Showing papers on "Bioreactor landfill published in 2014"
TL;DR: The concept of microbially mediated methane oxidation in landfill covers by using methanotrophic microorganisms has been widely adopted as a method to counter the rise in methane emissions as discussed by the authors.
Abstract: Mitigation of landfill gases has gained the utmost importance in recent years due to the increase in methane (CH4) emissions from landfills worldwide. This, in turn, can contribute to global warming and climatic changes. The concept of microbially mediated methane oxidation in landfill covers by using methanotrophic microorganisms has been widely adopted as a method to counter the rise in methane emissions. Traditionally, landfill soil covers were used to achieve methane oxidation, thereby reducing methane emissions. Meanwhile, the continual rise of CH4 emissions from landfills and the significant need to and importance of developing a better technology has led researchers to explore different methods to enhance microbial methane oxidation by using organic rich materials such as compost in landfill covers. The development and field application of such bio-based systems, explored by various researches worldwide, eventually led to more widely accepted and better performing cover systems capable of reducing CH4 emissions from landfills. However, the long-term performance of bio-based cover systems were found to be negatively affected by factors such as the material’s ability to self-degrade, causing CH4 to be generated rather than oxidized as well as the greater potential for forming pore-clogging exopolymeric substances. In order to design an effective cover system for landfills, it is essential to have a thorough understanding of the concepts incorporated into methodologies currently in favor along with their pros and cons. This review summarizes previous laboratory and field-scale studies conducted on various soil and bio-based cover systems, along with the modeling mechanisms adopted for quantifying CH4 oxidation rates. Finally, several issues and challenges in developing effective and economical soil and bio-based cover systems are presented.
111 citations
TL;DR: In this paper, column experiments were conducted to simulate the effects of biochar amendment to landfill cover soil and investigate whether biochar can promote the growth of methanotrophic bacteria able to oxidize CH4 into carbon dioxide (CO2).
Abstract: Biochar amendment to landfill cover soil is proposed as an economical solution to reduce methane (CH4) emissions from landfills without gas-recovery systems or in conjunction with gas recovery for near-complete CH4 removal. In this study, column experiments were conducted to simulate the effects of biochar amendment to landfill cover soil and investigate whether biochar amendment can promote the growth of methanotrophic bacteria able to oxidize CH4 into carbon dioxide (CO2). Acrylic columns were packed with coarse gravel (gas-distribution layer) and then filled with either soil or 20% biochar/80% soil. The columns were fed humidified synthetic landfill gas (25% CH4:25% CO2:50% N2) continuously for 4 months. Sampling ports along the length of the column were used to collect gas samples for measurement of the CH4 and CO2 concentrations. Additional isotopic analysis (δ13C) and temperature profiles were also used to evaluate the extent of CH4 oxidation as a function of depth. The deoxyribonucleic acid...
108 citations
TL;DR: In this article, the advanced oxidation process via heterogeneous photocatalysis (TiO2/UV) was coupled with seeded bioreactors with different inoculums types (raw leachate, soil extract and activated sludge).
77 citations
TL;DR: A simple, quick, effective and environmentally-friendly method for the treatment of the organic load of landfill leachate was developed and optimized at laboratory scale.
58 citations
TL;DR: The aim of this work was to study a hybrid bioreactor landfill technology for landfill methane production from municipal solid waste and showed that leachate pH in the anaerobicBioreactor maintained below 6.5, while in the hybrid Bioreactor quickly increased from 5.6 to 7.0 due to the aeration.
46 citations
44 citations
TL;DR: The relationship of BOD to COD of leachate from a mature landfill site is investigated over a period of six years to determine the indicator to be used for prediction of leACHate characteristic generating from landfill site as discussed by the authors.
Abstract: The relationship of BOD to COD of leachate from a mature landfill site are investigated over a period of six years to determine the indicator to be used for prediction of leachate characteristic generating from landfill site. Results of the investigation reveal that BOD:COD ratio is a good indicator of degradation of organic matter in landfill. It can be used as an indicator for degradation of organic matter that differentiate the acetogenic phase from methanogenic phase in this landfill Index Terms—BOD:COD ratio, landfill leachate, waste decomposition.
