Eutrophication Potential Research Articles

Assessment of the emissions of a low draught ship powered by batteries for river passenger transport, using a life cycle methodology

ABSTRACT Climate change and the reliance on carbon-intensive fuels have made electromobility necessary to reduce greenhouse gas (GHG) emissions in transport. This study analyses the potential environmental impact of a shallow-draught vessel operating within a section of Colombia’s Atrato River basin by estimating CO₂-equivalent emissions across various technological alternatives (conventional, hybrid, and electric) using a life cycle analysis. Data on engine performance, fuel type, and operating conditions were gathered. A battery propulsion system was modelled using both ‘conventional’ and renewable energy sources. The analysis focused on four impact categories: global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), and photochemical ozone creation potential (POCP). Results indicated significant reductions with renewable energy: 92.6% in GWP, 94.2% in AP, 82.4% in EP, and 93.7% in POCP. The selection of energy sources for electricity generation is crucial in assessing the viability of battery technology for sustainable shipping.

Dynamics of pollution and trophic status in selected sub-tropical surface water bodies in Haridwar district, India.

This study provides a detailed approach to evaluating water quality in the Haridwar district, Uttarakhand, India, by integrating physicochemical and microbiological investigations. It employs multivariate analysis and applies water quality and trophic state indices to evaluate the current state of the water and identify potential sources of contamination. The results from the correlation matrix highlight the dynamic interactions between different water quality parameters. Dissolved oxygen, total alkalinity, total suspended solids, biochemical oxygen demand, ammonium nitrogen, fecal coliform, pH, nitrate, and temperature exhibited varying temporal associations. Furthermore, principal component analysis (PCA) identified pH, temperature, and total alkalinity as key influencers across all seasons, while sewage pollution and agricultural runoff were recurring concerns. The enumeration of NSF WQI (National Sanitation Foundation Water Quality Index) (observed from 33.0 to 41.7) further affirmed consistently poor water quality and provided a quantitative metric for a comprehensive assessment. Trophic state index (ranged from 58.6 to 94.2) analysis indicated hyper-eutrophic conditions driven by nutrient concentrations in specific sites, which was further validated by phytoplankton analysis, which revealed the widespread occurrence of cyanobacteria in nearly all water bodies, signaling severe nutrient enrichment and the risk of potential eutrophication. Despite high nutrient levels causing pollution, the water in these water bodies consistently fell within the safe category for irrigation based on estimated sodium percentage, sodium adsorption ratio, and Wilcox diagram. However, it is not recommended to use these surface water bodies for irrigation due to the presence of high levels of organic pollution and a significant load of pathogenic bacteria.

Risk assessment of particle and gaseous emissions from diesel and methanol–diesel advanced dual-fuel engines

The study investigates the influence of engine load and methanol energy share on the ultrafine particulate matter (PM) and unregulated emissions from advanced dual-fuel (reactivity-controlled compression ignition (RCCI)) and conventional diesel combustion (CDC) engines. An automotive diesel engine was modified to operate in RCCI mode by integrating a port fuel injection system with methanol. Real-time PM and gas-phase emissions were measured using a DMS 500 particle sizer and FTIR (Fourier-Transform Infra-Red) emission analyser. The study aims to evaluate the effect of combustion modes and operating conditions on exhaust emissions and their effect on human health and the environment. A comprehensive toxicity assessment was conducted which included quantifying the cytotoxicity on BEAS-2B epithelial lung cells exposed to PM, assessing lung retention of PM particles due to inhalation, and determining the cancer risk potential from carbonyl emissions. The risk assessment findings show that RCCI engine-emitted PM particles exhibit lower lung retention than those from the CDC engine. Furthermore, the environmental impact assessment reveals that RCCI engines emit unregulated emissions and exhibit lower global warming potential, acidification potential, and eutrophication potential than CDC engines. Notably, RCCI engines that emitted unsaturated HCs (Hydrocarbons) and carbonyl emissions show higher ozone-forming potential and cancer risk potential.

