Prospective Water Supply Mix for Life Cycle Assessment and Resource Policy Support-Assessment of Forecasting Scenarios Accounting for Future Changes in Water Demand and Availability.

Freshwater comes from different sources unevenly distributed over time and space around the world and plays a key role in the planning of all social and economic sectors on a regional scale. In this context, a consistent framework for modeling regional water supply mix (WSmix) at a worldwide scale has already been developed for use in life cycle assessment (LCA). However, changes in water sources, driven by climate and socio-economic changes, will occur, affecting WSmix. This study aims to assess the need for a Prospective WSmix (P-WSmix) for implementation in LCA and water footprint studies as well as regional water management strategies. Environmental and socio-economic factors affecting future water supply are defined. Projections of the three main components of the P-WSmix (i.e., water sources mix (P-WOmix), technology evolutions, and associated electricity mix) are proposed for two water users (public water and irrigation), under three scenarios and time horizons until mid-21st century. For implementation of the P-WSmix in LCA, a P-WOmix database is provided for 74 countries on all continents as well as a prospective technological matrix and prospective electricity mixes. An illustrative case study shows the importance of including P-WSmix in LCI databases for the LCA of infrastructures or products with a long life span and tangible water use during use or end-of-life phase, through the example of a toilet flushing system. P-WSmix has an important added value in supporting regional adaptation strategies for the future water supply management.

Defining freshwater as a natural resource: A framework linking water use to the area of protection natural resources.

PURPOSE: While many examples have shown unsustainable use of freshwater resources, existing LCIA methods for water use do not comprehensively address impacts to natural resources for future generations. This framework aims to (1) define freshwater resource as an item to protect within the Area of Protection (AoP) natural resources, (2) identify relevant impact pathways affecting freshwater resources, and (3) outline methodological choices for impact characterization model development. METHOD: Considering the current scope of the AoP natural resources, the complex nature of freshwater resources and its important dimensions to safeguard safe future supply, a definition of freshwater resource is proposed, including water quality aspects. In order to clearly define what is to be protected, the freshwater resource is put in perspective through the lens of the three main safeguard subjects defined by Dewulf et al. (2015). In addition, an extensive literature review identifies a wide range of possible impact pathways to freshwater resources, establishing the link between different inventory elementary flows (water consumption, emissions and land use) and their potential to cause long-term freshwater depletion or degradation. RESULTS AND DISCUSSION: Freshwater as a resource has a particular status in LCA resource assessment. First, it exists in the form of three types of resources: flow, fund, or stock. Then, in addition to being a resource for human economic activities (e.g. hydropower), it is above all a non-substitutable support for life that can be affected by both consumption (source function) and pollution (sink function). Therefore, both types of elementary flows (water consumption and emissions) should be linked to a damage indicator for freshwater as a resource. Land use is also identified as a potential stressor to freshwater resources by altering runoff, infiltration and erosion processes as well as evapotranspiration. It is suggested to use the concept of recovery period to operationalize this framework: when the recovery period lasts longer than a given period of time, impacts are considered to be irreversible and fall into the concern of freshwater resources protection (i.e. affecting future generations), while short-term impacts effect the AoP ecosystem quality and human health directly. It is shown that it is relevant to include this concept in the impact assessment stage in order to discriminate the long-term from the short-term impacts, as some dynamic fate models already do. CONCLUSION: This framework provides a solid basis for the consistent development of future LCIA methods for freshwater resources, thereby capturing the potential long-term impacts that could warn decision makers about potential safe water supply issues in the future.

Environmental, economic and experimental assessment of the valorization of dredged sediment through sand substitution in concrete.

The integrated life cycle assessment (LCA), life cycle cost assessment (LCC) and laboratory-based experimental assessment were applied to provide insight for early stage decision-making on the valorization of the dredged sediments. The objective was to find a viable and sustainable solution for the valorization of the dredged sediment in concrete, holding up a certain level of standard concrete performance without compromising in terms of economy and environment. For the sensitivity analysis, parametric life cycle inventories were developed to assess the sensitivity of environmental and economic costs to the rate of sand substitution by sediment, as well as the variations in the concrete components. The workability of fresh concrete and the compressive strength of hardened concrete at 28 days were assigned as the quality indicators to evaluate the influence of sand substitution by sediment on the concrete performance. The compressive strength evaluation in the laboratory demonstrated that a maximum rate of sand substitution in concrete up to 40 % by predominantly sandy sediment could sustain the concrete strength class. However, LCA and LCC negated the rate of sand substitution by sediment higher than 20 %. The integrated environmental, economic, and experimental assessments demonstrated that the substitution of sand by predominantly fine sediment downgrades the strength class of concrete, even in the low rate of incorporation (10 %) and increases the environmental and economic costs. Inferred from the results, the maximum rate of sustainable sand substitution by sediment in concrete could be optimized through a compromise between the expected mechanical strength and workability of the concrete, the economic and environmental impacts of the superplasticiser and the sediment transport. Overall, integrating environmental and economic cost assessments into the laboratory-based assessment of the valorization scenarios would determine the threshold for the sustainable rate of incorporation of sediment in valorization scenarios.

