Luís Arroja

Application of life cycle assessment to the Portuguese pulp and paper industry

Abstract In this paper, the Life Cycle Assessment (LCA) methodology is applied to Portuguese printing and writing paper in order to compare the environmental impact of the use of two kinds of fuels (heavy fuel oil and natural gas) in the pulp and paper production processes. The results of inventory analysis and impact assessment show that the pulp and paper production processes play an important role in almost all of the analysed parameters, which do not always result in an important contribution to the corresponding impact categories. The substitution of heavy fuel oil by natural gas in the pulp and paper production processes seems to be environmentally positive.

Using Life Cycle Assessment methodology to assess UHT milk production in Portugal.

Milk and dairy products constitute an important ingredient in the human diet. Ultra-high temperature (UHT) milk is the main dairy product consumed in Portugal and its production entails large inputs of resources which derive on negative environmental effects such as nutrient enrichment of the ecosystem and climate change. In this study, Life Cycle Assessment (LCA) methodology was considered for the environmental assessment of packaged UHT milk produced in Portugal, including simple (whole, semi-skimmed and skimmed) and cocoa milk from a cradle-to-gate perspective and to identify the environmental hot spots. Results showed that the production of the raw milk in the dairy farm is the main hot spot in almost all the categories under assessment mainly due to the emissions from enteric fermentation, manure management and fertilisers production and application. Furthermore, on-site emissions derived from dairy factory are remarkable together with the packages and energy requirements production. The values reported in this study are in the range of other related papers. However, differences were also identified due to several reasons such as allocation approach, data sources, characterisation factors, farm management regimes and assumptions considered. Therefore, these aspects should be carefully addressed and sensitivity to the assumptions and uncertainty of the results should be evaluated.

Carbon dioxide emissions from forest operations in Portuguese eucalypt and maritime pine stands

Abstract A methodology for assessing fossil fuel-related carbon dioxide (CO2) emissions from operations performed in eucalypt and maritime pine stands was developed and applied to Portugal. This methodology includes all the operations carried out during site preparation, stand establishment, stand tending, logging and infrastructure establishment. For the year 2000, CO2 emissions for the entire area of maritime pine and eucalypt stands in Portugal were estimated to be 51 and 67 Gg CO2 year−1, respectively. These results demonstrate the more intensive nature of the management activities used in eucalypt stands, as these stands occupied an area approximately 30% smaller than maritime pine stands and produced only 5% more harvested wood than maritime pine stands. Wood logging accounted for approximately 40% of the total annual CO2 emissions in both stands. The results obtained from a sensitivity analysis suggest that annual CO2 emissions from eucalypt and maritime pine stands could be decreased by nearly 20% if, simultaneously, mowing is used instead of disking in clearing/cleaning operations, soil scarification is made by furrowing and ridging instead of ripping followed by subsoiling, and forwarders are used instead of modified farm tractors in wood extraction. A reduction of approximately 30% could be obtained for maritime pine stands if, in addition, natural regeneration is used instead of planting.

Life-cycle assessment of typical Portuguese cork oak woodlands

Cork forest systems are responsible for making an important economic contribution to the Mediterranean region, especially Portugal where the cork oak woodlands or montados contain about 32% of the worlds area. The environmental profile derived from reproduction cork production and extraction in two Portuguese regions (Tagus valley and Alentejo) representative of the Portuguese sector were assessed in detail using the Life-Cycle Assessment (LCA) methodology from a cradle-to-gate perspective. The production line was divided into four stages considering all the processes involved: stand establishment, stand management, cork stripping and field recovery. According to the environmental results, there were remarkable differences between the two production scenarios mainly due to the intensity and repetition of forest activities even though the cork yield was reported to be the same. The management system in the Alentejo region presented the worse environmental profile in almost all the impact categories under assessment, mainly due to the shorter cycle duration of the mechanical cleaning and pruning processes. Cork stripping was identified in both scenarios as the production stage with the highest contribution to the environmental profile due to the cleaning and pruning processes. A sensitivity assessment concerning the cork yield was performed since the average production yields in the Portuguese montados are lower than the ones used in this study. Thus, if the cork yield is reduced, the environmental profile in both scenarios gets worse since almost all the forest activities involved are the same.

Biosorption of milk substrates onto anaerobic flocculent and granular sludge.

