Kg Of CO2 Research Articles

Pathway to Carbon Neutrality in the Cement Industry: CO2 Uptake by Recycled Aggregates from Construction and Demolition Waste

Cementitious materials can capture CO2 through carbonation reaction during their service life and post-demolition. Indeed, construction and demolition waste (CDW) still have some potential for carbonation as they contain concrete and cement-based mortars. This research consists of an experimental programme to evaluate the CO2 capture of recycling aggregates (RAs) from CDW. Two types of CDW were studied, namely mixed recycled aggregates (MRAs) and recycled concrete aggregates (RCAs). The recycled aggregates were submitted to forced and accelerated carbonation at 23 °C, 60% relative humidity and 25% of CO2 concentration. This study contributes to the existing literature by investigating more realistic RA sources that have already absorbed atmospheric CO2 during their service life. From the experimental campaign, the results show that RCAs have higher carbonation potential when compared to MRAs due to the higher cementitious material content (Rc) and to the degree of natural carbonation. The recycled aggregates’ maximum CO2 capture was assessed by thermogravimetric analysis (TGA) at different CO2 exposure times. It was verified that the maximum CO2 capture, respectively, for MRAs and RCAs, occurred after 5 h and 12 h of exposition. In short, CDW captured from 5 wt.% to 35 wt.% of CO2 per tonne of cement paste, which corresponds to 0.6% to 4.1% per tonne of aggregate. It was concluded that the carbonation process of CDW has the potential to sequester from 123 kg to 225 kg of CO2 per tonne of cement paste for MRAs and 52 up to 491 kg of CO2 per tonne of cement paste for RCAs.

Comparative techno-economic and environmental analysis of a relocatable solar power tower for low to medium temperature industrial process heat supply

The primary objective of this study is to promote the adoption of solar power tower (SPT) technology in low to medium-temperature industrial process heat (IPH) applications and compare it with other heat generation alternatives. Through comprehensive techno-economic and environmental analyses, a proposed relocatable SPT-based IPH plant (PR-SPT-IPH), with a capacity of 1 MWth, is thoroughly evaluated against traditional concentrating solar-thermal power (CSP) technologies like parabolic trough collectors (PTC) and linear Fresnel reflectors (LFR), as well as natural gas (NG) and photovoltaic (PV)-based IPH systems. The techno-economic assessment of the PR-SPT-IPH is performed using an in-house developed MATLAB code, while the system advisor model (SAM) is used to simulate equivalent PTC-, LFR-, and PV-based IPH plants. The primary techno-economic assessment metric is the levelized cost of heat (LCOH), while the environmental analysis quantifies the avoided greenhouse gas (GHG) emissions and other pollutants resulting from NG combustion. The results show that the PR-SPT-IPH plant achieves the lowest LCOH of 2.42 cents/kWhth, generating annual thermal energy of 5.62 GWhth with a capacity factor of 48.27 %. With certain assumptions, this cost can be further reduced to 1.5 cents/kWhth, meeting the U.S. Department of Energy targets. The PR-SPT-IPH plant could annually avoid emitting 1112 kg of CO2, 54 kg of particulate matter, 1201.76 kg of NOx, and 5.08 kg of SO2. It could also save annual external costs between $43,100.28 and $153,194.67, while the annually saved fuel cost could reach $151,632. The study indicates that the PR-SPT-IPH plant surpasses PTC-, LFR-, NG-, and PV-based IPH plants both technically and financially. With reduced capital costs and appropriate incentives, the PR-SPT-IPH plant emerges as an economically and environmentally viable choice for low to medium-temperature IPH applications.

Sources of limestone dissolution from surface water-groundwater interaction in the carbonate critical zone

