Search

A detailed investigation of employing landfill gas together with additives such as hydrogen or propane or both as a primary low reactivity fuel in a reactivity controlled compression ignition combustion of a diesel engine is conducted. A 3401E caterpillar single-cylinder diesel engine with a bathtub piston bowl profile is utilized to execute the study. The engine is operated at various intake pressures of 1.6, 1.9, and 2.2 bar, and runs at a fixed engine speed of 1300 rpm. For verification purposes, the conduct of the present engine running on pure methane as a low reactivity fuel is compared to that of the same engine available in the literature. Next, a numerical simulation is made to assess the performance of the present engine running on landfill gas plus the additives. Based on the obtained results, injecting either hydrogen or propane or a combination of both up to a total amount of 10% by volume to the premixed of landfill gas and air, and advancing diesel fuel injection timing of about 20–30 deg. crank angle, render the landfill gas utilization quite competitive with using methane alone. Applying an enriched landfill gas in a reactivity controlled compression ignition diesel engine, as a power generator, drastically reduces the greenhouse gas emission to the atmosphere. Also, the CO and UHC mole fraction in the exhaust gas can be eliminated by either advancing the start of diesel injection or using hydrogen or propane or both as additives. In addition, utilizing hydrogen or propane or a combination of both with the primary fuel improves the peak pressure to about 16% in comparison with that of landfill gas alone.

Fast urbanization and economic prosperity generate huge amount of municipal solid waste (MSW). It is therefore critical to identify the determinants of greenhouse gas (GHG) emissions from MSW treatment and prepare potential GHG mitigation measures. A combined System Dynamics - Logarithmic Mean Divisia Index model is developed to identify the driving forces of GHG emission generated from MSW treatment and explore the mitigation potentials. Shanghai, a typical megacity in China is selected as a case study. Results showed that economic development, population scale and emission intensity were driving forces to induce GHG emissions from MSW treatment, while generation intensity and treatment structure were the factors to mitigate GHG emissions from MSW during 2000-2017. Scenario analysis further revealed that landfill gas utilization and MSW separation improvement were the most effective measures in reducing GHG emissions from MSW treatment, leading to about 88.07% and 85.48% of reduction compared with the business-as-usual scenario in 2050. Scenarios of improving incineration rate, reducing per capita MSW generation and restricting population growth will reduce GHG emissions by 72.29%, 30.06% and 0.30%, respectively. Utilizing landfill gas, improving MSW separation and promoting green behaviors are suggested to mitigate GHG emissions from MSW treatment.

The knowledge of mixed gas solubility in ionic liquids at high pressures, which becomes relevant in applications such as tertiary oil recovery and landfill gas utilization, is critical for the desi...

Anaerobic biodegradation of municipal solid waste produces a large amount of air pollutants. Therefore, it is important to estimate the quality and quantity of emitted pollutants from landfills worldwide. The aim of this study is to predict the amount of methane, carbon dioxide, carbon monoxide and non-methane organic compounds emitted from the Shahrekord, Iran landfill. The LandGEM model, introduced by the US Environmental Protection Agency, was utilized to predict the amount of the above-mentioned gases. Additionally, the AERMOD View model was used to estimate the dispersion of emitted pollutants from the Shahrekord landfill into the atmosphere. Metrological data, the most basic requirement enabling the models to work, were collected from the Islamic Republic of Iran Meteorological Organization. Results showed that the maximum amount of methane, carbon dioxide, carbon monoxide and non-methane organic compounds will be emitted from Shahrekord landfill in 2021. It is also elaborated that 114 million m3 of methane will be emitted between 1997 and 2023, with the potential to generate 188100 MW electrical energy. The modeling of pollutants' dispersion into the atmosphere shows that concentration of the pollutants emitted by the landfill was within permissible levels in the city of Shahrekord.

Rapid urbanization and economic growth has led to significant increase in municipal solid waste generation in India during the last few decades and its management has become a major issue because of poor waste management practices. Solid waste generated is deposited into open dumping sites with hardly any segregation and processing. Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) are the major greenhouse gases that are released from the landfill sites due to the biodegradation of organic matter. In this present study, CH4 and CO2 emissions from a landfill in north-east India are estimated using a flux chamber during September, 2015 to August, 2016. The average emission rates of CH4 and CO2 are 68 and 92 mg/min/m2, respectively. The emissions are highest in the summer whilst being lowest in winter. The diurnal variation of emissions indicated that the emissions follow a trend similar to temperature in all the seasons. Correlation coefficients of CH4 and temperature in summer, monsoon and winter are 0.99, 0.87 and 0.97, respectively. The measured CH4 in this study is in the range of other studies around the world. Modified Triangular Method (MTM), IPCC model and the USEPA Landfill gas emissions model (LandGEM) were used to predict the CH4 emissions during the study year. The consequent simulation results indicate that the MTM, LandGEM-Clean Air Act, LandGEM-Inventory and IPCC models predict 1.9, 3.3, 1.6 and 1.4 times of the measured CH4 emission flux in this study. Assuming that this higher prediction of CH4 levels observed in this study holds well for other landfills in this region, a new CH4 emission inventory (Units: Tonnes/year), with a resolution of 0.10 × 0.10 has been developed. This study stresses the importance of biodegradable composition of waste and meteorology, and also points out the drawbacks of the widely used landfill emission models.

