CH4 and N2O from mechanically turned windrow and vermicomposting systems following in-vessel pre-treatment

Methane (CH4) and nitrous oxide (N2O) are included in the six greenhouse gases listed in the Kyoto protocol that require emission reduction. To meet reduced emission targets, governments need to first quantify their contribution to global warming. Composting has been identified as an important source of CH4 and N2O. With increasing divergence of biodegradable waste from landfill into the composting sector, it is important to quantify emissions of CH4 and N2O from all forms of composting and from all stages. This study focuses on the final phase of a two stage composting process and compares the generation and emission of CH4 and N2O associated with two differing composting methods: mechanically turned windrow and vermicomposting. The first stage was in-vessel pre-treatment. Source-segregated household waste was first pre-composted for seven days using an in-vessel system. The second stage of composting involved forming half of the pre-composted material into a windrow and applying half to vermicomposting beds. The duration of this stage was 85 days and CH4 and N2O emissions were monitored throughout for both systems. Waste samples were regularly subjected to respirometry analysis and both processes were found to be equally effective at stabilising the organic matter content. The mechanically turned windrow system was characterised by emissions of CH4 and to a much lesser extent N2O. However, the vermicomposting system emitted significant fluxes of N2O and only trace amounts of CH4. In-vessel pre-treatment removed considerable amounts of available C and N prior to the second stage of composting. This had the effect of reducing emissions of CH4 and N2O from the second stage compared to emissions from fresh waste found in other studies. The characteristics of each of the two composting processes are discussed in detail. Very different mechanisms for emission of CH4 and N2O are proposed for each system. For the windrow system, development of anaerobic zones were thought to be responsible for CH4 release. High N2O emission rates from vermicomposting were ascribed to strongly nitrifying conditions in the processing beds combined with the presence of de-nitrifying bacteria within the worm gut.     

Mitigation of global greenhouse gas emissions from waste: conclusions and strategies from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report. Working Group III (Mitigation).

Greenhouse gas (GHG) emissions from post-consumer waste and wastewater are a small contributor (about 3%) to total global anthropogenic GHG emissions. Emissions for 2004-2005 totalled 1.4 Gt CO2-eq year(-1) relative to total emissions from all sectors of 49 Gt CO2-eq year(-1) [including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and F-gases normalized according to their 100-year global warming potentials (GWP)]. The CH4 from landfills and wastewater collectively accounted for about 90% of waste sector emissions, or about 18% of global anthropogenic methane emissions (which were about 14% of the global total in 2004). Wastewater N2O and CO2 from the incineration of waste containing fossil carbon (plastics; synthetic textiles) are minor sources. Due to the wide range of mature technologies that can mitigate GHG emissions from waste and provide public health, environmental protection, and sustainable development co-benefits, existing waste management practices can provide effective mitigation of GHG emissions from this sector. Current mitigation technologies include landfill gas recovery, improved landfill practices, and engineered wastewater management. In addition, significant GHG generation is avoided through controlled composting, state-of-the-art incineration, and expanded sanitation coverage. Reduced waste generation and the exploitation of energy from waste (landfill gas, incineration, anaerobic digester biogas) produce an indirect reduction of GHG emissions through the conservation of raw materials, improved energy and resource efficiency, and fossil fuel avoidance. Flexible strategies and financial incentives can expand waste management options to achieve GHG mitigation goals; local technology decisions are influenced by a variety of factors such as waste quantity and characteristics, cost and financing issues, infrastructure requirements including available land area, collection and transport considerations, and regulatory constraints. Existing studies on mitigation potentials and costs for the waste sector tend to focus on landfill CH4 as the baseline. The commercial recovery of landfill CH4 as a source of renewable energy has been practised at full scale since 1975 and currently exceeds 105 Mt CO2-eq year(-1). Although landfill CH4 emissions from developed countries have been largely stabilized, emissions from developing countries are increasing as more controlled (anaerobic) landfilling practices are implemented; these emissions could be reduced by accelerating the introduction of engineered gas recovery, increasing rates of waste minimization and recycling, and implementing alternative waste management strategies provided they are affordable, effective, and sustainable. Aided by Kyoto mechanisms such as the Clean Development Mechanism (CDM) and Joint Implementation (JI), the total global economic mitigation potential for reducing waste sector emissions in 2030 is estimated to be > 1000 Mt CO2-eq (or 70% of estimated emissions) at costs below 100 US$ t(-1) CO2-eq year(-1). An estimated 20-30% of projected emissions for 2030 can be reduced at negative cost and 30-50% at costs < 20 US$ t(-) CO2-eq year(-1). As landfills produce CH4 for several decades, incineration and composting are complementary mitigation measures to landfill gas recovery in the short- to medium-term--at the present time, there are > 130 Mt waste year(-1) incinerated at more than 600 plants. Current uncertainties with respect to emissions and mitigation potentials could be reduced by more consistent national definitions, coordinated international data collection, standardized data analysis, field validation of models, and consistent application of life-cycle assessment tools inclusive of fossil fuel offsets.     