Dissolution of carbonate minerals in karst aquifers has long been recognized to result from recharge of surface water undersaturated with respect to calcite from carbonic acid produced by hydration of dissolved atmospheric and respired CO2. However, dissolution also results from additional acids produced by reactions of redox sensitive solutes in the subsurface, which may represent a source of CO2 to Earth's atmosphere. Because the magnitude of dissolution by these additional acids is poorly constrained, we compare here fractions of dissolution from initial surface water undersaturation and subsurface redox reactions. Estimates are based on chemical mixing and geochemical (PHREEQC) modeling of time series measurements of water compositions at a spring vent that receives surface water during stream flooding and a stream sink-rise system in north-central Florida. During a single spring reversal, 9.2 × 105 kg of limestone dissolved. At the stream sink-rise system, where subsurface residence times are shorter than during the spring reversal, both limestone dissolution (102–104 kg) and precipitation (102–105 kg) occur as water flows through the conduits with residence times ranging from 10 to 70 h. At both sites, maximum calcite dissolution rates of ∼10 μM hr−1 occurs at subsurface residence times between 30 and 50 h. For subsurface residence time > ∼20–60 h, the models indicate that production of additional acid in the subsurface is required for ∼53 ± 7% of dissolution. Oxidation of organic carbon, ammonium, pyrite, iron, and/or manganese produce sufficient acid for additional dissolution, but dissolved oxygen is insufficient for these reactions, indicating some acidity is generated under anerobic conditions. Dissolution caused by subsurface reactions in our samples represents mobilization of 20 × 104-30 × 104 kg of CO2 via remineralization of organic carbon or carbonate dissolution by nitric and sulfuric acids. Acid produced by subsurface redox reactions during surface water-groundwater interactions, including non‑carbonic acids, are important in conduit development and carbon cycling in the carbonate critical zone.

Hybrid renewable/grid power systems, an essential for base transceiver station penetration in Rural Nigeria

The energy crisis in Nigeria has continued to impede the rapid expansion of the telecommunication industry, whose operating expenditure is galloping due to over-dependence on diesel generators as an alternative source of power to its base transceiver station (BTS). This fossil-fuel power source has also increased the industry’s carbon footprint. As a solution to these problems, the objective of this work is to provide a sustainable and quality hybrid DC power supply system for BTS that would increase access to information and communication technology or ICT infrastructure. This involves the integration of solar & wind energy with the grid. The sizing of the hybrid sub-systems was designed & simulated using MATLAB Simulink to test for functionality. A prototype of the design system was then implemented with the results showing an average power output that guarantees 21 hours/day of supply. By installing this hybrid system of 1.3 kW, approximately 2.55 kg of diesel (C10H20) would be un-utilized by one BTS, thereby preventing 3.6 kg of CO2 from been emitted to the atmosphere daily. Extrapolating these values shows 930.75 kg of diesel can be saved and reduce 1314 kg of CO2 emission within a year. Hence eliminating the need for diesel-backup generator for a grid connected or non-grid BTS sited in rural areas.

Quantifying the Environmental Impact of Private and Commercial Pilot License Training in Canada

As the global aviation sector expands to accommodate increasing air travel demand, the subsequent rise in flights exacerbates carbon dioxide (CO2) emissions, challenging the sector’s environmental sustainability. Targeting net-zero emissions by 2050, international aviation agencies are stressing the imperative of reducing emissions directly at their source. While the literature provides abundant estimates of aviation emissions from airline flights, there has been a lack of work aimed at quantifying CO2 emissions specific to the general aviation sector. This study investigates CO2 emissions attributed to the pilot training sub-sector within Canada’s general aviation sector. It specifically examines the initial phase of pilot training, known as ab initio training, extending through to the attainment of a commercial pilot license. Utilizing a mathematical framework alongside assumptions, combined with data on license issuances over a 23-year period, it estimated that each hour of flight training emits about 70.4 kg of CO2, varying between 44.9 kg and 94.9 kg per hour. Annual CO2 emissions from Canada’s ab initio pilot training are estimated at approximately 30,000 tons, with a possible range of 19,000 to 40,000 tons. The study also explores mitigation opportunities, such as flight simulation training devices and electric aircraft. Though focusing on Canada’s ab initio pilot training, the findings have international relevance.

Techno-Economic and Environmental Analysis of the Integration of PV Systems into Hybrid Vessels

Solar energy is one type of clean energy resource, and currently the IMO, EU and UK are targeting net zero carbon emissions by 2050. This paper delves into the integration of photovoltaic (PV) systems into hybrid vessels in order to meet their strategies and targets. The technical challenges that come with designing such systems as well as their economic and environmental impacts are examined. By optimizing the usage of harnessed solar energy, we discover the operational strategy that provides maximal benefits through day-to-day savings as well as over the 25 year lifespan of solar panels. It demonstrates impressive economic viability, with cost savings of up to GBP 4.55 per day and a payoff period as short as 9 years. It also displays a modest emission reduction of up to 8.002 kg of CO2, which serves as proof for a pathway to greener practices in the maritime industry. This report highlights the operational flexibility that a hybrid vessel possesses once paired with a PV system through the ability to withstand regulatory and market changes. Also, when looking ahead, further adoption of PV technology creates opportunities for innovation in adopting renewable energy solutions in maritime transportation.