Municipal Solid Waste (MSW) management in Chinese cities is a significant challenge. However, the comprehensive resource impacts of MSW treatment systems in Chinese cities are unclear. This study presents a mixed-unit hybrid life cycle assessment for MSW treatment systems. The comprehensive resource impacts of six MSW treatment systems in China are evaluated using this method: (1) landfilling, (2) landfilling with landfill gas utilization, (3) incineration with leachate spray, (4) composting + landfilling, (5) composting + incineration, and (6) incineration with leachate centralized treatment. The results show that composting + incineration has the lowest resource impacts except for raw coal extraction. Reusing by-products of MSW treatment systems can reduce resource extraction of the entire economy. By reusing the by-products, landfilling induces the largest extraction of fossil fuels and biomass, whereas landfilling with landfill gas utilization induces the largest extraction of mineral ores. Improving the diesel efficiency of the collection and transportation process, increasing by-product recovery efficiency, and decreasing moisture content of MSW have significant impacts on reducing resource impacts of MSW treatment systems. We also observed trade-offs in resource impacts of different MSW treatment systems. Compared to landfilling, landfilling with landfill gas utilization can reduce the induced fossil fuel extraction but increase the induced metal ore extraction. We observed similar situation when comparing incineration with leachate spray with composting + landfilling. Findings of this study provide scientific foundations to improve the resource efficiency of MSW treatment systems in Chinese cities. They also provide insights into the MSW management in other countries.

Various waste-to-energy (WTE) conversion technologies can generate energy products from municipal solid waste (MSW). Accurately evaluating landfill gas (LFG, mainly methane) emissions from base case landfills is critical to conducting a WTE life-cycle analysis (LCA) of their greenhouse gas (GHG) emissions. To reduce uncertainties in estimating LFG, this study investigated key parameters for its generation, based on updated experimental results. These results showed that the updated parameters changed the calculated GHG emissions from landfills significantly depending on waste stream; they resulted in a 65% reduction for wood (from 2412 to 848 t CO2e/dry t) to a 4% increase for food waste (from 2603 to 2708 t CO2e/dry t). Landfill GHG emissions also vary significantly based on LFG management practices and climate. In LCAs of WTE conversion, generating electricity from LFG helps reduce GHG emissions indirectly by displacing regional electricity. When both active LFG collection and power generation are considered, GHG emissions are 44% less for food waste (from 2708 to 1524 t CO2e/dry t), relative to conventional MSW landfilling. The method developed and data collected in this study can help improve the assessment of GHG impacts from landfills, which supports transparent decision-making regarding the sustainable treatment, management, and utilization of MSW.

Landfill gas accounts for 18% of US greenhouse gas emissions. The energy wasted via venting/flaring methane in landfill gas can be valued at 7.5 billion USD (annually). This work presents a novel utilization concept, wherein landfill gas-powered refrigeration enables large-scale atmospheric water harvesting, via dehumidification. This work analyzes the potential of landfill gas-powered atmospheric water harvesting towards meeting the water requirements of oilfields located near landfills. Heat and mass transfer-based analytical modeling is used to estimate the seasonal water harvest, and techno-economic analyses are presented to quantify the benefits for US oilfields. This technology is seen to be attractive for the Barnett Shale (Texas) and Kern County (California), which can be served by 30 landfills each, and are located in hot-humid and water-stressed areas. Results show that landfill gas-powered water harvesting can meet 34% of water requirements (hydraulic fracturing) in the Barnett Shale and 12–26% of water requirements (enhanced oil recovery) in Kern County oilfields, respectively. Landfill gas projects are economically more viable in the Barnett as compared to Kern County. The impact of landfill gas-powered water harvesting on CO2e emissions from landfills is quantified. Constraints and challenges associated with water harvesting are discussed. Importantly, this waste-to-value concept has worldwide relevance since landfills co-exist with population centers.

As a way of disposing municipal solid waste, waste-to-energy not only generates energy but also reduces greenhouse gas emissions. Indeed, waste-to-energy plays a crucial role in addressing various environmental issues such as climate change and security of energy supply. Two waste-to-energy approaches were compared with simple landfill in this study, i.e. incineration with energy recovery (electricity and heat), and landfill with landfill gas utilization. It is imperative to investigate which approach is more effective in terms of GHG emission reduction in the context of different climatic conditions. The effects on GHG emission reductions are examined in the Temperate Dry Zone and Tropical Moist Zone. An assumption is made that in 2020, the waste disposal approach will be switched from simple landfill to waste-to-energy approach in China. The contribution of different waste disposal approach to the GHG reduction (1 t municipal solid waste annually) during 2020–2060 is examined in this paper. Both landfill gas utilization and incineration with energy recovery approaches reduce GHG emissions in all cases compared to the simple landfill. However, this study revealed that landfill gas power generation system is more effective in the Tropical Moist Zone, whereas incineration with energy recovery is a better choice in the Temperate Dry Zone according to the comprehensive benefit. Similarly, the improvement of landfill gas collection rate and the heat recovery efficiency play a crucial role to reduce greenhouse gas emissions during the process of managing the municipal solid waste.

The generation rate of Municipal Solid Waste is expected to increase to 2.2 billion tonnes per year by 2025 worldwide. However, in developing countries, collection, transport and disposing of waste is still challenging while, in developed countries, emerging technologies are used to produce different by-products such as heat, electricity, compost and bio-fuels. This study assesses the different waste-to-energy technologies developed to date. This work is divided into four groups: biological treatment of waste; thermal treatment of waste; landfill gas utilization; and biorefineries. Furthermore, integrated solid waste management systems with waste-to-energy technologies are studied and some worldwide examples are provided.