Comparative Life Cycle Assessment of Traditional and Modern Materials in Heritage Building Restoration: A Case Study from Ushaiger Village

This paper presents a comparative life cycle assessment (LCA) of the traditional and modern materials used in heritage building restoration, focusing on mud, limestone, decorative plaster, blended hydraulic cement, and ready-mix concrete. The analysis examines key environmental impact categories, including global warming potential (GWP), ozone depletion potential (ODP), acidification potential (AP), eutrophication potential (EP), and water use across multiple life cycle stages. The results reveal that mud and limestone, while having lower initial environmental impacts in production, contribute significantly to ODP and GWP during transportation due to their heavy weight. Modern materials like blended hydraulic cement and ready-mix concrete exhibit the highest overall environmental impacts, particularly in GWP, AP, and water use, due to their energy-intensive production processes. Decorative plaster, while lower in initial impacts, gains higher environmental burdens over time due to its frequent replacement. This study highlights the need to optimize transportation and improve recycling practices for traditional materials, while also encouraging the exploration of alternative materials for reducing the environmental footprint of heritage restoration.

Short alkyl-chained Imidazolium-based Ionic Liquids: Promising green solution or potential environmental threat?

Ionic Liquids (ILs) are currently applied in a wide variety of fields, with promising outcomes in microalgae high value biocompounds extraction. The occurrence of these compounds in natural water systems, with their characteristic stability and low biodegradability, becomes a threat worthy of attention. In the present study, Dunaliella tertiolecta, Isochrysis galbana and Rhinomonas reticulata were exposed to 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM] Tf2N) for 72, 168 and 264h, at 20 and 25°C. Obtained results suggest that the N-containing cationic ring in the selected IL could act as a nitrogen source, aiding protein synthesis and growth in the three studied microalgae. Moreover, this specific IL might become a potential eutrophication agent when discharged in aquatic ecosystems, already pressured by climate change conditions. Important lipid contents, mainly in I. galbana and associated with increased cellular energy allocation values, could be related to mitochondrial stress, which is known to be a lipid accumulation promoting factor. Hence, we hypothesise that, since [BMIM] Tf2N does not appear to impair growth or biocompound accumulation, it could be a candidate for microalgae biomass pretreatment in biodiesel production. However, its life cycle and disposal must be carefully considered.

Environmental impacts of crop production systems in subtropical plateau regions: case study of Yunnan, China

Excessive fertilisation, improper nutrient management, and specific climatic factors are the main reasons for the high environmental risks associated with agricultural production in subtropical plateau regions. However, quantitative data of environmental impacts and emission reduction potential remain unclear. The development potential of such systems is likely to be significant. In that context, we conducted a case study in Yunnan Province, China, to quantify the environmental impact of crop production from 2002 to 2021. A life cycle assessment method was employed to identify the factors driving environmental impacts, and potential mitigation strategies were proposed. The yield and total nutrient input of grain crops in Yunnan Province increased over the 20-year period, and the environmental footprint of crop production in Yunnan Province was higher than that in other regions. The average annual mean greenhouse gas (GHG) emissions, soil acidification potential (AP), and water eutrophication potential (EP) of crop production from 2002 to 2021 were 837 kg CO2-eq·Mg−1, 15.7 kg SO2-eq·Mg−1, and 2.71 kg PO4-eq Mg−1, respectively. Environmental emissions from crops mainly originate from the application of agricultural inputs (including fertilisers (N, P, and K), pesticides, seed, diesel fuels, and plastic film) during the crop life cycle. There was a significant correlation between surplus nitrogen and environmental impacts. Scenario testing showed that optimised nutrient management practices could increase crop yield and reduce environmental costs. GHG emissions, AP, and EP from the production of rice, wheat, and maize are expected to decrease by 43.0–59.5%, 51.5–64.5%, and 57.4–71.5%, respectively (scenario 4, S4). Based on these findings, we propose that com-prehensive agricultural management measures can reduce the negative impacts of crop production on the environment in subtropical plateau areas and help achieve sustainable agricultural development.

