Greenhouse gas emissions from municipal solid waste management in Indian mega-cities: a case study of Chennai landfill sites

Assessment of urban greenhouse gas emissions towards reduction planning and low-carbon city: a case study of Montreal, Canada

Greenhouse gases (GHGs) can be produced from a broad range of anthropogenic activities at different spatial and temporal scales. In particular, emissions from urban area are an import source of GHGs. City is a complicated system consisting of various component and processes. Efforts have been made to reduce urban GHG emissions. However, there is a lack of available methods for effective assessment of such emissions. Many urban sources and factors which can influence the emissions are still unknown. In the present study, the GHG emissions from municipal activities was assessed. A model for the assessment of urban GHG emissions was developed. Based on the collected data, a case study was conducted to evaluate urban GHG emissions. The comprehensive assessment included the emissions from transportation, electricity consumption, natural gas, waste disposal, and wastewater treatment. There was a variation for GHG emissions from these sectors in different years. This study provided a new approach for comprehensive evaluation of urban GHG emissions. The results can help better understand the emission process and identify the major emission sources.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40068-024-00341-y.

Quantification and environmental impact of slaughter waste during its life cycle

Considering the lack of an in-depth and comprehensive study on slaughter waste quantification and its management, despite the growing demand for meat this study aims to quantify the slaughter waste generated in Mumbra, Thane, India, from the meat retail stores. The study also endeavors to find the composition of slaughter waste in municipal solid waste by employing the questionnaire survey method. The literature reviewed the published studies on the life cycle analysis of food products for global warming potential values for meat and vegetable products along with the vegetarian and non-vegetarian dietary patterns. In this study, it was observed that 55.93% of the population were non-vegetarian consumers and the composition of slaughter waste was 7% of total municipal solid waste disposed of in disposal sites resulting in greenhouse gas emission of 0.11 Gg CO2 Eq./year. The study presents the implementation of a biomethanation plant as a mitigation measure, along with an evaluation of the theoretical biogas potential and electricity generation capacity derived from slaughter waste, considering it as a potential feedstock. The outcomes of this study also highlight the necessity for further focused research in this specific area, aiming to increase consumer knowledge regarding the environmental impacts of meat-based diets. The finding of this study will help researchers and assists policymakers in facilitating effective management and understanding the scale of the emissions resulting from meat products and slaughter waste and identifying suitable mitigation approaches, and actively contributing to reducing the environmental footprint.

Evaluating the Ecological Footprint of Landfills: A Framework and Case Study of Fargo, North Dakota

There is growing interest in better understanding the environmental impacts of landfills and optimizing their operation. Accordingly, we developed a holistic framework to calculate a landfill's Ecological Footprint (EF) and applied that to the Fargo, North Dakota, landfill. Parallelly, the carbon footprint and biocapacity of the landfill were calculated. We calculated the EF for six scenarios (i.e., cropland, grazing land, marine land, inland fishing ground, forest land, and built land as land types) and six operational strategies typical for landfills. Operational strategies were selected based on the variations of landfill equipment, the gas collection system, efficiency, the occurrence of fugitive emissions, and flaring. The annual EF values range from 124 to 213,717 global hectares depending on land type and operational strategy. Carbon footprints constituted 28.01-99.98% of total EF, mainly driven by fugitive emissions and landfill equipment. For example, each percent increase in Fargo landfill's fugitive emissions caused the carbon footprint to rise by 2130 global hectares (4460 tons CO2e). While the landfill has biocapacity as grazing grass in open spaces, it remains unused/inaccessible. By leveraging the EF framework for landfills, operators can identify the primary elements contributing to a landfill's environmental impact, thereby minimizing it.

Impact of leachate and landfill gas on the ecosystem and health: Research trends and the way forward towards sustainability

Globally, a whopping increase in solid waste (SW) generation and the risks posed by climate change are major concerns. A wide spread practice for disposal of municipal solid waste (MSW) is landfill, which swells with population and urbanization. Waste, if treated properly, can be used to produce renewable energy. The recent global event COP 27 mainly stressed on production of renewable energy to achieve the Net Zero target. The MSW landfill is the most significant anthropogenic source of methane (CH₄) emission. On one side, CH₄ is a greenhouse gas (GHG), and on the other it is a main component of biogas. Wastewater that collects due to rainwater percolation in landfills creates landfill leachate. There is a need to understand global landfill management practices thoroughly for implementation of better practices and policies related to this threat. This study critically reviews recent publications on leachate and landfill gas. The review discusses leachate treatment and landfill gas emissions, focusing on the possible reduction technology of CH₄ emission and its impact on the environment. Mixed leachate will benefit from the combinational therapy method because of its intricate combination. Implementation of circular material management, entrepreneurship ideas, blockchain, machine learning, LCA usage in waste management, and economic benefits from CH₄ production have been emphasized. Bibliometric analysis of 908 articles from the last 37 years revealed that industrialized nations dominate this research domain, with the United States having the highest number of citations.

Accounting of the Use and Emissions of Polychlorinated Biphenyl Compounds (PCBs) in India, 1951-2100

Polychlorinated biphenyl compounds (PCBs) are highly toxic organic chemicals still prevalent in the environment. While global inventories of the use and emissions of PCBs have been developed, estimates for individual countries determined using bottom-up approaches are few and often show different trends from the global inventory. Here, we determine the past, present, and future consumption and emissions of PCBs in India. A mass balance model was used to estimate middle (low-high) emissions in the period 1950-2100. Up to 7296 tonnes of PCBs have been used in transformers. PCBs imported as wastes are estimated to be approximately 5000 (2400-9100) tonnes. Total emissions from the use and disposal of transformers, industrial processes, and imported waste disposal are estimated to become 13 (0.1-537) tonnes, 89.26 (0.5-178) tonnes, 63 (3-910) tonnes, respectively, in the period 1950-2100. Congener-specific emissions are relatively high for low-chlorinated PCBs (-8, 18, 28, 31, 52, 101, 110, 118, 153, range: 0.1-118 tonnes). We find that industrial emissions are becoming important sources of PCBs and may become predominant, depending on emission scenarios.

Dioxin-like POPs emission trends as a decision support tool for developing sustainable MSW management scheme -an exploratory study

The paper reports on an innovative application of dioxin-like persistent organic pollutants (dl-POPs) emission trends as a measure of environmental performance for designing feasible municipal solid waste management (MSWM) schemes. MSWM systems are highly dependent on the income status and the population density and it is quintessential for developing countries to devise strategies suiting to its characteristics rather than simply adapting successful processes/technologies in developed nations. Hence a lower-middle-income, high-density populated state of India - Kerala, which represents the typical scenario of majority of towns in developing countries was selected as the verification study site. Annual inventorisation of dl-POPs for the current scenario of the state was developed as a spatial model at the lowest administrative block level using geographical information system for the easy and effective comparative assessment. Further, a dl-POPs emission based MSWM scheme which could reduce up to 65% of emissions from current scenario has been developed and compared it with contemporary life cycle assessment (LCA) and life cycle cost analysis (LCCA) schemes in terms of green-house gas emissions (GHG) and landfill area requirements as environmental performance validation. Daily exposure dose of dl-POPs were predicted from the per-capita annual emission associated with different MSWM schemes and hazard quotients were also calculated to provide an overview of the health risk posed by the emissions. The predicted health risk factors were observed to be 5 times higher than the threshold level in current scenario whereas 10 times reduction in dose levels could be achieved through the proposed scheme of MSWM.

