Environmental impact of water supply and water use in a Mediterranean water stressed region

In this paper, the combined life cycle assessment of the water supply alternatives and the water use in a water-stressed watershed in Spain (the Segura) is presented. Although it is a dry area, agriculture and tourism are very profitable sectors with high water demands. Thus, external water supply alternatives including water transfers or desalination partly balance the reduced natural water availability to cover the existing water demands. In order to integrate both the impact of water supply alternatives and water use, the ReCiPe method was used to assess the water supply alternatives at the endpoint approach with the three specific damage categories: human health, ecosystem diversity and damage to resources availability. At the same time, the water use impact was calculated and grouped in the same categories. Firstly, one average cubic metre of water at the user's gate in the Segura Basin area was taken as the functional unit. As irrigation and drinking water constitute the principal water uses, it was considered that to separately analyse 1 m3 used for irrigation and 1 m3 destined to drinking purposes could provide interesting information. Then, these units were also considered as functional units. Then, three additional hypothetical scenarios were introduced: two of them defined by a strong variability in rainfall and the third by a sudden diminution of water transferred from a neighbouring basin. Regarding the facilities to provide 1 m3 at user's gate in the Segura Basin, results showed that the seawater desalination plants obtained the highest score for all the three considered damage categories, followed by the Tajo–Segura water transfer, the groundwater, the local surface waters and the water reuse. In relation to the water use impact, the damage to ecosystems diversity was very representative with respect to the one coming from water supply infrastructures because irrigation constituted 85 % of the total demand. The diversification of water supply alternatives within a region considerably increases any environmental impact, primarily stemming from the additional required infrastructures, and frequently from the use of external water sources for their uses. Thus, users and policy makers should be aware of the costs that a guaranteed water supply entails. In water-scarce territories, the use of external solutions such as desalination or water transfer either increase the environmental impact due to their high energy consumption or they are limited by existing climate variability. Therefore, they cannot be considered as the definite solution, which would be a balance between renewable sources and existing demands.

This study aims to assess the environmental impacts and the energy efficiency of organic and conventional vegetable production in Palas Basin, Kayseri, Turkey. Three organic and three conventional farmers representing the vegetable production in the region participated in face-to-face questionnaires. Life cycle assessment (LCA) was implemented to assess the global warming potential (GWP), eutrophication potential (EP), acidification potential (AP), and energy use, which were selected as environmental impact potentials. Additionally, the environmental risk assessment was conducted to understand the impact of pesticide use in the region. Six farmers were investigated individually, and it was found that all of the farmers had a common cultivation calendar, but there were differences in the application. Particularly, mineral fertilizer use and irrigation were excessive in some agricultural practices. Although the use of N- and P-based mineral fertilizers was one of the main differences between organic and conventional farming, irrigation was a common practice. Irrigation, the most influential practice, elevated not only water consumption but also EP, AP, and GWP as a result of electricity consumption by electrical pumps. Electricity consumption from irrigation contributed to the GWP most, and this value was in the range of 45%-95%. Mineral fertilizer use covered up to 40% of the EP, 31% of the GWP, and 37% of the AP for conventional farmers. Three different scenarios were developed to reduce the environmental impacts of the use of excessive mineral fertilizer and irrigation. The developed scenarios recommended the reductions by 38%, 44%, 25%, and 60% in GWP, EP, AP, and total energy inputs, respectively. This study demonstrates that LCA is beneficial in determining the environmental impact of hotspots in vegetable production and allows the development of different solutions to mitigate environmental impacts for agricultural sustainability. Integr Environ Assess Manag 2022;18:1733-1746. © 2022 SETAC.

The environmental impact of household's water use: A case study in Flanders assessing various water sources, production methods and consumption patterns

The clothing industry is a significant contributor to environmental degradation. Many life cycle assessment (LCA) studies have been conducted to analyse its environmental impacts, however the majority of studies focus on either just one or a few stages of the product life cycle, and/or on a specific type of product. Therefore, easily accessible life cycle inventory (LCI) data that can be used in decision making by practitioners and researchers are lacking. This study addresses this gap. By collating data through a systematic literature review and meta-analysis, it provides LCI data on energy use, water use and greenhouse gas emissions for a range of materials across all stages of the life cycle on a consistent basis. A framework is developed that groups each material at each life cycle stage according to the intensity of its energy and water use, and greenhouse gas emissions. The analysis revealed that the raw material extraction stage generally has the highest environmental impact. In this life cycle stage, flax is the virgin fibre with the lowest environmental impacts, recycled cotton is the recycled fibre which has the lowest environmental impacts and Indian silk is found to have the highest impacts. The review identifies the gaps in the availability of LCI data and provides recommendations for LCA studies to address these gaps, as without comprehensive data, robust decisions cannot be made. The results presented in this paper must be looked at in the wider context of consumption: the best way to reduce impacts is to reduce consumption. However, noting that production cannot be reduced to zero, the results of this study will aid pro-environmental decision making by stakeholders of the fashion industry, such as designers and consumers, as well as being of use to researchers.