An overview of limnological studies in Brazilian fish farms

Considering the growth of aquaculture and its potential environmental impacts, this study aimed to evaluate the patterns and trends of research on water quality in fish farms in Brazil, focusing on environmental differences between fishponds and net cages. We conducted a bibliometric survey from the Aquatic Sciences and Fisheries Abstracts (ASFA) and Web of Science databases, using the keywords "fish farm" or "fishpond" and "monitoring" and "water quality". After screening the retrieved documents, a total of 37 original studies were selected. Publication year, locality, pond type, culture characteristics, trophic state index, and values of chemical, physical and biological variables were collected. It was observed an increasing trend in the number of studies over time, with publication peaks in 2014 and 2018. Net cages were evaluated by 60% of the published research, which included between 3 and 750 tanks per study. Fishponds were evaluated by the remaining fraction of the studies, which included from 1 to 50 tanks per study. The five regions of the country were unequally represented: Southeast (54%), Northeast (24%), South (14%), North (5%), and Midwest (3%). Forty-seven distinct variables were recorded, and the most frequent were temperature, dissolved oxygen, and ph. Significant differences were observed in total phosphorus, chlorophyll-a, and orthophosphate concentrations among different pond types, with higher values in fishponds. The findings of our study showed high potential for eutrophication in the aquaculture systems in Brazil and highlighted the urgency for an effective management of this activity in the country. Nevertheless, there is still a lack of information and studies on this topic to support informed decision-making. We also propose some general guidelines.

Environmental Assessment of Organic Dairy Farms in the US: Mideast, Northeast, Southeast, and Mountain Regions

Greenhouse gases (GHGs), ammonia (NH3) emissions, eutrophication potential (EP), and use of fossil energy, direct land, and blue water of organic dairy farms are evaluated in the Mideast, Northeast, Southeast, and Mountain regions of the US. Eighteen archetypical organic dairy farms are modeled with GHGs per kg fat and protein corrected milk (FPCM) ranging between 0.83-1.45 kg CO2-eq with and 0.93-1.59 kg CO2-eq without carbon sequestration. Enteric methane (CH4) is the major contributor (42-58%) of farm GHGs, followed by CH4 from manure (15-27%), energy use (8-18%), and material inputs (3-24%). Enteric CH4 is affected by feed efficiency and milk production, manure CH4 by the type of manure handled and stored, and GHGs from energy by the content of fossil-fuel sources in the electricity grid mix. Manure is the major source of NH3 emissions ranging from 8.2-24.3 g/kg FPCM. Alternative GHG mitigation strategies show potential reductions of up to 23 and 51% for individual and combined strategies, respectively. While enteric CH4 is the greatest GHG contributor, manure management has greater GHG mitigation potential. The choice of CH4 predictive equations, N2O emission factors, allocation, and functional units could increase GHGs up to 43% in the evaluated organic dairy farms.

Life cycle assessment and modeling approaches in silvopastoral systems: A case study of egg production integrated in an organic apple orchard

This paper aimed to assess the environmental impacts of two organic silvopastoral farms in Austria, using a Life Cycle Assessment approach. The two farms (F1, F2), with egg production integrated into an apple orchard, were compared to standard practices for each product. The functional unit was ‘1 kg fresh Class I apples’ and ‘1 kg fresh Class I eggs’. The assessment covered two scopes: cradle-to-farm gate and cradle-to-retail for each product. Effects on climate (including carbon sequestration in the soil and woody biomass), eutrophication potential (EP), acidification potential (AP), and land occupation (LO) were assessed. Feed, manure, and land were three resource loops included in the system boundary. Two modeling approaches were used from cradle-to-farm gate for distributing the impacts of the entire system between apples and eggs: model 1 (M1) used economic allocation, while model 2 (M2) divided the system into two subsystems. Results varied considerably by model. M1 consistently showed higher impacts for apples and considerably lower for eggs compared to M2. At farm gate, the carbon footprint (CF) ranged from 0.09 to 0.17 kg CO2-eq/kg apple and 0.19–1.62 kg CO2-eq/kg egg across all analyzed systems and models. Carbon sequestration reduced emissions by 22–42% for apples and by 0.4–39% for eggs. Sequestration was mainly associated with the carbon contributions from plant biomass from apple production (84–99%), with manure contributing 0.7–9%. EP ranged from 0.19 to 1.7 g PO4-eq/kg apple and 0.7–35 g PO4-eq/kg egg and AP ranged from 0.8 to 2.9 g SO2-eq/kg apple and 2–36 g SO2-eq/kg egg across all analyzed systems and models. LO ranged from 0.3 to 0.6 m2/kg apple and 0.8–9 m2/kg egg across all analyzed systems and models. Post-harvest activities accounted for up to 29% of the total impacts for EP and AP, and up to 57% for CF from cradle-to-retail. In general, the impacts per kg egg or kg apple in F1 and F2 were lower in most impact categories relative to their reference systems, driven mainly by management factors and the production phase of the value chain. Further development of modeling approaches is needed.