41 citations
TL;DR: A combined process consisting of ex situ nitrification and in situ denitrification in landfill refuse was studied in pilot scale for nitrogen removal from municipal landfill leachate to provide valuable information for optimizing the design and operation of a landfill bioreactor.
38 citations
TL;DR: It was concluded that heterogeneous and anisotropic MSW with varied unit weight and saturated hydraulic conductivity significantly influenced the moisture distribution and generation and distribution of pore fluid pressures in landfill and considerably reduced the stability of bioreactor landfill slope.
36 citations
TL;DR: The aged refuse-based bioreactor/biofilter (ARB) has been shown to be a promising technology for the removal of various pollutants from landfill leachate and validates the principle of waste control by waste.
Abstract: Sanitary landfilling is a proven way for disposal of municipal solid waste (MSW) in developed countries in general and in developing countries in particular, owing to its low immediate costs. On the other hand, landfilling is a matter of concern due to its generation of heavily polluted leachate. Landfill leachate becomes more refractory with time and is very difficult to treat using conventional biological processes. The aged refuse-based bioreactor/biofilter (ARB) has been shown to be a promising technology for the removal of various pollutants from landfill leachate and validates the principle of waste control by waste. Based on different environmental and operational factors, many researchers have reported remarkable pollutant removal efficiencies using ARB. This paper gives an overview of various types of ARBs used; their efficiencies; and certain factors like temperatures, loading rates, and aerobic/anaerobic conditions which affect the performance of ARBs in eliminating pollutants from leachate. Treating leachate by ARBs has been proved to be more cost-efficient, environment friendly, and simple to operate than other traditional biological techniques. Finally, future research and developments are also discussed.
35 citations
TL;DR: A field study was developed in a new landfill for refuse from construction and demolition material recovery plants of small size in Europe, with the aim of evaluating the liquid and gas emissions in this type of facility at a large scale, finding neither odor nuisances nor significant landfill gas over the surface were detected.
TL;DR: The results showed that strong CH4 emissions were observed from the fresh leachate storage pond, with the fluxes values extremely higher than those of N2O, which became dominant once theLeachate entered the treatment plants of both systems, accounting for 8-12% of the removal of N-species gases.
TL;DR: A comprehensive set of laboratory experiments were conducted under both anaerobic and aerobic conditions to evaluate the feasibility of using enzymes in accelerating lignin-rich waste degradation.
TL;DR: The results are conclusive that the biogas generation could be improved by blending the old and new leachate in aBioreactor landfill system as compared with a conventional system employed in bioreactor landfills today for recirculating the same ageLeachate.
01 Jan 2014
TL;DR: In this article, the authors presented two comprehensive field studies at the Norman Landfill ( United States) and the Grindsted Landfill in Denmark, and the key findings from these integrated studies and the literature are the following: (1) Local hydrogeological conditions in the landfill area may affect the spreading of the contaminants; (2) investigations of landfill leachate plumes in geologic settings with clayey till deposits and fractured consolidated sediments are lacking; (3) the size of the landfill and the heterogeneity of the source may create a variable leaching pattern and maybe
Abstract: Landfills with solid waste are abundant sources of groundwater pollution all over the world. Old uncontrolled municipal landfills are often large, heterogeneous sources with demolition waste, minor fractions of commercial or industrial waste, and organic waste from households. Strongly anaerobic leachate with a high content of dissolved organic carbon, salts, and ammonium, as well as specific organic compounds and metals is released from the waste for decades or centuries. Landfill leachate plume hosts a variety of biogeochemical processes, which is the key to understand the significant potential for natural attenuation of specific organic contaminants in a leachate plume. The complexity of this system is exemplified with the presentation of two comprehensive field studies at the Norman Landfill (United States) and the Grindsted Landfill (Denmark). The key findings from these integrated studies and the literature are the following: (1) Local hydrogeological conditions in the landfill area may affect the spreading of the contaminants; (2) investigations of landfill leachate plumes in geologic settings with clayey till deposits and fractured consolidated sediments are lacking; (3) the size of the landfill and the heterogeneity of the source may create a variable leaching pattern and maybe also multiple plumes; and (4) significant natural attenuation of xenobiotic organic compounds occurs, but the complexity of leachate plumes with respect to compounds (inorganic and xenobiotic organic compounds) and biogeochemical processes may be an obstacle for the implementation of natural attenuation as a remedy. These findings highlight that demonstration of natural attenuation in terms of contaminant mass reduction at the field scale is difficult. However, very few alternatives to natural attenuation exist for remediation at landfill sites. Finally, the potential chemical or ecological impact from landfills located in former wetlands or near surface water bodies may deserve attention in future studies.
