate discharge, point of leachate discharge, and five locations downstream of the landfill. Sampling was conducted for one year starting July 2018. Physicochemical parameters, namely pH, biological oxygen demand, chemical oxygen demand, ammoniacal nitrogen, total suspended solids, and dissolved oxygen, were used to compute the water quality index (WQI). PAH concentrations were determined by liquid–liquid extraction of water samples followed by an analysis using gas chromatography. Results showed that WQI of Johan River was under Class III where intensive treatment was required to make it suitable for drinking purposes. The highest recorded PAH concentrations were fluoranthene (333.4 ppb) in the dry season and benzo(a) pyrene (93.5 ppb) in the wet season. A correlation coefficient (Rp) for a model prediction based on WQI-ANN and TEC-ANN (toxicity equivalent concentration) in the wet and dry seasons was 0.9915, 0.9431, 0.9999, and 0.9999, respectively. ANN results showed good model performance with Rp ≈ 0.9. This study suggested that ANN is a useful tool for water quality studies.
Municipal solid waste (MSW) has ranked among the most detrimental global issues of the decade, where it has been induced by the population trends, urbanization, and economic growth. The majority of conventional pollution treatment methods involve high capital and maintenance costs with sophisticated instruments and technology. Biomass valorization and phytoremediation has been described to be an effective and practicable alternative for expensive, conventional engineering techniques in managing MSW and remediating contamination. Modern biomass valorization methods are promising technologies that provide effective MSW reduction, at the same time providing measures for removing pollutants from leachate with its particular focus on biochar, which is resulted by torrefaction of the perishable waste. The simultaneous ability of phytoremediation to remove many types of contaminants in leachate by significant amounts is emphasized in the context with considerations to the challenges in the sector. Phytoremediation is limited by several factors such as contaminant specificity, time consumption, and some external factors, while biochar applications are limited due to substrate specificity. The study aimed to review scientific literature to provide a platform for biomass valorization and phytoremediation integration for developing economy context.
Graphical Abstract
This review focuses on contaminant removal from water using hydrogel-based materials. It highlights the recent results achieved, unresolved problems, and possible developments. Polymer and graphene hydrogels are promising new materials for removing inorganic (e.g., metals and metalloids) and organic (e.g., dyes) trace contaminants from water. They can be prepared as composites with practically any desired conventional or innovative adsorbent, to enhance the removal efficiency. Obtaining a three-dimensional highly effective network is one of the significant features of hydrogels, which confer specific characteristics on them. There are number of benefits of using hydrogels: easy separation and handling, the facility for large-scale application, and the ability to regenerate and reuse the hydrogels. At present, the experiments based on hydrogels for water purification are mostly limited to the laboratory scale and further research needed to move toward large-scale industrial applications. Moreover, the present studies are currently limited to a few types of contaminants, so that further experiments needed for removal of more contaminant types and mixtures of contaminants, considering that in practical situations. All these features are described and discussed in this review, which, to the best of our knowledge, is the first comprehensive review on hydrogel applications for contaminant removal from water.
The change in leachate quantity and characteristics during landfill development is examined with respect to data from a large Ontario (Canada) landfill. The data suggests that when fresh waste lifts are placed on older waste, the older waste acts as a bioreactor with respect to the fresh waste leachate. The attenuation effect on both leachate volume and quality through older waste shown by other researchers in lysimeter tests appears to be relevant to this large active landfill site. These results suggest that planned waste placement and fluid addition (natural or irrigation) may play major roles in the treatment of leachate before removal from the landfill and hence reduction of the landfill contaminating lifespan.
Investigations on the effect of leachate from municipal solid waste on the soils in landfill sites usually focus on the effect of leachate compounds on the engineering properties of the soil. Leachate chemical composition and its effect on the consistency of soil are important factors for designing liner systems. Soil samples from the bottom of the Esfahan, Iran, landfill were collected. Leachate samples were collected within the a landfill and a composting factory leachate lagoon. Effects the leachates on cation exchange capacity, electrical conductivity, pH, and consistency of the soil samples were investigated. The chemical property of leachate showed that leachate from the compost factory was contaminated by higher concentrations of heavy metals (Cu, Zn, Pb, Cd, Ni, and Hg); higher concentrations of Na+,Ca+2, Mg+2, and K+; and higher EC; and were more acidic than the landfill leachate. Liquid limits and plastic limits of the soil were higher from the effect of the compost factory leachate in comparison with the values for landfill leachate.