Greenhouse gas emissions from home composting of organic household waste

The emission of greenhouse gases (GHGs) is a potential environmental disadvantage of home composting. Because of a lack of reliable GHG emission data, a comprehensive experimental home composting system was set up. The system consisted of six composting units, and a static flux chamber method was used to measure and quantify the GHG emissions for one year composting of organic household waste (OHW). The average OHW input in the six composting units was 2.6–3.5 kg week^?1 and the temperature inside the composting units was in all cases only a few degrees (2–10 °C) higher than the ambient temperature. The emissions of methane (CH₄) and nitrous oxide (N₂O) were quantified as 0.4–4.2 kg CH₄ Mg^?1 input wet waste (ww) and 0.30–0.55 kg N₂O Mg^?1 ww, depending on the mixing frequency. This corresponds to emission factors (EFs) (including only CH₄ and N₂O emissions) of 100–239 kg CO₂-eq. Mg^?1 ww. Composting units exposed to weekly mixing had the highest EFs, whereas the units with no mixing during the entire year had the lowest emissions. In addition to the higher emission from the frequently mixed units, there was also an instant release of CH₄ during mixing which was estimated to 8–12% of the total CH₄ emissions. Experiments with higher loads of OHW (up to 20 kg every fortnight) entailed a higher emission and significantly increased overall EFs (in kg substance per Mg^?1 ww). However, the temperature development did not change significantly. The GHG emissions (in kg CO₂-eq. Mg^?1 ww) from home composting of OHW were found to be in the same order of magnitude as for centralised composting plants.     

Mass balances and life cycle inventory of home composting of organic waste

A comprehensive experimental setup with six single-family home composting units was monitored during 1 year. The composting units were fed with 2.6-3.5 kg organic household waste (OHW) per unit per week. All relevant consumptions and emissions of environmental relevance were addressed and a full life-cycle inventory (LCI) was established for the six home composting units. No water, electricity or fuel was used during composting, so the major environmental burdens were gaseous emissions to air and emissions via leachate. The loss of carbon (C) during composting was 63-77% in the six composting units. The carbon dioxide (CO(2)) and methane (CH(4)) emissions made up 51-95% and 0.3-3.9% respectively of the lost C. The total loss of nitrogen (N) during composting was 51-68% and the nitrous oxide (N(2)O) made up 2.8-6.3% of this loss. The NH(3) losses were very uncertain but small. The amount of leachate was 130 L Mg(-1) wet waste (ww) and the composition was similar to other leachate compositions from home composting (and centralised composting) reported in literature. The loss of heavy metals via leachate was negligible and the loss of C and N via leachate was very low (0.3-0.6% of the total loss of C and 1.3-3.0% of the total emitted N). Also the compost composition was within the typical ranges reported previously for home composting. The level of heavy metals in the compost produced was below all threshold values and the compost was thus suitable for use in private gardens.     