25 Mar 2014
TL;DR: In this paper, column experiments are used to simulate the effects of biochar amendments to landfill cover soils for methane mitigation, and qPCR targeting the pmoA (particulate methane monoxygenase) gene indicate a higher number of methanotrophs exist in the biochar- amended column, supporting the observed higher rates of methane oxidation.
Abstract: Biochar amendments to landfill covers have been proposed as an economic solution to reduce methane emissions from landfills without gas recovery systems, or in conjunction with gas recovery for near-complete methane removal in new landfills. In this study, column experiments are used to simulate the effects of biochar amendments to landfill cover soils for methane mitigation. Acrylic columns were packed with coarse gravel, and filled with either soil or 20% biochar/80% soil. Measurements of CH4, CO2 and temperature along the depth of the column allowed the determination of gas profiles and oxidation efficiencies over the course of the experiment. DNA-based assays and isotopic measurements (δ 13 CH4 and δ 13 CO2 (‰)) were used to infer the extent of microbial oxidation and to evaluate the distribution of methanotrophs within each column. qPCR targeting the pmoA (particulate methane monoxygenase) gene indicate a higher number of methanotrophs exist in the biochar- amended column, supporting the observed higher rates of methane oxidation. Batch incubation experiments were conducted to determine Michaelis-Menten kinetic parameters for methane oxidation. Initial results indicate that biochar is effective in increasing methanotrophic activity and promoting methane oxidation.
TL;DR: In this paper, the authors used LandGEM software to estimate the amount of gas emissions from Sanandaj sanitary landfill and the data about the quantity and quality of the landfill and waste production were collected based on existing standard methods.
Abstract: Sanitary landfill is the common strategy for municipal solid waste management in developing countries. Anaerobic decomposition of disposed wastes in landfill under favorable conditions will lead to the landfill gas (LFG) emissions, considering as emerging air pollutants. The emission of greenhouse gases, including methane, resulting from municipal solid waste disposal and treatment processes are considered as the major source of anthropogenic global emissions. Assessment and prediction of the emission rate are important for planning, proper application of methane as an energy source and determining the contribution of various greenhouse gas emissions to global warming. The purpose of this study was to estimate the amount of gas emissions from Sanandaj sanitary landfill. The data about the quantity and quality of the landfill and waste production were collected based on existing standard methods. Using LandGEM software the landfill emissions were estimated with considering the 50% content of methane, the methane production rate constant of 0.045/year and gas production potential constant of 200 m 3 /ton. The results of this study showed that the maximum mass of emitted gas is at the next year after the site closure (2021). It was estimated that total mass of LFG, methane, carbon dioxide and non-methane organic compounds were 23,150, 6184, 16,970, and 266 tons/year, respectively. Effective management in controlling LFGs not only results in air pollution reduction, green energy application for sustainable development, but also can use the financial benefits of the clean development mechanism to Kyoto protocol achievement for developing countries.
