Environmental Impact Categories Research Articles

Optimization of energy use efficiency and environmental assessment in soybean and peanut farming using the imperialist competitive algorithm

This study proposes using input-output analysis to improve energy use efficiency and assess environmental indicators in soybean and peanut farming. The research findings show that soybean production consumes 43170.20 MJ ha−1 of total energy and yields 40417.28 MJ ha−1 of output energy, while peanut production requires 28677.36 MJ ha−1 of total energy and produces 28677.36 MJ ha−1 of output energy. The LCA results indicate that on-farm emissions are associated with production inputs for both soybean and peanut systems, with diesel fuel and chemical fertilizers being the main contributors. Soybean farming shows higher levels of diesel fuel pollutants due to reduced usage, while peanuts have a higher prevalence of contaminants associated with diesel fuel. Using ICA to calculate optimized energy consumption results in 36672.77 MJ ha−1 for soybean production and 23485.45 MJ ha−1 for peanut production, leading to energy savings of 6075.33 MJ ha−1 and 5191.91 MJ ha−1, respectively. Additionally, the environmental impact category quantities for ICA analysis of soybean and peanut production reveal the resources per ton for soybean production to be 111.25 USD2013 and for peanut production to be 45.43 USD2013 in terms of energy use. The use of ICA demonstrates potential in maximizing energy efficiency and evaluating environmental indicators in soybean and peanut farming. By optimizing resource allocation and decision-making processes, ICA can help farmers reduce energy consumption and minimize environmental impact, ultimately leading to more sustainable and eco-friendly farming practices that benefit both the environment and the agricultural industry. Further research and implementation of ICA in farming practices have the potential to significantly improve energy efficiency and environmental sustainability in the soybean and peanut farming industry.

Management of textile waste in Europe: An environmental and a socio-economic assessment of current and future scenarios

Textile production and consumption continues to grow, and yet textile waste management in Europe remains suboptimal. This study assesses and compares the life cycle impacts of managing selected textile waste fractions via selected technologies, under current and future framework conditions. The study combines environmental and socio-economic analyses with data input from stakeholder consultation within the European Union. Preparing for reuse is the most beneficial management pathway from both an environmental and a socio-economic perspective. Overall, mechanical recycling is the second-most preferred pathway for most environmental impact categories. However, for recycling pathways to be economically competitive against incineration, either CO2 prices will have to increase, or technology and processing costs will have to decrease. The uncertainty analysis identified critical parameters, such as substitution factors and yields of most desirable products from the recycling processes. The results offer a detailed basis for prioritising technology pathways for future textile waste management in Europe.

Dynamic life cycle assessment of European electricity generation based on a retrospective approach

The composition of electricity varies significantly throughout the year. As a result, the environmental impact of the electricity mix is also highly variable. However, most LCA studies assume a static annual average electricity mix and neglect these fluctuations. Therefore, this study examines the time-varying environmental impacts of electricity generation in Germany, France, Italy, Spain, and Poland using a dynamic life cycle assessment. It shows that the impacts of environmental categories vary considerably depending on when the electricity is generated, resulting from the different energy generation patterns throughout the day and year. In particular, the integration of renewable energy sources such as photovoltaic systems and wind turbines leads to significant fluctuations of environmental impacts. To determine the magnitude of the variation, coefficients of variation are calculated for each environmental impact category for a representative year. High coefficients of variation of more than 20% can be observed for several environmental impact categories. In addition, both a production-based and a consumption-based approach were used for the dynamic life cycle assessment. Comparing these two approaches shows significant differences in impact category results, for example, for Italy, with an average of 15%. These differences highlight the importance of including cross-border electricity flows in assessing the environmental profile of electricity. Overall, the results of the study emphasize the need to implement dynamic electricity mix models in life cycle assessments, especially for systems with time-varying electricity consumption. The provided Excel spreadsheet files with hourly time profiles of environmental impacts for the countries studied facilitate the adoption of the developed models by other practitioners and provide a valuable tool for assessing environmental impacts.