Thoroughly updated and now in full color, the 15th edition of this market leading text brings the exciting field of soils to life. Explore this new edition to find:
A comprehensive approach to soils with a focus on six major ecological roles of soil including growth of plants, climate change, recycling function, biodiversity, water, and soil properties and behavior.
New full-color illustrations and the use of color throughout the text highlights the new and refined figures and illustrations to help make the study of soils more efficient, engaging, and relevant.
Updated with the latest advances, concepts, and applications including hundreds of key references.
New coverage of cutting edge soil science. Examples include coverage of the pedosphere concept, new insights into humus and soil carbon accumulation, subaqueous soils, soil effects on human health, principles and practice of organic farming, urban and human engineered soils, new understandings of the nitrogen cycle, water-saving irrigation techniques, hydraulic redistribution, soil food-web ecology, disease suppressive soils, soil microbial genomics, soil interactions with global climate change, digital soil maps, and many others
Applications boxes and case study vignettes bring important soils topics to life. Examples include “Subaqueous Soils—Underwater Pedogenesis,” “Practical Applications of Unsaturated Water Flow in Contrasting Layers,” “Soil Microbiology in the Molecular Age,” and "Where have All the Humics Gone?”
Calculations and practical numerical problems boxes help students explore and understand detailed calculations and practical numerical problems. Examples include “Calculating Lime Needs Based on pH Buffering,” “Leaching Requirement for Saline Soils,” "Toward a Global Soil Information System,” “Calculation of Nitrogen Mineralization,” and “Calculation of Percent Pore Space in Soils.”
Permeable reactive barriers are commonly used to treat contaminant plumes in the saturated zone.
However, no known applications of horizontal permeable reactive barriers (HPRBs) exist for oxidizing
volatile organic compounds (VOCs) in the unsaturated zone. In this study, laboratory column experiments
were carried out to investigate the ability of a HPRB containing solid potassium permanganate, to
oxidize the vapors of trichloroethylene (TCE), toluene, and ethanol migrating upward from a contaminated
saturated zone. Results revealed that an increase in initial water saturation and HPRB thickness
strongly affected the removal efficiency of the HPRB. Installing the HPRB relatively close to the water
table was more effective due to the high background water content and enhanced diffusion of protons
and/or hydroxides away from the HPRB. Inserting the HPRB far above the water table caused rapid
changes in pH within the HPRB, leading to lower oxidation rates. The pH effects were included in a
reactive transport model, which successfully simulated the TCE and toluene experimental observations.
Simulations for ethanol were not affected by pH due to condensation of water during ethanol oxidation,
which caused some dilution in the HRPB.
Due to the increasing concerns on global warming, scarce land for agriculture, and contamination impacts on human health, biochar application is being considered as one of the possible measures for carbon sequestration, promoting higher crop yield and contamination remediation. Significant amount of researches focusing on these three aspects have been conducted during recent years. Biochar as a soil amendment is effective in promoting plant performance and sustainability, by enhancing nutrient bioavailability, contaminants immobilization, and microbial activities. The features of biochar in changing soil physical and biochemical properties are essential in affecting the sustainability of an ecosystem. Most studies showed positive results and considered biochar application as an effective and promising measure for above-mentioned interests. Bio-engineered man-made filled slope and landfill slope increasingly draw the attention of geologists and geotechnical engineers. With increasing number of filled slopes, sustainability, low maintenance, and stability are the major concerns. Biochar as a soil amendment changes the key factors and parameters in ecology (plant development, soil microbial community, nutrient/contaminant cycling, etc.) and slope engineering (soil weight, internal friction angle and cohesion, etc.). This paper reviews the studies on the production, physical and biochemical properties of biochar and suggests the potential areas requiring study in balancing ecology and man-made filled slope and landfill cover engineering. Biochar-amended soil should be considered as a new type of soil in terms of soil mechanics. Biochar performance depends on soil and biochar type which imposes challenges to generalize the research outcomes. Aging process and ecotoxicity studies of biochar are strongly required.