Green building future: algal application technology

In the context of rising global energy demands driven by population growth and urbanization, the construction industry significantly contributes to greenhouse gas emissions during the construction phase and subsequent energy consumption. Fossil fuel dependency for heating and energy needs exacerbates climate change, necessitating urgent solutions. Algal technology emerges as a promising strategy for green building practices, addressing energy efficiency and emissions reduction. Algae's unique ability to absorb carbon dioxide (CO2) through photosynthesis is harnessed by deploying photobioreactors on building exteriors. Studies indicate that each kilogram of dry algae consumes 1.83 kg of CO2 while offering applications as organic fertilizer, oil, and protein sources. This technology not only diminishes CO2 emissions but also transforms wastewater and generates bioenergy, catering to building energy requirements. Algal technology's economic and environmental significance becomes evident through carbon capture, energy generation, and circular waste management, aligning with sustainability principles. This study highlights the potential of algal technology to shape the future of eco-friendly conscious construction practices, providing avenues for reduced emissions, efficient energy utilization, and sustainable development.

Optimizing in-situ CO2 mineralisation: geomechanics and scalability in dunite and serpentinite rocks – Examples from Australia and New Zealand

The collective drive towards achieving net-zero greenhouse gas emissions by 2050 has spurred interest in engineering solutions for carbon capture and storage worldwide. One such approach involves the permanent storage of CO2 in earth-abundant Ca-, Fe-, and Mg-bearing silicate rocks and minerals as carbonates via the process of CO2 mineralisation. This necessitates a thorough understanding of carbonate conversion under geologically relevant conditions. Nevertheless, research on CO2 injection for mineralisation via naturally fractured host rocks or induced fractures, with a research emphasis on rock mechanics and stimulated reservoir volumes (SRV) within geoengineering CO2 storage, is continuously expanding. This research addresses critical challenges related to identifying favourable geographic locations for CO2 mineralisation. It specifically focuses on the abundant availability of Mg, Ca, and Fe cations for exothermic CO2 reactions and their impact on fracture conductivity during in-situ mineralisation. A comprehensive analysis of 26 dunite and serpentinite samples from diverse locations in Australia and New Zealand, including 10 from a cored drilled hole, was conducted. Quantification of divalent cation (Mg, Ca, Fe) content and cation release capacity using XRF and XRD revealed higher cation percentages in dunite samples (approximately 30 %) compared to serpentinite samples (approximately 26 %). Additionally, the study estimated the stimulated rock mass-to-CO2 sequestered ratio, RCO2, with dunite samples averaging approximately 2.20 RCO2 values and serpentinite samples averaging approximately 2.53. Geomechanical testing enabled the prediction of fracture propagation pressures during aqueous CO2 injection for in-situ mineralisation and the estimation of fracture geometries, emphasizing the role of rock stiffness in determining fracture width (averaging 6.0 mm). Furthermore, the research estimated the rock volume exposed to CO2-laden fluid during injection, particularly focusing on the GHQ-3 sample, which theoretically amounted to approximately 600 kg of rock capable of sequestering around 300 kg of CO2 for a 10 m3 fluid volume with a CO2 concentration of 1molkg−1. The study established a relationship between injected volume and CO2 uptake, suggesting the potential for significant CO2 sequestration scalability by employing horizontal wells and fracturing additional zones, thereby creating and intersecting multiple transverse fractures along a single target zone.