Kinetics, product distribution and atmospheric implications of the gas-phase oxidation of allyl sulfides by OH radicals

Relative rate coefficients of the OH radical -initiated oxidation of allyl methyl sulfide (AMS, H₂CCHCH₂SCH₃) and allyl ethyl sulfide (AES, H₂CCHCH₂SCH₂CH₃) have been measured at atmospheric pressure of synthetic air and 298 K: k_AMS= (4.98 ± 1.42) and k_AES= (6.88 ± 1.49) × 10^-11 cm³ molecule^-1 s^-1 by means of in situ FTIR spectroscopy. In addition, the molar yields of the main reaction products of AMS with OH radicals formed in the absence and presence of nitric oxides (NO_X) were determined to be the following: sulfur dioxide (95 ± 12) % and (51 ± 12) % for acrolein (50 ± 9) % and (41 ± 9) %. In the reaction of AES with OH radicals, the following molar yields were obtained: for sulfur dioxide (88 ± 13) % and (56 ± 12) % for acrolein (36 ± 9) % and (41 ± 9) %. The present results suggest that the abstraction at C3 plays an important role in the oxidation mechanism as the addition to the double bond. This work represents the first study of the OH radical interaction with AMS and AES carried out under atmospheric conditions. The atmospheric implications were discussed in terms of the atmospheric residence times of the sulfur-containing compounds studied and the products formed in the presence and absence of NOx. SO₂ formation seems to be the main fate of the gas-phase allyl sulfides oxidation with significant acidifying potentials and short-chain aldehydes production like formaldehyde and acetaldehyde.

Experimental investigation of removal of flue gas emissions exhaust from municipal solid waste incinerator using photovoltaic-based electrostatic precipitator

For the past decades, the flue gas emitted from municipal solid waste incinerator, power plant, and various industries is a permanent problem for the environment and has been affecting human life. Many flue gas filtration devices have been emerging out over the years. Although the electrostatic precipitator was an appropriate device due to high filtration efficiency and little pressure drop and energy efficiency, the cost and design of the electrostatic precipitator is a major restriction for manufacturers and end-users. With recent advances in technology, designing a cost-effective and less complex electrostatic precipitator has become mandatory. This article aims to design and develop a solar-powered cost-effective needle-plate type electrostatic precipitator which includes a static power converters and high-voltage transformer-rectifier (T-R) set with an input voltage as 230V AC, output voltage as 80-kV direct current (DC), and output current of 40mA for mitigation of flue gas emissions exhaust from municipal solid waste incinerator. The analysis of flue gas at ESP inlet and outlet has been performed using Ecotech stack sampler and flue gas analyzer. The obtained experimental results are validated with emission standards provided in the Solid Waste Management rules book, India, 2016.

Overview of pretreatment technologies on vegetable, fruit and flower market wastes disintegration and bioenergy potential: Indian scenario

Disposal of segregated organic fractions of centralized wholesale market wastes (i.e. vegetable, fruit and flower markets waste) in dumpsites/landfills are not only a serious issue but also underutilizes the huge potency of these organic wastes. Anaerobic digestion (AD) is a promising technology for converting organic wastes into methane, as a carbon-neutral alternative to conventional fuels. The major challenges related to the AD process are poor biodegradation of wastes and buffering capacity within the anaerobic digester that lowers the biogas yield. To accelerate biodegradation and to enhance the process efficacy of anaerobic digestion, several pretreatment technologies (mechanical, thermal, biological, chemical and combined pre-treatments) for organic wastes prior to the AD process were developed. This review article presents a comprehensive analysis of research updates in pretreatment techniques for vegetable, fruit and flower markets wastes for enhancing biogas yields during the AD process. The technological aspects of the pretreatment process are described and their efficiency comparison with the resultant process yields and environmental benefits are also discussed. The challenges and technical issues associated with each pretreatment and future research directions for overcoming the field implementation issues are also proposed.

Efficiency of microbial fuel cells in the treatment and energy recovery from food wastes: Trends and applications - A review

The rising global population and their food habits result in food wastage and cause an obstacle in its treatment and disposal. Due to the rapid shift in the lifestyle of the human population and urbanization, almost one-third of the food produced is wasted from various sectors like domestic sources, agricultural sectors, and industrial sectors. These food resources squandered are rich in organic biomolecules which can cause complications upon direct disposal in the environment. Conventional disposal methods like composting, landfills and incineration demand high costs besides causing severe environmental and health issues. To overcome these demerits of the conventional methods and to avoid the loss of rich organic food resources, there is an immediate need for a sustainable and eco-friendly solution for the valorization of the food wastes. Microbial fuel cells (MFCs) are gaining attention, due to their ideal approach in the production of electricity and parallel treatment of organic food wastes. The MFCs are significant as an innovative approach using microorganisms and oxidizing the organic food wastes into bio-electricity. In this review, the recent advancements and practices of the MFCs in the field of food waste treatment and management along with electricity production are discussed. The major outcome of this work highlights the setting up of MFC for the treatment of higher volumes of food waste residues and enhancing the bioelectricity production in an optimal condition. For further improvements in the food waste treatments using MFCs, greater understanding and more research needs are to be focused on the commercialization, different operational modes, operational types, and low-cost fabrication coupled with careful examination of scale-up factors.

An Assessment of Air Quality within Facilities of Municipal Solid Waste Management (MSWM) Sites in Lahore, Pakistan

The pollutants emission during the process of municipal solid waste management (MSWM) is of great concern due to its hazardous effect on the environment and living organisms. An assessment of the air quality of MSWM sites was made after having 16 repetitive visits at solid waste disposal sites and transfer stations of Lahore during wet and dry seasons. Pollution parameters such as fine particulate matter (PM2.5) and greenhouse gases (GHG) were measured along with meteorological parameters. PM2.5 measurement was made by using particle counter Dylos and TSI’s Dust Trak. Both of these instruments were positioned simultaneously at the source site and downwind (50 m). CH4 and meteorological parameters were measured by Aeroqual 500 series, while the Extech CO220 monitor was used to measure CO2 concentration. An assessment of air quality showed the levels of their mean values as CH4 and CO2 ranged between 1.5–13.7 ppm and 443.4–515.7 ppm, respectively. The PM2.5 ranged between 127.1 and 307.1 µg/m3 at sources and 172.3 and 403.8 µg/m3 downwind (50 m). GHG showed lower levels than the proposed limit value, which could not cause any health issues, while PM2.5 was 6–10 times higher than the Pak-EPA established standards. Higher pollutant concentration was recorded in the dry season than the wet season. Regression analysis was performed to predict correlation of PM2.5 with GHG and meteorological parameters. GHG as well as meteorological parameters also exhibited a correlation with PM2.5. It was estimated that the ambient air of such sites is not safe for public health. So, it is necessary to use safe practices for MSWM and its emission control to prevent nearby communities and the environment.