Pyrolysis is the thermo-chemical conversion of carbonaceous feedstock in the absence of oxygen to produce bio-fuel (bio-oil, bio-char and syn-gas). Bio-fuel production from municipal green waste (MGW) through the pyrolysis process has attracted considerable attention recently in the renewable energy sector because it can reduce greenhouse gas emissions and contribute to energy security. This study analyses properties of MGW feedstock available in Rockhampton city of Central Queensland, Australia, and presents an experimental investigation of producing bio-fuel from that MGW through the pyrolysis process using a short sealed rotary furnace. It was found from the experiment that about 19.97% bio-oil, 40.83% bio-char and 29.77% syn-gas can be produced from the MGW. Then, a four-stage steady state simulation model is developed for pyrolysis process performance simulation using Aspen Plus software. In the first stage, the moisture content of the MGW feed is reduced. In the second stage, the MGW is decomposed according to its elemental constituents. In the third stage, condensate material is separated and, finally, the pyrolysis reactions are modelled using the Gibbs free energy minimisation approach. The MGW's ultimate and proximate analysis data were used in the Aspen Plus simulation as input parameters. The model is validated with experimentally measured data. A good agreement between simulation and experimental results was found. More specifically, the variation of modelling and experimental elemental compositions of the MGW was found to be 7.3% for carbon, 15.82% for hydrogen, 7.04% for nitrogen and 5.56% for sulphur. The validated model is used to optimise the biofuel production from the MGW as a function of operating variables such as temperature, moisture content, particle size and process heat air-fuel ratio. The modelling and optimisation results are presented, analysed and discussed.
The characterization of municipal solid waste is important in designing waste management, and waste to energy systems. This work characterizes the municipal solid waste of Arusha city; the results show that the HHV of municipal solid waste is about 12.42 MJ/kg. Thermo-degradation analysis shows that the municipal solid waste has activation energy ranges between 60 and 70 KJ/mole and ISSN: 3159-0040
-exponential factor ranges between 1.07 x 10 3 to 9.29 x 10 5 (S-1).
Compacted biochar-amended clay (BAC) has been proposed as an alternative landfill final cover material in this study. Biochar has long been proposed to promote crop growth, mitigate odor emission, and promote methane oxidation in field soils. However, previous studies showed that soil-gas permeability was increased upon biochar application, which will promote landfill gas emission. The objective of the present study is to investigate the possibility of using compacted BAC as an alternative material in landfill final cover by evaluating its gas permeability. BAC samples were prepared by mixing 425-μm-sieved peanut shell biochar with kaolin clay in different ratios (0, 5, 10, and 15 %, w/w) and compacting at different degrees of compactions (DOC) (80, 85, and 90 %) with an optimum water content of 35 %. The gas permeability of the BACs was measured by flexible wall gas permeameter and the microstructure of the BACs was analyzed by SEM with energy-dispersive x-ray spectroscopy (EDX). The results show that the effects of biochar content on BAC gas permeability is highly dependent on the DOC. At high DOC (90 %), the gas permeability of BAC decreases with increasing biochar content due to the combined effect of the clay aggregation and the inhibition of biochar in the gas flow. However, at low DOC (80 %), biochar incorporation has no effects on gas permeability because it no longer acts as a filling material to the retard gas flow. The results from the present study imply that compacted BAC can be used as an alternative final cover material with decreased gas permeability when compared with clay.