Greenhouse gas emission reduction and environmental quality improvement from implementation of aerobic waste treatment systems in swine farms

Trading of greenhouse gas (GHG) emission reductions is an attractive approach to help producers implement cleaner treatment technologies to replace current anaerobic lagoons. Our objectives were to estimate greenhouse gas (GHG) emission reductions from implementation of aerobic technology in USA swine farms. Emission reductions were calculated using the approved United Nations framework convention on climate change (UNFCCC) methodology in conjunction with monitoring information collected during full-scale demonstration of the new treatment system in a 4360-head swine operation in North Carolina (USA). Emission sources for the project and baseline manure management system were methane (CH4) emissions from the decomposition of manure under anaerobic conditions and nitrous oxide (N2O) emissions during storage and handling of manure in the manure management system. Emission reductions resulted from the difference between total project and baseline emissions. The project activity included an on-farm wastewater treatment system consisting of liquid-solid separation, treatment of the separated liquid using aerobic biological N removal, chemical disinfection and soluble P removal using lime. The project activity was completed with a centralized facility that used aerobic composting to process the separated solids. Replacement of the lagoon technology with the cleaner aerobic technology reduced GHG emissions 96.9%, from 4972 tonnes of carbon dioxide equivalents (CO2-eq) to 153 tonnes CO2-eq/year. Total net emission reductions by the project activity in the 4360-head finishing operation were 4776.6 tonnes CO2-eq per year or 1.10 tonnes CO2-eq/head per year. The dollar value from implementation of this project in this swine farm was US$19,106/year using current Chicago Climate Exchange trading values of US$4/t CO2. This translates into a direct economic benefit to the producer of US$1.75 per finished pig. Thus, GHG emission reductions and credits can help compensate for the higher installation cost of cleaner aerobic technologies and facilitate producer adoption of environmentally superior technologies to replace current anaerobic lagoons in the USA.     

Role of waste management with regard to climate protection: a case study.

According to the Kyoto Protocol and the burden-sharing agreement of the European Union, Austria is required to cut greenhouse gas (GHG) emissions during the years 2008 to 2012 in order to achieve an average reduction of 13%, based on the level of emissions for the year 1990. The present contribution gives an overview of the history of GHG emission regulation in Austria and identifies the progress made towards the realization of the national climate strategy to attain the GHG emission targets. The contribution uses Austria as an example of the way in which proper waste management can help to reduce GHG emissions. The GHG inventories show that everything must be done to minimize the carbon input due to waste deposition at landfill sites. The incineration of waste is particularly helpful in reducing GHG emissions. The waste-to-energy by incineration plants and recovery of energy yield an ecologically proper treatment of waste using state-of-the-art techniques of a very high standard. The potential for GHG reduction of conventional waste treatment technologies has been estimated by the authors. A growing number of waste incinerators and intensified co-incineration of waste in Austrian industry will both help to reduce national GHG emissions substantially. By increasing the number and capacity of plants for thermal treatment of waste the contribution of proper waste management to the national target for reduction of GHG emissions will be in the range of 8 to 14%. The GHG inventories also indicate that a potential CO2 reduction of about 500 000 t year(-1) is achievable by co-incineration of waste in Austrian industry.     