Conversion of biodigestate into activated carbon for electrochemical application: Process performance and life cycle assessment

Carbons derived from pyrolysis and activation of waste biomass are attracting much attention as components of energy technologies, such as batteries, supercapacitors and fuel cells. This experimental study focuses on the production of a high-surface-area biochar (LAC) obtained from the treatment of lignin-rich waste of a biodigester plant, by applying KHCO3 as an activating agent. The pyrolysis-activation conditions were set by following the process by thermogravimetric analysis and by checking the purity and porosity of the resulting carbon by several analytical techniques. The best pyrolysis condition provided a microporous carbon featuring up to 1840 m2 g−1, which was demonstrated at a 25 g biodigestate batch-scale. Moreover, the production process was critically analyzed by means of life cycle assessment to identify environmental hotspots and thus derive recommendations for process optimization. The impact of substance- and energy-recovery and the use of renewable energy sources on the sustainability of the product was demonstrated in several scenarios, complemented by benchmarking and an outlook regarding further optimization needs. In the best case scenario, the global warming potential of the proposed biochar could be reduced to 15.9 kg CO2-eq per kg of LAC. The activating agent KHCO3 was dominant in almost all environmental impact categories, hence, a theoretical recovery process for this substance was suggested and evaluated via life cycle assessment.

Optimization of leucomalachite green degradation through electron beam and persulfate oxidation using box-behnken design and life cycle assessment

This study explored the treatment of Leucomalachite Green (LMG) solutions using an electron beam and sodium persulfate (Na2S2O8), employing Box-Behnken design (BBD) to optimize operational variables such as absorbed dose, initial pH and Na2S2O8 concentration. The findings highlighted an optimal absorbed dose of 4.5 kGy, a Na2S2O8 concentration of 1.0 mM, and an initial pH of 6, leading to a remarkable 97.77% removal of LMG. The adjusted R2 for the model indicated a close match of 1.4% between predicted and actual outcomes under these optimized conditions, affirming the quadratic model's suitability for predicting the LMG removal process using combined EB and Na2S2O8. To assess the environmental impact of the LMG treatment, the study applied SimaPro 9.4 with the TRACI tool, examining ten distinct environmental impact categories. The results unveiled that deionized water and Na2S2O8 exhibited a notable impact on global warming (GW) and ecotoxicity (ET) in controlled laboratory settings. Furthermore, a comparative analysis of four scenarios shed light on the environmental implications of different energy sources. Notably, electricity generated from waste incineration demonstrated a substantial influence on all environmental indicators. In contrast, natural gas emerged as the cleanest source for electricity generation, offering a promising avenue for reducing environmental impacts. This study presents a practical method for addressing dye contaminants through the employment of EB in conjunction with Na2S2O8, with potential implications for broader applications.

Life cycle assessment of synthetic natural gas production from captured cement’s CO2 and green H2

Research on the environmental benefits of carbon capture and utilization (CCU) in cement production so far, has predominantly emphasized energy efficiency enhancements and CO2 emission reductions at a CCU product level, neglecting broader environmental consequences for the sector. This research broadens this perspective by providing an extensive life cycle assessment (LCA) of a circular Portland cement (CPC) model. Synthesized methane is used as input fuel through green hydrogen and calcium-looping (CaL) post-combustion captured CO2 from cement flue gas. Comparative analysis with ordinary Portland cement (OPC) reveals significant reductions in climate change and fossil resource use environmental impact categories. However, trade-offs are evident in acidification, water use, and minerals and metals resource consumption. The electrolysis system is a critical contributor due to the high electricity demand for hydrogen production, and its environmental impact depends largely on the renewable electricity source. The wind-based electrolysis model yields the most favourable results, followed by mixed (50% solar – 50% wind) and solar scenarios. These findings offer valuable insights for the cement industry, supporting stakeholders decision making on the adoption of sustainable circular production methods.

Mitigating environmental impacts of food consumption in the European Union: Is the power truly on our plates?