Environmental impact assessment of the electrokinetic adsorption barriers to remove different herbicides from agricultural soils

In this study, the sustainability of the electrokinetic remediation soil flushing (EKSFs) process integrated without and with adsorption barriers (EKABs) have been evaluated for the treatment of four soils contaminated with Atrazine, Oxyfluorfen, Chlorosulfuron and 2,4-D. To this purpose, the environmental effects of both procedures (EKSFs and EKABs) have been determined through a life cycle assessment (LCA). SimaPro 9.3.0.3 was used as software tool and Ecoinvent 3.3 as data base to carry out the inventory of the equipment of each remediation setup based on experimental measurements. The environmental burden was quantified using the AWARE, USEtox, IPPC, and ReCiPe methods into 3 Endpoint impact categories (and damage to human health, ecosystem and resources) and 7 Midpoints impact categories (water footprint, global warming potential, ozone depletion, human toxicity (cancer and human non-cancer), freshwater ecotoxicity and terrestrial ecotoxicity). In general terms, the energy applied to treatment (using the Spanish energy mix) was the parameter with the greatest influence on the carbon footprint, ozone layer depletion and water footprint accounting for around 70 % of the overall impact contribution. On the other hand, from the point of view of human toxicity and freshwater ecotoxicity of soil treatments with 32 mg kg−1 of the different pesticides, the EKSF treatment is recommended for soils with Chlorosulfuron. In this case, the carbon footprint and water footprint reached values around 0.36 kg of CO2 and 114 L of water per kg of dry soil, respectively. Finally, a sensitivity analysis was performed assuming different scenarios.

Environmental sustainability in hospitals: Dual analysis of electrical consumption and pollutant emissions

The emission of pollutants following electricity consumption is significant, and hospitals are major contributors to energy consumption. Hence, the aim of this study was a survey of electrical consumption rate and environmental pollutants emissions in selected hospitals. This descriptive-analytical and cross-sectional study was conducted over three years and based on electricity bills and bed indicators in selected hospitals in Tehran, Iran. Emissions Calculator software was used to calculate the emission of pollutants caused by electricity consumption. Kolmogorov Smirnov, Least Significant Difference (LSD), and one-way ANOVA tests were used to analyze the data. Results showed that the total average electricity consumption for each active day bed and occupied day bed was 9.6 and 13.6 times higher than the recommended standards. The average electricity consumption for each active day bed in hospitals A, B, and C was 13.7, 10.2, and 5 times higher than the standard value, respectively, while for occupied day beds, the consumption was 17.3, 15.1, and 8.5 times higher than the standard value, respectively. Additionally, the total electricity consumption in these hospitals resulted in the emission of 41837100 kg of CO2, 124815 kg of SO2, 103699 kg of NOx, 9769 kg of CO, 4885 kg of PM10, and 757 kg of VOCs into the environment. Based on the monthly active bed index and occupied day bed, there was a significant difference in the average electrical consumption among A, B, and C hospitals (p = 0.0001). Electricity consumption in the studied hospitals exceeds standards. Implementing optimal designs for lighting, heating, and cooling, along with energy optimization training, technical audits, and inspections are essential for both economic benefits and reducing environmental pollutants.

Analysis of Hybrid Ship Machinery System with Proton Exchange Membrane Fuel Cells and Battery Pack

As marine traffic is contributing to pollution, and most vessels have predictable routes with repetitive load profiles, to reduce their impact on environment, hybrid systems with proton exchange membrane fuel cells (PEMFC-s) and battery pack are a promising replacement. For this purpose, the new approach takes into consideration an alternative to diesel propulsion with the additional benefit of carbon neutrality and increase of system efficiency. Additionally, in the developed numerical model, control of the PEMFC–battery hybrid energy system with balance of plant is incorporated with repowering existing vessels that have two diesel engines with 300 kWe. The goal of this paper is to develop a numerical model that analyzes and determines an equivalent hybrid ship propulsion system for a known traveling route. The developed numerical model consists of an interconnected system with the PEMFC stack and a battery pack as power sources. The numerical model was developed and optimized to meet the minimal required power demand for a successful route, which has variable loads and sees ships sail daily six times along the same route—in total 54 nautical miles. The results showed that the equivalent hybrid power system consists of a 300 kWe PEMFC stack and battery pack with 424 kWh battery and state of charge varying between 20 and 87%. To power this new hybrid power system, a hydrogen tank of 7200 L holding 284.7 kg at pressure of 700 bar is required, compared to previous system that consumed 1524 kg of diesel and generated 4886 kg of CO2.