Experiments were performed for adsorption of milk‐based substrates onto anaerobic biomass at 35 °C. The influence of two parameters was studied, namely, the type of biomass (flocculent or granular) and the sludge adaptation to the substrate. It was found that flocculent sludge presented an adsorption capacity roughly 3 times higher than that of granular sludge. The adsorption data fit well with the Freundlich and Langmuir isotherms. Apparently, short‐term sludge adaptation is not influential on the adsorption behavior. On the other hand, long‐term adapted sludge showed a higher adsorption capacity than nonadapted sludge, which probably is an indirect effect of different microbial populations. These results suggest that the role of adsorption in the anaerobic treatment of complex substrates containing fat cannot be overlooked, especially for flocculent sludge systems, since organic matter accumulation could cause process failure due to biomass washout.

Identification of methodological challenges remaining in the assessment of a water scarcity footprint: a review

PurposeThis work presents a systematic review, updating the information on the currently available methods to calculate the water footprint (WF), and addressing the following methodological challenges, as they have not been deeply studied to date: (1) accounting and assessing the environmental impacts related to changes in evapotranspiration (ET); (2) inventory of actual blue freshwater consumption in agriculture; (3) temporal and spatial variation to establish explicit characterisation factors (CFs) and (4) adequate connection between inventory flows and spatio-temporal explicit CFs.MethodsA systematic review relying on the guidelines of Pullin and Stewart (Conserv Biol 20(6):1647–1656, 2006) was conducted. Taking into account five specific formulated research questions in the WF field, WF studies were selected based on two ‘types’ of screening criteria: keyword searches and the WF study filter.Results and discussionFrom the 128 papers in peer-reviewed journals on product WF from a life cycle perspective, this literature review shows that major methodological challenges remain partially unsolved, which could degrade the accuracy of product WF assessments. To understand how land use affects ET, and depending on the land cover and size of the land use production system, actual ET can be estimated based on meteorological data on water balance equations embedded in crop and forest growth models, from field measurements at meteorological stations and more recently from remote sensing. For accounting for blue water consumption in agriculture, there are two types of approaches that lead to quite different results: inventory from actual farming records of applied irrigation and inventory from modelled ET associated with irrigation. Depending on the question being addressed, the practitioner can apply either approach. Furthermore, when a single freshwater scarcity CF is determined for large sub-watersheds, especially when the sub-watersheds have non-uniform freshwater availability and demand, uncertainty in the freshwater use-related impacts is introduced. Regarding the connection between inventory flows and spatio-temporal explicit CFs, the difficulty in identifying the exact location of background processes and characterising the local environmental characteristics (e.g. edaphoclimatic conditions, land cover) can hinder the elaboration of an accurate spatially differentiated impact assessment, as more generic CFs can be applied.ConclusionsThis systematic review shows that there are clearly future research needs with respect to the interrelations between freshwater use and potential damages in the areas of protection of resources, human health and ecosystem quality. It is also of paramount importance to understand the effects of land use and land cover change and water irrigation on WF damage.

Analysis of raw cork production in Portugal and Catalonia using life cycle assessment

PurposeThis study aims to (1) evaluate the environmental impacts associated with the three types of raw cork produced in Portuguese cork oak woodlands (in Alentejo region) considering two alternative practices for stand establishment (plantation and natural regeneration), (2) compare the environmental impacts of raw cork production in Portuguese cork oak woodlands and in Catalonian cork oak forests, and (3) assess the influence of different allocation criteria for partitioning the environmental impacts between the different types of raw cork produced.MethodsA cradle-to-gate approach was adopted starting with stand establishment up to cork storage in a field yard. The system boundaries include all management operations undertaken during the following stages: stand establishment, stand tending, cork stripping, and field recovery. The allocation of the environmental impacts to reproduction, second, and virgin cork was based on mass and market price criteria. An alternative allocation approach was simulated by allocating environmental impacts also to the wood produced in the cork oak stands. The impact assessment was performed using the characterization factors recommended by the International Reference Life Cycle Data System (ILCD).Results and discussionIn Portugal, cork produced from naturally regenerated stands has a better environmental performance than cork produced from planted stands, but the differences are smaller than 10 %. Different management models of cork oak stands in Portugal and Catalonia (agro-silvopastoral system and forest system, respectively) originate different impact levels, which tend to be significantly lower in Catalonia. The environmental hot spots in the two regions are also distinct. In Catalonia, they are associated with cleaning, road maintenance, and worker and cork transport. In Portugal, they are fertilization, pruning, and cleaning. The two allocation criteria affect significantly the results obtained for virgin cork in Portugal and for virgin and second cork in Catalonia. Besides, when impacts are also allocated to wood, mass allocation should be avoided as it would not create incentives for a sustainable management of cork oak stands.ConclusionsThe environmental impact from Catalonian cork may be reduced by decreasing mechanized shrub cleaning and road maintenance operations through the introduction of livestock in cork oak forests, and also by a better planning of management operations. For the Portuguese cork, improvements may be achieved by optimizing fertilizer dosage, planting nitrogen-fixing crops and pastures that improve soil quality, avoiding unnecessary operations, improving the efficiency of management operations, and increasing tree density.