In the context of the sustainable use of our planet's resources, there is a pressing need for environmentally friendly diets. Moreover, health issues linked to inadequate nutrition are rising, further emphasising the need for more balanced diets. The aim of the planetary health diet developed by the EAT-Lancet commission is to sustainably feed 10 billion people in 2050 while not exceeding planetary limits. According to these guidelines, the EU should reduce red meat intake by 80 % and multiply legume intake by 15. This significant shift from animal to plant-based proteins could modify trade partnerships and EU dependency on plant-based proteins for animal feed, currently discussed within the EU protein strategy. This study evaluates land use changes and environmental consequences of this change in dietary patterns by applying a consequential life cycle assessment approach combined with an agri-economic model, additionally assessing if this diet shift could help to achieve EU Green Deal targets. For this simulation, the partial equilibrium model CAPRI was used, which is a global agricultural market model focusing on Europe, including bilateral trade worldwide. We found that the diet shift results in gaps between domestic demand and supply which are compensated by increased imports of legumes and additional exports of red meat from the EU due to an increased demand for red meat in non-EU countries, as a consequence of decreased red meat prices. Land use changes within NUTS-2 regions indicate broad disparities depending on regional specialisation and profitability. The results from our life cycle assessment show limited benefits for most environmental impact categories within the EU given the considerable change in diets. GHG emissions from the agricultural sector would be reduced by 9 %, representing 4 % of the change needed to achieve overall EU GHG emission targets i.e., a reduction of 55 % by 2030 compared to 1990 levels. Yet, the mitigation potential allocated to EU production of shifting diets could be greater if international trade were not offsetting expected local environmental benefits. Indeed, if EU red meat and animal feed production were reduced proportionally to the demand shift, domestic legume production could hypothetically be extended in the available agricultural areas coming along with improvements in all environmental impact categories. Scientific contribution and media regularly point out the significant influence of individual consumer behaviour as an impulse for change: “the power is on our plates”, while the results of our simulations show that this holds only to a limited extent. To minimise environmental pollution, strong supply-side policies are needed to complement the power on the consumers' plates.

Life Cycle Assessment as a Decision-Making Tool for Photochemical Treatment of Iprodione Fungicide from Wastewater

Water contamination with various micropollutants is a serious environmental concern since this group of chemicals cannot always be removed efficiently with advanced treatment methods. Therefore, alternative chemical- and energy-intensive oxidation processes have been proposed for the removal of refractory and/or toxic chemicals. However, similar treatment performances might result in different environmental impacts. Environmental impacts can be determined by adopting a life cycle assessment methodology. In this context, lab-scale experimental data related to 100% iprodione (a hydantoin fungicide/nematicide selected as the model micropollutant at a concentration of 2 mg/L) removal from simulated tertiary treated urban wastewater (dissolved organic carbon content = 10 mg/L) with UV-C-activated persulfate treatment were studied in terms of environmental impacts generated during photochemical treatment through the application of a life cycle assessment procedure. Standard guidelines were followed in this procedure. Iprodione removal was achieved at varying persulfate concentrations and UV-C doses; however, an “optimum” treatment condition (0.03 mM persulfate, 0.5 W/L UV-C) was experimentally established for kinetically acceptable, 100% iprodione removal in distilled water and adopted to treat iprodione in simulated tertiary treated wastewater (total dissolved organic carbon of iprodione + tertiary wastewater = 11.2 mg/L). The study findings indicated that energy input was the major contributor to all the environmental impact categories, namely global warming, abiotic depletion (fossil and elements), acidification, eutrophication, freshwater aquatic ecotoxicity, human toxicity, ozone depletion, photochemical ozone creation, and terrestrial ecotoxicity potentials. According to the life cycle assessment results, a concentration of 21.42 mg/L persulfate and an electrical energy input of 1.787 kWh/m3 (Wh/L) UV-C light yielded the lowest undesired environmental impacts among the examined photochemical treatment conditions.

Wasted Food, Wasted Resources? A Critical Review of Environmental Impact Analysis of Food Loss and Waste Generation and Treatment.

