Life Cycle Assessment Production Research Articles

Quality model for recycled plastics (QMRP): An indicator for holistic and consistent quality assessment of recycled plastics using product functionality and material properties

One of the key challenges for plastics in a circular economy is its degradation during use, washing and reprocessing. The reduced quality of recycled plastic waste leads to its use in inferior applications. This study presents a novel quality model which incorporates degradation, degree of mixing and contaminations. The model estimates a single quality value between 0 and 1 based on the mathematical relationship that uses: 1) a list of material properties , 2) minimum and maximum permissible values per property, 3) an ideal or desired value (or range) for the property and 4) relative importance (or weighing) factor (J) for the property. The quality model for recycled plastic (QMRP) was tested for three different real-life scenarios to evaluate the quality of recycled plastic for applications in food packaging film and toys. The results showed the superior prediction of QMRP in comparison to the existing models, in terms of application-based assessment, inclusion of all aspects of quality, credit allocation to upcycling and the use of a Go/No-go criteria. A single value quality indicator is to be applied in correlation studies, application prioritization for product development, managerial decision making and as a substitution ratio for the allocation of avoided products in life cycle assessment (LCA) studies. The QMRP indicator can be used by the recyclers to assess the quality of its material and strategically position their recycled plastic grades in the market. • First model for quality assessment of recycled plastic which includes all properties. • The quality model (QMRP) indicates the best application of the recyclates. • The model highlights the importance of non-mechanical properties. • The model reflects the quality using a single value. • The outcome can be used as substitution ratio in life cycle assessment.

Correction to: Addressing the use and end-of-life phase of pharmaceutical products in life cycle assessment

The original version of this article unfortunately contained a mistake which was missed during typesetting.

Addressing the use and end-of-life phase of pharmaceutical products in life cycle assessment

Pharmaceutical residues in the environment can pose significant risks to ecosystems and human beings due to adverse pharma-specific effects. Existing life cycle assessment (LCA) studies do not usually consider the use and end-of-life (EoL) phase of pharmaceuticals and thus exclude relevant potentially toxic emissions of an active pharmaceutical ingredient (API). Therefore, a simplified inventory model for the use and EoL phase of pharmaceuticals is provided by estimating API flows and emissions to the environment. Both the qualitative description of the use and EoL phase of pharmaceuticals and the quantification of the flows within each life cycle phase are based on literature and expert knowledge. Existing approaches to determine the API emissions are adjusted to make them applicable in LCA. In addition, different uses and EoL scenarios (e.g. depending on the patients’ disposal behaviour) are specified, and assumptions are highlighted. Finally, the model is exemplarily applied to the oral intake of ibuprofen to test its applicability. Eleven potential flows and emissions of an API are identified and quantified for different application forms (pulmonary, oral, cutaneous). The model is applied to ibuprofen where potential API emissions result from administered and unused products. Referred to the administered amount of ibuprofen (reference flow), the product is mainly metabolized (73.1%). The unmetabolized (parental) compound enters the sewage treatment plant where it is degraded (13.94%), or emitted to surface water (8.35%), air (0%) and sewage sludge (0.36%). The remainder cannot be clearly assigned to one of the flows (4.25%). The results of this example are hardly comparable to existing measured data because they are related to the functional unit. The effect of assumptions, limitations due to data availability and the geographic scope reveal the need for further research. To facilitate the consideration of the use and EoL phase of pharmaceuticals in future pharma-LCAs, a simplified inventory model specified for German conditions, is provided which allows to calculate inventory results with easily and publically accessible data. However, remaining challenges such as the lack of data to model the behaviour of metabolites in the sewage treatment plant, missing approaches to include specific pharmaceuticals (e.g. hormones, anticancer drugs), the consideration of other sewage treatment technologies such as ozonization, the integration of API emissions from sewage sludge (e.g. due to the use as fertilizer) or the scope expansion with regard to the geographic validity of the model shall be further examined.