GHG emission factors developed for the recycling and composting of municipal waste in South African municipalities

GHG (greenhouse gas) emission factors for waste management are increasingly used, but such factors are very scarce for developing countries. This paper shows how such factors have been developed for the recycling of glass, metals (Al and Fe), plastics and paper from municipal solid waste, as well as for the composting of garden refuse in South Africa. The emission factors developed for the different recyclables in the country show savings varying from ?290 kg CO₂ e (glass) to ?19 111 kg CO₂ e (metals – Al) per tonne of recyclable. They also show that there is variability, with energy intensive materials like metals having higher GHG savings in South Africa as compared to other countries. This underlines the interrelation of the waste management system of a country/region with other systems, in particular with energy generation, which in South Africa, is heavily reliant on coal. This study also shows that composting of garden waste is a net GHG emitter, releasing 172 and 186 kg CO₂ e per tonne of wet garden waste for aerated dome composting and turned windrow composting, respectively. The paper concludes that these emission factors are facilitating GHG emissions modelling for waste management in South Africa and enabling local municipalities to identify best practice in this regard.     

Cost effective waste management through composting in Africa

Greenhouse gas (GHG) emissions per person from urban waste management activities are greater in sub-Saharan African countries than in other developing countries, and are increasing as the population becomes more urbanised. Waste from urban areas across Africa is essentially dumped on the ground and there is little control over the resulting gas emissions. The clean development mechanism (CDM), from the 1997 Kyoto Protocol has been the vehicle to initiate projects to control GHG emissions in Africa. However, very few of these projects have been implemented and properly registered. A much more efficient and cost effective way to control GHG emissions from waste is to stabilise the waste via composting and to use the composted material as a soil improver/organic fertiliser or as a component of growing media. Compost can be produced by open windrow or in-vessel composting plants. This paper shows that passively aerated open windrows constitute an appropriate low-cost option for African countries. However, to provide an usable compost material it is recommended that waste is processed through a materials recovery facility (MRF) before being composted. The paper demonstrates that material and biological treatment (MBT) are viable in Africa where they are funded, e.g. CDM. However, they are unlikely to be instigated unless there is a replacement to the Kyoto Protocol, which ceases for Registration in December 2012.     

Determination of nitrous oxide, methane, and ammonia emissions from a swine waste composting process

The amounts of harmful gas emissions from the process of composting swine waste were determined using an experimental composting apparatus. Forced aeration (19.2–96.1 l/m³/min) was carried out continuously, and exhaust gases were collected and analyzed periodically. With weekly turning and the addition of a bulking agent in order to decrease the moisture content and increase air permeability, the temperature of most of the contents rose to 70°C and composting was complete within 3–5 weeks. NH₃, CH₄, and N₂O emissions were high in the early stage of composting. About 10%–25% of the nitrogen in the raw material was lost as NH₃ gas during composting. The emission rate of NH₃ mainly depended on the aeration rate, so that as the aeration rate rose, the level of NH₃ emissions increased. The CH₄ and N₂O emissions could be kept lower with adequate treatment at more than 40 l/m³/min aeration. N₂O may be mainly the result of the denitrification of NO _x -N in the additional matured compost used as a composting accelerator. Received: September 11, 1998 / Accepted: November 8, 1999     

Home composting as an alternative treatment option for organic household waste in Denmark: An environmental assessment using life cycle assessment-modelling

An environmental assessment of the management of organic household waste (OHW) was performed from a life cycle perspective by means of the waste-life cycle assessment (LCA) model EASEWASTE. The focus was on home composting of OHW in Denmark and six different home composting units (with different input and different mixing frequencies) were modelled. In addition, incineration and landfilling was modelled as alternatives to home composting. The most important processes contributing to the environmental impact of home composting were identified as greenhouse gas (GHG) emissions (load) and the avoided emissions in relation to the substitution of fertiliser and peat when compost was used in hobby gardening (saving). The replacement of fertiliser and peat was also identified as one of the most sensible parameters, which could potentially have a significant environmental benefit. Many of the impact categories (especially human toxicity via water (HTw) and soil (HTs)) were affected by the heavy metal contents of the incoming OHW. The concentrations of heavy metals in the compost were below the threshold values for compost used on land and were thus not considered to constitute a problem. The GHG emissions were, on the other hand, dependent on the management of the composting units. The frequently mixed composting units had the highest GHG emissions. The environmental profiles of the home composting scenarios were in the order of −2 to 16 milli person equivalents (mPE) Mg⁻¹ wet waste (ww) for the non-toxic categories and −0.9 to 28 mPE Mg⁻¹ ww for the toxic categories. Home composting performed better than or as good as incineration and landfilling in several of the potential impact categories. One exception was the global warming (GW) category, in which incineration performed better due to the substitution of heat and electricity based on fossil fuels.     