Food loss and waste (FLW) comes with significant environmental impacts and thus prevents a sustainable food system transition. Here we conducted a systematic review of 174 screened studies that assessed the environmental impacts of FLW generation and treatment. We found that the embodied impacts of FLW along the supply chain and impacts from FLW treatment received equal attention, but few studies have included both. The reviewed studies show narrow geographical (mostly conducted in industrialized countries) and food supply chain (mostly focused on the consumption stage) coverage. Life cycle analysis (LCA), material flow analysis (MFA), or their combination are the most commonly used to quantify FLW related environmental impacts. More method standardization, integration, and innovation and better FLW data with regional and stage resolution from a first-hand source are badly needed. Among the various proposed mitigation strategies covering technology, economy, behavior, and policy aspects, process optimization and waste management options are the most discussed. Our review calls for a more holistic environmental impact assessment of FLW generation and treatment and analysis of the trade-offs among different environmental impact categories and between supply chain stages, which would better inform relevant policy on effective environmental impact mitigation strategies toward sustainable food systems.

Eco-efficient asphalt recycling for urban slow mobility

Cycling infrastructures contribute to advancing zero-impact transport systems, aligning with the European Commission’s proactive climate change mitigation policies. This paper explores the potential of innovative and sustainable pavements for cycling paths with mixtures composed of road-milling materials. This investigation involves low-environmental-impact bituminous-based mixtures differing from recipe, mixing method, and laying. Up to 100% secondary aggregates are used as alternative materials to design the Grande Raccordo Anulare delle Biciclette (GRAB), a 44-km cycling ring in Rome. According to the European standard EN 15804, their “from cradle to gate” life cycle analysis allows a comprehensive assessment and comparison of the environmental impact. Core and additional environmental impact categories and resource use indicators were quantified using primary data from asphalt producers and secondary data from the Ecoinvent database in the SimaPro software. Within the H2020 InfraROB project (grant agreement no. 955337), which aims at enhancing road infrastructure integrity, performance, and safety through autonomous robotic solutions and modularization, experimental sections have been constructed using a cold-mixed asphalt composed entirely of recycled asphalt and a rejuvenating additive. The results underscore the potential of the examined low-impact approach in conserving Earth’s resources, ensuring long-lasting infrastructure for vulnerable urban populations and fostering sustainable environmental management.

Modeling the environmental impacts of Asparagopsis as feed, a cow toilet and slurry acidification in two synthetic dairy farms

Intensive dairy farming, particularly enteric fermentation and manure management, is a major contributor to negative impacts on the local and global environment. A wide range of abatement measures has been proposed to reduce livestock-related emissions, yet the individual and combined effects of these innovations are often unknown. In this study, we performed an attributional life cycle assessment of three innovative measures modeled in two synthetic German dairy farm systems: Feeding of the seaweed Asparagopsis, installing an in-house cow toilet system, and performing on-field slurry acidification. These measures were modeled both individually and in combination to account for single and cumulative effects and compared to a reference scenario under current practices. Our results showed that feeding high levels of Asparagopsis and the combination of all three measures were most effective at reducing global warming potential (20–30 %), while only the latter mitigated eutrophication (6–9%) and acidification potential (14–17 %). The cow toilet required additional adapted manure management (separated storage and injection of urine) to effectively reduce eutrophication (8–10 %) and acidification potential (19–23 %) and to decrease global warming potential (3–4%) and abiotic depletion (4–5%). Slurry acidification slightly affected all considered environmental impact categories. All three measures involved trade-offs, either between LCA impact categories (global warming potential vs. abiotic depletion), the location of impacts (off- vs. on-farm), or the emission reduction in individual gases (ammonia vs. nitrous oxide). Measure combinations could compensate for the observed trade-offs. Our study highlights the potential of novel abatement measures but also shows the interdependencies of measures in different stages. This calls for a revisiting of current priorities in funding and legislation, which often focus on single objectives and measures (e.g. ammonia reduction) toward the preferential use of measures that are effective without driving trade-offs or improving resource efficiency.

Comparative environmental analysis of sugar beet production using a solar-driven robot and conventional systems from a sustainability perspective