Characteristics of municipal fresh solid wastes from the selected large urban centres in Uganda: Implication for re-use and soil amendment strategies

In Uganda, the municipal solid wastes are generally a menace to the environment, ranging from indiscriminate dumping, open burning, and landfills, which would be utilized to augment agricultural fields through organic manure. The National Environment Management Authority (NEMA) of Uganda, however from 2009 to 2012 initiated and implemented a Clean Development Mechanism project. This project was established and conducted in nine urban centers with the key objective of reducing methane and other environmental nuisances while generating compost manure. The in-coming fresh municipal wastes at composting facilities were sorted into six categories; i) wood and wood products, ii) food and food wastes, iii) textiles, iv) garden, yard and park wastes, v) paper and pulp, and vi) glass, plastics, and metals. These were laboratory analyzed based on standard procedures, characterized and investigated for the pH, total organic carbon (TOC), total nitrogen (TN), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) (g kg^-1). Statistical analyses were performed based on One-Way ANOVA, implemented in the SPSS program. The results indicate that the municipal fresh solid wastes were mainly dominated by biodegradable organic matter; garden, yard, and park wastes (49%), food and food wastes (43.2%), and the other wastes falling below 5.4%. Overall, the pH was 7.7 ± 0.02, TOC 318.2 ± 2.90, TN 12.1 ± 0.10, C/N 26.7 ± 0.20, P 4.4 ± 0.04, K 35.0 ± 0.49, Ca 38.9 ± 0.51, and Mg 5.8 ± 0.09. The concentration of the fresh wastes and macro-nutrients varied per municipality and were congruent with the economic activities and population lifestyles. We detected the effect of season/month on the concentration of wastes which corresponded with the various agronomical activities. The results from this study suggest that the notion of composting is potentially a viable organic waste management strategy in the country which can ultimately generate sufficient organic manure for agricultural input and thus enhanced carbon sequestration.Implications: In this study, we characterized the in-coming fresh municipal solid wastes and investigated the pH, total organic carbon (TOC), total nitrogen (TN), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) (g kg^-1). We found that the municipal fresh solid wastes were mainly dominated by biodegradable organic matter (>90%). The results from this study suggest the notion of composting to be potentially a viable organic waste management strategy in Uganda which can ultimately generate sufficient organic manure for agricultural input. This is typically vital for enhancing carbon sequestration towards minimizing greenhouse gas emissions.

Trace volatile compounds in the air of domestic waste landfill site: Identification, olfactory effect and cancer risk

Landfill sites are regarded as sources of volatile compounds (VOCs) and odors emitted to the atmosphere. Surface emissions of VOCs and odors were investigated in a rural domestic waste landfill site located in southwest China. A total of 76 chemical compounds belonging to 3 chemical families were identified and quantified. The total number of VOCs (TVOC) detected ranged from 18.1 to 806.3 mg/m³, while odorous gases and greenhouse gases ranged from 0.4 to 21.2 and 0-100.5 mg/m³, respectively. High emissions were found in the air surrounding the leachate storage pool (LSP) and dumping area (DPA). The dominant species of VOCs were hexaldehyde, m-xylene, propylene oxide, acetophenone, and 2-butanone. The traceability analysis showed that the odors and VOCs diffused to the downwind boundary mainly came from the DPA and LSP. According to the olfactory effect analysis and cancer risk assessment, the main odor-causing gaseous pollutants were hydrogen sulfide, propionic acid, styrene, and 2-pentanone, while benzene, trichlorethylene, and 1,3-butadiene were the dominant carcinogens. This study provides new insights into the emission characteristics, olfactory effects, and cancer risks of VOCs and odors emitted from rural domestic solid waste landfill sites.

Techno-economic assessment of landfill gas (LFG) to electric energy: Selection of the optimal technology through field-study and model simulation

Landfill Gas (LFG) is a renewable energy resource. LFG quality and production rate are determined factors for the selection of the optimal technology for electric energy production. Environmental legislation, flue gas emissions, carbon footprint and maturity of technology should also be considered. The most common process for electric energy production from LFG is by Internal Combustion Engines (ICEs), which require approximately 40% minimum methane concentration. Microturbines have been also employed for electric energy production from LFG, requiring minimum methane concentration of approximately 35%. On the other hand, a relatively novel process, Gradual Oxidation (GO), can produce electric energy from LFG at methane concentrations as low as 1.5%. The present study examines the applicability of the above technologies for electric energy production from LFG, from various cells, at the landfill of Heraklion, Crete, Greece, from an economic point of view. The LandGEM (EPA) simulation model has been modified to account for the long them reduction of methane concentration in LFG, and has been adjusted, based on field measurements. The Net Present Values (NPVs) (for 15-years and 25-years from installation) for three distinct scenarios, with total electric energy production capacity of 800 kW, per scenario (using just ICEs, combination of ICE and GO or just microturbines), were calculated. The results indicated that the most profitable scenario (among the ones studied) was the one with the use of two microturbines with capacity 400 kW, each, yielding 15-years and 25-yeasr NPVs of 2.68 and 3.69 M€, respectively, for initial capital investment of 2.24 M€.

Modeling gaseous emissions and dispersion of two major greenhouse gases from landfill sites in arid hot environment

As waste production exponentially increases, landfill continues to be the common method of waste disposal. Landfills represent significant anthropogenic sources of methane (CH₄) and carbon dioxide (CO₂); the main constituents of greenhouse gases (GHGs) resultant from microbial decomposition of organic waste. In the present study, ISC-AERMOD dispersion model was employed to estimate the release and dispersion rates of CH₄ and CO₂ from major landfill sites across Kuwait under different seasonal conditions. Results revealed that dispersions of CH₄ and CO₂ were influenced by the dominant northwestern and southeastern wind directions and thus, the dispersion of CH₄ and CO₂ extended predominantly toward northeastern direction. In terms of seasonal variation, the maximum concentrations of CH₄ and CO₂ were detected in winter and spring seasons, close to the landfill zone, and the dispersion of CH₄ and CO₂ fluxes during winter and spring seasons was longer than that during summer and fall seasons. Consequently, residential areas close to the disposal sites were exposed to higher concentrations of CH₄ and CO₂ gases during winter and spring. The findings of this study can serve as the basis for selecting suitable landfill locations under desert climatic conditions as determined by the distances over which gaseous emissions can diffuse.