Natural gas is racing neck and neck with coal to be the top fuel for generating electricity in the U.S. thanks to increased use of techniques, such as hydraulic fracturing, that extract the gas from unconventional sources. Since burning natural gas emits half as much carbon dioxide as does burning coal, the natural gas boom has helped lower per capita carbon emissions in the U.S. over the past decade. However, a major downside of natural gas is that it leaks. Millions of tons every year—roughly 9 million tons in the U.S. alone—spill into the atmosphere during extraction, storage, and transport. Because natural gas comprises 95% methane, a greenhouse gas that traps 86 times as much heat as does carbon dioxide over a 20-year period, leaking just 2–3% of the gas that’s produced worldwide can wipe out its environmental benefits over coal. “The short-term climate punch of waste methane is equivalent

A system dynamics (SD) approach that models the economic potential of a regional incineration plant by using landfill gas to evaporate waste leachate is proposed in this study. A case study is provided to demonstrate application of the proposed approach, which takes an incineration plant and an adjacent sanitary landfill located at Chengdu City, China into account. Two scenarios are divided by different ratios of leachate evaporation and landfill gas utilization to examine the economic revenues obtained by the incineration plant. The optimal scenario with the best economic performance is identified to incorporate into future waste management practice. The limitations of this approach are discussed, laying a foundation for further work.

In this analysis, the integration of Power-to-Gas for creating hydrogen enriched natural gas and renewable natural gas are compared with conventional natural gas for their lifecycle greenhouse gas emissions and costs. In this analysis, the authors examine the use of Power-to-Gas concept to generate hydrogen for hydrogen enriched natural gas and renewable natural gas, which is consumed by industrial end users, and power generation facilities. To perform this analysis, a simulation is developed of a hydrogen production facility, which utilizes a number of 2 MW Polymer Electrolyte Membrane (PEM) electrolyzers. A lifecycle assessment is implemented to examine the resultant emissions performance of the hydrogen enriched natural gas and renewable natural gas in comparison to conventional natural gas. In addition, the authors employ an economic analysis for developing both hydrogen enriched natural gas and renewable natural gas facilities. A carbon credit value is used to monetize the significant emissions reductions provided by both fuel types. The analysis performed herein is specifically topical to the energy systems of Ontario, Canada, where there is a substantial natural gas infrastructure and the introduction of a cap-and-trade system is being touted by the provincial government.

The United Nation is achieving its sustainable development objectives by focusing on the greener technologies for waste to energy (WTE) conversion. This necessitates the exploration of every conceivable sustainable route in different sectors. Among these, sustainable bio-economy, electricity, and waste management are the most dynamic areas. However, till now sustainability judgments for the generation of electricity from waste-to-energy supply chain (WTE-SC) technologies have been restricted in scale with respect to the three-dimensional sustainability structure (social, environmental, and economic). In most of the cases, the assessments were controlled by various environmental factors/indicators, via overlooking the economic and social indicators. In this review, we have tried to summarize a variety of state-of-the-art WTE technologies including biological and thermal treatment, landfill gas utilization and biorefineries technologies etc. These technologies can be implemented by various policy makers and agencies to deal with the communities fear before spreading and executing the relevant rules and regulations. The implementation of these rules and regulations for WTE-SC were scheduled to decide the barriers and challenges from the perspective of finance, institution, technology, and regulation.

The improvement of landfill gas utilization efficiency will produce considerable environmental and economic benefits. This study simulated the fermentation of domestic waste through the addition of functional strains. The related gas-liquid parameters and microbial community diversity were measured, and the Tax4Fun analysis method was used to predict the methanogenic function of the methanogens. The results showed the following: i) Only the addition of Proteiniphilum acetatigenes and Bacteroides thetaiotaomicron produced significant colonization by functional microorganisms and strengthened the decomposition of organic matters in the fermentation system, especially protein, which improved the gas production efficiency. The average gas production by the PB (An experimental group only added Proteiniphilum acetatigenes and Bacteroides thetaiotaomicron) group was 1353.70 mL which was higher than that of the other groups by 19.27%–57.59%. ii) The dominant methanogens were Methanobacterium which mainly produced methane by using hydrogen and carbon dioxide as substrates according to the functional prediction. The results of the study reveal the biological strengthening mechanism of domestic waste landfill gas, which is conducive to improving the energy recycling efficiency of landfills.

Three landfill gas (LFG) valorization technologies were compared using energy and exergy efficiency and a streamlined Life-Cycle Assessment (LCA) method. The technologies were (i) steam reforming and hydrogen utilization in an in situ cogeneration fuel cell (SR-IS-FCC), (ii) biogas utilization in an in situ gas engine cogeneration plant (IS-GEC), and (iii) amine scrubbing and biomethane utilization in an ex situ gas engine cogeneration plant (AS-ES-GEC). The SR-IS-FCC alternative recorded the highest exergy efficiency and savings in cumulative energy demand (CED), and the lowest global warming potential (GWP) when all the heat is utilized in situ; otherwise, the highest exergy efficiency and the lowest GWP and CED were associated with the AS-ES-GEC alternative. The results indicate that AS-ES-GEC is the preferential choice when heat cannot be utilized in situ. Otherwise, SR-IS-FCC records the best values for the three criteria, and the AS-ES-GEC technology is the least interesting alternative.

Siloxanes are used in industrial applications including electronics, automotive industry, textiles, construction, medical equipment, food packaging, medicine and cosmetics because of their antimicrobial properties, hydrophobicity and biocompatibility. Presence of siloxanes in landfill gas creates operational challenges at biogas-to-energy facilities due to accumulation of silicon oxides on engine components, increasing the energy recovery costs. In this study, the projected siloxane content in municipal solid waste was estimated based on the trends in patent applications for silicone-based products and siloxanes used in consumer products. Paper/paperboard and construction wood are the two waste categories with the highest silicone use. Based on the analyses of trends in silicone-based patents granted and silicone use in wood and paper, the quantities of siloxanes entering landfills are estimated to increase by approximately 29% in conjunction with a 5% increase in silicone-containing products within the next 10 years and 78% within the next 25 years. These projections take into account the lag time between the use of silicone in consumer products, product use period before being discarded and decomposition times in landfills.