Hybrid process improvement framework to reduce the eutrophication potential of in-situ leaching for uranium extraction: A qualitative study

The UK government has embarked on a comprehensive revaluation of its investment in Nuclear Power (NP) in response to a confluence of factors, including rising oil and gas prices, the shift towards independent energy extraction, and mounting concerns about climate change. Central to this revaluation is the Hinkley Point C (HPC) Project, a new nuclear power station, which aligns with the UK’s decarbonisation and NetZero ambition but requires improvements highlighted by the Électricité de France’s (EDF) life cycle analysis, particularly in its Eutrophication Potential (EP). Eutrophication, a form of environmental damage stemming from excessive organism activity due to elevated nutrient loading remains is a key concern. Eutrophication is particularly relevant to nuclear power due to the nutrient emissions associated with uranium mining and milling processes. These processes contribute significantly to eutrophication, accounting for 58% of the EP per kilowatt-hour delivered. This study undertakes the development of a Hybrid Process Improvement Framework (HPIF) aimed at mitigating EP associated with uranium extraction in nuclear power plants and identifies diesel combustion in support of in-situ leaching (ISL) techniques for Uranium Extraction as the predominant contributor to EP impact. Consequently, the research underscores the necessity for a novel HPIF design aimed at reducing diesel combustion and, by extension, the overall EP value. By promoting sustainable practices, the research supports a broader move towards resource-efficient and low-impact industrial processes, crucial for the UK’s overall Net Zero strategy. Further, the study adopts the DMADV methodology for the design of the HPIF process, thus ensuring a well-structured and data-driven approach in managing the HPIF configuration process. For validation, we employ semi-structured open-ended qualitative interviews with a unique set of subject experts (n = 21) comprising nuclear industry practitioners, academic researchers, and policymakers. Insights from the analysed data from 21 subject experts indicate that the HPIF is a novel tool that can address the larger objective of responding to critical environmental concerns within the nuclear power industry. We conclude that the HPIF can mitigate EP reduction challenges associated with uranium extraction for nuclear power plants. The HPIF integrates and synthesises the methodologies of three established studies focused on reducing diesel fuel consumption in diesel generators. It systematically addresses key parameters, including load profiles, optimal generator type, number of generators, and scheduling strategies, tailored to specific load demands. By employing the advanced calculations derived from these three studies, HPIF effectively targets the fundamental issue contributing to EP value—namely, the diesel combustions of diesel generators. This framework specifically addresses the challenge of reducing EP values associated with diesel fuel usage.

Seasonal Variation of Physicochemical Properties in the Lower River Benue, Nigeria

The study investigates the impact of seasonal changes on water quality in the River Benue, Nigeria. Conducted over eighteen months from January 2020 to June 2021, the research focuses on three locations: Ibi, Lau, and Mayo-Ranewo. Key physicochemical parameters such as temperature, pH, turbidity, conductivity, Biochemical Oxygen Demand (BOD), hardness, dissolved oxygen (DO), fluoride, and nitrate were measured to assess water quality. The findings reveal significant seasonal variations in these parameters, influenced by rainfall patterns, land use, and anthropogenic activities. Temperature ranged from 25.56°C to 30.70°C, remaining within acceptable limits for tropical waters, supporting stable biological processes. However, turbidity levels exceeded recommended values, indicating the presence of suspended solids that could impair water quality and harm aquatic life. Total dissolved solids (TDS) and conductivity showed potential contamination risks, likely due to agricultural runoff and urban discharges. Dissolved oxygen (DO) levels were generally adequate, especially during the wet season, enhancing oxygen content through increased photosynthetic activity and water inflows. However, BOD spiked with rainfall, signalling organic pollution and potential eutrophication risks. Seasonal shifts in pH and water hardness reflected changes in runoff and photosynthesis, with values largely within acceptable ranges for aquatic life. Fluoride and nitrate concentrations increased in the wet season, primarily due to agricultural runoff, highlighting the influence of land-based activities on water quality.