Greenhouse Gas Emissions from Solid Waste Management in Saudi Arabia—Analysis of Growth Dynamics and Mitigation Opportunities

The continuous growth in population, urbanization, and industrial development has been increasing the generation of solid waste (SW) in the Kingdom of Saudi Arabia. Consequently, the associated greenhouse gas (GHG) emission is also following an increasing trend. The collection and use of greenhouse gases emitted from solid waste management practices are still limited. A causality analysis examined the driving factors of the emissions from solid waste management. The methane (CH4) emissions from municipal solid waste (MSW) increased with an increase in gross domestic product (GDP) per capita and urban population, and an increase in foreign direct investment (FDI) inflows and literacy rate was likely to reduce CH4 emissions from municipal solid waste and vice versa. The CH4 emission generated from industrial solid wastes was found to be positively related to GDP per capita, urban population, and FDI inflows. However, a decrease in the unemployment rate was likely to increase CH4 emissions from industrial solid wastes. The future greenhouse gas emissions were projected under different possible socio-economic conditions. The scenario analysis based on different variations of population and GDP growth revealed that methane emission from total waste would increase at an average annual rate of 5.13% between 2020 and 2050, and is projected to reach about 4000 Gg by the end of the year 2050. Although the Kingdom has been taking some initiatives towards climate change mitigation, it has significant opportunities to adopt some of the best practices in solid waste management including reduction, recycling, composting and waste-to-energy, and carbon capture and utilization. This study also put emphasis on developing appropriate policy approaches for climate change mitigation based on the circular economy which is gaining momentum in the Kingdom.

Carbon emission and energy potential of a novel spatiotemporally anaerobic/semi-aerobic bioreactor for domestic waste treatment

The biogas generation mechanism and its utilization potential in a novel spatiotemporally anaerobic/semi-aerobic bioreactor (STASAB) system with three activated bioreactors (C1, C2 and C3) was analyzed. Methane generation potential was obtained by measurements and estimation methods with similar values of 23.38 and 27.79 kg CH₄/t waste, respectively. CH₄ and CO₂ production was quickly achieved in the STASAB, and the total amount of CH₄ and CO₂ was low due to the mixed leachate-recirculation operation process among bioreactors, which were at different stages of operation. The microbial communities in different bioreactors were diverse. The leachate-recirculation operation was a critical parameter to effectively enhance the microbial community structure in the STASAB, which can regulate CH₄, CO₂ and N₂O production with global warming potential of 7.479 kg CO₂e/(t·d). The STASAB had higher energy potential of 1.011 kWh/(t·d) compared with that of conventional landfills and sequentially anaerobic/semi-aerobic bioreactors. Moreover, direct electricity production in the STASAB is recommended for energy utilization with 38.38% GHG emission reduction, and with 131.43 million CNY (Chinese Yuan) benefit per year for national rural waste disposal via utilization of biogas from the STASAB for power generation. Hence, the STASAB shows a notable potential for treating domestic waste in rural areas.

Bio-reserves inventory-improving substrate management for anaerobic waste treatment in a fast-growing Indian urban city, Chennai

India is one among the Asia's newly industrialized countries, in which urban centres generate large amount of municipal solid wastes due to the rapid urbanization. To demonstrate urban waste potentials for biogas production by anaerobic digestion, a comprehensive analysis on the availability of organic waste hotspots and its biogas potential for the exemplary case of Chennai, India, was undertaken. The identified hotspots and their biogas potential were plotted with Geographical Information System as thematic maps. The results of biogas potential tests revealed strong variations in the biogas potentials of individual waste streams from 240.2 to 514.2 mL_N/g oDM (organic dry matter) with oDM reduction in the range of 36.4-61.5 wt.-%. Major waste generation hotspots were identified from the surveyed urban bio-reserves and the biogas potentials within an effective area of 5 km radius surrounding the hotspot were estimated. It was found that the biogas potential of individual hotspots ranged between 38.0-5938.7 m³/day. Further results revealed that the biogas potential during anaerobic co-digestion, by considering nearby bio-reserves in the effective areas of major hotspots, with and without residential organic waste, ranged between 4110.4-18-106.1 m³/day and 253.2-5969.5 m³/day, originating from 144.0-620.0 tons and 3.1-170.5 tons, respectively. Despite variations in the composition of the wastes, the Carbon/Nitrogen ratio, oDM reduction, biogas production and substrate availability were improved during co-digestion of nearby bio-reserves within the major hotspots, thereby improving the prevailing barriers in substrate management during anaerobic digestion of wastes.

Temporal and spatial variation of greenhouse gas emissions from a limited-controlled landfill site

Landfilling biodegradable waste is an important source of global greenhouse gas (GHG) emissions. Among the several types of landfill, limited-controlled landfill is a common method used to dispose of domestic solid waste, especially in developing countries. However, information about GHG emissions from limited-controlled landfill sites has rarely been reported. In this study, the GHG emissions from a typical limited-controlled landfill site were investigated under a regular period for one year. The number and positions of static chambers were arranged according to the guidance on Monitoring Landfill Gas Surface Emissions by the UK Environment Agency to obtain representative data from the heterogeneous surface of the landfill. Inverse distance weighting (IDW) was applied to evaluate and visualise the GHG emissions from the whole landfill surface based on the measurements of distributed static chambers. As an important GHG source of the landfill site, the emissions from the landfill leachate treatment plant were also measured. The results revealed that CH₄ and N₂O emission fluxes from the landfill area were 1324.73 ± 2005.17 mg C m^-2 d^-1 and 2.16 ± 2.33 mg N m^-2 d^-1, respectively, and the fluxes from the leachate treatment plants were 23.92 ± 29.20 mg C m^-2 d^-1 and 16.40 ± 16.89 mg N m^-2 d^-1, respectively. CH₄ and N₂O releases preferred to present spatial heterogeneity, while temporal heterogeneity was expected to exist in CH₄ and CO₂ emissions. The annual GHG emissions from the limited-controlled landfill was calculated to be 1.078 Gg CO₂-eq yr^-1, which was the least among all types of landfill sites. In addition, the GHG emission factor was 0.042 t CO₂-eq t^-1 waste yr^-1 which could not be ignored compared to the sanitary landfills. Therefore, it is advisable to give more attention and determine a potential solution for reducing GHG emissions from limited-controlled landfill sites.

Improving Municipal Solid Waste Collection Services in Developing Countries: A Case of Bharatpur Metropolitan City, Nepal

Municipal solid waste management is one of the major challenges that cities in developing countries are facing. Although waste collection services are critical to build a smart city, the focus of both scholarship and action/activism has been more on the utilization of waste than on collection. We devised a choice experiment to elicit the preferences of municipal residents with regard to the various attributes of solid waste collection services in the Bharatpur Metropolitan City of Nepal. The study showed that households identify waste collection frequency, timing of door-to-door waste collection services, and cleanliness of the streets as the critical elements of municipal waste collection that affect their welfare and willingness to pay. While almost all households (95%) were participating in the waste collection service in the study area, more than half (53%) expressed dissatisfaction with the existing service. Women were the main actors engaged in waste collection and disposal at household level. The results of the choice analysis suggest that households prefer a designated waste collection time with waste collection bins placed at regular intervals on the streets for use by pedestrians who often throw garbage on the streets in the absence of bins. For these improvements, households were willing to pay an additional service fee of 10–28% on top of what they were already paying. The study also finds that municipal waste collection can be improved through the involvement of Tole Lane Committees in designing the timing and frequency of the service and by introducing a system of progressive tariffs based on the number of storeys per house.