The problem of utilizing landfill gas is examined. Foreign companies currently utilizing landfill gas and their technologies for cleaning, drying, and liquefying landfill gas are listed. Introduction of these technologies would not only clean up cities and adjacent natural areas but also provide economic benefits from utilizing landfill gas.

Greenhouse Gas (GHG) emissions are a growing problem in the United States (US). Methane (CH4) is a potent GHG produced by several stages of the natural gas sector. Current scrutiny focuses on the natural gas boom associated with unconventional shale gas; however, focus should still be given to conventional wells and outdated equipment. In an attempt to quantify these emissions, researchers modified an off-road utility terrain vehicle (UTV) to include a Full Flow Sampling system (FFS) for methane quantification. GHG emissions were measured from non-producing and remote low throughput natural gas components in the Marcellus region. Site audits were conducted at eleven locations and leaks were identified and quantified at seven locations including at a low throughput conventional gas and oil well, two out-of-service gathering compressors, a conventional natural gas well, a coalbed methane well, and two conventional and operating gathering compressors. No leaks were detected at the four remaining sites, all of which were coal bed methane wells. The total methane emissions rate from all sources measured was 5.3 ± 0.23 kg/hr, at a minimum.

The model depSIM is a dump simulation model, which allows a detailed and time-scaled focus into the complex processes of a landfill. Description of the mechanical model: The biological, chemical and physical processes in the waste body are closely connected with each other and can be described mechanically. Therefore, a number of differential equations are needed and implemented in the model. The porous media body is examined under the acceptance of a compressible gas phase, a materially incompressible solid state, an organic phase and a liquid phase. For the verification of the numerical model the long-time behaviour (100 years) was simulated. Further details about the model and the mechanical background are summarized in Robeck, Ricken et Widmann: A finite element simulation model of biological conversion processes in landfills [1]. Use potentials: The developed model allows a differentiated, time wise and locally calculation and representation of the temperature, the organic conversion rate, the local pressure ratios and the gas current speeds. There were several case studies with the depSIM model in Germany which show the correlation between the temperature, gas production and gas potential. Therefore three different landfills were evaluated. Here, in the correlation between measured temperature in the landfill body and the temperature in the model was shown. The average divergence between both was less than 2 degree. By the detailed calculation of the gas speeds in every point of the dump an essential improvement arises compared with conventional arithmetic models for gas forecast and gas capture. These forecast models are based on estimated initial parameters. This allows only forecasts for a complete dump or a dump segment, but allows no coupled calculation of the relevant parameters. The model depSIM offers a spatially differentiated consideration of the gas production. However, just a spatially exact, quantitative forecast of the gas production is necessary for dump operator and authorities. The right forecast is elementary for the right dimensioning of the gas collection system and gas treatment and the possible use in combined heat and power units. All gas streams can be shown with the simulation model along the dump surface spatially and time wise differentiated. This allows a locally differentiated dump gas management with a division in areas with active or passive gas collection or to estimate the feasibility of a methane oxidation layer. OA gold - CA extern

Low methane content landfill gas is not suitable for feeding engines and is generally flared. This type of landfill gas may be enriched by removing the inert carbon dioxide. An innovative process, based on the carbon dioxide captured by means of accelerated carbonation of bottom ash was proposed and studied for the above purpose. The process was investigated at a laboratory scale, simulating different landfill gas compositions. The enrichment process is able to decrease the carbon dioxide concentration from 70 to 80% in volume to 60% in volume, requiring about 36 kg of bottom ash per Nm3 of landfill gas. Using this result it was estimated that an industrial scale plant, processing 100–1000 Nm3/h of low methane content landfill gas requires about 28,760–2,87,600 t of bottom ash for a one year operation. The specific cost of the studied enrichment process was evaluated as well and ranges from 0.052 to 0.241 Euro per Nm3 of entering landfill gas. The energy balance showed that about 4–6% of the energy entered with the landfill gas is required for carrying out the enrichment, while the use of the enriched landfill gas in the engine producing electricity allows for negative carbon dioxide emission.

Energy recovery is widely considered an important part of hierarchy of waste management. Previously, researchers have primarily focused on cost-effectiveness analysis of solid waste management, ignoring the global warming potential (GWP) impacts. By integrating greenhouse gas (GHG) emissions and the cost–benefit analysis, we analyzed the cost–benefit of GHG emissions for two waste to energy (WtE) methods: incineration with combined heat and power (ICHP) which produces electricity and heat, and landfill disposal with landfill gas utilization (LGU). We calculated both costs and benefits per ton certified GHG emission reductions (CER) for 20 clean development mechanism (CDM) projects with WtE technology in typical northern and southern cities in China. Furthermore, benefits were analyzed under two different scenarios: benefit only from recovery energy revenues; benefit from recovery energy revenues plus gate fee revenues. The results show that: (1) ICHP projects are beneficial from the GHG reduction standpoint; (2) The ratio of CER revenues to benefit is very high during 2008–2011. However, the decrease of CER price in CDM projects causes the disposal gate fee from local government to become more and more important for these two WtE technologies, especially for LGU. However, with or without the CDM, there is still a huge GHG reduction potential in solid waste management in China. Policies should be developed to facilitate and encourage WtE, and the selection of WtE method depends on geographical region and economics.