In this study, eight fly ash samples and three bottom ash samples from different areas are collected for analysis of their physicochemical properties and emission content of dioxin precursors and metals. Their surface characteristics, their effects on dioxin precursors, and important aspects of the compositions of residual ash (fly ash and bottom ash) are investigated. Poly-chlorobenzenes (PCBzs) in the fly ash of a fluidized bed incinerator (FBI) are 7.35 to 357.94 μg/kg, and in that of a fire grate incinerator (FGI) are 6.74 to 96.52 μg/kg. The concentrations in bottom ash are the same (i.e., 2.23 to 2.99 μg/kg) regardless of the furnace type. The concentrations of polycyclic aromatic hydrocarbons (PAHs) in FGI fly ash samples (0.293 to 1.783 mg/kg) are less than these in samples from FBIs (1.820 to 38.012 mg/kg). Low boiling point PAHs (mainly 2- and 3-ringed PAHs) and high boiling point PCBzs (mainly Hx
CB and Pe
CBz) are the major constituents of residual ash. Different distributions of PCBzs and PAHs are mainly dictated by the incineration characteristics of FBI and FGI. Al and Fe, as non-toxic “light metals” are the major constituents of the residual ash, and Ni and Zn as non-toxic heavy metals play important roles in the total heavy metal. Cu, Pb, and Cr are the three major toxic heavy metals. The correlation of the metals and the dioxin precursors is discussed and distinguished.
Improving soil physical properties by means of biochar application has been proposed in recent publications. The objective of this study was to investigate to what extent the addition of corn stover (CS) and biochars produced from the pyrolysis of corn stover feedstock (CS) at 350 and 550 degrees C temperatures (CS-350, CS-550) affected aggregate stability, volumetric water content (theta(V)), bulk density, saturated hydraulic conductivity (Ks) and soil water repellency of specific soils. Organic amendments (CS, CS-350, CS-550) were incorporated into a Typic Fragiaqualf (TK) and a Typic Hapludand (EG) soils at the rate of 7.18 t C ha(-1), which corresponded to 17.3, 11.3 and 10.0 t biochar ha(-1) for the CS, CS-350 and CS-550 treatments, respectively. After 295 d of incubation (1295), soils were sampled as (i) undisturbed samples for bulk density and Ks; and (ii) mildly disturbed samples for theta(V) (at -15, -1, -0.3, -0.1, -0.08, -0.06, -0.04, and -0.02 bar), aggregate stability and soil water repellency. The theta(V) at time 0 (TO) was also determined at -15, -1 and -0.3 matric potentials for the different treatments. Biochar application significantly increased (P < 0.05) aggregate stability of both soils, the effect of CS-550 biochar being more prominent in the TK soil than that in the EG soil, and the reverse pattern being observed for the CS-350 biochar. Biochar application increased the By at each matric potential although the effect was not always significant (P < 0.05) and was generally more evident in the TK soil than that in the EG soil, at both T0 and T295. Biochar addition significantly (P < 0.05) increased the macroporosity (e.g., increase in theta(V) at -0.08 to 0 bar) in the TK soil and also the mesoporosity in the EG soil (e.g., increase in theta(V) from -1 to -0.1 bar). Both biochars significantly increased (P < 0.05) the Ks of the TIC soil, but only CS-350 biochar significantly increased (P < 0.05) the Ks in the EG soil. Biochar was not found to increase the water repellency of these soils. Overall results suggest that these biochars may facilitate drainage in the poorly drained TIC soil. However, the present results are biochar-, dose- and soil-specific. More research is needed to determine changes produced in other biochar, dose and soil combination, especially under field conditions.
Unconfined compressive strength (UCS) of synthetic biochar mixed clays (BMC) treated with lime-GGBS has been investigated. Biochar utilized in this study was produced from the slow pyrolysis of green waste residue. Treated biochar mixed clays have also been tested for microstructural and mineralogical developments. Results of this study showed that a lime content of 2 wt%, which is much lower than the conventionally used 10 wt% lime for synthetic clay, can be effectively incorporated to improve BMCs. X-ray Diffraction analysis carried out on treated BMCs showed the development of cementitious minerals (C-S-H, ettringite). Scanning Electron Microscopy with Energy Dispersive Spectrum (EDS) enabled identification of three separate types of microstructural interactions between biochar and soil particles, namely interface cementation, surface deposition and pore space filling by cementitious minerals, all of which are responsible for the enhancement of UCS with curing.
