Fluidoen mekanika

162 p

Fluidoen mekanika

162 p

Hezegune eraikiak ur grisen tratamendurako

Constructed wetlands are low cost, easy to install and sustainable grey-water treatment systems, due to their capacity for removing conventional pollutants. Constructed wetlands are classifiedas free water surface flow type and subsurface flow type, being the last one more effective for wastewater treatment. Hybrid systems that combine both types of wetlands are increasingly used to harness the best of each wetland type. In order to achieve a satisfactory wastewater purification, an adequate selection of the design parameters is essential, being a key point the adequate choice of plant species. Grey-water fed to the constructed wetland contains large amounts of organic matter and nutrients, being plants and microorganisms responsible for the elimination of these pollutants. Additionally wastewater carries suspended solids and nitrogen compounds. The formers are eliminated by filtration in the gravel bed, while the latter bynitrification and denitrification. In this work, the main characteristics of the constructed wetland types and their advantages and disadvantages have been commented, as well as the characterization of the entering wastewater and a summary of the main physical, chemical and biological processes that are carried out for the purification of water in constructed wetlands.; Hezegune eraikiak ur grisen tratamendurako sistema merkeak, instalatzeko errazak eta jasangarriak dira, ohiko kutsatzaileak eliminatzeko gaitasun handia dutelako. Gainazaleko eta gainazal azpiko fluxuko erakoak dira hezegune eraiki mota nagusiak, azkenak hondakin uren tratamendurako eraginkorragoak izanik. Bakoitzaren hoberena aprobetxatzeko, gero eta erabiliagoak dira bi hezegune motak konbinatzen dituzten sistema hibridoak. Hondakin-uren arazketa ona izan dadin, ezinbestekoa da diseinu-parametroen aukeraketa egokia, eta funtsezkoa da landarediaren hautaketa. Izan ere, hezegune eraikian elikatzen diren ur grisek materia organiko eta mantenugai ugari daramatzate, eta landareak eta mikroorganismoak izango dira kutsatzaile horien eliminazioaren arduradun. Karga organiko handia izateaz gain, hezegunean elikatzen diren hondakin-urek solido esekiak eta konposatu nitrogenatuak daramatzate. Hortaz, hezeguneek ohantze iragazleak izan ohi dituzte lehenengoak eliminatzeko, eta nitrifikazio- eta desnitrifikazio-prozesuak gauzatzen dituzte konposatu nitrogenatuak desagerrarazteko. Lan honetan, hezegune eraiki moten ezaugarriak eta horien abantailak zein desabantailak aztertu dira, bertan elikatzen diren uren karakterizazioa laburtu da, eta, azkenik, hezegune eraikietan urak arazteko gauzatzen diren prozesu fisiko, kimiko zein biologiko nagusiak bildu dira

Katalizatzaileen prestakuntza industri prozesuetarako

Prozesu katalitikoak gero eta gehiago erabiltzen ari dira industria eskalan. Prozesu hauetan erabiltzen diren katalizatzaileak arreta handiz prestatu behar dira, solidoak ezaugarri fisiko-kimiko (aktibotasun, hautakortasun ete egonkortasun) onak eduki ditzan, eta erreakzio katalitikoa egoki gerta dadin. Artikulu honetan industria eskalan masa-katalizatzaileak eta katalizatzaile inpregnatuak prestatzeko normalean erabiltzen diren metodoak deskribatzen dira eta prestakuntza-etapa bakoitza zertan datzan aztertzen da

Ohizko energiak vs. energia berriztagarriak

Fosil-erregaien erreserbak gero eta urriagoak dira eta munduko leku mugatuetan baino ez daude. Gainera, erregai mota hau erabiltzen duten prozesuak oso kutsatzaileak izan ohi dira. Arazo hauek dira medio, gizartean energia aurrezteko konpromisoa gero eta finkatuago dago (batez ere herrialde industrializatuetan) eta gero eta energia lor tzeko prozesu eraginkorragoak eta garbiagoak diseina tzen ari dira. Hala ere, oraindaino energia garbia eta ugaria lor tzeko lehendabiziko pausuak baino ez dira eman. Lan honetan ohizko energiak eta energia berriztagarriak deskribatzen dira eta bai eta energia mota bakoi tzaren abantailak eta desabantailak

Ohizko energiak vs. energia berriztagarriak

Fosil-erregaien erreserbak gero eta urriagoak dira eta munduko leku mugatuetan baino ez daude. Gainera, erregai mota hau erabiltzen duten prozesuak oso kutsatzaileak izan ohi dira. Arazo hauek dira medio, gizartean energia aurrezteko konpromisoa gero eta finkatuago dago (batez ere herrialde industrializatuetan) eta gero eta energia lor tzeko prozesu eraginkorragoak eta garbiagoak diseina tzen ari dira. Hala ere, oraindaino energia garbia eta ugaria lor tzeko lehendabiziko pausuak baino ez dira eman. Lan honetan ohizko energiak eta energia berriztagarriak deskribatzen dira eta bai eta energia mota bakoi tzaren abantailak eta desabantailak