Carbon Footprint Estimation in Road Construction: La Abundancia–Florencia Case Study

The environmental impact of road construction and rehabilitation can be associated with the increase of greenhouse gas (GHG) emissions, which are highly related to climate change. Consequently, departments of transportation have recently focused on the development and implementation of tools to evaluate the performance of projects and minimize GHG emissions. An example is the use of life cycle assessment (LCA) to analyze and quantify the environmental impact of a product, system, or process, from cradle to grave. In this regard, the present case study quantifies the carbon footprint associated with the construction of the La Abundancia–Florencia highway, located in the province of San Carlos in Costa Rica. The analysis is also intended to generate consciousness both in the public and private sectors on the environmental impacts of road construction. After an LCA study, it was determined that the construction of the hot mix asphalt (HMA) layer generates a carbon footprint of 65.8 kg of CO2e per km of road. In addition, it was evident that HMA production generates the greatest environmental impact, among all the considered LCA production and construction stages, with a GHG contribution of 38% to 39% from bitumen only. Consequently, special attention to HMA production is required in order to minimize GHG emissions.

A new method of biophysical allocation in LCA of livestock co-products: modeling metabolic energy requirements of body-tissue growth

In agricultural life cycle assessment (LCA), the allocation method chosen to divide impacts among co-products is an important issue, since it may change conclusions about a product’s impacts. We developed a biophysical allocation method to assign upstream environmental burdens and the use of raw materials at farm gate to the livestock co-products at the slaughterhouse based on their metabolic energy requirements. Biophysical allocation is designed to build a relationship between co-products of a meat-production system and their associated net metabolic energy requirements. A metabolic growth model (Gompertz function) was combined with an energy calculation model to estimate metabolic energy requirements for the growth of an animal from birth to slaughter age. Allocation factors were calculated based on the energy required to maintain and produce body tissues (excluding waste), as a function of their chemical (protein and lipid) and physiological properties. This method was applied for an average beef cow and then compared to other allocation methods (e.g., mass, dry matter, protein, and economic). At slaughter age, carcass tissues required the most energy (44 %) due to their high quantity of protein; the gastrointestinal tract and liver required about 28 and 5 %, respectively, of total metabolic energy requirements due to their roles in body metabolism. Biophysical allocation considers the energy cost of building and maintaining the tissues, regardless of their final uses. It reflects physical relationships among co-products as well as other allocation methods do. It also reveals the cause-effect relationship between tissues according to the energy required to maintain physiological functions. Once the growing time until slaughter is set, biophysical allocation factors are not influenced over time, unlike those of economic allocation, which is highly influenced by price variability. This study provides a generic and robust biophysical allocation method for estimating environmental burdens of co-products, in accordance with ISO allocation rules. The method can be considered an original contribution to international debates on allocation methods applied to livestock products in LCA. In this paper, it is applied to cattle-related product, but it is generic and the principles can be adapted to any kind of livestock species. It should be considered and discussed by stakeholders in livestock production industries.

The potential contribution to climate change mitigation from temporary carbon storage in biomaterials

While lasting mitigation solutions are needed to avoid climate change in the long term, temporary solutions may play a positive role in terms of avoiding certain climatic target levels, for preventing the crossing of critical and perhaps irreversible climatic tipping points. While the potential value of temporary carbon storage in terms of climate change mitigation has been widely discussed, this has not yet been directly coupled to avoiding climatic target levels representing predicted climatic tipping points. This paper provides recommendations on how to model temporary carbon storage in products in life cycle assessment (LCA), in order to include the potential mitigation value relative to crossing critical climatic target levels. Further, estimates are made on potential magnitude of this value, highlighting the importance of including this aspect in climate change impact assessment of biomaterials. The recently developed approach for quantifying the climate tipping potential (CTP) of emissions is used, with some adaption, to account for the value of temporary carbon storage. CTP values for short-, medium- and long-term carbon storage in chosen biomaterials are calculated for two possible future atmospheric greenhouse gas (GHG) concentration development scenarios. The potential magnitude of the temporary carbon storage in biomaterials is estimated by considering the global polymer production being biobased in the future. Both sets of CTP values show the same trend; storage which releases the carbon again before the climatic target level is reached increases the CTP value of the product compared to a situation with no storage of the product, whereas storage extending beyond the time where the climatic target level is predicted to be crossed according to the GHG concentration scenarios contributes with negative CTP values, which means mitigation. The longer the duration of the storage, the larger the mitigation potential. Temporary carbon storage in biomaterials has a potential for contributing to avoid or postpone the crossing of a climatic target level of 450 ppm CO2e, depending on GHG concentration development scenario. The potential mitigation value depends on the timing of sequestration and re-emission of CO2. The suggested CTP approach enables inclusion of the potential benefit from temporary carbon storage in the environmental profile of biomaterials. This should be seen as supplement to the long-term climate change impacts given by the global warming potential which does not account for temporary aspects like benefits from non-permanent storage in terms of avoiding a critical climatic target level.