Greenhouse Gas Emissions from Landfills: A Review and Bibliometric Analysis

The landfill is an important method of disposal of municipal solid waste. In particular, the landfill is especially vital in many developing countries, with it being the main biodegradable waste disposal method due to its simple management and ability for mass manipulation. Landfills have recently been shown to be an important source of greenhouse gas (GHG) emissions by researchers in different countries. However, few reviews have been conducted within the related fields, which means that there is still a lack of comprehensive understanding related to relevant study achievements. In this study, a bibliometric analysis of articles published from 1999 to 2018 on landfill GHG emissions was presented to assess the current trends, using the Web of Science (WOS) database. The most productive countries/territories, authors and journals were analyzed. Moreover, the overall research structure was characterized based on co-cited references, emerging keywords and reference citations by means of bibliometric analysis. Due to the increasing amount of attention being paid to the GHG emissions and their mitigation methods, this study provided comprehensive bibliometric information on GHG emissions from landfills over the past two decades and highlighted the importance of the development and dissemination of updated knowledge frameworks.

Quantifying greenhouse gas emissions from municipal solid waste dumpsites in Cameroon

Open dumpsites that receive municipal solid waste are potentially significant sources of greenhouse gas (GHG) emissions into the atmosphere. There is little data available on emissions from these sources, especially in the unique climate and management of central Africa. This research aimed at quantifying CH₄, N₂O and CO₂ emissions from two open dumpsites in Cameroon, located in Mussaka-Buea, regional headquarters of the South West Region and in Mbellewa-Bamenda, regional headquarters of the North West Region. Emissions were measured during the wet season (May 2015 and August 2016) at the Mussaka and Mbellewa dumpsites respectively. Dumpsite surfaces were partitioned into several zones for emission measurements, based on the current activity and the age of the waste. Static flux chambers were used to quantify gas emission rates thrice a day (mornings, afternoons and evenings). Average emissions were 96.80 ± 144 mg CH₄ m^-2 min^-1, 0.20 ± 0.43 mg N₂O m^-2 min^-1 and 224.78 ± 312 mg CO₂ m^-2 min^-1 in the Mussaka dumpsite, and 213.44 ± 419 mg CH₄ m^-2 min^-1, 0.15 ± 0.15 mg N₂O m^-2 min^-1 and 1103.82 ± 1194 mg CO₂ m^-2 min^-1 at the Mbellewa dumpsite. Emissions as high as 1784 mg CH₄ m^-2 min^-1, 2.3 mg N₂O m^-2 min^-1 and 5448 mg CO₂ m^-2 min^-1 were measured from both dumpsites. Huge variations observed in emissions between the different zones on the waste surface were likely a result of the heterogeneous nature of the waste, different stages in waste decomposition and different environmental conditions within the waste. Management activities that disturb waste, such as spreading and compressing potentially increase gas emissions, while covering waste with a layer of soil potentially mitigate gas emissions. Recommendations were for dumpsites to be upgraded to sanitary landfills, and biogas production from such landfills should be exploited to reduce CH₄ emissions.

Environmental burden by an open dumpsite in urban India

Open municipal solid waste (MSW) dumpsites are nowadays looming hotspots for water, air, and land pollution. Fresh and old MSW samples collected from a dumpsite in the coastal city of India were analyzed for moisture content, volatile content, energy content, elements, and toxic heavy metals. The compositional analysis results showed that fresh MSW consisted of 36% by weight bio-waste (food waste, yard waste, coconut waste) and around 30% recyclable materials (plastics, paper, cardboard, and metals). Approximately, 62% of the total fresh MSW was found to be combustible materials (plastics, paper, textile, rubber, cardboard, yard waste, and coconut husks). The analysis of old MSW samples collected from different depths (3-4 m and 6-7 m) showed the dominance of plastics (25-33%) and mixed residue (28-55%) having high energy content. Measurements of gaseous emission below 6-7 m from the surface indicated a higher concentration of methane (CH₄:5.85 ± 0.12%) and lower concentration of carbon monoxide (CO: 3.82 ± 1.3 ppm), and hydrogen sulfide (H₂S:10.15 ± 2.2 ppm). Haphazard dumping, waste characteristics, waste pile compaction processes and heat propagation due to deliberate fire may stimulate spontaneous fires.

Assessment of methane emissions and energy recovery potential from the municipal solid waste landfills of Delhi, India

Rising rate of MSW generation and unscientific disposal in the open dumping sites are responsible for emission of high concentrations of methane in developing countries. IPCC Default method (DM), First-order decay (FOD) and LandGEM were used to estimate methane emissions from the unengineered landfill sites of Delhi-Okhla, Bhalswa and Ghazipur between 1984 and 2015. During the period, the total CH₄ emissions was found to be 1288.99, 311.18, 779.32 Gg from the 3 landfill sites of Delhi as predicted by DM, FOD and LandGEM respectively. The energy generation potential from methane for the year 2015 was found to vary from 4.16 × 10⁸ to 9.86 × 10⁸ MJ for Ghazipur, 2.08 × 10⁸ to 4.06 × 10⁸ MJ for Okhla and 3.42 × 10⁸ to 8.11 × 10⁸ MJ for Bhalswa. Efficient utilization of methane from the landfills as an energy source can be a sustainable waste management option.

Intergovernmental panel on climate change's landfill methane protocol: Reviewing 20 years of application

The Intergovernmental Panel on Climate Change (IPCC) protocol for predicting national methane emission inventories from landfills was published 22 years ago in the 1996 Revised Guidelines. There currently exists a broad dataset to review landfill parameters and reported values and their appropriateness in use and application in a range of site-specific, regional, and national estimates. Degradable organic carbon (DOC) content was found to range from 0.0105 to 0.65 g C/g waste, with an average of 0.166 g C/g waste. The fraction of DOC that would anaerobically degrade (DOC _f) was reported to range from 50-83%, whereas higher and lower values have been experimentally determined for a variety of waste components, such as wood (0-50%) and food waste (50-75%). Where field validation occurred for the methane correction factor, values were substantially lower than defaults. The fraction of methane in anaerobic landfill gas ( F) default of 50% is almost universally applied and is appropriate for cellulosic wastes. The methane generation rate constant ( k) varied widely from 0.01 to 0.51 y^-1, representing half-lives from 1 to 69 years. Methane oxidation (OX) default values of 0 and 10% may be valid, but values greater than 30% have been reported for porous covers at managed sites. The IPCC protocol is a practical tool with uncertainties and limitations that must be addressed when used for purposes other than developing inventories.