Waste analysis and energy use estimation during MR-HIFU treatment: first steps towards calculating total environmental impact

ObjectivesTo assess the environmental impact of the non-invasive Magnetic Resonance image-guided High-Intensity Focused Ultrasound (MR-HIFU) treatment of uterine fibroids, we aimed to perform a full Life Cycle Assessment (LCA). However, as a full LCA was not feasible at this time, we evaluated the CO2 (carbon dioxide) emission from the MRI scanner, MR-HIFU device, and the medication used, and analyzed solid waste produced during treatment.MethodsOur functional unit was one uterine fibroid MR-HIFU treatment. The moment the patient entered the day care-unit until she left, defined our boundaries of investigation. We retrospectively collected data from 25 treatments to assess the CO2 emission based on the energy used by the MRI scanner and MR-HIFU device and the amount and type of medication administered. Solid waste was prospectively collected from five treatments.ResultsDuring an MR-HIFU treatment, the MRI scanner and MR-HIFU device produced 33.2 ± 8.7 kg of CO2 emission and medication administered 0.13 ± 0.04 kg. A uterine fibroid MR-HIFU treatment produced 1.2 kg (range 1.1–1.4) of solid waste.ConclusionsEnvironmental impact should ideally be analyzed for all (new) medical treatments. By assessing part of the CO2 emission and solid waste produced, we have taken the first steps towards analyzing the total environmental impact of the MR-HIFU treatment of uterine fibroids. These data can contribute to future studies comparing the results of MR-HIFU LCAs with LCAs of other uterine fibroid therapies.Critical relevance statementIn addition to (cost-) effectiveness, the environmental impact of new treatments should be assessed. We took the first steps towards analyzing the total environmental impact of uterine fibroid MR-HIFU.Key points• Life Cycle Assessments (LCAs) should be performed for all (new) medical treatments.• We took the first steps towards analyzing the environmental impact of uterine fibroid MR-HIFU.• Energy used by the MRI scanner and MR-HIFU device corresponded to 33.2 ± 8.7 kg of CO2 emission.Graphical

Design of a Solar Dish Receiver and Life Cycle Assessment of a Hot Water System

The energy sector is the main source of greenhouse gases, so it has the highest potential for improvement. The improvements can be achieved by generating energy from renewable sources. It is necessary to combine production from renewable sources with storage systems. Thermal energy storage using concentrated solar power systems is a promising technology for dispatchable renewable energy that can guarantee a stable energy supply even in remote areas without contributing to greenhouse gas emissions during operation. However, it must be emphasised that greenhouse gases and other impacts can occur during the production process of concentrating solar system components. This paper analyses the receiver design to produce thermal energy for the existing CSP dish plant at the Energy Center of the Politecnico di Torino. The plant is designed to produce electrical energy in the spring and summer periods. In addition to this energy production, the CSP can be adopted to produce thermal energy, through hot water, during the less favourable periods of the year in terms of global solar radiation. The surface heat flux is calculated in the first part of the analysis to obtain the maximum internal temperature in the receiver, which is 873.7 °C. This value is a constraint for the choice of material for the solar receiver. A life cycle assessment is performed to compare the emissions generated during the production of the main components of the CSP system with the emissions generated by the methane-fuelled water heater to produce the same amount of thermal energy. It can be concluded that the production of the main components of the CSP system results in lower greenhouse gas emissions than the operational phase of a conventional system. Given the assumptions made, the utilization of methane leads to the emission of approximately 12,240 kg of CO2, whereas the production of the CSP system results in emissions totalling 5332.8 kg of CO2 equivalent

Sustainable utilization of concrete slurry waste in eco-friendly artificial lightweight cold-bonded aggregates: An alternative pathway for efficiently sequestrating CO2

Concrete slurry waste (CSW) has the potential of capturing or sequestering CO2. This study designed the low-carbon artificial lightweight cold-bonded aggregates with ultra-high volume of CSW, OSP and MSWIBA (CSW-ALCBAs), and the CO2 sequestrating, compressive strength, and physical properties, leaching toxicity and CO2 emissions of CSW-ALCBAs were investigated. Meanwhile, a novel carbonization device was designed to quantitatively evaluate the potential of CSW-ALCBAs for CO2 adsorption. The results show that both OSP and MSWIBA have the effect of enhancing the CO2 sequestration of CSW-ALCBAs. Besides, the strength, water absorption and apparent density of CSW-ALCBAs also satisfy the demands of GB/T 17461.1–2010. CSW-ALCBAs also exhibit excellent ability to solidify heavy metals and the removal rate of heavy metals is above 80% excepting Cr. ALCBAs with 85% CSW+5% OSP+10% MSWIBA can absorb 29.1313 kg of CO2 (1000 kg ALCBAs), has the highest compressive strength of 1.3 MPa after curing 28 days, water absorption rate is 15.05% and apparent density is 1.3318 g/m3. Overall, this innovative design of CSW-augmented ALCBAs can open up a new area of CSW application that develops technically feasible and cost-efficient carbon-negative building materials.