Open dumping, the most commonly practiced method of solid waste disposal in Indian cities, creates serious environment and economic challenges, and also contributes significantly to greenhouse gas emissions. The present article attempts to analyse and identify economically effective ways to reduce greenhouse gas emissions from municipal solid waste. The article looks at the selection of appropriate methods for the control of methane emissions. Multivariate functional models are presented, based on theoretical considerations as well as the field measurements to forecast the greenhouse gas mitigation potential for all the methodologies under consideration. Economic feasibility is tested by calculating the unit cost of waste disposal for the respective disposal process. The purpose-built landfill system proposed by Yedla and Parikh has shown promise in controlling greenhouse gas and saving land. However, these studies show that aerobic composting offers the optimal method, both in terms of controlling greenhouse gas emissions and reducing costs, mainly by requiring less land than other methods.

At present, deposition of garbage in landfills is one of the most popular methods to dispose of solid waste produced in municipal areas. In a landfill, large amounts of organic garbage is deposited, where certain types of bacteria flourish and decompose the garbage, whereby heat is produced as by-product. During the decades of operation, considerable quantities of heat are generated in these microbiologically active zones. In such zones, the temperature is typically about 40-60 °C. Knowing this quantities could obviously help planning an energy management system. In this respect, the objective is to extract as much heat from the landfill as possible, and utilize it for applications such as space heating, domestic hot water production, greenhouses, etc. The present paper aims to outline the methods of estimation of the amount of heat that is produced in a landfill during the decades of its operation. The methodology of measurement of thermal conditions and of the heat output capacity is presented, with an example of data, collected so far.

This paper employs a review of the technical literature to estimate the potential decrease in greenhouse gas (GHG) emissions that could be achieved by increasing the application of gas engines in China in three sectors: urban public transport vehicle; shipping; and thermal power plants. China’s gas engine development strategies and three types of gas resource are discussed in the study, which indicates that gas engines could decrease GHG emissions by 520 megatonnes (Mt) of carbon dioxide equivalent (CO2e) by 2020. This would account for 9.7 % of the government’s target for decreasing GHG emissions and is dominated by methane recovery from the use of coal mine gas (CMG) and landfill gas (LFG) for power generation. In the public urban transport vehicle and shipping sectors the low price of natural gas and the increasing demand for the control of harmful emissions could spur the rapid uptake of gas engine vehicles. However, the development of CMG- and LFG-fuelled power plants has been limited by the unwillingness of local enterprises to invest in high-performance gas engine generators and the associated infrastructure. Therefore, further compulsory policies that promote CMG use and LFG recovery should be implemented. Moreover, strict regulations on limiting methane leakage during the production and distribution of gas fuels are urgently needed in China to prevent leakage causing GHG emissions and largely negating the climate benefits of fuel substitution. Strategies for increasing the application of gas engines, promoting gas resources and recovering methane in China are instrumental in global GHG mitigation strategies.

Gas produced by landfill is bio-gas that has a high concentration of methane that could cause global warming if not controlled. Good management of a landfill in controling the production of methane gas, can be used as an alternative sources of energy to produce electrical energy. Monitoring of methane gas production needs to be done continuously for the energy conversion process can take place perfectly without polluting the environment. Fixed monitoring system described in this paper is the result of design and development including hardware and software of monitoring technology for methane gas to facilitate research in doing observations of a landfill performance.keywords : final disposal, landfill gas, methane, landfill performance, fixed landfill gas monitoring system

Landfill gas (with methane content of 35–55%) adds significantly to global warming if released to the atmosphere. Under the EU Landfill Directive, all landfill sites are obliged to collect this gas if supplied with biodegradable municipal waste. Landfill gas (LFG) can be (i) flared, (ii) combusted to produce electricity, or (iii) upgraded to biomethane. The last scenario is of special interest. In the USA, LFG is now classified as a cellulosic biofuel; in the EU, there is a mandatory target of 10% share of renewables in transport by 2020. A significant challenge for upgrading LFG to biomethane is the high nitrogen content resulting from negative pressure in the landfill. Cost analyses were conducted to compare three technology solutions for LFG upgrading with accessible LFG flow of 250–500 m3/h. If injection to the transmission grid is considered, then a single-step pressure swing adsorption (PSA) system may be viable. The optimal solution suggested is an on-site service station; the cost of this system (including propane addition and service station) was assessed as e0.84/mn3 LFG biomethane. This required a subsidy of e0.55/mn3; this is available in Ireland under the Biofuel Obligation Certificate scheme. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd

The aim of the study was to evaluate the impact of the landfill on the groundwater environment. The assessment of water status in the region of landfill sealed with a layer of clay with a thickness of 0.5 m, was based on the own research and monitoring received from the municipal office, and conducted in 2007–2010. Waters flowing out of the landfill revealed an increase in pollution indicators such as: total organic carbon (TOC), concentrations of PAHs and heavy metals including zinc, cadmium, and chromium. It was demonstrated that the landfill sealed with a clay layer does not reduce the outflow of leachate to groundwater, but also that the purity of these waters is influenced by increased agricultural activity in the areas adjacent to the landfill.

The article discusses landfills for disposal of municipal solid waste, landfill biogas as an energy resource and its negative properties. We consider the problems of growth of volumes of solid municipal waste in the world and use of landfill gas for energy purposes. Moreover, the article analyzes the ratio of the volume fractions of the major macrocomponents of landfill biogas and the reasons for the high nitrogen content in the composition of the landfill gas. It shows the results of research in the field of cogeneration and trigeneration energy from gas mixtures and formulates the principles of creation of better treatment and landfill gas combustion systems. We develop an effective and lowcost method for increasing the methane component in reducing the nitrogen content in the landfill gas and consider the application of biological products on the basis of methane effluent for processing substrates in the body of the landfill to increase the proportion of methane and environmental safety. The article assesses the expected effect, the positive results of the implementation of the proposed method and proposes set of measures to improve the efficiency of degassing municipal solid waste (MSW) landfill. The demand of this technology for the exploited and newly commissioned MSW landfills inRussiaand abroad is approved.