Assessment of applicability index for better management of municipal solid waste: a case study of Dhanbad, India

Selection of suitable municipal solid waste management (MSWM) options is one of the major challenges in urban areas of the developing countries. Success of MSWM requires accurate data of generation rate, composition and physico-chemical characteristics of solid wastes. Improper handling of solid waste can have significant environmental and aesthetical impacts. The present study proposes a new method (applicability index - P_ik values) for identifying the most appropriate disposal option with the help of applicability values of Composting-C_P, Incineration-I_P and Landfill-L_P for individual components of MSW based on the results of the physico-chemical analysis of the collected representative solid waste samples from the study area, Dhanbad, India. The mean values of moisture content, carbon, hydrogen, oxygen, nitrogen, sulfur, volatile organic carbon, fixed carbon, ash content, density and calorific values (CV) of individual components were used as input values in this process. Based on the proposed applicability index (P_ik), the highest P_ik values were obtained for incineration (I_P) for plastics, polythene, paper, coconut shell, wood, cardboard, textile, thermocol (polystyrene), rubber, sugarcane bagasse, cow dung and leather wastes (I_P > C_P > L_P) due to high CV of these solid waste components; the highest P_ik values were obtained for composting (C_P) of kitchen waste (C_P > I_P > L_P); and the highest P_ik values for inert wastes were obtained for landfill option (L_P > I_P > C_P). The highest P_ik value for a particular waste for a specific treatment option signifies that the waste is suitable for treatment/disposal using that option.

Remote sensing of methane and nitrous oxide fluxes from waste incineration

Incomplete combustion processes lead to the formation of many gaseous byproducts that can be challenging to monitor in flue gas released via chimneys. This study presents ground-based remote sensing approaches to make greenhouse gas (GHG) flux measurements of methane (CH₄) and nitrous oxide (N₂O) from a waste incineration chimney at distances of 150-200 m. The study found emission of N₂O (corresponding to 30-40 t yr^-1), which is a consequence of adding the reduction agent urea to decrease NO_X emissions due to NO_X regulation; a procedure that instead increases N₂O emissions (which is approximately 300 times more potent as a GHG than CO₂ on a 100-year time scale). CH₄ emissions of 7-11 t yr^-1 was also detected from the studied chimney despite the usage of a high incineration temperature. For this particular plant, local knowledge is high and emission estimates at corresponding levels have been reported previously. However, emissions of CH₄ are often not included in GHG emission inventories for waste incineration. This study highlights the importance of monitoring combustion processes, and shows the possibility of surveying CH₄ and N₂O emissions from waste incineration at distances of several hundred meters.

Methane emissions from a landfill in north-east India: Performance of various landfill gas emission models

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.

Effects of open dumping of MSW on metal contamination of soil, plants, and earthworms in Ranchi, Jharkhand, India

Influence of open dumping of municipal solid wastes (MSW) on metal contamination of soil, plants, and earthworms in Ranchi, Jharkhand, India, was studied over 6-month period. Dumpsite in the study area exists in two sections, old section where waste dumping has stopped and new section where wastes are currently disposed. Soil around dumpsite had high concentration of Co, Cr, Cu, Pb, and Zn than that at control site. Geoaccumulation index indicated uncontaminated to moderate level of soil contamination at old dumpsite and soil at new dumpsite was found to be uncontaminated. Parthenium hysterophorus, Lantana camara, and Calotropis procera were the main plants found in patchy distribution around dumpsite. Plants exhibited almost similar levels of metal concentration in roots and shoots. P. hysterophorus and L. camara showed high bioaccumulation capacity and low translocation capacity. C. procera showed moderate bioaccumulation capacity and high translocation capacity as the concentration of metals was higher in the shoot. P. hysterophorus and L. camara due to higher bioaccumulation capacity and lower translocation capacity appear to be suitable for phytostabilization of metal-contaminated soil. Earthworms present at the dumpsite showed high concentration of Cr, Cu, Pb, and Zn with bioconcentration factor > 1. Results highlights that soil contamination due to metals is occurring at the dumpsite which is also leading to transfer of metals to plants and earthworms which can pose serious risk to environment and human health. The plants identified can be used for decontamination of metals from the dumpsite.

Quantitative analysis of the methane gas emissions from municipal solid waste in India

Increased emissions of greenhouse gases have altered the global ambient temperature and adversely affected global climatic conditions. The municipal solid waste (MSW) generated by households is considered the third largest anthropogenic source of methane (CH₄) emissions, constituting 11% of all global CH₄ emissions. The current study derived total MSW CH₄ emission estimates using the IPCC default method (DM), modified triangular method (MTM) and first order decay method (FOD). The estimated CH₄ emission was higher for the DM than the other methods, and was comparable to estimates from other studies. This study observed that the net annual emission of CH₄ from landfills in India increased from 404 Gg in 1999–2000 to 990 Gg and 1084 Gg in 2011 and 2015, respectively. We also found that CH₄ emissions were highly correlated (R² = 0.8) with the gross state domestic product (GSDP) of states and the gross domestic product (GDP) of the country, which is an indicator of human well-being. The MSW management policy of India needs to be reviewed in a current policy context, as the management and efficient utilization of MSW technologies might help increase the use of CH₄ as an energy source and thereby improve its sustainable and cost-effective management.

A Framework for Assessing Uncertainty Associated with Human Health Risks from MSW Landfill Leachate Contamination

Landfilling is a cost-effective method, which makes it a widely used practice around the world, especially in developing countries. However, because of the improper management of landfills, high leachate leakage can have adverse impacts on soils, plants, groundwater, aquatic organisms, and, subsequently, human health. A comprehensive survey of the literature finds that the probabilistic quantification of uncertainty based on estimations of the human health risks due to landfill leachate contamination has rarely been reported. Hence, in the present study, the uncertainty about the human health risks from municipal solid waste landfill leachate contamination to children and adults was quantified to investigate its long-term risks by using a Monte Carlo simulation framework for selected heavy metals. The Turbhe sanitary landfill of Navi Mumbai, India, which was commissioned in the recent past, was selected to understand the fate and transport of heavy metals in leachate. A large residential area is located near the site, which makes the risk assessment problem both crucial and challenging. In this article, an integral approach in the form of a framework has been proposed to quantify the uncertainty that is intrinsic to human health risk estimation. A set of nonparametric cubic splines was fitted to identify the nonlinear seasonal trend in leachate quality parameters. LandSim 2.5, a landfill simulator, was used to simulate the landfill activities for various time slices, and further uncertainty in noncarcinogenic human health risk was estimated using a Monte Carlo simulation followed by univariate and multivariate sensitivity analyses.

Management practices and modeling the seasonal variation in health care waste

Purpose

Management of hazardous waste is a big challenge to a common biomedical waste treatment facility (CBWTF) because of variations in the amount of different kinds of waste collected and treated from various health-care facilities (HCFs). Hence, prediction of health-care waste (HCW) will be very helpful for the CBWTF in allocation of resources, transportation, storage and disposal of medical waste (MW). This study aims to focus on the current MW handling and disposal practices at CBWTF in Uttarakhand, India. The study also models the seasonal variation in the HCW quantities collected and treated in CBWTF at Uttarakhand (India).

Design/methodology/approach

Data were collected for two years (2013 and 2014) from CBWTF, and polynomial regression models were used to represent the complex nonlinear relationship among the variables.

