The Scientific Journal of Riga Technical University
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Challenges in Standardizing Global Emission Factors for Peatlands
No full textPeatlands have a crucial role in the global carbon cycle, acting as significant carbon sinks, but become a significant source of greenhouse gas (GHG) emissions when peat extraction is taking place. This article presents a comprehensive overview of peatland ecosystems, emphasizing their classification across various climatic zones and the complex set of different characteristics that determine contribution to GHG emissions. Currently, inconsistency exists in definition of emission factors used between countries leading to varied approaches in estimating peatland emissions and posing significant challenges in the comparison and aggregation of global data on peat extraction related GHG. The aim of the study is to analyse the disparities in emission factors and calculation methodologies employed by different countries. Data from national GHG emission reports are submitted under the UNFCCC and the Kyoto Protocol. Emissions report data calculations and emission factors can be based either on nationally determined data or on data specified in the IPCC guidelines. Consequently, emission factor data for four countries - Latvia, Finland, Sweden and Germany - are collected and processed, which were compared with IPCC guideline data. The data were compared in two ways: by equating units of measurement and by modeling. The results show there is a pronounced difference between the emission factors of each country, however, all these factors are lower than the maximum values specified in the IPCC guidelines. It was also determined that comparing the total emission factors with the modeled results, no significant difference is observed between these results. The study concludes that emission factors are predetermined differently for each country, and it is not possible to specify the differences among assumptions for parameters included in the determination of the emission factors. The results suggest there is a need for development of more transparent accounting of emissions with regard to the diverse environmental and anthropogenic factors influencing peatland ecosystems. Factors like composition, depth of peat, water table levels, and local land-use practices further compound this variability in emission accounting. Addressing these challenges is crucial for enhancing the accuracy and reliability of GHG emission reporting under international frameworks like the United Nations Framework Convention on Climate Change and the Kyoto Protocol
Analysis of Introducing Plastic Waste Enzymatic Recycling for Sustainable Waste Management in Latvia
No full textEconomic growth, urbanisation, and consumer consumption habits have contributed to the yearly increase in the municipal solid waste amount. A significant portion of household waste consists of plastic materials and packaging, which currently cannot be fully and endlessly recycled, does not decompose in nature, and degrades into micro- and nanoparticles entering the soil, air, aquatic environments, and organisms. According to an OECD report from 2022, the amount of plastic waste produced globally is expected to triple by 2060, with around half being landfilled and less than one-fifth being recycled. As waste volumes are going to increase, the need to ensure appropriate waste recycling technology is addressed in this study by introducing enzymatic plastic waste recycling in Latvia. Enzymatic recycling has an advantage over mechanical recycling technology because it can depolymerise plastics without degrading the quality of the material. The methodology applied in this study includes data analysis of the waste amount in Latvia, analysis of the existing plastic recycling plant operation, life cycle assessment of existing and proposed methods, and socio-economic impact evaluation. The proposed solution meets the objectives of promoting sustainable plastic waste recycling through the introduction of enzymatic recycling; therefore, it aligns with the European Union’s targets to follow circular economy principles
Rīgas Politehnikuma / Rīgas Politehniskā institūta profesora Heinriha Malhera (1848–1927) darbība un devums Latvijai
No full textRīgas Politehnikumā (RP) tā pastāvēšanas pirmajās desmitgadēs strādāja daudz ārzemnieku, viņu vidū arī viens no starptautiski atpazīstamākajiem docētājiem un zinātniekiem ģeodēzists un hidrotehniķis Heinrihs Malhers (Heinrich Malcher; 1848–1927), kurš turpināja strādāt arī pēc augstskolas reorganizācijas par Rīgas Politehnisko institūtu (RPI; 1896). 20 gadu profesors bija RP / RPI Inženieru nodaļas vadītājs (1882–1902). Līdzās pedagoģiskajam darbam H. Malhers izprojektēja ūdensvadu Jelgavai (1881), vadīja Rīgas pilsētas pirmā triangulācijas tīkla izveidi, nodarbojās ar pilsētas notekūdeņu novadīšanas jautājumiem, darbojās Rīgas Tehniskajā biedrībā. Mūža nogalē viņš dzīvoja Čehijā, Kujavī ciematā, kur izveidoja pirmo ūdens sadales sistēmu un strādāja par celtniecības konsultantu un inspektoru
CONECT 2023 XVI International Scientific Conference of Environmental and Climate Technologies
Full text link10–12 May 2023 | Riga, Latvi
A Sustainability-based Approach for Geotechnical Infrastructure