In depth characterisation of hydrocyclones: Ascertaining the effect of geometry and operating conditions on their performance

Hydrocyclones are used for densification of waste streams prior to drying or for classification of solid and liquids in two-phase streams. They are becoming popular in industrial units due to their simplicity, low energy consumption and high versatility. However, the effect of geometry and operating conditions on the cut diameter and solid recovery efficiency have been independently studied, and therefore there are no studies approaching the influence of all the parameters simultaneously. Thus, a detailed experimental study was conducted to ascertain the effect of the hydrocyclone body (diameter and angle) and the vortex finder and spigot size and shape, as well as operating conditions (inlet pressure and solid concentration) on the separation efficiency curve, cut diameter, solid and volume recovery and the main features of the outlet streams. It has been proven that separation efficiency and outlet stream composition are sensitive to both the geometry of the hydrocyclone and the operating parameters. Therefore, knowledge of their influence is essential for the design of industrial units where liquid reutilisation is a major concernThis work has been carried out with the financial support from the University of the Basque Country UPV/EHU (Projects US12=11 and US16=26) and the collaboration of Novattia Desarrollos Ltd. Javier Izquierdo thanks the University of the Basque Country UPV/EHU for his Ph.D. grant. Xabier Sukunza thanks the Ministry of Economy and Competitiveness for his Ph.D. grant (FPU18=04935)

Use of Biochar from Rice Husk Pyrolysis: Part A: Recovery as an Adsorbent in the Removal of Emerging Compounds

[EN] One of the main products of pyrolysis is char. For the better performance and improvement of its physicochemical properties, it is necessary to make temperature changes. In this study, different temperatures have been tested for the pyrolysis of rice husk, and the biochar obtained from the process went through an evaluation to test its yield in the removal of emerging compounds such as azithromycin (AZT) and erythromycin (ERY). For this, pyrolysis of rice husk has been carried out at temperatures of 450, 500, 550, and 600 degrees C, and the biochars have been characterized by ultimate analysis and proximate analysis, as well as specific surface area tests. Then, different adsorption tests have been carried out with a 200 mg L-1 drug (AZT and ERY) solution prepared in the laboratory. All biochars have been found to present removal percentages higher than 95%. Therefore, obtaining biochar from rice husk at any temperature and using it in the removal of high-molecular-weight compounds are quite suitable.This work was carried out with financial support from the Department of Civil and Environmental Engineering at Universidad de los Andes. This publication was partially made possible by the call for proposals CI-0120: "Publish your new knowledge or expose your new creations" from the Office Vice President for Research and Creation at Universidad de los Andes

Katalizatzaileen prestakuntza industri prozesuetarako

Prozesu katalitikoak gero eta gehiago erabiltzen ari dira industria eskalan. Prozesu hauetan erabiltzen diren katalizatzaileak arreta handiz prestatu behar dira, solidoak ezaugarri fisiko-kimiko (aktibotasun, hautakortasun ete egonkortasun) onak eduki ditzan, eta erreakzio katalitikoa egoki gerta dadin. Artikulu honetan industria eskalan masa-katalizatzaileak eta katalizatzaile inpregnatuak prestatzeko normalean erabiltzen diren metodoak deskribatzen dira eta prestakuntza-etapa bakoitza zertan datzan aztertzen da

Modelling and simulation of subsurface horizontal flow constructed wetlands

[EN] As a consequence of the poor implantation of sanitation systems, more than 80% of the wastewater from human activity is dumped, which poses a threat to public health and generates water stress. In contrast, its depuration and reuse for irrigation improves the efficiency of the water management cycle and reduces the use of fresh water. In the context of grey water purification in rural areas of Europe, constructed wetlands are the preferred option. Furthermore, in developing countries, they are particularly attractive as an alternative to conventional purification systems. The design of such facilities tends to avoid the complexity of the interactions between solids, pollutants, microorganisms, and plants. In this work, a more rigorous mathematical model is proposed, which considers the mass balances of the substrate and the microorganisms, in addition to the degradation kinetics typical of biotechnological processes, the life cycles of microorganisms, and their horizontal and vertical transport processes. This model was tuned based on the responses of already installed systems located in Zapote (Costa Rica) and San Salvador (El Salvador). The model foresees start-up times close to three months, in addition to depuration efficiencies reaching above 90%, which corresponds with previously reported values. The developed simulation tool is also employed to study the response of the model to various disturbances, such as punctual stops or seasonal variations in the incoming flow.The authors wish to thank the technicians of ADES Santa Marta and the School of Chemical Engineering and Food Engineering from the Faculty of Engineering and Architecture of the University of El Salvador for their help and for providing the information required to carry out this work. Leire García and Mikel Manso wish to thank the Development Cooperation Office of the University of the Basque Country UPV/EHU for the financial aid provided to travel to El Salvador. Engineering Without Borders - Basque Country wish to thank the County Council of Biscay (projects DESA/0027/2017, DESA/0024/2019 and SUBV/COOP/SENS/0012/2019) and the Bilbao Council (projects 2019-017085 and 2020-015220) for their financial support