The addition of charcoal (or biochar) to soil has significant carbon sequestration and agronomic potential, making it important to determine how this potentially large anthropogenic carbon influx will alter ecosystem functions. We used column experiments to quantify how hydrologic and nutrient-retention characteristics of three soil materials differed with biochar amendment. We compared three homogeneous soil materials (sand, organic-rich topsoil, and clay-rich Hapludert) to provide a basic understanding of biochar-soil-water interactions. On average, biochar amendment decreased saturated hydraulic conductivity (K) by 92% in sand and 67% in organic soil, but increased K by 328% in clay-rich soil. The change in K for sand was not predicted by the accompanying physical changes to the soil mixture; the sand-biochar mixture was less dense and more porous than sand without biochar. We propose two hydrologic pathways that are potential drivers for this behavior: one through the interstitial biochar-sand space and a second through pores within the biochar grains themselves. This second pathway adds to the porosity of the soil mixture; however, it likely does not add to the effective soil K due to its tortuosity and smaller pore size. Therefore, the addition of biochar can increase or decrease soil drainage, and suggests that any potential improvement of water delivery to plants is dependent on soil type, biochar amendment rate, and biochar properties. Changes in dissolved carbon (C) and nitrogen (N) fluxes also differed; with biochar increasing the C flux from organic-poor sand, decreasing it from organic-rich soils, and retaining small amounts of soil-derived N. The aromaticity of C lost from sand and clay increased, suggesting lost C was biochar-derived; though the loss accounts for only 0.05% of added biochar-C. Thus, the direction and magnitude of hydraulic, C, and N changes associated with biochar amendments are soil type (composition and particle size) dependent.
Pyrolysis has been examined as an attractive alternative to incineration for municipal solid waste (MSW) disposal that allows energy and resource recovery; however, it has seldom been applied independently with the output of pyrolysis products as end products. This review addresses the state-of-the-art of MSW pyrolysis in regards to its technologies and reactors, products and environmental impacts. In this review, first, the influence of important operating parameters such as final temperature, heating rate (HR) and residence time in the reaction zone on the pyrolysis behaviours and products is reviewed; then the pyrolysis technologies and reactors adopted in literatures and scale-up plants are evaluated. Third, the yields and main properties of the pyrolytic products from individual MSW components, refuse-derived fuel (RDF) made from MSW, and MSW are summarised. In the fourth section, in addition to emissions from pyrolysis processes, such as HCl, SO2 and NH3, contaminants in the products, including PCDD/F and heavy metals, are also reviewed, and available measures for improving the environmental impacts of pyrolysis are surveyed. It can be concluded that the single pyrolysis process is an effective waste-to-energy convertor but is not a guaranteed clean solution for MSW disposal. Based on this information, the prospects of applying pyrolysis technologies to dealing with MSW are evaluated and suggested.
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This study focuses on the characterization of leachate generated from Gohagoda dumpsite in Kandy, Sri Lanka, assessment of its spatial and temporal variations, and identification of subsurface canals and perched water bodies in the wetland system affected by the leachate flow. Leachate samples were collected monthly throughout dry and rainy seasons from different points of the leachate drainage channel over a period of 1 year and they were tested for quality parameters: pH, temperature, electrical conductivity, total dissolved soils, alkalinity, hardness, total solids, vola-tile solids, total suspended solids, volatile suspended solids, biochemical oxygen demand (BOD 5), chemical oxygen demand, nitrate-nitrogen, nitrite-nitrogen, phosphates, ammonium-nitrogen, chloride, dissolved organic carbon, total organic carbon and heavy metals. Sequential soil extraction procedures were performed for the characterization of leachate-affected local soil. A geophys-ical survey using direct current resistivity technique was conducted at locations downstream of the dumpsite. Leachate characteristics indicated that the leachate is in the methanogenic phase and the results strongly suggest that the leachate may be polluting the river where the leachate is discharged directly. Leachate exceeds the allowable limits of Sri Lankan wastewater discharge standards for many of the parameters. Significant difference (P \ 0.05) was observed for most of organic and inorganic parameters among all sampling locations. Many parameters showed a negative correlation with pH. The affected soils showed high heavy metal concentrations. Resistivity study confirmed a confined leachate flow at the near surface with few subsurface canals. However, no separate subsurface plume movement was observed. The results of this research can effectively be used for the establishment of an efficient and effective treatment method for the Gohagoda landfill leachate.
