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

Including an odor impact potential in life cycle assessment of waste treatment plants

Odors occupy a leading position among air quality issues of growing concern. Odors can be emitted from different economic sectors, from industrial to agricultural, including waste treatment activities. Although there are different techniques to determine odor emissions, a standardized indicator has not still been defined to include odor impact into methodological tools such as Life Cycle Assessment. In this sense, some proposals can be found in current literature. Considering these approaches, the present work proposes the Odor Impact Potential, an indicator to be used in Life Cycle Assessment or in waste treatment technologies benchmarking. A simple method is reported to calculate the Odor Impact Potential value from different types of data: chemical analysis of odorants or olfactometric determinations. Data obtained in a previous work for an industrial scale anaerobic digestion plant have been used to present an example of application. Additional Odor Impact Potential calculations from other published data (thermal waste treatment plant and wastewater treatment plant) are also included. The aim of Odor Impact Potential is not to replace parameters such as odor emission rates, odor concentration, or odor emission factors but to use those values to calculate the odor-derived impact in Life Cycle Assessment studies

Recovery of organic wastes in the Spanish wine industry : technical, economic and environmental analyses of the composting process

The main organic wastes produced in modern wine industries include grape pomace (62%), lees (14%), stalk (12%) and dewatered sludge (12%). Some of these wastes are being used as by-products (grape pomace and lees) whereas the rest of organic wastes (stalk and wastewater sludge) has been traditionally incinerated or disposed in landfill. In this work, composting is proposed for the recovery of stalk and wastewater sludge to produce a sanitized organic amendment for application in the vineyard, closing the organic matter cycle. The environmental and economical analyses of the different alternatives to manage organic wastes from the wine industry are also presented. Composting costs are almost negligible when compared to other management options. From the environmental point of view, in-situ composting presents the best performance in 8 of the 10 impact categories analysed. Finally, the energy balance shows that the 4 composting systems involved less energy than the systems based on Mineral Fertilizer consumption

Determination of the energy and environmental burdens associated to the biological treatment of source-separated municipal solid wastes

Environmental burdens of four different full-scale facilities treating source-separated organic fraction of Municipal Solid Wastes (OFMSW) have been experimentally evaluated. The studied facilities include different composting technologies and also anaerobic digestion plus composting. Home composting, as an alternative to OFMSW management, was also included in the study. Energy (electricity and diesel), water consumption and emissions of volatile organic compounds (VOC), ammonia, methane and nitrous oxide have been measured for each process. Energy consumption ranged between 235 and 870 MJ Mg OFMSW⁻¹ while the emissions of the different contaminants considered per Mg OFMSW were in the range of 0.36-8.9 kg VOC, 0.23-8.63 kg NH₃, 0.34-4.37 kg CH₄ and 0.035-0.251 kg N₂O, respectively. Environmental burdens of each facility are also analyzed from the point of view of process efficiency (i.e. organic matter stabilization degree achieved, calculated as the reduction of the Dynamic Respiration Index (DRI) of the waste treated). This study is performed through two new indices: Respiration Index Efficiency (RIE), which includes the reduction in the DRI achieved by the treatment process and Quality and Respiration Index Efficiency (QRIE), which also includes the quality of the end product. Finally, a Life Cycle Assessment is performed using the Respiration Index Efficiency (RIE) as the novel functional unit instead of the classical LCA approach based on the total mass treated

Towards the implementation of new regional biowaste management plans : environmental assessment of different waste management scenarios in Catalonia

In the present work, different scenarios for the treatment of the organic fraction of municipal waste at regional scale are proposed and assessed by means of LCA. The geographical area under study is Catalonia (Spain). The current Catalan waste management scenario treating 1218 Gg of organic waste is analyzed and compared to a new scenario treating the same amount of waste but fulfilling the European Landfill Directive and the new recently approved Catalan waste management plan. As final disposal (incineration and sanitary landfill) of untreated municipal solid waste is not permitted, the new scenario includes increasing anaerobic digestion treatment of source selected organic fraction of municipal solid waste while maintaining the existing composting plants for this type of waste. Gaseous emissions treatment equipment will be provided when not installed in composting plants. Home composting is also included. Non-source selected organic fraction of municipal solid waste will be treated by composting. Different scenarios for sensitivity analysis have also been proposed dealing with the influence of transport, fugitive methane emissions from anaerobic digestion plants and the use of compost among other issues. The new scenario proposed decreases the impact in five out of the six impact categories studied (from a 49% in eutrophication potential to a 9% in ozone depletion potential). The inclusion of methane fugitive emissions in anaerobic digestion installations in impacts calculation impairs the environmental benefits of this type of treatment facilities (increasing global warming potential value up to a 31%). Improvement of landfill gas collection is of utmost importance in decreasing global warming potential

Environmental impact analysis at full-scale OFMSW biological treatment plants : focus on gaseous emissions /