Comparative environmental and economic life cycle assessment of phytoremediation of dredged sediment using Arundo Donax, integrated with biomass to bioenergy valorization chain.

The economic and environmental life cycle assessment (LCA) was integrated into a laboratory-based experiment to evaluate the feasibility and sustainability of phytoremediation of chloride-rich marine dredged sediment, using perennial reed Arundo Donax along with biomass valorization. As a prerequisite for life cycle assessments, a baseline mathematical model was developed to estimate the yields of biomass to bioenergy valorization chain including the estimation of biomass yield per m3 sediment, bioenergy yields from valorization schemes, expected green electricity yield, and the phytoremediation time frame. This mathematical model was applied to develop a parametric life cycle inventory for two scenarios of sediment phytoremediation separately or integrated with biomass valorization, for LCA and further sensitivity and uncertainty analysis. Comparative LCA unveiled that the cost and environmental impacts of annual phytoremediation of 1m3 sediment alone or integrated with biomass valorization are much inferior to the corresponding sediment landfill as the inevitable alternative approach for sediment management. With the chloride bioaccumulation capacity of 9940 mg per kg dry biomass of A. donax, the phytoremediation of sediment with chloride concentration higher than 1650 mg/kg may not be achievable in a realistic time frame. Due to the importance of considering sediment depth and the effectiveness of the plant rooting system in estimating the performance of phytoremediation and the time frame, the volume of sediment (1m3) is a more appropriate functional unit than the surface area (ha) for LCA studies of phytoremediation. In addition, considering the volume of sediment as a functional unit retains comparability to other valorization scenarios such as sediment incorporation in cementitious matrices and management scenarios such as landfill, which are generally expressed on a volume or mass basis. Integrating biomass-derived bioenergy production into phytoremediation could offer local and global benefits in terms of economy and environment mainly due to carbon sequestration and avoiding fossil-based fuels.

Environmental assessment of a territory: an overview of existing tools and methods.

In order to reduce our environmental impact, methods for environmental assessment of human activities are urgently needed. In particular in the case of assessment of land planning scenarios, there is presently no consensual and widely adopted method although it is strongly required by the European Directive (2001/42/EC) on Strategic Environmental Assessment. However, different kinds of tools and methods are available such as human and environmental risk assessment, the ecological footprint, material flow analysis, substance flow analysis, physical input-output table, ecological network analysis, exergy, emergy or life cycle assessment. This review proposes a discussion on these tools and methods specifically applied to territories. After the meaning of territory is clarified, these approaches are presented and analyzed based on "key features" such as formalization, system modeling, inventoried flows, indicators provided and usability. This comparison highlights the strengths and weaknesses of each tool. It also emphasizes that the approach of life cycle assessment could provide a relevant framework for the environmental assessment of territories as it is the only method which can avoid burden shifting between life cycle stages, environmental impacts and territories.

Mining Impacts Assessment Using the LCA Methodology: Case Study of Afema Gold Mine in Ivory Coast.