Full text linkUrban growth needs large cities, and the current emphasis on landscape preservation makes using underground spaces both an opportunity and a significant necessity. However, underground construction techniques significantly impact the sustainability of the built environment, including infrastructure systems and their entire supply chains. Nowadays, there is a shortage of quantitative methodologies to assess and measure the sustainability of underground building processes that effectively integrate the three pillars of sustainability (environmental, social, and economic). Thus, this study aims to solve the abovementioned issues by explaining how to incorporate sustainability goals into geotechnical projects to address measure-driven strategies and eco-design-based solutions appropriately. This study illustrates a novel methodology based on the Life Cycle Thinking approach, with a particular emphasis on geotechnical ground improvement techniques. Specifically, the suggested method incorporates the concept of the EU Taxonomy, following the EU Green Deal, with the Envision framework to guide decision-makers toward a more sustainable, resilient, and equitable infrastructure design. In addition, incorporating a cradleto-grave Life Cycle Assessment (LCA) into the suggested methodological approach will improve the quantitative estimation of the performance of construction processes. The definition of the proposed method will provide the guidelines to systematically assess the sustainability of geotechnical infrastructures to allow further the selection of an optimal solution to reduce their impact from an environmental, social, and economic point of view
Numerical Model and System for Prediction and Reduction of Indoor COVID-19 Infection Risk
Full text linkAirborne aerosol transmission is a significant route of SARS-CoV-2 and other viruses in indoor environments. The developed numerical model assesses the risk of a COVID-19 infection in a room based on the measurements of temperature, relative humidity, CO2 and particle concentration, as well as the number of people and occurrences of speech, coughing, and sneezing obtained through a dedicated low-cost sensor system [1]. As the model operates faster than real-time, it can dynamically feed this information back to the measurement system or building management system, and it can activate an air purifier with filtration and UV-C disinfection when the predicted infection risk is high. This solution enhances energy efficiency as (1) lower ventilation intensity is necessary in the cold season to reach the same safety level and (2) the purifier is activated only if the predicted infection risk is above a certain threshold.The model is integral and takes into account the average values of simulated variables. However, it considers the inhomogeneous vertical distribution of concentration of droplets and aerosol particles. The droplets expelled by a potentially infectious person at a certain height through breathing, speaking, coughing, and sneezing are characterized by the total amount of expelled liquid, droplet size distribution and virus particle concentration. The rate of droplet evaporation depends on the temperature and relative humidity. Droplets are redistributed within the room vertically through turbulent diffusion and gravitational force. If the final droplet diameter is less than 5 mm, these particles are considered airborne and can leave the room only by ventilation, filtration, or by sedimentation on surfaces through Brownian diffusion. As a person in the room inhales these droplets and aerosols, the risk of infection increases as the number of absorbed virions grows, with the probability of infection being 50% when 300 virions have been inhaled.The parameter studies using the model indicate that the coughing and sneezing events greatly increase the probability of infection in the room, therefore the identification of these events is crucial for the applied measurement system. A method for determining the unknown ventilation intensity by measuring the number of people and the CO2 concentration is proposed and tested
KxKali v0.1: A Work-in-Progress Tool for Streamlining Thermal Comfort Evaluation in Building Design and Occupancy
Full text linkThermal comfort evaluation is crucial in the design of buildings, as it impacts the well-being and productivity of building occupants. Many national regulations and international standards provide guidelines for assessing thermal comfort. In order to simplify this process, we have developed a program called KxKali, which is intended to evaluate thermal comfort based on temperature and relative humidity data input using the adaptative comfort model of EN 16798. The current version of the software, v0.1, is only able to accept data from computer simulation using the official Spanish simulation software HULC and performs graphing and counting automatically, without the need for the user to edit, modify or handle any data manually. By using HULC as the source of input data, the tool can take advantage of the software’s established reputation and acceptance among professionals in the building design industry in Spain, streamlining the comfort evaluation process by eliminating the need to generate input data manually, or using additional software. However, future versions are planned to accept data from other software and also monitored data. In addition, there are plans to implement the evaluation of thermal comfort following other