Techno-Environmental Evaluation of Alkaline Treatment in Flax Reinforced Thermoplastics.

A combination of thermoplastics and natural fiber reinforcements is considered an ideal choice to mitigate environmental impacts and enhance recyclability or reusability. Chemical treatments are often employed to enhance the thermomechanical properties of natural fiber-reinforced plastics. Nevertheless, it is of paramount importance to assess the techno-economic impact of such chemical treatments and environmentally friendly materials for their implementation in mass productions on an industrial scale. In this work, high-density polyethylene is reinforced with sodium hydroxide (NaOH)-treated and untreated flax fibers to study its impact on mechanical and environmental properties. The composites treated with NaOH exhibited a 37% increase in tensile strength. However, life cycle assessment performed on the NaOH-treated samples showed that they had a global warming potential of 5.8 kg of CO2, a terrestrial acidification potential of 0.0269 kg of SO2, and a human carcinogenic toxicity of 0.031 kg of 1,4-DCB compared to the untreated samples. In summary, the techno-environmental analysis reveals a novel approach to identifying chemical treatments based on their technical and environmental effects.

Use of recycled concrete and rice husk ash for concrete: A review

The rapid development of populations and the demand in the consumption of concrete is generating the need to produce larger quantities of cement, which brings with it negative effects for the environment. Approximately 0.87 kg of CO2 is produced by the manufacture of cement; In addition, the use of aggregates is generating great concern in the construction industry, due to the costs and the restriction of these. Similarly, the accumulation of construction and demolition waste (RCA) and rice husk ash (RHA) contribute to pollution. Therefore, the objective of this manuscript is to review the literature on the use of RCA and RHA for the elaboration of concrete. For this, indexed articles were used, between the years 2017-2021. The results showed that when 8% RHA is added, the concrete reaches a compressive strength of 70 MPa; as well as, the flexural strength of concrete by adding 50% RCA + 1.50% basalt microfibers was increased by 29.44%. On the other hand, when RHA is added by 15% it reaches a compressive strength of 48.8 MPa; in turn, the mechanical performance at bending with 10% seashell by fine aggregate and 20% RHA by cement, reached a resistance of 65 MPa. Concluding, that the behavior of concrete undoubtedly depends on the proportions of either RCA or RHA; however, the percentages must be no more than 8% and 15% respectively.

Production of Chestnut Coppice Biomass in a Framework of Low Mechanization and High Expectations to Combat Climate Change and Other Social Expectations

Climate change has become one of the most critical problems facing modern society. Sustainable forest management can be an important solution to counter the increasing concentration of carbon dioxide in the atmosphere. In particular, management of the chestnut forest could prove to be an effective strategy to absorb carbon dioxide as this species is characterized by sustained growth, so it has a high capacity to store carbon, and through the use of wood products, it is possible to sequester it for a considerable period. Chestnut (Castanea sativa Mill.) forests cover an area of about 800,000 ha in Italy, most of which is managed as coppice. It plays a central role in the Latium Region where its productive function is very important, as it provides timber of excellent quality. The purpose of this paper is to verify whether the current management of chestnut is efficient, as well as whether retractable wood products can contribute to the fight against climate change. The chestnut coppice located in the municipality of Tolfa (Lazio region, Italy) produces timber for 352 m3/ha and stores about 390,000 kg of CO2. Wood residues and losses during woodworking, together with emissions for the use of machineries, generate emissions of 368,000 kg of CO2. The chestnut semi-finished products, with long-term use prospects, retain a net volume of 22,000 kg of CO2. Although this is good for combating climate change, the amount of CO2 stored is very low, less than 6% of the CO2 stored by functional unit. Chestnut wood has a high versatility of use, so it could replace several products generated by fossil raw materials. Moreover, the implementation of precision forestry, the adoption of forest management more oriented to favor larger plants, the development of local economies and the reduction in the carbon footprint of the wood supply chain through the use of sustainable technologies would increase the capacity for climate change mitigation and increase the added value of its products.

