Life cycle assessment of bottom ash management from a municipal solid waste incinerator (MSWI)

Thermal treatment of Municipal Solid Waste (MSW) results in various types of solid wastes, distinguishing mainly bottom, boiler and fly ashes and slag. To minimise waste generation it necessary to carry out primary measures for controlling residue outputs that involve optimising control of the combustion process. Obviously, after primary measures a secondary treatment is required. The conventional bottom ash management is to carry out a solidification process. This solidification or stabilization process produces a material with physical and mechanical properties that promote a reduction in contaminant release from the residue matrix. Solidification methods commonly make use of inorganic binder reagents such as cement, lime and other pozzolanic materials. Once waste is stabilized, it is usually sent to the landfill. However, despite the heavy metal content, it is getting more and more common the use of this waste as a natural aggregate. In particular, it could be used as a raw material for clinker production, cement mortar or frit production. Other possible management options included its utilization as a drainage layer on a landfill and as a sub-base material in a road construction. In this work it was assessed different bottom ash management options. In this work the Life Cycle Assessment (LCA) methodology was applied to assess the environmental impact of different bottom ash management options. Specifically, the conventional ash solidification was compared with the ash recycling in Portland cement production

A case study for environmental impact assessment in the process industry: municipal solid waste incineration (MSWI)

Life Cycle Assessment (LCA) has been introduced in the evaluation of chemical processes and or products in order to take into account the Supply Chain and its environmental constraints and burdens. Regarding to the environmental assessment of chemical processes and/or products two main variables need to be taken into account: Natural Resources Sustainability (NRS) and Environmental Burdens Sustainability (EBS). NRS includes the use of energy, water and materials whereas EBS is given by the environmental sustainability metrics developed by the Institution of Chemical Engineers (IChemE). The main components of EBS have been classified in 5 environmental impacts to the atmosphere (acidification, global warming, human health effects, stratospheric ozone depletion and photochemical ozone formation), 5 aquatic media impacts (aquatic acidification, aquatic oxygen demand, ecotoxicity (metals), ecotoxicity (others) and eutrophication) and 2 land impacts (hazardous and non-hazardous waste disposal). To reduce the number of variables and thus, the complexity, the development of a normalisation and weighting procedure is required. This work proposes the normalization of EB based on the threshold values of the European Pollutant Release and Transfer Register (E-PRTR) and a similar procedure based on the values given by the BREF document on waste incineration for the NRS normalisation. This procedure will help in the decision making process in the waste management field and in the particular, in Municipal Solid Waste Incineration (MSWI)

Superfoods: A super impact on health and the environment?

Given the current trend in superfoods consumption and the forecasts for their growth in the coming years, this article provides an overview of the three sustainability dimensions of the novel market, addressing consumers´ perception from a social and economic perspective, and focusing on their environmental performance. The review highlights the need for regulation and provision of well-designed information for consumers, among whom are segments that currently mistrust their health claims, which are mainly the motivating reason for consumption. On the other hand, the carbon footprint of superfoods production is similar to that of other conventional agri-foods, although distribution from the countries of origin and future changes to intensive and commercially-oriented production systems to meet demand could endanger this column of sustainability.This work was supported by the Spanish Ministry of Science and Innovation through the KAIROS-BIOCIR project (PID2019-104925RB) (AEO/FEDER, UE). Ana Fernández-Ríos thanks the Ministry of Economy and Competitiveness of Spanish Government for their financial support via the research fellowship RE2020-094029

Towards sustainable dietary patterns under a water-energy-food nexus life cycle thinking approach

The big challenge of the next decades is meeting the global nutritional demand, while reducing the pressure on food resources and the GHG emissions. In this regard, the overall goal consists of redesigning the food systems and promoting sustainable dietary patterns is a crucial aspect. This article focuses on reviewing the state-of-the-art of the combined Life Cycle Assessment (LCA) and the Water-Energy-Food (WEF) Nexus approach in assessing the effects of diet transitions. Diet LCAs differ in methodology, design, and assessed environmental impacts. The WEF nexus, which aims at finding synergies and trade-offs between the water, energy, and food resources systems, has been applied to different contexts and levels. However, a limited number of nexus methods have been developed at the food and diet levels, and no commonly recognizable methodology for the nexus assessment has been achieved. An integrated LCA and WEF Nexus approach can be a decisive tool to improve the understanding of the interconnections in the nexus, as it enables the consideration of entire supply chains.This study is part of the Ceres-Procon Project: Food production and consumption strategies for climate change mitigation (CTM2016-76176-C2-2-R) (AEI/FEDER, UE), financed by the Spanish Ministry of Economy and Competitiveness, which aims to determine strategies to improve the sustainability of current food production and consumption

When life cycle thinking is necessary for decision making: emerging cleaner technologies in the chlor-alkali industry