Comments on the international consensus model for the water scarcity footprint (AWARE) and proposal for an improvement

PurposeIt is challenging for practitioners to navigate through the multitude of life cycle assessment (LCA) approaches due to the rich literature and a lack of systematisation. The LCA flexibility allowed by standards results in a multitude of applications and, as referred to in previous works, as an “alphabet soup”. This paper proposes a scheme for a clearer classification of currently used LCA approaches, with consideration of the 4-stage framework coming from standards.MethodsThis systematisation was first established through literature research serving as a preliminary tentative framework. A text mining task was carried out in a second stage, involving 2044 published articles among 7558 of the last 10 years. For text mining, a dictionary collected keywords and synonyms of the LCA approaches. Such keywords were then extracted from the text together with their context (multiword). The final multiword analysis allowed the association of each keyword (i.e. each LCA approach) with a specific LCA stage (Goal and Scope, Life Cycle Inventory, Life Cycle Impact Assessment, Interpretation). The preliminary framework was adapted, further enriched and validated based on the text mining results.ResultsAs a result of the text mining activities, the preliminary tentative framework was partially confirmed and enriched with new insights, especially in the field of “explorative” LCA approaches, which also include “prospective” and “scenario-based” LCA. For most of the currently used LCA approaches, a link to a unique LCA stage was not recorded. However, clear trends were detected. The text mining task also highlighted a high number of works in which different approaches are compared or counterposed, especially in the field of attributional and consequential LCA. Some issues were found with the connotations of “traditional” approaches, which could be defined more specifically as “non-explorative”.ConclusionsUnlike other works focused on notions from selected literature, text mining activities can provide bottom-up feedback on a larger scale more automatically. In addition, this work brought out novel LCA approaches, for which future developments will confirm a final definition and systematisation. As an additional advantage, the presented methodology is easily replicable. Hence, the presented framework can be updated along with developments in LCA approaches.

The environmental impacts of iron and steel industry: a life cycle assessment study

Beef production exerts strong environmental pressures and can also generate negative social effects. In this study, the impacts on biodiversity, environment and society of beef production in the Mexican tropics, were evaluated through the Life Cycle Assessment (LCA) approach. The functional unit of the study was 1 kg live weight of calf and focused on three productive systems: native silvopastoral (NSP), intensive silvopastoral (ISP) and monoculture (MC). This research was divided into four analysis steps. (1) social impacts; (2) damage to biodiversity; (3) methane emissions and 4) environmental LCA impacts. Using the Social-LCA, we evaluated 18 social indicators, grouped into five categories: human rights, working conditions, health and safety, socio-economic repercussions, and governance. The results showed similarities between the three livestock systems, which revealed a deficient social performance. For projecting the biodiversity damage of pasture land use from an LCA perspective, characterization factors (CFs) were estimated. CFs consist of dimensionless figures representing the potential for damage per unit area of pasture land (potential species loss per m2). The CFs were calculated for three levels of pasture land use intensity (minimal/NSP, light/ISP, intense/MC). Based on the characterization factors developed, the MC showed the least potential species loss. Enteric methane emissions from the production systems were determined using the IPCC Tier 2. The results revealed that the emissions values from enteric methane calculated with Tier 1 overestimated the emissions compared to Tier 2 methodology. LCA indicated a lower environmental impact of the MC on four of the seven categories analyzed, highlighting its lower contribution to climate change and reducing species loss. However, consumption of water and scarcity of fossil fuel resources increased. To achieve tropical sustainable livestock farming, further lines of research should be aimed at evaluating its economic impacts and propose management systems that guarantee better social and environmental performance.

Environmental impact of water-use in buildings: Latest developments from a life-cycle assessment perspective

Water use in buildings accounts for a large share in global freshwater consumption where research on the impacts of life cycle water use receive little or no attention. Moreover, there is very limited knowledge regarding such impacts that focus on the life cycle emissions from water consumption in building environments in the world’s most water-stressed countries. Hence, this study attempted to quantify the environmental impacts of operational water use in a multi-family residential building through a life cycle assessment (LCA). A small part of a Middle Eastern country, Doha (Qatar), has been selected for the primary assessment, while water-use impact in Miami (Florida) was chosen as a second case study, as both locations fall into similar climate zone according to ASHRAE Climate Zone Map. The LCA score indicated much higher impacts in the Doha case study compared to Miami. The variation in the result is mainly attributed to the raw water treatment stage in Doha, which involves energy-intensive thermal desalination. Again, relative comparison of the annual water and electricity use impacts for the modeled building was performed at the final stage for both locations. Water use was attributable for 18% of the environmental impacts in Miami, while this value increased to 35% in Doha. This initial assembled LCA result will be beneficial to both water authorities and building research communities in establishing more sustainable water use policies for specific regions/countries that will ultimately benefit the overall building environment.