In the context of rapid global population growth and climate change, balancing agricultural productivity with environmental sustainability has never been more important. Precision farming technologies, including robotics, are touted as having huge potential to increase farm productivity, reduce energy and resource use and compact soil, while reducing the overall environmental impact of on-farm production. This comprehensive study presents, for the first time, a detailed analysis and environmental benchmarking of two organic sugar beet production (SBP) systems, conventional (CONV) and robotic (RBT), based on field experiments in Lithuanian conditions where a solar-powered robot is integrated into the production system to carry out sowing and weeding operations. In order to reduce the potential environmental impact and to understand the consequences of using the robot in agriculture, a Life Cycle Assessment (LCA) of the entire SBP process up to the factory gate was carried out. The results of the analysis show that the conventional system has higher total GHG emissions than the robotic system, 36.98 and 27.18 kg CO2eq t−1, respectively, with poultry manure being the largest contributor. The higher beet yield in the RBT system, mainly due to effective weed control, resulted in a higher GHG emissions ratio (14.72) and a higher sustainability index (13.72). The LCA results showed that the CONV system had a higher negative environmental impact than the RBT in all eleven environmental impact categories assessed, with the most pronounced difference in the Ozone Depletion (OD) category. Diesel fuel was identified as the most important environmental factor for organically growing sugar beet in all considered impact categories, with the most notable environmental impact (about 94%) in the terrestrial ecotoxicity category in both systems. Normalization of the results showed that marine aquatic ecotoxicity (ME) had the greatest (78%) influence of all exposure categories for both cultivation systems, CONV – 22079.82, and RBT 18121.61 kg 1.4-DBeq per ton of produced sugar beet. The study found that increasing yields and reducing fossil fuel use in organic farming are the two most promising strategies for achieving sustainability and efficiency in food production.

Access to bedding and outdoor runs for growing-finishing pigs: is it possible to improve welfare without increasing environmental impacts?

Providing bedding or access to an outdoor run are husbandry aspects intended to improve pig welfare, which is currently financially supported through animal welfare schemes in several European countries. However, they may significantly affect the environment through changes in feed efficiency and manure management. Therefore, the aim of this paper was to compare farms differing in animal welfare relevant husbandry aspects regarding (1) the welfare of growing-finishing pigs and (2) environmental impact categories such as global warming (GW), acidification (AC), and freshwater (FE) and marine eutrophication (ME), by employing an attributional Life Cycle Assessment. We collected data on 50 farms with growing-finishing pigs in seven European countries. Ten animal-based welfare indicators were aggregated into three pig welfare indices using principal component analysis. Cluster analysis of farms based on husbandry aspects resulted in three clusters: NOBED (31 farms without bedding or outdoor run), BED (11 farms with bedding only) and BEDOUT (eight farms with bedding and outdoor run). Pigs on farms with bedding (BED and BEDOUT) manipulated enrichment more often (P < 0.001), pen fixtures less frequently (P = 0.003) and showed fewer oral stereotypies (P < 0.001) than pigs on NOBED farms. There were fewer pigs with a short(er) tail on farms with than without bedding (P < 0.001). Acidification of BEDOUT and BED farms was significantly higher (compared to NOBED farms P = 0.002) due to higher ammonia emissions related to farmyard manure. Also, BEDOUT farms had higher ME than NOBED farms (P = 0.035). There were no significant differences regarding GW and FE between husbandry clusters, due to the large variability within clusters regarding feed composition and conversion. Therefore, both husbandry aspects associated with improved animal welfare have a significant influence on some environmental impacts, such as acidification and marine eutrophication. Nevertheless, the large variation within clusters suggests that trade-offs may be minimised through e.g. AC and ME.

Environmental Impact Assessment of Organic Wheat Cracker Value Chains with and without Nettle Powder as a Natural Additive: A Case of Sweden

Due to the growing global population and consequent increased demand for food, the global production of cereal crops has increased. Wheat is one of the most important food crops in the world, as its products, e.g., bread and crackers, have served as important sources of nutrition for many years. However, the environmental impacts of wheat-derived food products are not frequently explored. This study presents an environmental impact assessment of organic wheat crackers within the context of Swedish winter wheat production using both primary and literature-based data. A cradle-to-consumer gate life cycle analysis (LCA) approach using the functional unit (FU) of 1 kg of crackers was applied while considering two cracker value chains: (i) without additives and (ii) using nettle powder as a natural additive. Four environmental impact categories—cumulative energy demand (CED), climate change impact (GWP), acidification, and eutrophication—were explored, with a particular focus on CED and GWP. The analysis results indicated that the total CED values were about 13 MJ/FU and 14 MJ/FU for crackers without and with the additive, respectively. Similarly, the total GWP values were 379 g CO2 eq/FU and 464 g CO2 eq/FU, respectively. The post-harvest processing and handling stage was an environmental hot spot in both cases. The introduction of the nettle additive has increased the quantified values of all four of the investigated impact categories. These insights will enable food processors and policy makers to communicate the environmental impacts and make informed decisions to improve the sustainability of wheat crackers. This paper contributes to a database of the environmental impacts of wheat products, specifically LCA data of organic wheat crackers and the LCA method for further LCA studies of snacks and other wheat products with plant-based functional additives.