State of the Art Review of Attributes and Mechanical Properties of Hempcrete

The global surge in environmental pollution, largely attributed to industrialization, has fueled a pressing need for sustainable solutions. In response, the construction sector is increasingly focusing on bio-based materials such as hemp, recognized for its low environmental footprint and prominent carbon-negative quality. As designers, housebuilders, and an environmentally conscious society pivot towards ecological alternatives to standard building materials, hempcrete emerges as a promising candidate. As a composite material mainly made from hemp hurd/shiv, water, and lime, hempcrete offers the ability to sequester carbon long after its incorporation into structures. As a result, the hemp cultivation process—which can be completed within less than four months—ensures that more carbon is absorbed during production and deployment than emitted, e.g., per one study, sequestration on the order of 300 kg of CO2 per m3 of hempcrete. In comparison to concrete, hempcrete offers a more sustainable footprint, given its recyclability post life cycle. This state-of-the-art review paper delves deep into different aspects of hempcrete, summarizing its multifaceted attributes, particularly its compressive strength. Based on the study conducted, the paper also suggests strategies to augment this strength, thereby transitioning hempcrete from a non-load-bearing material to one capable of shouldering significant weight. As architects and designers consistently strive to align their projects with high ecological standards, focusing not just on aesthetic appeal but also environmental compatibility, hempcrete becomes an increasingly fitting solution for the future of construction.

Green hydrogen production using proton membrane electrolysis of clean drinking water

With the EU’s green strategy and its member countries making a conscious effort to move away from fossil fuels and cut greenhouse gas emissions, there has been an uptick in technologies that produce green energy. Power-to-X has become an important topic in recent times, due to the so-called emission-free process of creating hydrogen from excess renewable energy. This research investigated this claim of being emission-free by analysing the method of obtaining extremely clean (pure) drinking water to produce hydrogen. A linear equation was produced that determines the carbon dioxide (CO2) intensity per kilowatt-hour of electricity used in producing a kilogram of water used to produce hydrogen. It was found that carbon dioxide emissions were produced by small-, medium- and large-capacity projects based in Denmark. Indicatively, for a 1 GW project facility, it was calculated that such a plant can produce 160 161 kg of carbon dioxide per year, so apparently, nothing comes without a cost.

Ecological footprint of different laying hen production systems in San Jeronimo municipality Antioquia, Colombia

In recent years, fish production has increased worldwide due to population growth and consumer interest in this type of product, proving an increase in the waste generated, with concomitant negative impact on the environment. Ecological footprint methodology is one of the sustainability indicators most used for assessing process environmental impact. This technique quantifies the effect of anthropogenic activities on the environment concerning water, forest products, infrastructure and carbon footprint, providing integral, comparable and reliable results. In this study, the environmental impact generated by taking advantage of red tilapia (Oreochromis Spp.) viscera to produce chemical silage and its implementation in the feeding of laying hens was determined, using the ecological footprint methodology as an indicator of sustainability. The productive system consisted of a red tilapia (Oreochromis ssp.) production farm located in the municipality of San Jerónimo, Antioquia (Colombia). The productive variables of the laying hens, laying percentage, egg weight and feed conversion ratio were evaluated. This chemical silage production process generates a reduction of 1.493 kg of CO2 per month compared to that generated by fresh viscera and are discharged into shallow dumps. Additionally, the main categories that generate the greatest impact on the production system are the use of natural resources and wastewater disposal. On the other hand, the productive variables of laying hens of the Isa Brown breed were not significantly affected by the inclusion of chemical silage at the 95% significance level, maintaining the percentage of laying and improving feed conversion. It was concluded that the use of fish by-products to produce feed for laying hens generates a reduction in the environmental load when compared to conventional waste disposal processes (landfill disposal). Red tilapia (Oreochromis Spp.) viscera chemical silage can be used as an alternative protein substitute in feeding laying hens for improved production performance. Key words: Ecological footprint, fish waste, layer hen, chemical silage, wastewater