Greenhouse gas emissions from biogenic waste treatment: options and uncertainty

A simplified life cycle assessment was conducted to estimate greenhouse gas (GHG) emissions and energy production from each component of biogenic waste treated in an open dumping site, and by composting, anaerobic digestion, and incineration employed with additional options. The impact of uncertainties and sensitivities of the parameters in the treatment methods were investigated. We conducted a sensitivity analysis to identify the most sensitive parameters, and we discussed the relationship between uncertainty and sensitivity. Our results revealed that the moisture content of food waste and the biomass-derived carbon and methane concentration of the landfill gas of biogenic waste subjected to open dumping are the most sensitive parameters across all the treatment methods. The net GHG emissions from food waste treated in an open dumping site ranged over ten times (0.30 ? 3.67 Gg CO₂ eq/Gg). In addition, by employing additional options for the open dumping site, including soil cover, a landfill gas collection system, shifting to a semi-aerobic condition, and energy conservation by using a gas engine, we found that the net GHG emissions could be reduced by 10, 27.9, 37.4 %, and up to 56.7 %, respectively. Shifting to a semi-aerobic system is the most effective method for reducing GHG emissions, followed by landfill gas collection.     

The impact of municipal solid waste treatment methods on greenhouse gas emissions in Lahore, Pakistan

The contribution of existing municipal solid waste management to emission of greenhouse gases and the alternative scenarios to reduce emissions were analyzed for Data Ganj Bukhsh Town (DGBT) in Lahore, Pakistan using the life cycle assessment methodology. DGBT has a population of 1,624,169 people living in 232,024 dwellings. Total waste generated is 500,000 tons per year with an average per capita rate of 0.84kg per day. Alternative scenarios were developed and evaluated according to the environmental, economic, and social atmosphere of the study area. Solid waste management options considered include the collection and transportation of waste, collection of recyclables with single and mixed material bank container systems (SMBCS, MMBCS), material recovery facilities (MRF), composting, biogasification and landfilling. A life cycle inventory (LCI) of the six scenarios along with the baseline scenario was completed; this helped to quantify the CO2 equivalents, emitted and avoided, for energy consumption, production, fuel consumption, and methane (CH4) emissions. LCI results showed that the contribution of the baseline scenario to the global warming potential as CO2 equivalents was a maximum of 838,116 tons. The sixth scenario had a maximum reduction of GHG emissions in terms of CO2 equivalents of -33,773 tons, but the most workable scenario for the current situation in the study area is scenario 5. It saves 25% in CO2 equivalents compared to the baseline scenario.     

Assessment of the environmental impact of management measures for the biodegradable fraction of municipal solid waste in São Paulo City

There is increasing concern about landfilling of biodegradable wastes. Therefore, biological treatment processes such as composting and biogasification have been considered as alternative strategies for managing those wastes. In this work, life cycle assessment was employed to compare the environmental impacts of landfilling, composting, and biological treatment of municipal solid waste in S?o Paulo City, Brazil. Energy consumption, recovered resources, and emissions to air and water were quantified and analyzed in terms of their potential contribution to global warming, acidification, and nutrient enrichment impact. The results demonstrated that processes that require high levels of energy consumption, such as wastewater treatment, play an important role in the outcome of environmental impact potentials. It was found that the landfilling of all waste is generally the worst strategy from an environmental point of view. However, significant reductions in the resulting impacts can be accomplished through biogasification and composting of the biodegradable fraction. Regarding composting, the application of a biofilter for gas treatment reduced significantly the gaseous emissions.     