Urban water systems around the world are going through a period of substantial change: they are evolving towards more complex water supply alternatives; are being placed under increasing pressure to achieve higher quality effluent and biosolids discharges; and are being confronted with a growing number of broader environmental management challenges. This thesis explored the use of the Life Cycle Assessment (LCA) methodology for assisting in that process of change, because of LCA’s strengths in combining practicality and flexibility with ‘big picture’ thinking. The overarching goals were to: (1) explore LCA principles that do or do not provide useful perspectives for urban water planners, and (2) identify situations where the benefits from life-cycle thinking will be impeded by gaps in data and modelling approaches. The analytical starting point was a comparison of two different configurations for a city-scale, integrated water supply and wastewater system: a ‘traditional’ approach dependent on low-energy dam-sourced mains water supply; and one with a more complex mix of contemporary water supply infrastructure intended to reduce the intensity of freshwater extraction and nutrient discharge. This change incurs a substantial increase in energy use, meaning the reduced pressure on local aquatic ecosystems may come at the expense of large increases in other life-cycle impacts. Notably however, the results generated in this thesis indicate that an exclusive focus on energy use is unlikely to be a robust approach to factoring these bigger picture environmental impacts into water industry decision making. Furthermore, it is the wastewater components of the system, rather than the water supply components, that make the largest contribution to most of the life-cycle impacts. An excessive focus on the energy or greenhouse gas (GHG) implications of growing urban water demands is, therefore, unlikely to chart the industry on an optimal course to a more environmentally benign system configuration. The estimates for direct (scope 1) greenhouse gas emissions in this thesis utilise a comprehensive set of locally relevant empirical data and expert knowledge. Based on that, direct emissions could comprise 20% or more of the overall GHG footprint for urban water infrastructure systems. The substantial spatial variability associated with all the largest direct emission sources should be an important consideration in the urban water decision making process. For assessing the option to dispose of sewage treatment plant (STP) biosolids onto farmlands, the uncertainty associated with estimating field fluxes of carbon and nitrogen is likely to be more important than the more traditional focus on biosolids transport energy. The second major case study considered in this thesis is focussed on the issue of biosolids reuse for agricultural purposes. When that practice is assessed against a broader set of impact categories than just energy use or GHG emissions, it becomes apparent that conventional life-cycle impact assessment (LCIA) models could bias against this as a preferred fertiliser source. With respect to nutrient discharge, metals toxicity, and phosphorus recovery, there is a disconnect between the results produced with these impact assessment models, and the scientific knowledge and industry priorities that currently guide the associated Australian policy debate. Growing use of LCA in the Australian agricultural sector will encourage the use of those very models that are least well placed to provide useful critique of biosolids applications to soils, hence could lead to a weakening of agricultural support for this practice. This could pose a risk for water utilities already dependent on farmers to absorb the majority of their STP biosolids. Phosphorus recovery and organics toxicity are both issues that could benefit from analysis incorporating the life-cycle perspective, since for both there is the prospect that water industry mitigation actions could shift the environmental burden to somewhere else in its supply chains. However, the analyses presented here suggest that the available LCIA models are not up to this task in either case. For the assessment of minerals resource depletion, the choice of impact assessment models could also have a substantial effect on the results that are obtained. A number of priority tasks are identified here, that would advance the LCA modelling framework so it can provide more meaningful contribution to urban water cycle planning. Ozone depletion assessment is another issue where the adoption of conventional LCIA approaches will fail to provide any useful insight to the urban water industry. There is a strong case for including N2O emissions in such assessments, and doing so clearly indicates this could have a material influence on the conclusions draw from analysis of water infrastructure systems. Quantifying the ozone enhancing effects of CO2 and CH4 emissions remains a bridge too far for the available LCIA models, but their increasing and complex influence suggests there may be a need for evolution in the metrics used to assess the ozone depletion issue. The urban water industry would likely be affected by any changes in international ozone-layer policy as a result of the increased scientific focus on these non-halocarbons, and should keep a watching brief on this issue. The work undertaken in this thesis clearly identifies the value that can be derived from the LCA approach to infrastructure and options analysis. Furthermore, the compilation of whole-of-system data provides benchmarks that offer valuable benefits for the task of considering environmental trade-offs – whether that be from comparing across different water system technology options, and/or comparing across impacts that occur at different localities or points in time, and/or comparing across different environmental issues. In all respects, the goal should be to strive for robust consideration across all important life-cycle contributions and impacts. The challenge is to appropriately direct effort into the issues that matter, rather than those that are easiest to deal with. Incidental benefits derived from detailed industry data collection can be substantial, however they do not necessarily ensure that LCA delivers its fullest value. Detailed consideration may well be required on uncertain issues that are beyond the traditional expertise of the analyst. Practitioners should also resist the temptation to uncritically adopt historical convention in the choice of LCA impact assessment models. Lack of rigour in the definition of inventory data and/or impact assessment models doesn’t prevent LCA studies from being completed, but it will greatly diminish the value of the LCA exercise.