Findings

The fixed trends in the waste generated in two years represent the seasonal variations and illness patterns. The load of approximately 527 kg/day biomedical waste, including all the three categories (red, yellow and blue), was estimated at CBWTF at Uttarakhand, India. The composition of the total waste was calculated as: yellow category (327 kg/day, 62.23 per cent), red category (190 kg/day, 36.66 per cent) and blue category (10 kg/day, 1.44 per cent). CBWTF needs to run an incinerator for 3.30 h, autoclaving machine for 4 h and shredder for 20 min daily as per the calculated load.

Research limitations/implications

This study is focused on only one CBWTF in Uttarakhand, so the model needs to be validated considering other facilities.

Practical implications

The model will help the CBWTF to plan its capacity and allocate resources.

Social implications

Infectious waste coming out from HCFs can be managed in a proper way.

Originality/value

This study is the first of its kind conducted for CBWTF, Uttarakhand, India.

Energy production through organic fraction of municipal solid waste-A multiple regression modeling approach

In the 21st century, people migrated from rural to urban areas for several reasons. As a result, the populations of Indian cities are increasing day by day. On one hand, the country is developing in the field of science and technology and on the other hand, it is encountering a serious problem called 'Environmental degradation'. Due to increase in population, the generation of solid waste is also increased and is being disposed in open dumps and landfills which lead to air and land pollution. This study is attempted to generate energy out of organic solid waste by the bio- fermentation process. The study was conducted for a period of 7 months at Erode, Tamilnadu and the reading on various parameters like Hydraulic retention time, organic loading rate, sludge loading rate, influent pH, effluent pH, inlet volatile acids, out let volatile fatty acids, inlet VSS/TS ratio, outlet VSS/TS ratio, influent COD, effluent COD and % of COD removal are recorded for every 10 days. The aim of the present study is to develop a model through multiple linear regression analysis with COD as dependent variable and various parameters like HRT, OLR, SLR, influent, effluent, VSS/TS ratio, influent COD, effluent COD, etc as independent variables and to analyze the impact of these parameters on COD. The results of the model developed through step-wise regression method revealed that only four parameters Influent COD, effluent COD, VSS/TS and Influent/pH were main influencers of COD removal. The parameters influent COD and VSS/TS have positive impact on COD removal and the parameters effluent COD and Influent/pH have negative impact. The parameter Influent COD has the highest order of impact, followed by effluent COD, VSS/TS and influent pH. The other parameters HRT, OLR, SLR, INLET VFA and OUTLET VFA were not significantly contributing to the removal of COD. The implementation of the process suggested through this study might bring in dual benefit to the community, viz treatment of solid waste and creation of energy.

Translating landfill methane generation parameters among first-order decay models

Landfill gas (LFG) generation is predicted by a first-order decay (FOD) equation that incorporates two parameters: a methane generation potential (L₀) and a methane generation rate (k). Because non-hazardous waste landfills may accept many types of waste streams, multiphase models have been developed in an attempt to more accurately predict methane generation from heterogeneous waste streams. The ability of a single-phase FOD model to predict methane generation using weighted-average methane generation parameters and tonnages translated from multiphase models was assessed in two exercises. In the first exercise, waste composition from four Danish landfills represented by low-biodegradable waste streams was modeled in the Afvalzorg Multiphase Model and methane generation was compared to the single-phase Intergovernmental Panel on Climate Change (IPCC) Waste Model and LandGEM. In the second exercise, waste composition represented by IPCC waste components was modeled in the multiphase IPCC and compared to single-phase LandGEM and Australia's Solid Waste Calculator (SWC). In both cases, weight-averaging of methane generation parameters from waste composition data in single-phase models was effective in predicting cumulative methane generation from -7% to +6% of the multiphase models. The results underscore the understanding that multiphase models will not necessarily improve LFG generation prediction because the uncertainty of the method rests largely within the input parameters. A unique method of calculating the methane generation rate constant by mass of anaerobically degradable carbon was presented (k_c) and compared to existing methods, providing a better fit in 3 of 8 scenarios. Generally, single phase models with weighted-average inputs can accurately predict methane generation from multiple waste streams with varied characteristics; weighted averages should therefore be used instead of regional default values when comparing models.

IMPLICATIONS

Translating multiphase first-order decay model input parameters by weighted average shows that single-phase models can predict cumulative methane generation within the level of uncertainty of many of the input parameters as defined by the Intergovernmental Panel on Climate Change (IPCC), which indicates that decreasing the uncertainty of the input parameters will make the model more accurate rather than adding multiple phases or input parameters.

Characterization of municipal solid waste in high-altitude sub-tropical regions

Solid waste management (SWM) is one of the most challenging issues owing to lack of authentic data on different elements of SWM, namely, storage, collection, transportation, separation, processing and disposal. This study presents an assessment of existing status of SWM in conjunction with municipal solid waste (MSW) generation rates, physical and chemical characterization of MSW in high-altitude sub-tropical regions. Weighing of empty and fully loaded trucks per trip revealed total quantity of MSW collected. The average efficiency of MSW collection was 70%. From the baseline data, it is inferred that the population and MSW generation rates are not co-related. The collected MSW included biodegradables (organic wastes), paper, plastic, glass, ceramics, metals, inert materials, ash and debris. The data analysis indicated that the biodegradable components dominate the characterization at 54.83% followed by inert, ash and debris at 21.06%, paper at 8.77%, plastic at 8.18%, glass and ceramics at 4.45% and metals at 2.71%. Statistical measures were also applied and 90% confidence interval (CI) was generated for the characterization data measuring its statistical significance.

A framework for assessment and characterisation of municipal solid waste landfill leachate: an application to the Turbhe landfill, Navi Mumbai, India

Rapid industrialisation, growing population and changing lifestyles are the root causes for the generation of huge amounts of solid waste in developing countries. In India, disposal of municipal solid waste (MSW) through open dumping is the most common waste disposal method. Unfortunately, leachate generation from landfill is high due to the prolonged and prominent monsoon season in India. As leachate generation rate is high in most of the tropical countries, long-term and extensive monitoring efforts are expected to evaluate actual environmental pollution potential due to leachate contamination. However, the leachate characterisation involves a comprehensive process, which has numerous shortcomings and uncertainties possibly due to the complex nature of landfilling process, heterogeneous waste characteristics, widely varying hydrologic conditions and selection of analytes. In order to develop a sustainable MSW management strategy for protecting the surface and ground water resources, particularly from MSW landfill leachate contamination, assessment and characterisation of leachate are necessary. Numerous studies have been conducted in the past to characterise leachate quality from various municipal landfills; unfortunately, none of these propose a framework or protocol. The present study proposes a generic framework for municipal landfill leachate assessment and characterisation. The proposed framework can be applied to design any type of landfill leachate quality monitoring programme and also to facilitate improved leachate treatment activities. A landfill site located at Turbhe, Navi Mumbai, India, which had not been investigated earlier, has been selected as a case study. The proposed framework has been demonstrated on the Turbhe landfill site which is a comparatively new and the only sanitary landfill in Navi Mumbai.