As methane constitutes about 50% of landfill biogas, reduction of methane emissions from municipal solid waste (MSW) landfills results in climate change mitigation. As such, it is important for a landfill lifetime model to properly reflect the manner in which biogas is managed. The goal of this research is to compare landfill biogas management in a conventional landfill with a bioreactor landfill during a 100-year time horizon. This comparison concentrates on the greenhouse gas (GHG) emissions balances and electricity generation potential from recovered biogas using reciprocating internal combustion engines (RICE), which leads to avoiding GHG emissions due to fossil fuel displacement. The results estimated that the total amount of GHG emissions released to atmosphere, including fugitive methane emissions and the avoided effect of electrical energy production, was 668 and 803 kg carbon dioxide (CO2) equivalents (CO2E) per metric ton (t) of landfilled MSW for the conventional and the bioreactor landfill, respectively. This study underscores the importance of installing an aggressive gas collection system early for bioreactor landfills, and for investigating methods of improving gas collection efficiency during active landfilling.

The study was conducted to measure the emission from landfill in the years 2005–2011. The results are used to diagnose the emissions of CH4. The mean value of CH4 in vol. % in the collection wells ranged from 0 to 2.14 vol. % the mean concentration of CH4 in mg/m3 ranged from 0 to 25 251 mg/m3 the average concentration of CH4 in mg/Nm3 at the measuring and control points ranged from 2.2 to 24.1 mg/Nm3. CH4 emissions from the landfill do not exceed the reporting thresholds the landfill does not meet conditions for being included in the Integrated Register of Pollutants.

This study is to estimate the viability of aerobic stabilization technology for reducing greenhouse gas (GHG) emissions from landfills in Korea. In this study, methane emissions were estimated by applying Landfill gas estimation model (LandGEM) to Y landfill in Korea. By comparison of an anaerobic condition (baseline) and an aerobic condition, the amount of CO 2 eq savings was calculated. The CO 2 eq savings take place inside the landfilled waste during aeration due to the conversion of previously anaerobic biodegradation to aerobic processes, releasing mainly CO 2 . It was demonstrated that 86.6% of the total GHG emissions occurring under anaerobic conditions could be reduced by aerobic stabilization technology. This means the aerobic stabilization technology could reduce environmental contamination through early stabilization and GHG emissions considerably at the same time. Therefore, the aerobic stabilization technology is one of the optimal technologies that could be employed to domestic landfill sites to achieve sustainable landfill.Keywords : Greenhouse gas, Sustainable landfill, Methane, Aerobic stabilization technology

Biogas in landfill is being captured by natural and engineered processes. The natural processes are represented by biological activities such as bacterial methane oxidation and plant uptake for carbon dioxide at topsoil layer. Landfill gas is transported through soil layers in landfill top or in nearby areas before being released to the atmosphere. Whilst transported in the soil layers the biogas is mixed with atmospheric air and the methane may hence be oxidized by the methanotrophic bacteria in the soil using oxygen from atmosphere. Methane oxidation is affected by different environmental factors such as; temperature, water content, nutrients, substrate and oxygen concentrations. One of the ways to decrease greenhouse emissions in the future is to plant fast growing woody crops thereby sequestering carbon and displacing fossil fuels by harvesting woody biomass for bio-energy, or by storing carbon in long-lived woody products. Plant uptake for carbon dioxide is affected by some parameters such as; CO2 concentration, nitrogen concentration, water content and temperature. The engineered processes are represented by various physical biogas extractions; gas is collected using network of collection pipes and wells. The gas collection efficiency in landfills is between 40-90%. Landfill gas can be collected by either a passive or an active collection system. Passive gas collection systems use existing variations in landfill pressure and gas concentrations to vent landfill gas into the atmosphere or a control system. Active gas collection is considered a good means of landfill gas collection. An active collection system composed of extraction wells connected to header pipe to a pump that delivers gas for energy recovery.

The most effective strategy to manage and treat solid urban residues, with the least environmental impact as well as lowest economic and energy costs, is a challenge for sustainability in current society, who actually pay for the final management of these residues. This manuscript analyzes the potential of biogas generation in an urban solid residue treatment plant, and the potential use for cogeneration in situ at the landfill. The objective is to identify the energy potential associated with the landfill and its potential use to accelerate the evaporation of leachate through the supply of heat, reducing the risks of exceeding the collection capacity of the leachate ponds. The change in legislation for generation within the special regime in Spain (2014) introduced a sudden change in the direction of energy policies, which affected significantly the profitability of these facilities. This manuscript analyzes the application of both legislations, previous (2007) and current (2014), for the case of a cogeneration system installed in this landfill. The results obtained indicate that even with a much more restrictive legislation in force, acceptable values are obtained for the evaluation of the investment – however, better results were obtained for the previous legislation that favored the special regime. The new regulation constrains the maximum and minimum annual operating hours for landfill cogeneration. It results in relevant periods with limited use of biogas for electricity generation. Biogas storage for delayed future consumption in the same installation and biogas selling for external use in boilers are proposed as options for this biogas in excess. They can reduce greenhouse gases emissions from the non-used biogas and can improve the economic results of the facility.

Diverting organics from landfills to compost piles is generally recognized as a means to reduce greenhouse gas emissions. This article provides a detailed review of the Climate Action Reserve (CAR) and the U.S. EPA Waste Reduction Model (WARM) protocols on landfill diversion and composting for food scraps and yard waste. The primary benefits associated with diversion are methane avoidance. The equations used to quantify methane avoidance include first-order decay rate constants for different feedstocks to predict how quickly organics will decay. The total methane generation potential of the different feedstocks is also included. The equations include estimates of gas collection efficiencies in landfills. The decay rate constants have been determined from laboratory incubations and may not be representative of decomposition within a landfill. Estimates of gas capture efficiency have been improved and more closely reflect actual landfill conditions. Gas capture efficiency will vary based on landfill...