The chlor-alkali industry sector produces chlorine, sodium/potassium hydroxide and hydrogen by the electrolysis of brine. Nowadays, three different electrolysis techniques are applied: mercury, diaphragm, and membrane cell technology. From all these technologies, the European Commission labels the membrane process as the Best Available Technique (BAT) for the chlor-alkali industry. The membrane cell technology has fewer exhausts to the environment and it is relatively more efficient in the use of electric power that mercury and diaphragm. Nevertheless, despite the fact that the overall energy intensity has been reduced, the issue of energy consumption is still a major matter. A promising approach for reducing the electricity demand of chlor-alkali electrolysis is using oxygen-depolarised cathodes (ODC). ODCs are long known and have been successfully used in chlorine production through electrolysis of hydrogen chloride (HCl). The achieved environmental benefit of this technique is a reduction of energy consumption. However, the overall reduction of energy consumption is lower, as some energy is required to produce pure oxygen and because hydrogen is not co-produced, which could otherwise be used in chemical reactions or to produce steam and electricity via combustion or fuel cells. In this sense, the reduced electricity demand does not necessarily imply cleaner chlorine production. For that reason, this work proposes the use of the life cycle assessment (LCA) methodology to determine the environmental performance of the existing electrolysis technologies and to compare it with the ODC technique

Product vs corporate carbon footprint: A case study for the spirit drinks sectors

The use of Life Cycle Assessment (LCA) has become a common mechanism to evaluate and report the environmental performance of services and products due to its holistic approach and for its standardised method which guaranteeing reproducibility. There is a huge ongoing effort to improve and promote the use of LCA in Europe, by means of the Single Market of Green Products Initiative, which promotes the use of the Product Environmental Footprint (PEF) and the Organisation Environmental Footprint (OEF). Although LCA has been applied in a great variety of industries, there is an even higher worldwide trend of simplification focussing on a single indicator, carbon footprint (CF), relevant to global warming, which is internationally considered as a critical environmental concern. The scope of the CF assessment could be corporate (when all production processes of a company are evaluated) or product (when one of the products is evaluated throughout its life cycle). However, sometimes product CF studies collect corporate data, since for most companies it is easier to report global annual consumptions and emissions instead of the product's specific inputs and outputs. In this framework, this study aims to apply and compare the product and corporate CF methodologies to the case study of the spirit drinks sector in Cantabria (Northern Spain). In particular, to a SME dedicated to the artisanal elaboration of premium spirit drinks such as gin and vodka. The value obtained of the Product Carbon Footprint (PCF) was 0.57 kg CO2 eq. for a bottle (70 cl) of classic gin whereas the Corporate Carbon Footprint (CCF) presented a value of 4.58×103 kg CO2 eq. for Scope 2 and 5.58×104 kg CO2 eq. for Scope 3 in the year 2017. The results indicated that significant environmental impacts were caused during the production of the glass bottle as well as the production of the electricity required in the beverage company

Environmental challenges of the chlor-alkali production: Seeking answers from a life cycle approach

Life Cycle Assessment (LCA) has been used to assess the environmental sustainability of the chlor-alkali production in Europe. The three current technologies applied nowadays are mercury, diaphragm, and membrane cell technology. Despite, having achieved higher energy efficiencies since the introduction of membrane technology, energy consumption is still one of the most important issues in this sector. An emerging technology namely oxygen-depolarised cathodes (ODC) is suggested as a promising approach for reducing the electrolysis energy demand. However, its requirement of pure oxygen and the lack of production of hydrogen, which could otherwise be valorised, are controversial features for greener chlorine production. The aim of this work is to evaluate and compare the environmental profiles of the current and emerging technologies for chlorine production and to identify the main hot spots of the process. Salt mining, brine preparation, electrolysis technology and products treatment are included inside the system boundaries. Twelve environmental impact categories grouped into natural resources usage and environmental burdens are assessed from cradle to gate and further normalised and weighted. Furthermore, hydrogen valorisation, current density and allocation procedure are subjected to sensitivity analysis. Results show that the electrolysis stage is the main contributor to the environmental impacts due to energy consumption, causing 99.5–72% of these impacts. Mercury is the less environmentally sustainable technology, closely followed by diaphragm. This difference becomes bigger after normalisation, owing to hazardous waste generated by mercury technique. Conversely, best results are obtained for ODC instead of membrane scenario, although the reduction in energy requirements is lesser than expected (7%).This work was funded by the Spanish Ministry of Economy and Competitiveness (MINECO) project CTM2013-43539-R. The authors are grateful for this funding

Techno-economic and environmental assessment of methane oxidation layer measures through small-scale clean development mechanism - The case of the Seychelles