Environmental assessment of cenosphere and GGBFS-based geopolymers: A path to greener construction materials

This study investigates the viability of utilizing cenospheres as an alternative precursor material for geopolymer formulation, comparing their performance against ground-granulated blast furnace slag (GGBFS) across various parameters such as strength, durability, cost, and environmental impacts. A cradle-to-gate life cycle assessment was performed to evaluate the environmental impact of geopolymer mixtures containing varying proportions of cenosphere and GGBFS, relative to conventional cement mortar (CM). Additionally, a multi-criteria decision-making (MCDM) analysis was employed by assigning varied importance levels to identify the optimal formulation derived from performance (strength and durability), cost, and environmental impact. The findings demonstrate that GGBFS/cenosphere-based geopolymers lower global warming potential (GWP) by 24–33 % compared to CM. Moreover, incorporating 25–75 % cenospheres in geopolymers reduces GWP by 4–7 % and energy consumption by 5 % compared to purely GGBFS-based geopolymers. The eutrophication potential (EP) and acidification potential (AP) were also reduced by 3–10 % and 5–15 %, respectively, by adding 25–75 % cenospheres in geopolymers. However, the cost is also increased by 6–18 %. Based on the MCDM analysis, geopolymers containing cenosphere possess higher overall sustainability than conventional cement-based mortars.

A Hybrid Pre-Assessment Assists in System Optimization to Convert Face Masks into Carbon Nanotubes and Hydrogen

With extensive attention being paid to the potential environmental hazards of discarded face masks, catalytic pyrolysis technologies have been proposed to realize the valorization of wastes. However, recent catalyst selection and system design have focused solely on conversion efficiency, ignoring economic cost and potential life-cycle environmental damage. Here, we propose an economic-environmental hybrid pre-assessment method to help identify catalysts and reactors with less environmental impact and high economic returns among various routes to convert discarded face masks into carbon nanotubes (CNTs) and hydrogen. In catalyst selection, it was found that a widely known Fe–Ni catalyst exhibits higher catalytic activity than a cheaper Fe catalyst, potentially increasing the economic viability of the catalytic pyrolysis system by 38%–55%. The use of this catalyst also results in a carbon reduction of 4.12–10.20 kilogram CO2 equivalent for 1 kilogram of discarded face masks, compared with the cheaper Fe catalyst. When the price of CNTs exceeds 1.49 × 104 USD·t–1, microwave-assisted pyrolysis is the optimal choice due to its superior environmental performance (in terms of its life-cycle greenhouse gas reduction potential, eutrophication potential, and human toxicity) and economic benefits. In contrast, conventional heating pyrolysis may be a more economical option due to its good stability over 43 reaction regeneration cycles, as compared with a microwave-assisted pyrolysis catalyst with a higher conversion efficiency. This study connects foundational science with ecological economics to guide emerging technologies in their research stage toward technical efficiency, economic benefits, and environmental sustainability.

Life cycle assessment in additive manufacturing of copper alloys—comparison between laser and electron beam

Additive manufacturing is becoming increasingly important for industrial production. In this context, directed energy deposition processes are in demand to achieve high deposition rates. In addition to the well-known laser-based processes, the electron beam has also reached industrial market maturity. The wire electron beam additive manufacturing offers advantages in the processing of copper materials, for example. In the literature, the higher energy efficiency and the resulting improvement in the carbon footprint of the electron beam are highlighted. However, there is a lack of practical studies with measurement data to quantify the potential of the technology. In this work, a comparative life cycle assessment between wire electron beam additive manufacturing (DED-EB) and laser powder additive manufacturing (DED-LB) is carried out. This involves determining the resources for manufacturing, producing a test component using both processes, and measuring the entire energy consumption. The environmental impact is then estimated using the factors global warming potential (GWP100), photochemical ozone creation potential (POCP), acidification potential (AP), and eutrophication potential (EP). It can be seen that wire electron beam additive manufacturing is characterized by a significantly lower energy requirement. In addition, the use of wire ensures greater resource efficiency, which leads to overall better life cycle assessment results.

Environmental impacts and nitrogen-carbon-energy nexus of vegetable production in subtropical plateau lake basins.