16 Sep 2014
TL;DR: In this paper, the principles of geothermal heating systems can be applied to landfills to recover the heat for space heating and other purposes, and case studies indicate the high level of efficiency and cost effectiveness of landfill based geothermal systems, with simple payback periods in the range of 4 to 7 years when compared to conventional space heating technology.
Abstract: It is well known in the solid waste industry that waste disposed in landfills generates heat. Until recently, efforts to recover the heat and use landfills as a heat source did not exist. Landfill heat is generated from degradation of various waste types as a result of chemical and biological processes. Waste temperatures in landfills can range from 20oC to over 90oC under certain conditions. The principles of geothermal heating systems can be applied to landfills to recover the heat for space heating and other purposes. Landfill based geothermal systems are more efficient than ground based systems because ambient temperatures in landfills are warmer than the ground by 10oC to 45oC. Case studies indicate the high level of efficiency and cost effectiveness of landfill based geothermal systems, with simple payback periods in the range of 4 to 7 years when compared to conventional space heating technology.
TL;DR: In this article, a numerical two-phase flow model was used to examine the effects of unsaturated hydraulic properties on the moisture distribution, pore fluid pressures, and the stability of a bioreactor landfill slope with horizontal trench as leachate recirculation system.
Abstract: In bioreactor landfill, the leachate flow and moisture distribution depend upon saturated and unsaturated hydraulic properties of municipal solid waste (MSW). The effects of unsaturated parameters have not been studied because of scarcity of the data and variation in unsaturated parameters due to MSW heterogeneity, degree of decomposition, and pore structure. In this study, a numerical two-phase flow model was used to examine the effects of unsaturated hydraulic properties on the moisture distribution, pore fluid pressures, and the stability of a bioreactor landfill slope with horizontal trench as leachate recirculation system. Unsaturated hydraulic parameters were based on the van Genuchten model and obtained from previously published laboratory studies. The unsaturated hydraulic properties of MSW are found to significantly influence the leachate distribution, pore water and capillary pressures, and landfill slope stability during the operations of leachate injection and subsequent gravity drainage. Further research is needed for better understanding and accurate measurement of hydraulic properties and shear strength parameters of unsaturated MSW.
TL;DR: In this article, a parametric analysis based on a val- idated two-phase flow model is presented to guide the design of Drainage Blankets (DBs) for given hydraulic properties of MSW, the leachate injection rate and the dimensions and locations of the DB.
TL;DR: The analyzing results show that the influence depth and leachate recirculation volume increase with the increase of infiltration pond pressure head and MSW void ratio, which indicates that the field compaction of MSW has a great influence on the leachates recirculating.
Abstract: During leachate recirculation, a bioreactor landfill will experience more rapid and complete settlement, which is mainly attributed to the weight of municipal solid waste (MSW) and its biodegradation. The settlement of MSW may cause the decrease of void ratio of MSW, which will influence the permeability of MSW and the leachate quantity that can be held in bioreactor landfills. In this study, a new one-dimensional model of leachate recirculation using infiltration pond is developed. The new method is not only capable of describing leachate flow considering the effect of MSW settlement, but also accounting separately leachate flow in saturated and unsaturated zones. Moreover, the effects of operating parameters are evaluated with a parametric study. The analyzing results show that the influence depth of leachate recirculation considering the effect of MSW settlement is smaller than the value without considering the effect. The influence depth and leachate recirculation volume increase with the increase of infiltration pond pressure head and MSW void ratio. This indicates that the field compaction of MSW has a great influence on the leachate recirculation.
TL;DR: The article emphasizes conditions for economic viability of the technology and concludes with outlining existing gaps and future research needs to improve the understanding and performance of aerobic bioreactor landfilling.
Abstract: Historically, municipal solid waste landfills have been designed and operated as disposal facilities with suboptimal degradation under anaerobic conditions, resulting in slow waste stabilization and generation of landfill gas rich in methane and high strength leachate. Recently, aerobic bioreactor landfilling is being promoted as a promising method that enhances waste stabilization while producing a relatively weaker leachate and no methane generation. The authors review transformation processes and benefits associated with aerobic bioreactor landfilling. Factors affecting the operation of aerobic bioreactor landfills were detailed and performance indicators were defined with technical and operational considerations. The article emphasizes conditions for economic viability of the technology and concludes with outlining existing gaps and future research needs to improve the understanding and performance of aerobic bioreactor landfilling.