As a way of disposing municipal solid waste (MSW), waste-to-energy (WtE) not only generates energy but also reduces greenhouse gas (GHG) emissions. This paper analyzes two WtE options, i.e. incineration with energy recovery (electricity and heat) (Incineration E hereafter), and landfill with landfill gas (LFG) utilization (Landfill E hereafter). It is imperative to investigate which approach is more effective in terms of GHG emission reduction in different climatic conditions. Two typical northern and southern cities in China, i.e. Tianjin in North China and Xiamen in South China are selected in this study. GHG accounting was undertaken per ton of waste received at the waste plant while GHG contributions were categorized as indirect emissions, direct emissions, substituted fossil fuel emissions and avoided emissions. The results show that North China should adopt Incineration E, while Landfill E is the better choice for South China. This study also benchmarks the waste management practices in these two cities to international practices in Europe in terms of the avoided emissions from both Incineration E and Landfill E approaches. The findings indicate that the energy recovery efficiency in Europe is higher than that of China, especially for Incineration E. Therefore, more efforts are required in China to enhance the substituted fossil fuel emissions, e.g. improving the energy recovery efficiency.

The main wastes of the Estonian shale oil industry – oil shale semi-coke and ashes – are deposited in landfills. The Kohtla-Jarve oil shale semi-coke and ash landfill, which is likely the largest of its kind in the World, was started in 1938. The environmental risks connected with the landfill were assessed and prioritized. The most significant hazard to human health is emission of harmful landfill gases and the water contamination in the local river network is harmful for aqueous organisms. The spatial expansion of subsurface contamination predicted by the groundwater transport model completed is practically insignificant from the viewpoint of health services. The landfill's leachates must be captured and purified, and the closed part of the landfill should be covered by greenery. The partial landfill capping recently executed is useless. The EU Landfill Directive requirements imposed on the hydraulic resistance of geological barriers cannot prevent the leakage of contaminants from a landfill.

Landfill is the dominant disposal choice for the non-classified waste, which results in the stockpile of materials after a long term stabilization process. A novel landfill, namely renewable landfill (RL), is developed and applied as a strategy to recycle the residual materials and reuse the land occupation, aim to reduce the inherent problems of large land occupied, materials wasted and long-term pollutants released in the conventional landfill. The principle means of RL is to accelerate the waste biodegradation process in the initial period, recover the various material resources disposal and extend the landfill volume for waste re-landfilling after waste stabilized. The residual material available and risk assessment, the methodology of landfill excavation, the potential utilization routes for different materials, and the reclamation options for the unsanitary landfill are proposed, and the integrated beneficial impacts are identified finally from the economic, social and environmental perspectives. RL could be draw as the future reservoirs for resource extraction.

Waste that was generated by human activities needed to be treated properly in order to reduce harmful to environment. At present, landfill is the most common treatment method of Municipal Solid Waste (MSW) all over the world, due to it’s lowest net treatment cost when comparing with the other methods, i.e. thermal treatment and composting. However, it is quite clear that the landfill method is not an ultimate and sustainable way for the MSW treatment. Indeed, it works in such a way that the waste would be transferred into land and waiting for final disposal process in the future, causing a large land usage and long-term treatment. But still, there are a lot of valuable materials that needs to be reclaimed inside the dump waste. Green manufacturing of Eco-Materials from Landfill Dump Site by urban mining has been developed. The pilot reclaiming landfill has a daily capacity of 50 Tons, by using land excavation and passing through trommel screen and magnetic separation. The reclaim materials consist of non-degradable plastic, metal, glass and soil. Metal and glass have been used for recycling purposed. The non-degradable plastic has a proportion around 35% of reclaim materials in the form of Refuse Derived Fuel (RDF) and shall be used for green and clean energy to produce electricity by using gasification technology. This research described the green manufacturing process of urban mining to get the valuable eco-materials. The results shown that the new and eco-materials from landfill dump site can be used as clean and green energy that helps reduce the global warming effects and impact to environment.

Estimation of the landfill gas (LFG) and electricity potential is one of the significant aspects of an integrated landfill development. In view of this, geological surveys were undertaken in all the government operated landfills in Lagos to appraise ground conditions for the exploitation of the anaerobically generated LFG. Thereafter, attempts were made to estimate the electricity potentials based on various equations and models. The geology of the landfill areas is essentially that of the Oligocene to Pleistocene Coastal Plain Sands except for that of Epe landfill area which is of Recent Deposits. The lithologies of the landfills in the Coastal Plain Sands areas seem suitable for landfill gas capture upon capping. Using stoichiometry, an achievable electrical power of 123.75 MW was deduced. By juxtaposition with an established Malaysian scenario, the yearly electrical energy was placed at 646,663.2 MWh with a tariff revenue in excess of US$64.68 million/year. Furthermore, an accruing carbon credit of about US$31.73 million/year is expected from certified emission reduction (CER) under the Kyoto Protocol. However, estimations by comparison with gas capturing sites across the globe yielded a mean of 38.35 MW. This is about 30 % of the theoretical and is capable of providing electricity to over 230,000 inhabitants. Hinged on actuality, this latter evaluation may aid to eradicate spurious estimations for practical purposes, and is critical in terms of global LFG capture economics. The concomitant benefits of LFG exploitation are expected to be exponentially higher in terms of reduction of greenhouse gases and mitigation of environmental hazards.