Life cycle assessment of mycelium-based composite materials

Mycelium-based composites (MBCs) show promising acoustic and thermal insulation, fire safety, and mechanical strength properties and are suitable for multiple applications in the construction, packing or furniture industry. A life cycle assessment confirmed climate change and fossil energy demand benefits in a laboratory scale production modelled for Germany. MBC are associated with 0.3668 kg CO2e / kg MBC (EN 15804 + A2). The electricity required to run MBC production and hemp cultivation, if used as a substrate, contribute significantly to the environmental impact categories considered. Compared to conventional insulation materials, environmental advantages of MBC can be confirmed. Particularly, MBC has a better climate change impact than extruded polystyrene, quadcore sandwich panel, foam concrete and rockwool. However, since the end-of-life is not assessed, the wood-fiber and straw panels perform better regarding climate change. Moreover, MBC has lower fossil energy demand than all conventional insulation materials. Land-use and water demand are higher than for conventional materials.

Environmental Sustainability of Building Materials in Turkey: Reference Information Recommendations for European Green Deal Declarations

This study provides weight and normalization reference information for declaring the environmental information of building materials produced and exported in Turkey. Reference information was first determined for the global warming potential based on greenhouse gas (GHG) emissions, which is the subject of the European Union Green Deal Carbon Border Adjustment Mechanism (CBAM). For a more holistic approach, reference information is also recommended for environmental impact categories acidification, air pollution, ecological toxicity, eutrophication, fossil fuel depletion, human health, indoor air quality, land use, ozone depletion, photochemical smog formation, and water depletion, in addition to GHG emissions. Reference information is determined based on the life cycle assessment (LCA) methodology defined in the international standards ISO 14040 and ISO 14044. Semi-structured interviews were held with twenty-one industry stakeholders in Turkey to determine the weight reference values. The results obtained from the semi-structured interviews were combined using the analytic hierarchy process (AHP) method. Normalization reference information was determined by compiling Turkey’s national emission values. The suggested reference information has been tested using a case study. Total environmental impact scores were calculated for floor coverings and exterior wall finishes, including global warming potentials based on GHG emissions, and eleven other environmental impact categories. The findings support the need to use regional reference information in Turkey. The reference information recommended in this study can be used both in declarations within the scope of the EU Green Deal and in other possible environmental impact declarations resulting from building materials.

Cold Sintering Enables the Reprocessing of LLZO-Based Composites.

All-solid-state batteries have the potential for enhanced safety and capacity over conventional lithium ion batteries, and are anticipated to dominate the energy storage industry. As such, strategies to enable recycling of the individual components are crucial to minimize waste and prevent health and environmental harm. Here, we use cold sintering to reprocess solid-state composite electrolytes, specifically Mg and Sr doped Li7 La3 Zr2 O12 with polypropylene carbonate (PPC) and lithium perchlorate (LLZO-PPC-LiClO4 ). The low sintering temperature allows co-sintering of ceramics, polymers and lithium salts, leading to re-densification of the composite structures with reprocessing. Reprocessed LLZO-PPC-LiClO4 exhibits densified microstructures with ionic conductivities exceeding 10-4 S/cm at room temperature after 5 recycling cycles. All-solid-state lithium batteries fabricated with reprocessed electrolytes exhibit a high discharge capacity of 168 mA h g-1 at 0.1 C, and retention of performance at 0.2 C for over 100 cycles. Life cycle assessment (LCA) suggests that recycled electrolytes outperforms the pristine electrolyte process in all environmental impact categories, highlighting cold sintering as a promising technology for recycling electrolytes.