TL;DR: The Intergovernmental Panel on Climate Change’s Waste Model is used to estimate the methane generated from a Malaysian sanitary landfill, and this type of modelling could constitute a sensible starting point for landfills to introduce careful planning for efficient gas recovery in individual landfilling sites.
TL;DR: In this paper, the authors formulates the criteria required for converting the LandGem equation as per Indian condition and using it for Indian landfill sites, which is verified with their application for two landfills sites of Mumbai, Deonar and Mulund.
Abstract: Mostly in India, solid waste without any segregation is deposited into open dumping sites. Through these sites, there is uncontrolled emission of methane and landfill gas. The landfill gas has tremendous potential in terms of converting and using them as source of fuel. The emission of landfill gas depends on types of wastes, its rate of biodegradability, its methane potential, level of segregation and many more. In order to estimate the level of landfill gas emission, there are various US EPA recommended models are available. One of them is LandGem. But this model has been derived as per the US climatic conditions and their type of waste. It is needed to be converted into Indian conditions before applying it for Indian landfill site. This paper formulates the criteria required for converting the LandGem equation as per Indian condition and using it for Indian landfill sites. The model is verified with its application for two landfills sites of Mumbai, Deonar and Mulund.
TL;DR: In this paper, the optimal location of a horizontal trench system for leachate addition in a bioreactor landfill is determined based on a parametric study that used a numerical two-phase flow model that involved different slope configurations and landfill waste depths.
Abstract: The primary objective of bioreactor landfill is to achieve adequate and rapid distribution of moisture in landfilled municipal solid waste (MSW) to accelerate the anaerobic biodegradation of the organic fraction within MSW. A horizontal trench system (HT) is commonly adopted for leachate distribution in MSW under pressurized conditions. However, this approach should be implemented carefully due to the potential instability of landfill slopes that comes from the generation and distribution of excessive pore fluid pressures. In this study, HT design charts are presented that determine the optimal location of horizontal trench systems from the side slope (i.e., minimum lateral setback distance) under continuous leachate addition with maximum applied injection pressures, for which the landfill slopes remain stable [factor of safety (FOS) where FOS ≥ 1.5]. Use of any higher injection pressure and/or shorter lateral setback distance of HT than the one presented in the design charts would result in an unacceptable design of the bioreactor side slope (FOS < 1.5). The design chart was developed based on a parametric study that used a numerical two-phase flow model that involved different slope configurations and landfill waste depths. MSW heterogeneity and anisotropy, as well as unsaturated hydraulic properties, were taken into consideration in these simulations. Transient changes in pore water and gas pressures due to leachate recirculation were accounted for dually in the slope stability computations. The importance of these design charts is illustrated using a practical example. Site-specific conditions and the expertise and prior experience of a designer or operator must also be adequately considered and utilized with the design charts presented here for the safe design of a horizontal trench system in a bioreactor landfill.
TL;DR: In this article, the authors used the Inter-governmental Panel on Climate Change 1996 first order decay (FOD) model to obtain methane generation rate and potential values at Malaysian landfills.