Application of Qual2Kw model as a tool for water quality management: Cértima River as a case study

Modelling can be a useful management tool because models allow the understanding of water body response to different pollution pressure scenarios which may help on the decision-making process and in prosecuting the Water Framework Directive objectives. This study aims to evaluate the usage of simple water quality models (Qual2Kw) applied to small river basins in order to better understand the response of a river to different loads of nitrogen and phosphorus. Qual2Kw model was applied to Cértima River (Portugal), a small river that ends in a shallow lake called Pateira Fermentelos and represents a very important ecosystem to the local community. Along its pathway, Cértima River has a significant enrichment in nutrients due to agriculture, livestock, domestic sewage and industrial effluents discharged into the river. In case of nitrogen, the highest loads are from domestic (44%) and diffuse (35%) sources. The main sources of phosphorous are domestic (46%), livestock (24%) and diffuse sources (20%). Cértima River is strongly enriched with nutrients, and neither nitrogen nor phosphorous is limiting the algal growth. According to the criterion of Dodds et al. (Water Res, 32(5):1455–1462, 1998), the river is classified as eutrophic. By comparing in stream measurements with Qual2Kw simulations, it can be concluded that it would be necessary to decrease the actual pollutants loads of nitrogen and phosphorous 5 and 10 times, respectively, in order to change Cértima River classification from eutrophic to mesotrophic.

Erratum to: Suspended solids in freshwater systems: characterisation model describing potential impacts on aquatic biota

Purpose High concentration of suspended solids (SS)—fine fraction of eroded soil particles—reaching lotic environments and remaining in suspension by turbulence can be a significant stressor affecting the biodiversity of these aquatic systems. However, a method to assess the potential effects caused by SS on freshwater species in the life cycle impact assessment (LCIA) phase still remains a gap. This study develops a method to derive endpoint characterisation factors, based on a fate and effect model, addressing the direct potential effects of SS in the potential loss of aquatic invertebrate or algae and macrophyte species.

Divergences on the environmental impact associated to the production of maritime pine wood in Europe: French and Portuguese case studies.

Life Cycle Assessment (LCA) has become a common methodology to evaluate the environmental performance of forest systems in recent years. This study aims to estimate the environmental profile associated with maritime pine wood production in two representative European countries: Portugal and France. Different forest management regimes based on low and high intensive conditions were evaluated and differences in logging equipment, biomass yield and lifespan were also reported. The study was completed with a sensitivity analysis based on two allocation approaches (economic and volumetric) since biomass from thinning processes is harvested and can be used as a co-product. The production of maritime pine in Portugal under low intensity conditions should present the best environmental results with reductions of 50-94% in comparison with the worst scenario. It is mainly associated with the absence of forest activities in periods previous to the logging stage. French intensive forest scenario ranks as the second best alternative of pine wood production. The remaining scenarios reported worse results in terms of environmental impacts mostly due to the remarkable repetition of a selection of those forest activities with large fuel requirement (mainly on site preparation and stand establishment and tending). Regardless of the scenario, logging related activities such as final cutting and forwarding were identified as the hotspots mainly due to the fuel requirements. Fertilizer production (if required), thinning and cleaning processes reported also remarkable contributions to the categories under assessment. In addition, an economic estimation for each forest management scenario has been performed mainly considering fuel, machinery and labor costs. According to the results, the Portuguese low intensive scenario is the best choice together with the French intensive scenario under an economic point of view because of the lowest production costs per functional unit. Activities related with the logging stage have also been identified as economic hotspots.