Descripció del recurs: el 02 de novembre de 2010En les darreres dècades el tractament dels residus municipals mitjançant l'ús de sistemes de tractament biològic com el compostatge i la digestió anaeròbica, s'ha estès àmpliament a nivell Europeu com alternativa a l'ús dels abocadors. Tot i això, aquest tipus de tractaments estan relacionats amb una sèrie d'aspectes ambientals positius i negatius que caldria estudiar. En aquesta línia, l'objectiu d'aquesta Tesi sorgeix de l'interès relacionat amb l'estudi dels impactes ambientals procedents del tractament de la Fracció Orgànica dels Residus Municipals (FORM) en plantes reals representatives a Catalunya. Les plantes seleccionades, que utilitzen diferents tecnologies (compostatge en piles voltejades, compostatge en túnels, compostatge en piles confinades i digestió anaeròbica més compostatge), s'han estudiat mitjançant l'eina d'anàlisi del cicle de vida (ACV). Per obtenir els valors presentats en aquest treball es va haver de desenvolupar una metodologia i uns procediments analítics específics. L'estudi es va enfocar principalment cap a l'anàlisi de les emissions d'amoníac, compostos orgànics volàtils (COV) i dels fluxos de materials en de les plantes avaluades. Els resultats obtinguts proporcionen dades reals d'emissions gasoses i els seus corresponents impactes ambientals de plantes reals de tractament biològic a escala industrial actualment en funcionament a Catalunya. D'altra banda, és important destacar que una part de les anàlisis presentades en aquesta Tesi es van dur a terme en col·laboració amb el grup d'investigació RICICLA de la Università degli Studi di Milano (Itàlia) com a part d'una estada de recerca on es va analitzar l'impacte ambiental produït per les emissions gasoses en instal·lacions industrials de tractament biològic de FORM, però en aquest cas enfocat principalment a l'impacte per males olors. Aquesta Tesi representa l'inici d'una nova línia d'estudi en el Grup d'Investigació en Compostatge del Departament d'Enginyeria Química de la Universitat Autònoma de Barcelona en la determinació d'emissions gasoses i identificació d'impactes ambientals en plantes de tractament biològic a escala industrial. Aquest projecte, iniciat l'any 2005, va ser desenvolupat en cooperació amb l'Agència de Residus de Catalunya (ARC) que el va finançar. L'Agència també va facilitar l'accés a les instal·lacions analitzades en aquesta Tesi

Including an odor impact potential in life cycle assessment of waste treatment plants

Odors occupy a leading position among air quality issues of growing concern. Odors can be emitted from different economic sectors, from industrial to agricultural, including waste treatment activities. Although there are different techniques to determine odor emissions, a standardized indicator has not still been defined to include odor impact into methodological tools such as Life Cycle Assessment. In this sense, some proposals can be found in current literature. Considering these approaches, the present work proposes the Odor Impact Potential, an indicator to be used in Life Cycle Assessment or in waste treatment technologies benchmarking. A simple method is reported to calculate the Odor Impact Potential value from different types of data: chemical analysis of odorants or olfactometric determinations. Data obtained in a previous work for an industrial scale anaerobic digestion plant have been used to present an example of application. Additional Odor Impact Potential calculations from other published data (thermal waste treatment plant and wastewater treatment plant) are also included. The aim of Odor Impact Potential is not to replace parameters such as odor emission rates, odor concentration, or odor emission factors but to use those values to calculate the odor-derived impact in Life Cycle Assessment studies

Environmental impact of two aerobic composting technologies using life cycle assessment

Background, aim, and scope: composting is a viable technology to treat the organic fraction of municipal solid waste (OFMSW) because it stabilizes biodegradable organic matter and contributes to reduce the quantity of municipal solid waste to be incinerated or land-filled. However, the composting process generates environmental impacts such as atmospheric emissions and resources consumption that should be studied. This work presents the inventory data and the study of the environmental impact of two real composting plants using different technologies, tunnels (CT) and confined windrows (CCW). - Materials and methods: inventory data of the two composting facilities studied were obtained from field measurements and from plant managers. Next, life cycle assessment (LCA) methodology was used to calculate the environmental impacts. Composting facilities were located in Catalonia (Spain) and were evaluated during 2007. Both studied plants treat source separated organic fraction of municipal solid waste. In both installations the analysis includes environmental impact from fuel, water, and electricity consumption and the main gaseous emissions from the composting process itself (ammonia and volatile organic compounds). - Results and discussion: inventory analysis permitted the calculation of different ratios corresponding to resources consumption or plant performance and process yield with respect to 1 t of OFMSW. Among them, it can be highlighted that in both studied plants total energy consumption necessary to treat the OFMSW and transform it into compost was between 130 and 160 kWh/t OFMSW. Environmental impact was evaluated in terms of global warming potential (around 60 kg CO₂/t OFMSW for both plants), acidification potential (7.13 and 3.69 kg SO₂ eq/t OFMSW for CT and CCW plant respectively), photochemical oxidation potential (0.1 and 3.11 kg C₂H₄ eq/t OFMSW for CT and CCW plant, respectively), eutrophication (1.51 and 0.77 kg PO3−4/t OFMSW for CT and CCW plant, respectively), human toxicity (around 15 kg 1,4-DB eq/t OFMSW for both plants) and ozone layer depletion (1.66 × 10⁻⁵ and 2.77 × 10⁻⁵ kg CFC−11 eq/t OFMSW for CT and CCW plant, respectively). - Conclusions: this work reflects that the life cycle perspective is a useful tool to analyze a composting process since it permits the comparison among different technologies. According to our results total energy consumption required for composting OFMSW is dependent on the technology used (ranging from 130 to 160 kWh/t OFMSW) as water consumption is (from 0.02 to 0.33 m3 of water/t OFMSW). Gaseous emissions from the composting process represent the main contribution to eutrophication, acidification and photochemical oxidation potentials, while those contributions related to energy consumption are the principal responsible for global warming. Recommendations and perspectives: this work provides the evaluation of environmental impacts of two composting technologies that can be useful for its application to composting plants with similar characteristics. In addition, this study can also be part of future works to compare composting with other OFMSW treatments from a LCA perspective. Likewise, the results can be used for the elaboration of a greenhouse gasses emissions inventory in Catalonia and Spain

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