Greenhouse gas emissions estimation from proposed El Fukhary Landfill in the Gaza Strip

Landfills throughout the world are contributing to the global warming problem. This is due to the existence of the most important greenhouse gases (GHG) in landfill gas (LFG); namely, methane (CH4) and carbon dioxide (CO2). The aim of this paper is quantifying the total potential emissions, as well as the variation in production with time of CH4 from a proposed landfill (El Fukhary landfill) in the Gaza Strip, Palestine. Two different methods were adopted in order to quantify the total potential CH4 emissions; the Default methodology based on the intergovernmental panel on climate change (IPCC) 1996 revised guidelines and the Landfill Gas Emissions model (LandGEM V3.02) provided by the United States Environmental Protection Agency (EPA). The second objective of the study has been accomplished using the Triangle gas production model. The results obtained from both Default and LandGEM methods were found to be nearly the same. For 25 years of disposing MSW, El Fukhary landfill expected to have potential CH4 emissions of 1.9542 ± 0.0037 ×109 m3. Triangle model showed that the peak production in term of CH4 would occur in 2043; 28 years beyond the open year. Moreover, the model shows that 50 % of the gas will be produced approximately at the middle of the total duration of gas production. Proper control of Methane emissions from El Fukhary landfill is highly suggested in order to reduce the harmful effects on the environment.

IMPLICATIONS

Although, GHG emissions are extensively discussed in the developed countries throughout the world, it has gained little concern in the developing countries because they are forced most of the time to put environmental concerns at the end of their priority list. The paper shows that developing countries have to start recognizing their fault and change their way of dealing with environmental issues especially GHG emissions (mainly Methane and carbon dioxide). The authors estimated the potential methane emissions from a proposed central landfill that has been approved to be built in Palestine, a country that is classified as a developing country.

Impact of socioeconomic status on municipal solid waste generation rate

The solid waste generation rate was expected to vary in different socioeconomic groups due to many environmental and social factors. This paper reports the assessment of solid waste generation based on different socioeconomic parameters like education, occupation, income of the family, number of family members etc. A questionnaire survey was conducted in the study area to identify the different socioeconomic groups that may affect the solid waste generation rate and composition. The average waste generated in the municipality is 0.41 kg/capita/day in which the maximum waste was found to be generated by lower middle socioeconomic group (LMSEG) with average waste generation of 0.46 kg/capita/day. Waste characterization indicated that there was no much difference in the composition of wastes among different socioeconomic groups except ash residue and plastic. Ash residue is found to increase as we move lower down the socioeconomic groups with maximum (31%) in lower socioeconomic group (LSEG). The study area is a coal based city hence application of coal and wood as fuel for cooking in the lower socioeconomic group is the reason for high amount of ash content. Plastic waste is maximum (15%) in higher socioeconomic group (HSEG) and minimum (1%) in LSEG. Food waste is a major component of generated waste in almost every socioeconomic group with maximum (38%) in case of HSEG and minimum (28%) in LSEG. This study provides new insights on the role of various socioeconomic parameters on generation of household wastes.

Atmospheric polychlorinated biphenyls in Indian cities: levels, emission sources and toxicity equivalents

Atmospheric concentration of Polychlorinated biphenyls (PCBs) were measured on diurnal basis by active air sampling during Dec 2006 to Feb 2007 in seven major cities from the northern (New Delhi and Agra), eastern (Kolkata), western (Mumbai and Goa) and southern (Chennai and Bangalore) parts of India. Average concentration of Σ25PCBs in the Indian atmosphere was 4460 (± 2200) pg/m(-3) with a dominance of congeners with 4-7 chlorine atoms. Model results (HYSPLIT, FLEXPART) indicate that the source areas are likely confined to local or regional proximity. Results from the FLEXPART model show that existing emission inventories cannot explain the high concentrations observed for PCB-28. Electronic waste, ship breaking activities and dumped solid waste are attributed as the possible sources of PCBs in India. Σ25PCB concentrations for each city showed significant linear correlation with Toxicity equivalence (TEQ) and Neurotoxic equivalence (NEQ) values.

Review of past research and proposed action plan for landfill gas-to-energy applications in India

Open dumps employed for disposal of municipal solid waste (MSW) are generally referred to as landfills and have been traditionally used as the ultimate disposal method in India. The deposition of MSW in open dumps eventually leads to uncontrolled emission of landfill gas (LFG). This article reviews the MSW disposal practices and LFG emissions from landfills in India during the period 1994 to 2011. The worldwide trend of feasibility of LFG to energy recovery projects and recent studies in India indicate a changed perception of landfills as a source of energy. However, facilitating the implementation of LFG to energy involves a number of challenges in terms of technology, developing a standardized framework and availability of financial incentives. The legislative framework for promotion of LFG to energy projects in India has been reviewed and a comprehensive strategy and action plan for gainful LFG recovery is suggested. It is concluded that the market for LFG to energy projects is not mature in India. There are no on-ground case studies to demonstrate the feasibility of LFG to energy applications. Future research therefore should aim at LFG emission modeling studies at regional level and based on the results, pilot studies may be conducted for the potential sites in the country to establish LFG to energy recovery potential from these landfills.

Emission assessment at the Burj Hammoud inactive municipal landfill: viability of landfill gas recovery under the clean development mechanism

This paper examines landfill gas (LFG) emissions at a large inactive waste disposal site to evaluate the viability of investment in LFG recovery through the clean development mechanism (CDM) initiative. For this purpose, field measurements of LFG emissions were conducted and the data were processed by geospatial interpolation to estimate an equivalent site emission rate which was used to calibrate and apply two LFG prediction models to forecast LFG emissions at the site. The mean CH(4) flux values calculated through tessellation, inverse distance weighing and kriging were 0.188±0.014, 0.224±0.012 and 0.237±0.008 l CH(4)/m(2) hr, respectively, compared to an arithmetic mean of 0.24 l/m(2) hr. The flux values are within the reported range for closed landfills (0.06-0.89 l/m(2) hr), and lower than the reported range for active landfills (0.42-2.46 l/m(2) hr). Simulation results matched field measurements for low methane generation potential (L(0)) values in the range of 19.8-102.6 m(3)/ton of waste. LFG generation dropped rapidly to half its peak level only 4 yrs after landfill closure limiting the sustainability of LFG recovery systems in similar contexts and raising into doubt promoted CDM initiatives for similar waste.

Framework for life cycle sustainability assessment of municipal solid waste management systems with an application to a case study in Thailand

At present, there are many environmental, economic and social problems associated with poor municipal solid waste (MSW) management in Thailand. The development of sustainable solid waste management systems is a crucial aspect and should be based on an integrated approach. Therefore, an integrated system was designed for Nonthaburi Municipality incorporating recycling, anaerobic digestion, incineration and landfill technologies. In order to assess sustainability, a clear methodology was developed via life cycle thinking and a set of endpoint composite indicators has been proposed considering the most critical ultimate damages/effects of MSW management on the environment, the economy and society. The results showed that the appropriate integration of technologies offers important prospects with regards to socio-economic and environmental aspects, contributing, therefore, to improved sustainability for the overall MSW management system. The methodology and the proposed indicators would be useful in strategic planning, including decision- and policy-making with respect to the development of appropriate sustainable MSW management systems.