The potential environmental gains from recycling waste plastics: Simulation of transferring recycling and recovery technologies to Shenyang, China

With the increasing attention on developing a low-carbon economy, it is necessary to seek appropriate ways on reducing greenhouse gas (GHG) emissions through innovative municipal solid waste management (MSWM), such as urban symbiosis. However, quantitative assessments on the environmental benefits of urban symbiosis, especially in developing countries, are limited because only a limited number of planned synergistic activities have been successful and it is difficult to acquire detailed inventory data from private companies. This paper modifies and applies a two-step simulation system and used it to assess the potential environmental benefits, including the reduction of GHG emissions and saving of fossil fuels, by employing various Japanese plastics recycling/energy-recovery technologies in Shenyang, China. The results showed that among various recycling/energy-recovery technologies, the mechanical waste plastics recycling technology, which produces concrete formwork boards (NF boards), has the greatest potential in terms of reducing GHG emissions (1.66 kg CO₂e/kg plastics), whereas the technology for the production of refuse plastic fuel (RPF) has the greatest potential on saving fossil fuel consumption (0.77 kgce/kg-plastics). Additional benefits can be gained by applying combined technologies that cascade the utilization of waste plastics. Moreover, the development of clean energy in conjunction with the promotion of new waste plastics recycling programs could contribute to additional reductions in GHG emissions and fossil fuel consumption.     

Japan’s greenhouse gas reduction scenarios toward net zero by 2050 in the material cycles and waste management sector

The first draft scenario toward net zero greenhouse gas (GHG) emissions by 2050 for the material cycles and waste management sector was presented by the Ministry of the Environment, Japan in August 2021. The details of the future GHG emission estimation used to create the draft scenario are described in this document. For multiple scenarios where more aggressive measures, such as carbon capture, utilization, and storage (CCUS), were included in addition to business-as-usual and the current policy continuity scenario, future GHG emissions were estimated as the sum of the products of activities and emission factors indicating changes in measures between scenarios. The estimation outcomes demonstrated that future GHG emissions from the solid waste management sector could be anticipated to be zero or even negative when material conversion to biomass, primarily for plastics, recycling to raw materials, and installation of CCUS at incineration facilities are assumed. Extensions of prior plans are not enough to reach the goal of net zero emissions, according to the measures necessary and the volume and pace of their implementation suggested in this study. Stakeholders should collaborate with great ambition.

     

Waste management activities and carbon emissions in Africa

This paper summarizes research into waste management activities and carbon emissions from territories in sub-Saharan Africa with the main objective of quantifying emission reductions (ERs) that can be gained through viable improvements to waste management in Africa. It demonstrates that data on waste and carbon emissions is poor and generally inadequate for prediction models. The paper shows that the amount of waste produced and its composition are linked to national Gross Domestic Product (GDP). Waste production per person is around half that in developed countries with a mean around 230 kg/hd/yr. Sub-Saharan territories produce waste with a biogenic carbon content of around 56% (+/−25%), which is approximately 40% greater than developed countries. This waste is disposed in uncontrolled dumps that produce large amounts of methane gas. Greenhouse gas (GHG) emissions from waste will rise with increasing urbanization and can only be controlled through funding mechanisms from developed countries.     

The use of life cycle assessment for the comparison of biowaste composting at home and full scale

Environmental impacts and gaseous emissions associated to home and industrial composting of the source-separated organic fraction of municipal solid waste have been evaluated using the environmental tool of life cycle assessment (LCA). Experimental data of both scenarios were experimentally collected. The functional unit used was one ton of organic waste. Ammonia, methane and nitrous oxide released from home composting (HC) were more than five times higher than those of industrial composting (IC) but the latter involved within 2 and 53 times more consumption or generation of transport, energy, water, infrastructures, waste and Volatile Organic Compounds (VOCs) emissions than HC. Therefore, results indicated that IC was more impacting than HC for four of the impact categories considered (abiotic depletion, ozone layer depletion, photochemical oxidation and cumulative energy demand) and less impacting for the other three (acidification, eutrophication and global warming). Production of composting bin and gaseous emissions are the main responsible for the HC impacts, whereas for IC the main contributions come from collection and transportation of organic waste, electricity consumption, dumped waste and VOCs emission. These results suggest that HC may be an interesting alternative or complement to IC in low density areas of population.     