Methane is the second most prevalent greenhouse gas and has a global warming potential at least 28 times as high as carbon dioxide. Municipal solid waste landfills are reported to be the third-largest source of anthropogenic methane emissions in the United States, responsible for 18 percent of emissions in 2011. Capturing landfill gas for use as an energy source for electricity or heat produces alternative energy as well as environmental benefits. A host of federal and state policies encourage the development of landfill-gas-to-energy projects. Our research provides the first systematic economic assessment of the role these policies play in adoption decisions. Results suggest that renewable portfolio standards and investment tax credits have contributed to the development of these projects, accounting for 13 of 277 projects during our data period from 1991 to 2010. These policy-induced projects have led to 12.5 million metric tons of carbon dioxide-equivalent reductions in greenhouse gas emissions and a net benefit of $52.59 million.

Bio-sludge generated from wastewater treatment plants is typically disposed of in landfills. Among the pressure of environmental problems, alternative options for bio-sludge disposal have been proposed. In addition to landfills, burning sludge in cement kilns and composting are new options for managing bio-sludge in Thailand. The objective of this study is to evaluate the environmental impact of alternative waste management practices for bio-sludge, including landfilling with landfill gas utilization systems, cement kilns, and composting, compared with conventional landfills. The environmental impact from each scenario was calculated at midpoints and damage levels using the IMPACT 2002+ method. The results indicate that landfilling with landfill gas utilization systems shows the greatest potential for greenhouse gas reduction compared with conventional landfills. The cement kiln option has the highest potential for aquatic acidification, terrestrial acidification and nitrification. While the fertilizer option has lowest potential for those impacts, the potential for aquatic eutrophication and terrestrial ecotoxicity is highest in this option. Finally, the endpoint analysis showed that the fertilizer option has a high performance in regard to human health and climate change, and it was recommended for selection as a first priority for bio-sludge disposal in Thailand.

This paper presents an analysis of the electricity generation from municipal solid waste (MSW), via landfill gas valorization technology, at the landfill of Gaziantep City, Turkey. Rapid increase in population, and industrial developments, throughout the world including Turkey results in larger amount of waste materials generated, increased need for energy, and adverse affects on the environment and human health. Turkey plans to produce 1/3 of its electricity demand using renewable energy sources by the year of 2023. It is recommended to use each year around 25 million tonnes of the MSW generated nationwide for a renewable energy supply. In this study, a concise summary of current status of electricity generation from a MSW landfill gas plant (via biogas harnessing) located in Gaziantep City was analyzed as a case study.Implcatons:MSW management has become a major challenge in Turkey, due to the increase in the amount of solid waste, which causes negative environmental impact and results in suboptimal use of raw materials and energy. An implication of waste-to-energy technology from MSW has been applied successfully in Gaziantep, where total MSW generated has increased steadily over last 15 years. The study showed the importance and benefit of energy recovery from MSW in both economic and environmental issues in Turkey.

The city of Astana, the capital of Kazakhstan, which has a population of 804,474, and has been experiencing rapid growth over the last 15 years, generates approximately 1.39 kg capita-1 day-1 of municipal solid waste (MSW). Nearly 700 tonnes of MSW are collected daily, of which 97% is disposed of at landfills. The newest landfill was built using modern technologies, including a landfill gas (LFG) collection system. The rapid growth of Astana demands more energy on its path to development, and the viability analysis of MSW to generate electricity is imperative. This paper presents a technical–economic pre-feasibility study comparing landfill including LFG utilization and waste incineration (WI) to produce electricity. The performance of LFG with a reciprocating engine and WI with steam turbine power technologies were compared through corresponding greenhouse gases (GHG) reduction, cost of energy production (CEP), benefit–cost ratio (BCR), net present value (NPV) and internal rate of return (IRR) from the analyses. Results demonstrate that in the city of Astana, WI has the potential to reduce more than 200,000 tonnes of GHG per year, while LFG could reduce slightly less than 40,000 tonnes. LFG offers a CEP 5.7% larger than WI, while the latter presents a BCR two times higher than LFG. WI technology analysis depicts a NPV exceeding 280% of the equity, while for LFG, the NPV is less than the equity, which indicates an expected remarkable financial return for the WI technology and a marginal and risky scenario for the LFG technology. Only existing landfill facilities with a LFG collection system in place may turn LFG into a viable project.

The natural gas supply chain includes production, processing, and transmission of natural gas, which originates from conventional, shale, coal bed, and other reservoirs. Because the hydrocarbon products and the emissions associated with extraction from different reservoir types can differ, when expressing methane emissions from the natural gas supply chain, it is important to allocate emissions to particular hydrocarbon products and reservoir types. In this work, life cycle allocation methods have been used to assign methane emissions from production wells operating in shale formations to oil, condensate, and gas products from the wells. The emission allocations are based on a data set of 489 gas wells in routine operation and 19 well completion events. The methane emissions allocated to natural gas production are approximately 85% of total emissions (mass based allocation), but there is regional variability in the data and therefore this work demonstrates the need to track natural gas sources by both for...

Hydrogen sulfide (H2S) in landfill gas, formed with the biodegradation of municipal solid waste, is a major odorous component in a landfill. It poses a potential risk to humans and causes odor problems and complaints by the residents near landfills. Many studies have been conducted on landfill gas qualities. Also, various H2S control technologies have been used in different industrial sectors. However, comprehensive reviews on H2S issues in landfill gas are rare. An understanding of the formation of H2S encountered in landfill gas and the emission at which it occurs helps assess risk and problems. The authors review recent publications from different perspectives on H2S odor in landfills, including H2S generation the impact on the environment and human health, H2S levels in the landfill environment, and H2S control technologies at landfills.