Environmental impact assessment studies are mandatory for major industrial or infrastructure projects in most countries. These studies are usually limited to on-site impacts during exploitation but do not consider indirect impacts generated off-site or those concerning other steps of the project, including dismantling. National regulations in various countries have recently begun to include these neglected impacts to obtain a better appreciation of project trade-offs. Several scientists have highlighted the substantial potential of using the life cycle assessment methodology to increase the level of detail and completeness of environmental impact assessment (EIA) studies. Even if mining activities are known to produce significant local impacts, their consequences outside an extraction site have not yet been well documented. The implementation of the life cycle assessment (LCA) methodology in the EIA procedure has been carried out in a Au mining project by separating on-site and off-site impacts during the entire life cycle of the mine from prospection to site restoration following the end of exploitation. Mining projects occur over large time periods and require diverse materials and processes. The main difficulty of such analysis is the data collection that needs to be extrapolated for some of the activities. Even with these limitations, the Afema case study highlighted the significant share of off-site impacts (from a spatial perspective) and the major contribution of the exploitation phase of the mine (from a temporal perspective). Operating activities, especially excavation, ore, and waste rock transportation, blasting, ore processing, and tailing treatments, are the main impacts produced during the exploitation phase and are involved in climate change, particulate matter formation, and land destruction. Therefore, this standardized LCA method should be recommended by the regulatory authorities for use in EIA procedures. Integr Environ Assess Manag 2021;17:465-479. © 2020 SETAC.

Life cycle assessment case study: Tertiary treatment process options for wastewater reuse.

Tertiary treatment process (including filtration and/or disinfection) is necessary to obtain a water quality suited for high-quality reuse from wastewater treatment. Industrial pilots representing small real-size treatment units were set up downstream of a conventional secondary treatment of a wastewater treatment plant in the South of France and their performance followed for 2 y. Life cycle assessment (LCA) methodology is used to compare the environmental impacts of different treatment processes. Five tertiary treatment trains were studied: 1) sand filtration (SF) + storage followed by ultraviolet (UV) dynamic reactor disinfection (SF-UVD), 2) sand filtration + UV batch reactor disinfection (SF-UVB), 3) ultrafiltration (UF), 4) ultrafiltration and UV batch reactor disinfection (UF-UVB), and 5) microfiltration (MF) and storage followed by dynamic UV disinfection (MF-UVD). The chosen functional unit is "To supply 1 m3 of water with a quality in compliance with the highest standard of the French reuse regulations." The combination of SF with UV disinfection or the use of UF alone was found to be equivalent in terms of environmental impact for most of the midpoint indicators chosen. Combination of UF with UV disinfection was significantly more impacting because the electricity consumption was nearly doubled. This study was conducted on an industrial pilot; it may thus be representative of industrial facilities implemented to treat higher water flows. Integr Environ Assess Manag 2017;13:1113-1121. © 2017 SETAC.

Occurrence and fate of acrylamide in water-recycling systems and sludge in aggregate industries.

Acrylamide is a hazardous substance having irritant and toxic properties as well as carcinogen, mutagen, and impaired fertility possible effects. Acrylamide might be found in the environment as a consequence of the use of polyacrylamides (PAMs) widely added as a flocculant for water treatment. Acrylamide is a monomer used to produce polyacrylamide (PAM) polymers. This reaction of polymerization can be incomplete, and acrylamide molecules can be present as traces in the commercial polymer. Thus, the use of PAMs may generate a release of acrylamide in the environment. In aggregate industries, PAM is widely involved in recycling process and water reuse (aggregate washing). Indeed, these industries consume large quantities of water. Thus, European and French regulations have favored loops of recycling of water in order to reduce water withdrawals. The main goal of this article is to study the occurrence and fate of acrylamide in water-recycling process as well as in the sludge produced by the flocculation treatment process in aggregate production plants. Moreover, to strengthen the relevance of this article, the objective is also to demonstrate if the recycling system leads to an accumulation effect in waters and sludge and if free acrylamide could be released by sludge during their storage. To reach this objective, water sampled at different steps of recycling water process has been analyzed as well as different sludge corresponding to various storage times. The obtained results reveal no accumulation effect in the water of the water-recycling system nor in the sludge.

Fast characterization of non domestic load in urban wastewater networks by UV spectrophotometry.

Urban wastewater treatment plant efficiency, as well as biosolid quality, depends on urban wastewater quality, which can be affected by non domestic discharges (industrial, commercial etc.). The characterization of wastewater quality and non domestic discharge is complex, expensive and time consuming. However, these discharges must be controlled and reduced if possible. The development of a simple and fast methodology, namely based on alternative methods such as UV spectrophotometry, has been carried out and applied to different areas of a medium sized town of Southern Québec (Canada). Several autosamplers and on line/on site measurements have been used in critical control points of the network areas, for a dry weather campaign in four areas (industrial, commercial, hospital and university). The flow rate study, completed by the exploitation of conductivity measurements and the qualitative examination of UV spectra allows the discrimination of non domestic loads and their variability study from one point to another. The identification of critical discharges and organic shock loads has been possible with low investment, and mitigation actions have been proposed.