regulations. The ultimate goal of this project is to convert KxKali into a user-friendly and widely accessible web-app that professionals can use in the design phase without performing any additional work apart from what they are already doing for energetic certification, which may improve building design by allowing architects and engineers to quickly evaluate different thermal comfort scenarios and optimize their design for comfort, and also facilitate the process of post-occupancy evaluations (POE). The goal of this presentation is to show the current capabilities of the KxKali tool, and to obtain feedback from other specialists on how to improve it and make it more widely useful. In the paper, the limitations of using simulation data from HULC and the ongoing developments of KxKali such as accepting monitoring data and converting it into a web-app will be discussed. Additionally, the paper will showcase mockups of the future web-app version of the tool, providing a glimpse into its intended user interface, and the expected reporting and output
Sustainable Technology of Wood Charcoal Diffuser for Indoor Acoustical Quality
Full text linkWood charcoal is sustainable, renewable, environmentally friendly material using which the acoustic device may be produced. Charcoal made of wood waste materials allows to improve indoor acoustical quality. The current article aims to investigate sound scattering coefficients of quadratic residue diffusers with the covering of oak (Quercus robur) wood charcoal elements. The sound scattering coefficient is calculated due to the reverberation time measurement in the reverberation chamber. The calculation results of the scattering coefficient show the growth of scattering in the frequencies – the highest value reached 0.88 (diffuser N7 with charcoal). The effectiveness of diffusers to diffuse sound waves increases as the number of wells grows. The diffuser with 80 % charcoal elements showed a higher scattering coefficient comparing to the diffuser without charcoal elements
Accelerating Microorganism Strain Selection for Enhanced Productivity: A Review of Microdroplet Technology Solutions for Screening Mutant and GMO Strains
Full text linkThis article reviews state-of-the-art microdroplet technological solutions for screening microorganisms mutant and GMO strains. Microorganisms used in the production of various products – single-cell protein, single-cell oil, enzymes, pigments and other bioactive compounds – can always be improved and their properties enhanced to increase the production of products of interest, to simplify microbial cultivation process, improve efficiency or adapted strains to use cheaper raw materials such as agroindustrial by-products. Microorganisms can be improved using either classical mutagenesis techniques or genetic engineering methods. Regardless of the selected method for mutant or GMO creation, during the process most promising microorganism strains must be selected, which is usually a slow and labour-intensive process. The use of microdroplets is a promising technological solution to speed up strain selection. This review looks at the latest developments in microdroplet technology, compares their variations, and identifies future prospects
Impact Assessment of Steel Circularity Scenarios: Case Study of Steel Radiator based on Life Cycle Assessment (LCA) Methodology
Full text linkSteel is one of the most used materials in the industry and the building sector. Its production causes severe environmental impacts due to direct emissions within extraction and processing stages (e.g. CO, SOx, NOx, and PM2), the intensive use of primary resources, contamination of wastewater, and significant amounts of hazardous and solid waste. In this context, the purpose of the current study is to perform a life cycle analysis (LCA) of four different types of steel used in the manufacturing of a steel-based radiator, namely: standard steel as a baseline scenario, steel with a recycling fraction of 40 % of scrap, steel with a recycling fraction of 60 % of scrap, fully recycled steel from scraps, and a hypothetical ‘Carbon-free’ steel production process. The baseline scenario relies on data from an existing company producing steel radiators. The LCA study is conducted within SimaPro 9.4 software with data obtained from the Ecoinvent 3.8 database and adjusted according to the defined scenarios and the functional unit of ‘1 kg of steel’. The environmental impact is assessed according to EN 15804 requirements for construction product sustainability. The results have shown that standard steel has the highest impact (176.87 μPt), followed by 40 % scrap steel (137.46 μPt), 60 % scrap steel (104.36 μPt), ‘carbon-free’ steel (76.14 μPt), and 100 % scrap steel (38.17 μPt). The climate change indicator is found to be one of the most sensitive for steel production. The selection of ‘carbon-free’ or 100 % scrap steel permits a decrease of impacts by 70 % and 84 %, respectively. The study concludes that the choice of steel is a fundamental point in reducing the environmental impact of construction products such as steel-made radiators within the whole life cycle perspective. Furthermore, the results obtained through the EN 15804 method, tailored explicitly for the Environmental Product Declaration (EPD), can be reused or taken as a starting point for further studies in the environmental labelling sector