Environmental impact assessment via life cycle analysis on ultrafiltration membrane fabricated from polyethylene terephthalate waste to treat microalgal cultivation wastewater for reusability

The current study had conducted the life cycle analysis (LCA) to assess the environmental impact of microalgal wastewater treatment via an integrated membrane bioreactor. The functional unit selected for this analysis was 1 kg of treated microalgal wastewater with contaminants eliminated by ultrafiltration membrane fabricated from recycled polyethylene terephthalate waste. Meanwhile, the applied system boundary in this study was distinguished based on two scenarios, namely, cradle-to-gate encompassed wastewater treatment only and cradle-to-cradle which included the reutilization of treated wastewater to cultivate microalgae again. The environmental impacts and hotspots associated with the different stages of the wastewater treatment process had clearly elucidated that membrane treatment had ensued the highest impact, followed by microalgal harvesting, and finally cultivation. Among the environmental impact categories, water-related impact was found to be prominent in the following series: freshwater ecotoxicity, freshwater eutrophication and marine ecotoxicity. Notably, the key performance indicator of all environmental impact, i.e., the global warming potential was found to be very much lower at 2.94 × 10−4 kg CO2 eq as opposed to other literatures reported on the LCA of wastewater treatments using membranes. Overall, this study had proffered insights into the environmental impact of microalgal wastewater treatment and its stimulus for sustainable wastewater management. The findings of this study can be instrumental in making informed decision for optimizing microalgal wastewater treatment and reutilization assisted by membrane technology with an ultimate goal of enhancing sustainability.

Introducing a new method to assess the benefits of resources recovered from wastewater to the natural environment

Resources recovery can improve the economic efficiency and reduce the negative environmental impacts of municipal wastewater treatment plants (MWWTP). The recovered resources can also actively benefit the natural environment enabling a reciprocal relationship between human society and nature. Focusing on these benefits can reveal new resources recovery opportunities. Moreover, for certain environmental impact categories such as emissions of reactive nitrogen, mere damage reduction is insufficient because these emissions are already beyond planetary limits. However, quantitative methods to assess nature benefits are lacking. A new method is developed to calculate the potential nature benefits in three categories: Freshwater restoration, biomass assimilation of nutrients, and soil organic matter sequestration and it is demonstrated on a real-life MWWTP. Focusing on resources recovery helps to purify the wastewater sufficiently for discharge and to benefit the natural environment. Treated wastewater discharge into a river can support freshwater restoration depending on the effluent quality. High quality is achieved by the sufficient removal of the nutrients and organic matter and discharging into a high-flow stream. The recovery of nutrients helps to close the nutrient cycle through biomass assimilation. To maximize this benefit, the nutrient recovery efficiency from the MWWTP must be maximized. But, increasing the nutrient uptake efficiency in agriculture is also crucial, especially for nitrogen. The wastewater sludge products can be applied to soil to sequester organic matter and the products with low volatile solids should be preferred. The development of the new method is a start to recognizing and assessing the potentially positive role of humans in nature.

Life Cycle Assessment of the Domestic Micro Heat and Power Generation Proton Exchange Membrane Fuel Cell in Comparison with the Gas Condensing Boiler Plus Electricity from the Grid

The energy demand of private households contributes globally to 36.5% of the total CO2 emissions. To analyze the emissions reduction potential, we conducted a comparative life cycle assessment of a proton exchange membrane fuel cell in a residential application and a conventional system with a stand-alone gas condensing boiler and electricity from a grid mix. The period under review was referred to as the service life of the PEMFC and is assumed to be 10 years (83,038 h of PEMFC). The applicability of this in a single-family house built between 1991 and 2000 under German climatic conditions was investigated. The functional unit is set to the thermal energy demand of 16,244 kWh/a and electricity demand of 4919 kWh/a of a single-family house. The impact assessment method “CML 2001–August 2016” was used in this investigation. The manufacturing phase of the proton exchange membrane fuel cell showed disadvantages, whereby the use phase had significant advantages in most of the environmental impact categories as compared to the conventional energy supply system. Considering the whole life cycle, the advantages from the use phase could outperform the disadvantages from the manufacturing phase in most of the impact categories, except for ADP elements and TETP.