Vegetables are important economic crops globally, and their production has approximately doubled over the past 20 years. Globally, vegetables account for 13% of the harvested area but consume 25% of the fertilizer, leading to serious environmental impacts. However, the quantitative evaluation of vegetable production systems in subtropical plateau lake basins and the establishment of optimal management practices to further reduce environmental risks are still lacking. Using the life cycle assessment method, this study quantified the global warming, eutrophication, acidification, and energy depletion potential of vegetable production in a subtropical plateau lake basin in China based on data from 183 farmer surveys. Our results indicated that vegetable production in the study area, the Erhai Lake Basin, was high but came at a high environmental cost, mainly due to low fertilizer efficiency and high nutrient loss. Root vegetables have relatively high environmental costs due to the significant environmental impacts of fertilizer production, transportation, and application. A comprehensive analysis showed that the vegetable production in this region exhibited low economic and net ecosystem economic benefits, with ranges of 7.88-8.91 × 103 and 7.35-8.69 × 103 $ ha-1, respectively. Scenario analysis showed that adopting strategies that comprehensively consider soil, crop, and nutrient conditions for vegetable production can reduce environmental costs (with reductions in global warming potential (GWP), eutrophication potential (EP), acidification potential (AP), and energy depletion potential (EDP) by 10.6-28.2%, 65.1-73.5%, 64.5-71.9%, 47.8-70.4%, respectively) compared with the current practices of farmers. This study highlighted the importance of optimizing nutrient management in vegetable production based on farmers' practices, which can achieve more yield with less environmental impacts and thereby avoid the "trade-off" effect between productivity and environmental sustainability.

Spatially Explicit Life Cycle Global Warming and Eutrophication Potentials of Confined Dairy Production in the Contiguous US

Assessing the spatially explicit life cycle environmental impacts of livestock production systems is critical for understanding the spatial heterogeneity of environmental releases and devising spatially targeted remediation strategies. This study presents the first spatially explicit assessment on life cycle global warming and eutrophication potentials of confined dairy production at a county scale in the contiguous US. The Environmental Policy Integrated Climate model was used to estimate greenhouse gases (GHGs), NH3, and aqueous nutrient releases of feed production. The Greenhouse gases, Regulated Emissions, and Energy use in Transportation model and Commodity Flow Survey were used to assess GHGs and NH3 from feed transportation. Emission-factor-based approaches were primarily used to calculate GHGs from enteric fermentation, and GHGs, NH3, and aqueous nutrient releases from manure management. Characterization factors reported by the Intergovernmental Panel on Climate Change and Tool for Reduction and Assessment of Chemicals and other Environmental Impacts model were used to compute global warming and eutrophication potentials, respectively. The analyses revealed that life cycle global warming and eutrophication potentials of confined dairy production presented significant spatial heterogeneity among the US counties. For example, the life cycle global warming potential ranged from 462 kg CO2-eq/head to 14,189 kg CO2-eq/head. Surprisingly, sourcing feed locally cannot effectively reduce life cycle global warming and eutrophication potentials of confined dairy production. The feed supply scenarios with the lowest life cycle environmental impacts depend on the life cycle environmental impacts of feed production, geographic locations of confined dairy production, and specific impact categories. In addition, installing buffer strips in feed-producing hotspots can effectively reduce life cycle nutrient releases of confined dairy production. If 200 counties with the highest life cycle EP of corn adopt buffer strips, the reduction in life cycle EP of confined dairy production could reach 24.4%.

Dynamic process simulation for life cycle inventory data acquisition – Environmental assessment of biological and chemical phosphorus removal

In Sweden, phosphorus is commonly removed from municipal wastewater treatment by chemical precipitation (CP). Recently, such alternatives as enhanced biological phosphorus removal (EBPR) have garnered interest due to the increased risk of chemical shortage. In this study, a life cycle assessment (LCA) was performed to compare EBPR and CP in three scenarios: 1) baseline – precipitation chemicals available, 2) stricter effluent requirements – precipitation chemicals available, and 3) chemical shortage – no precipitation chemicals available. Data acquisition that was based on dynamic process simulation was useful, yielding more site-specific results, in contrast to standard literature values. The results indicated substantial differences in greenhouse gas emissions between configurations (around three times higher methane emissions for EBPR compared to CP configurations – although this finding requires further validation). These differences suggest that different emission factors for EBPR and CP should be considered. Furthermore, it is suggested to include waterline methane emissions, at least when the configuration incorporates anaerobic reactors in the water line. Further validation of emissions is necessary, especially for EBPR plants with side-stream hydrolysis and digester reject water treatment. The LCA results showed a similar overall environmental impact for both configurations, but the results of individual impact categories differed. EBPR caused greater climate impact due to the larger direct emissions of methane. Toxicity was more important for CP, based on the inherent heavy metal content in precipitation chemicals. Freshwater eutrophication was similar for both configurations, assuming that precipitation chemicals were available. However, if the recipient is sensitive, implementing EBPR reduces the freshwater eutrophication potential by 75% during a chemical shortage, and should be considered.