PurposeLow carbon repair epitomises sustainable maintenance management for heritage buildings. However, there is little recognition of this aspect, coupled with impractical assessment of repair impact strategies. This paper aims to present a decision-making process based on life cycle assessment (LCA) approach of lime plaster repair options for heritage buildings.Design/methodology/approachCalculation procedures of LCA were carried out to enable sustainable maintenance management appraisal for heritage buildings upon embodied carbon expenditure expended from lime plaster repair during the maintenance phase.FindingsCalculation procedures could be understood as a carbon LCA of lime plaster repair and recognised in reducing CO2 emissions. This underpins low carbon of lime plaster repair in achieving sustainable maintenance management of heritage buildings.Practical implicationsIt must be emphasised that the LCA approach is not limited to heritage buildings and can be applied to any repair types, materials used and building forms. This supports environmentally focused economies and promotes sustainable maintenance management solutions.Social implicationsThe LCA approach highlights the efficiency of repair impact strategies through evaluation of low carbon repairs options.Originality/valueThe LCA approach results show that low carbon repair, contextualised within maintenance management, relays the “true” embodied carbon expenditure and stimulates sustainable development of heritage buildings.

Life cycle assessment of water supply alternatives in water-receiving areas of the South-to-North Water Diversion Project in China

Applied life cycle assessment (LCA) studies often lead to a comparison of rather few alternatives; we call this the “ad hoc LCA approach.” This can seem surprising since applied LCAs normally cover countless options for variations and derived potentials for improvements in a product life cycle. In this paper, we will suggest an alternative approach to the ad hoc approach, which more systematically addresses the many possible variations to identify the most promising. We call it the “structural LCA approach.” The goals of this paper are (1) to provide basic guidelines for the structural approach, including an easy expansion of the LCA space; (2) to show that the structural LCA approach can be used for different types of optimization in LCA; and (3) to improve the transparency of the LCA work. The structural approach is based on the methodology “design of experiments” (Montgomery 2005). Through a biodiesel well-to-wheel study, we demonstrate a generic approach of applying explanatory variables and corresponding impact categories within the LCA methodology. Explanatory variables are product system variables that can influence the environmental impacts from the system. Furthermore, using the structural approach enables two different possibilities for optimization: (1) single-objective optimization (SO) based on response surface methodology (Montgomery 2005) and (2) multiobjective optimization (MO) by the hypervolume estimation taboo search (HETS) method. HETS enables MO for more than two or three objectives. Using SO, the explanatory variable “use of residual straw from fields” is, by far, the explanatory variable that can contribute with the highest decrease of climate change potential. For the respiratory inorganics impact category, the most influencing explanatory variable is found to be the use of different alcohol types (bioethanol or petrochemical methanol) in biodiesel production. Using MO, we found the Pareto front based on 5 different life cycle pathways which are nondominated solutions out of 66 different analyzed solutions. Given that there is a fixed amount of resources available for the LCA practitioner, it becomes a prioritizing problem whether to apply the structural LCA approach or not. If the decision maker only has power to change a single explanatory variable, it might not be beneficial to apply the structural LCA approach. However, if the decision maker (such as decision makers at the societal level) has power to change more explanatory variables, then the structural LCA approach seems beneficial for quantifying and comparing the potentials for environmental improvement between the different explanatory variables in an LCA system and identifying the overall most promising product system configurations among the chosen PWs. The implementation of the structural LCA approach and the derived use of SO and MO have been successfully achieved and demonstrated in the present paper. In addition, it is demonstrated that the structural LCA approach can lead to more transparent LCAs since the potentially most important explanatory variables which are used to model the LCAs are explicitly presented through the structural LCA approach. The suggested structural approach is a new approach to LCA and it seems to be a promising approach for searching or screening product systems for environmental optimization potentials. In the presented case, the design has been a rather simple full factorial design. More complicated problems or designs, such as fractional designs, nested designs, split plot designs, and/or unbalanced data, in the context of LCA could be investigated further using the structural approach.

Petroleum industry environmental performance