Abstract: Methane emissions and oxidation were measured during the wet and dry seasons at the Air Hitam, Jeram, and Sungai Sedu landfills in Malaysia. The resulting levels of methane emissions and oxidation were then modeled using the Inter-governmental Panel on Climate Change 1996 first order decay (FOD) model to obtain methane generation rate and potential values. Emissions measurements were performed using a fabricated static flux chamber. A combination of gas concentrations in soil profiles and surface methane and carbon dioxide emissions at four monitoring locations in each landfill was used to estimate the methane oxidation capacity. The methane potential value was 151.7 m3 t−1 for the Air Hitam and Jeram sanitary landfills and 75.9 m3 t−1 for the Sungai Sedu open dumping landfill. The methane generation rate value of the Jeram and Air Hitam sanitary landfills during the wet season was 0.136 year−1, while that of Jeram during the dry season was 0.072 year−1. The methane generation rate values of the Sungai Sedu open dumping landfill during the wet and dry seasons were 0.008 and 0.0049 year−1, respectively. The observed values of methane generation rate and potential assist to accurately estimate total methane emissions from Malaysian landfills using the Inter-governmental Panel on Climate Change FOD model.
TL;DR: The results showed that N2O concentration in the F bioreactor varied from undetectable to about 130 ppm, while it was much higher in the ABioreactor with the concentration varying from undetected to about 900 ppm, closely related to the leachate quality in both bioreactors.
TL;DR: In this article, the authors analyzed Jerubaiciai landfill leachate resulting from the dynamics of the exchange of meteorological conditions and therefore increasing the amount of waste generated.
Abstract: The more urbanized society is, the larger the volumes of waste generated, and more problems are associated with their management. The aim of this article is to analyze Jarubaiciai landfill leachate generated content and dynamics of the factors causing this problem. This article analyzes Jerubaiciai landfill leachate resulting from the dynamics of the exchange of meteorological conditions and therefore increasing the amount of waste. This study was carried out from 05/15/2008 to 12/31/2008. The reference periods covers all seasons and are representative of Sightseeing meteorological conditions. Throughout the year, 6500 m3 leachate is formed at the Jerubaiciai landfill. The study found that during the year the amount of waste was 1050 tons of waste per weak. The landfill is covered by approximately. When the average air temperature is about - 10 °C, the leachate recycled content ranges from 40 to 140 m3. At the average temperature of 0 °C the leachate recycled content ranges from 250 - 270 m3 of leachate. During winter when the temperatures are below 0°C, 250-270 m3 of leachate transpires through the pile of waste. In summer, the total amount of precipitation was 52%, and the amount of leachatee setting-up to only 23% of the total filtrate. Correlation between air temperature and leechate r=0,784. It shows that air temperature strongly affects the amount of extracted filtrate. It was concluded that when the amount of waste in landfill increases, the amount of leachate discharged also increases at r = 0.641.
TL;DR: The results showed that landfill bioreactors can significantly enhance the biodegradation and upgrade the biostablization, and the leachate recirculation and pH adjustment in the bioreactor had a positive effect on municipal solid waste degradation.
Abstract: A laboratory experiment was carried out to determine the effect of landfill bioreactor with additives of fly ash and cinder, leachate recirculation, and pH adjustment on the disposal municipal solid waste. Four simulators were used with one sanitary landfill and three landfill bioreactors. The results showed that landfill bioreactors can significantly enhance the biodegradation and upgrade the biostablization, and the leachate recirculation and pH adjustment in the bioreactor had a positive effect on municipal solid waste degradation. The landfill bioreactors could increase 11.7% landfill space and reduce the concentration of chemical oxygen demand concentration in leachate by over 60% than a sanitary landfill.
20 Aug 2014
TL;DR: Overall, the two-phase flow model is found to produce results comparable with those of the published studies and assures that the model can be used for the prediction of moisture distribution and for the rational design of leachate recirculation systems in bioreactor landfills.
Abstract: A numerical two-phase flow model is presented to determine the moisture distribution and pore water and gas pressures within unsaturated municipal solid waste (MSW) in bioreactor landfills during leachate recirculation. The numerical model used is the Fast Lagrangian Analysis of Continua (FLAC), which is based on finite difference approach. The model governing equations and mathematical formulations is briefly explained. Validation of the model is examined by simulating the published laboratory and field studies and published modeling studies. Overall, the two-phase flow model is found to produce results comparable with those of the published studies. This assures that the model can be used for the prediction of moisture distribution and for the rational design of leachate recirculation systems in bioreactor landfills.