Unclosed coastal landfills in small island developing states are major sources of greenhouse gases and other environmental impacts. This is a major problem for sustainable waste management systems mainly due to the lack of economic resources. The clean development mechanism (CDM) appears as a possibility to facilitate sustainable financing. Implementing a methane oxidation layer (MOL) emerges as a feasible technical option for this kind of small landfills since landfill gas extraction is usually not viable. This paper presents a techno-economic and environmental assessment of MOL implementation in the Providence landfill (Seychelles) as a small-scale CDM measure. Results show that the MOL measure could avoid by 2030 between 94 and 20 kt CO2 eq. Concerning profitability, results clearly show that it depends on the existence of stabilized biomass material within the island. Thus, the MOL measure starts to be profitable in some scenarios for certified emission reductions (CER) prices higher than 26 €/t CO2 eq. that seem possible depending on the emissions? market development. When not profitable under CDM, the MOL measure might be used to reduce CO2 emissions from the domestic climate effort under the Paris Agreement since the unitary abatement costs is between 10 and 423 €/t CO2 eq. Moreover, the MOL measure contributes to the sustainable development goals (SDG) achievement ? mainly SDG8, SDG13, and SDG14. Finally, results call for a prompt action in Seychelles since the sooner the MOL is implemented after the landfill is closed, the more profitable.Jorge Cristóbal acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities through the “Beatriz Galindo” grant BEAGAL18/00035. Maria Margallo and Rubén Aldaco also want to thank the co-funding of the Spanish Ministry of Science and Competitiveness through the KAIROS-BIOCIR Project PID2019-104925RB (AEO/FEDER, UE)

Revisiting the LCA+DEA method in fishing fleets. How should we be measuring efficiency?

Life Cycle Assessment and Data Envelopment Analysis have been repeatedly combined in the literature as LCA+DEA method with the aim of enhancing the utility of life-cycle based methods in order to account for eco-efficiency verification and environmental impactminimization. Despite its evolution through time, it lacks specific standards that norm the combination of the two methods. In this sense, this study noted that its development has evolved in the frame of mainstream cultural perspectives to measure environmental impacts (i.e., hierarchist approaches). Therefore, the main objective of the study is to compare the benchmarking results obtained through DEA computation using different Cultural Theoryapproaches to calculate environmental impacts. For this, a case study for the Cantabrian purse seining fishing fleet was chosen. Hence, three different DEA matrices were constructed attending to the three main human visions on environmental issues: hierarchist, individualist and egalitarian. All three matrices represented the same set of inputs to be optimized, but differed in the nature of the output flow, representing landed fish, energy content or biomass removal. Results suggest that optimization of environmental impacts is strongly influenced by the cultural perspective selected. In the particular case of fishing fleets, benchmarking environmental impacts based on anthropocentric views may be ignoring the health of fishing stocks and the trophic complexity of the ecosystems. Methodological conclusions are directed towards the need to define more flexible and holistic frameworks in LCA+DEA modelling with the aim of enrichening the set of predetermined assumptions, including the Cultural Theory, to avoid biased interpretations.The authors thank the Ministry of Economy and Competitiveness of the Spanish Government for their financial support via the project GeSAC-Conserva: Sustainable Management of the Cantabrian Anchovies (CTM2013-43539-R) and Yago Lorenzo-Toja, Sara González-García and Lucía Lijó for valuable scientific exchange. Jara Laso thanks the Ministry of Economy and Competitiveness of Spanish Government for their financial support through the research fellowship BES-2014-069368 and the Ministry of Rural Environment, Fisheries and Food of Cantabria for support with data collection. Reviewers are also thanked for the valuable and detailed suggestions

Best available techniques in municipal solid waste incineration: state of the art in Spain and Portugal

In the year 2010 more than 24 Mt and 5 Mt of Municipal Solid Waste (MSW) were generated in Spain and Portugal. Landfilling, incineration and recycling are the most common treatments. In 2010, in the Iberian Peninsula between 58-6 2 % of the MSW generated was sent to the landfill, 9-19 % was incinerated and the rest was recycled and composting (EUROSTAT, 2010). Despite landfilling is still the most common practice, waste treatment by means of an incineration process has increased. The main advantages of this type of waste treatment are the reduction of mass and volume of residues and the energy recovery. Nevertheless, incineration had gained a bad reputation owing to the environmental impact, in particular, due to the emissions of acid gases, dioxins and furans (PCDD/F) and greenhouse gases. To assess the environmental advantages and disadvantages as well as the potential environmental impacts of waste incineration a life cycle perspective is required. Within this framework is the development of FENIX-Giving Packaging a New Life, a 3-year European LIFE+ funded project. This work is just the first step within this project where a database and a model based on Life Cycle Assessment (LCA) to assess the environmental impacts of waste incineration in Spain and Portugal will be developed. Particularly, the aim of this paper is to review the different technologies applied to MSW solid waste incineration and to carry out both the diagnosis of the current situation at the incineration plants in Spain and Portugal and to collect data to develop the Life Cycle Inventory (LCI)