Sustainable waste management in Africa through CDM projects

Only few Clean Development Mechanism (CDM) projects (traditionally focussed on landfill gas combustion) have been registered in Africa if compared to similar developing countries. The waste hierarchy adopted by many African countries clearly shows that waste recycling and composting projects are generally the most sustainable. This paper undertakes a sustainability assessment for practical waste treatment and disposal scenarios for Africa and makes recommendations for consideration. The appraisal in this paper demonstrates that mechanical biological treatment of waste becomes more financially attractive if established through the CDM process. Waste will continue to be dumped in Africa with increasing greenhouse gas emissions produced, unless industrialised countries (Annex 1) fund carbon emission reduction schemes through a replacement to the Kyoto Protocol. Such a replacement should calculate all of the direct and indirect carbon emission savings and seek to promote public–private partnerships through a concerted support of the informal sector.     

A methodology to determine gaseous emissions in a composting plant

Environmental impacts associated to different waste treatments are of interest in the decision-making process at local, regional and international level. However, all the environmental burdens of an organic waste biological treatment are not always considered. Real data on gaseous emissions released from full-scale composting plants are difficult to obtain. These emissions are related to the composting technology and waste characteristics and therefore, an exhaustive sampling campaign is necessary to obtain representative and reliable data of a single plant. This work proposes a methodology to systematically determine gaseous emissions of a composting plant and presents the results obtained in the application of this methodology to a plant treating source-separated organic fraction of municipal solid waste (OFMSW) for the determination of ammonia and total volatile organic compounds (VOC). Emission factors from the biological treatment process obtained for ammonia and VOC were 3.9 kg Mg OFMSW⁻¹ and 0.206 kg Mg OFMSW⁻¹ respectively. Emissions associated to energy use and production were also quantified (60.5 kg CO₂ Mg OFMSW⁻¹ and 0.66 kg VOC Mg OFMSW⁻¹). Other relevant parameters such as energy and water consumption and amount of rejected waste were also determined. A new functional unit is presented to relate emission factors to the biodegradation efficiency of the composting process and consists in the reduction of the Respiration Index of the treated material. Using this new functional unit, the atmospheric emissions released from a composting plant are directly related to the plant specific efficiency.     

The estimation of N2O emissions from municipal solid waste incineration facilities: The Korea case

The greenhouse gases (GHGs) generated in municipal solid waste (MSW) incineration are carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). In South Korea case, the total of GHGs from the waste incineration facilities has been increasing at an annual rate 10%. In these view, waste incineration facilities should consider to reduce GHG emissions.This study is designed to estimate the N₂O emission factors from MSW incineration plants, and calculate the N₂O emissions based on these factors. The three MSW incinerators examined in this study were either stoker or both stoker and rotary kiln facilities. The N₂O concentrations from the MSW incinerators were measured using gas chromatography-electron capture detection (GC-ECD) equipment.The average of the N₂O emission factors for the M01 plant, M02 plant, and M03 plant are 71, 75, and 153 g-N₂O/ton-waste, respectively. These results showed a significant difference from the default values of the intergovernmental panel on climate change (IPCC), while approaching those values derived in Japan and Germany. Furthermore, comparing the results of this study to the Korea Energy Economics Institute (KEEI) (2007) data on waste incineration, N₂O emissions from MSW incineration comprised 19% of the total N₂O emissions.