Production and recycling of blast furnace slag: A life cycle assessment approach in India

AbstractThis article investigated the cradle‐to‐gate environmental impact of granulated blast furnace slag (GBFS) produced in the steel industry and replacement of blast furnace (BF) slag (50%) in place of clinker in Portland slag cement using GaBi software (Indian extension database). In case of GBFS production, maximum burden on the environment is due to BF slag production and the amount of electricity consumed (161 MJ/ton) during the granulation process. The influence of electricity sources on GBFS production was studied via scenario analysis. For investigation, solar and thermal electricity mixes were considered in 50:50 and 75:25 ratios. For the 75:25 ratios, the abiotic depletion potential (fossil), acidification, eutrophication, global warming, and human toxicity potential show a decreasing trend of approximately 45%, 49%, 48%, 46%, and 41%, respectively. The scenario analysis of BF slag transportation (from 100 to 750 km) demonstrates a negative impact due to fuel. The results quantitatively confirm that the addition of GBFS can lower the overall impact for construction and steel industries.

Spatially Explicit Impact of Land Use Changes in the Bay Area on Anthropogenic Phosphorus Emissions and Freshwater Eutrophication Potential.

Land use changes significantly impact anthropogenic phosphorus (P) emissions, their migration to a water environment, and the formation of freshwater eutrophication potential (FEP), yet the spatiotemporally heterogeneous relationships at the regional scale have been less explored. This study combines land use classification, P-flow modeling, spatial analysis, and cause-effect chain modeling to assess P emissions and P-induced FEP at a fine spatial resolution in Guangdong-Hong Kong-Macao Greater Bay Area and reveals their dynamic responses to land use changes. We find that land conversion from cultivated land to impervious land corresponded to an increase in P emissions of 4.1, 1.8, and 0.5 Gg during 2000-2005, 2005-2010, and 2010-2015 periods, respectively, revealing its dominant but weakening role in the intensification of P emissions especially in less-developed cities. Expansion of aquacultural land gradually became the primary contributor to the increase in both the amount and intensity of P emissions. Land conversions from cultivated land to impervious land and from natural water bodies to aquacultural land led to 35.9% and 25.3% of the increase in FEP, respectively. Our study identifies hotspots for mitigating the environmental pressure from P emissions and provides tailored land management strategies at specific regional development stages and within sensitive areas.

A two-step approach to recycling hydroponics waste nutrient solutions using fertiliser drawn forward osmosis and chemical precipitation

Hydroponic waste nutrient solutions (HWNS) present significant environmental and economic challenges due to their high phosphorus content and potential for eutrophication. Addressing these issues requires innovative approaches that mitigate environmental impacts and recover valuable resources. This study introduces a novel two-step approach that combines Fertiliser Drawn Forward Osmosis (FDFO) and chemical precipitation to recycle HWNS effectively.In the first phase, FDFO was employed to concentrate HWNS using a commercial hydroponic fertiliser as the draw solution. This process resulted in a diluted fertiliser solution (potentially suitable for reuse in hydroponics irrigation) and a concentrated HWNS rich in phosphorus. The concentrated HWNS was then subjected to chemical precipitation in the second phase, where phosphorus was recovered as calcium phosphate by adding sodium hydroxide at an optimised pH of 9.5.Bench-scale experiments demonstrated a 93% water recovery rate using FDFO and an impressive 99.5% phosphorus removal efficiency through chemical precipitation. These results indicate that the combined FDFO and chemical precipitation processes effectively recover water and phosphorus from HWNS and reduce reliance on synthetic fertilisers and freshwater in hydroponic systems.The findings of this study demonstrate that the two-step approach not only enhances water and phosphorus recovery but also improves the efficiency of the chemical precipitation process by achieving higher recovery rates resulting in more sustainable hydroponic systems.