Aims
This study aims to (i) determine the effects of incorporating 47 Mg ha−1 acacia green waste biochar on soil physical properties and water relations, and (ii) to explore the different mechanisms by which biochar influences soil porosity.
Methods
The pore size distribution of the biochar was determined by scanning electron microscope and mercury porosimetry. Soil physical properties and water relations were determined by in situ tension infiltrometers, desorption and evaporative flux on intact cores, pressure chamber analysis at −1,500 kPa, and wet aggregate sieving.
Results
Thirty months after incorporation, biochar application had no significant effect on soil moisture content, drainable porosity between –1.0 and −10 kPa, field capacity, plant available water capacity, the van Genuchten soil water retention parameters, aggregate stability, nor the permanent wilting point. However, the biochar-amended soil had significantly higher near-saturated hydraulic conductivity, soil water content at −0.1 kPa, and significantly lower bulk density than the unamended control. Differences were attributed to the formation of large macropores (>1,200 μm) resulting from greater earthworm burrowing in the biochar-amended soil.
Conclusion
We found no evidence to suggest application of biochar influenced soil porosity by either direct pore contribution, creation of accommodation pores, or improved aggregate stability.
The aim of the study was to investigate the impact of municipal solid waste incinerator (MSWI) bottom ash (BA) codisposed with municipal solid waste (MSW) on landfill stabilization according to the leachate quality in terms of organic matter and nitrogen contents. Six simulated landfills, that is, three conventional and three recirculated, were employed with different ratios of MSWI BA to MSW. The results depicted that, after 275-day operation, the ratio of MSWI BA to fresh refuse of 1 : 10 (V : V) in the landfill was still not enough to provide sufficient acid-neutralizing capacity for a high organic matter composition of MSW over 45.5% (w/w), while the ratio of MSWI BA to fresh refuse of 1 : 5 (V : V) could act on it. Among the six experimental landfills, leachate quality only was improved in the landfill operated with the BA addition (the ratio of MSWI BA to fresh refuse of 1 : 5 (V : V)) and leachate recirculation.
The gradual rise in average global temperature over the last few decades is the evidence of adversities of climate change. Therefore, the research and development efforts to investigate and materialize innovative and economically viable methods to mitigate carbon emission have received unprecedented priority. One of the plausible methods to sequester carbon in a sustainable manner could be to fix carbonaceous materials on a very long-term basis by thermochemical transformation of agricultural biomass residues into biochar. It has been reported in the literature that the pyrolysis of organic materials can yield up to 50–70 % (w/w) biochar as a value-added product. Furthermore, biochar can have a carbon composition ≥60–80 %, which is equivalent to ≥2.20–2.94 ton CO2 sequestered/ton biochar. Therefore, even after a conservative estimation (e.g., 20 % liberation of carbon from the biochar after land application) of kinetics of biochar-bound carbon loss, a substantial amount of CO2 can be sequestered into soil for a very long term (≥100 s to 1,000 years or even more). On the other hand, amendment of agricultural soil with biochar has been found to enhance physicochemical as well as biological characteristics of the soil. Biochar can act as buffering agent for acidic soils; enhance water retention capacity, favorable matrix formation for beneficial microbial flora, and degradation of toxic compounds; and provide bioavailable nutrients to plants or to the beneficial microbial consortia. The present cost of commercially available biochar is ≅100–500 $/ton (without any carbon credit basis), which is considerably higher than other soil amendment chemicals, such as lime (≅50 $/ton), which is the main deterrent to its marketability. However, under one or more of the favorable conditions such as government subsidies/carbon credit gains, mass scale production (demand–supply dynamics), and data on long-term benefits correlated with techno-economics can make biochar commercially successful. This will have a substantial positive impact on mitigation of carbon emission.
Landfills are one of the main sources of methane in The Netherlands. Methane emissions from landfills are estimated to be about 180–580 ktonnes (Gg) per year at a total of 760–1730 ktonnes. Landfill gas recovery and utilization is recognized as a cost-effective way of reducing greenhou