Carbon sequestration in LCA, a proposal for a new approach based on the global carbon cycle; cases on wood and on bamboo

There are many recent proposals in life cycle assessment (LCA) to calculate temporary storage of carbon in bio-based products. However, there is still no consensus on how to deal with the issue. The main questions are: how do these proposals relate to each other, to what extent are they in line with the classical LCA method (as defined in ISO 14044) and the global mass balances as proposed by the IPCC, and is there really a need to introduce a discounting system for delayed CO2 emissions? This paper starts with an analysis of the widely applied specification of PAS 2050 and the ILCD Handbook, both specifying the credit for carbon sequestration as ‘optional’ in LCA. From this analysis, it is concluded that these optional calculations give rather different results compared to the baseline LCA method. Since these optional calculations are not fully in line with the global carbon mass balances, a new calculation method is proposed. To validate the new method, two cases (one on wood and one bamboo products) are given. These cases show the practical application and the consequences of the new approach. Finally, the main issue is evaluated and discussed: is it a realistic approach to allocate less damage to the same emission, when it is released later in time? This paper proposes a new approach based on the global carbon cycle and land-use change, translated to the level of individual products in LCA. It is argued that only a global growth of forest area and a global growth of application of wood in the building industry contribute to extra carbon sequestration, which might be allocated as a credit to the total market of wood products in LCA. This approach is different from approaches where temporary storage of carbon in trees is directly allocated to a product itself. In the proposed approach, there seems to be no need for a discounting system of delayed CO2 emissions. The advantage of wood and wood-based products can be described in terms of land-use change on a global scale in combination with a credit for heat recovery at the end-of-life (if applicable).

Assessing freshwater ecotoxicity of agricultural products in life cycle assessment (LCA): a case study of wheat using French agricultural practices databases and USEtox model

Purpose A life cycle assessment (LCA) was conducted on winter wheat, based on real agricultural practices databases, on a sample divided into four production scenarios. The main objectives of this study are (1) to assess the environmental impact of winter wheat, using an LCA covering field practices, and the transport and storage of grain until it is sold to a miller; (2) to use the USEtox model (Rosenbaum et al. in Int J Life Cycle Assess 13:532–546, 2008) to assess the part of the total freshwater ecotoxicity impact due to pesticide use, its variability among plots, and to identify the active ingredients with the strongest impact; (3) and with the help of fungicide, insecticide, herbicide experts, to identify active ingredients to replace these high-impact pesticides and estimate the effect of such a substitution on total freshwater ecotoxicity.

Product specific emissions from municipal solid waste landfills

For the inventory analysis of environmental impacts associated with products in Life Cycle Assessment (LCA) there is a great need for estimates of emissions from waste products disposed at municipal solid waste landfills (product specific emissions). Since product specific emissions can not be calculated or measured directly at the landfills, they must be estimated by modeling of landfill processes. This paper presents a landfill model based on a large number of assumptions and approximations concerning landfill properties, waste product properties and characteristics of various kinds of environmental protection systems (e.g. landfill gas combustion units and leachate treatment units). The model is useful for estimation of emissions from waste products disposed in landfills and it has been made operational in the computer tool LCA-LAND presented in a following paper. In the model, waste products are subdivided into five groups of components: general organic matter (e.g. paper), specific organic compounds (e.g. organic solvents), inert components (e.g. PVC), metals (e.g. cadmium), and inorganic non-metals (e.g. chlorine,) which are considered individually. The assumptions and approximations used in the model are to the extent possible scientifically based, but where scientific information has been missing, qualified estimates have been made to fulfill the aim of a complete tool for estimation of emissions. Due to several rough simplifications and missing links in our present understanding of landfills, the uncertainty associated with the model is relatively high.