Biofilter response to biomass reactivation for VOC treatment

[Abstract] This research has undertaken a comparative study on using a fresh activated sludge or a refrigerated/ reactivated sludge as active biomass source for biofiltration purposes. A sludge sample was initially selected based on the ratio between volatile solid content and total solid content before and after refrigeration at 6 oC for 90 days. The degradation rate of the activated sample for three addition doses of toluene was established before and after refrigeration. The same procedure was also carried out for ethylbenzene and p-xylene after refrigeration/reactivation. Surprisingly, the degradation rate for toluene was higher after refrigeration and the results were very similar for an addition of 2 and 8 µL. Subsequently, one biofilter was inoculated with the activated sample and another with the reactivated sample, and both were fed with toluene ranging from 2.6 to 26.2 g toluene m-3 h-1. Concerning the elimination capacity of both biofilters, no relevant differences were found. It was concluded that the active biomass degrading toluene was not affected by refrigeration, in spite of the fact that the SV/ST ratio decreased after the storage period. The elimination capacity of the other two biofilters (ethylbenzene and p-xylene) was highly influenced by the gas flow rate. 1 INTRODUCTION Environmental regulations for pollution control are frequently enacted before «suitable» (affordable, effective and environmentally friendly) technologies have been fully developed. Amongst biotechnologies, biofiltration is a seemingly simple system whose effectiveness relies on the optimization of several operating parameters and the selection of a suitable packing material and degrading biomas

Multiple Intelligence Informed Resources for Addressing Sustainable Development Goals in Management Engineering

The competence-based model focuses on acquiring skills and abilities, yet each student’s individual circumstances condition the way in which they learn, develop, and implement them. Accordingly, there is a growing interest in defining learning activities that consider the diverse range of intelligences, abilities, and prevailing mindsets in each individual in order to promote inclusive education and sustainable development. This article seeks to design a methodology for the teaching–learning resources associated with the nature of the prevailing intelligence in the competence-based model. Thus, the “competence-intelligence-resource triangle” was proposed for promoting inclusive education in the degree in Management Engineering at the University of the Basque Country (UPV/EHU). A total of 99 teaching–learning resources, 11 competences, and 9 types of intelligence were combined. As far as the multiple intelligence approach is concerned, the 50 students surveyed prioritized logical–mathematical, interpersonal, intrapersonal, linguistic, and spatial intelligences. As a conclusion, the use of teaching–learning resources designed for promoting different types of intelligence in the competence-based model constitutes an adaptive strategy for the students to successfully acquire competences

Bioiragazpena: gasen korronteak tratatzeko aukera garbia

Gasen tratamendurako metodo biologikoak, mikroorganismoek molekula kutsatzaileak degradatzeko duten ahalmenean oinarritzen dira. Metodo hauetariko bat bioiragazpena dugu eta teknologia "garbia", "merkea" eta "eraginkorra" da. Aplikazio ugari ditu, besteak beste, H2S-a bezalako konposatu kirasdun edota toxikoak dituzten gas emarien tratamendua. Kutsatzailearen kontzentrazioa txikia denean eta tratatu behar den gas bolumena handi samarra denean erabiltzen da batez ere. Beraz, hainbat industriak igorritako gasak tratatzeko aplikazio zuzena du

Bioiragazpena: gasen korronteak tratatzeko aukera garbia

Gasen tratamendurako metodo biologikoak, mikroorganismoek molekula kutsatzaileak degradatzeko duten ahalmenean oinarritzen dira. Metodo hauetariko bat bioiragazpena dugu eta teknologia "garbia", "merkea" eta "eraginkorra" da. Aplikazio ugari ditu, besteak beste, H2S-a bezalako konposatu kirasdun edota toxikoak dituzten gas emarien tratamendua. Kutsatzailearen kontzentrazioa txikia denean eta tratatu behar den gas bolumena handi samarra denean erabiltzen da batez ere. Beraz, hainbat industriak igorritako gasak tratatzeko aplikazio zuzena du

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

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

Sustainable mold biomachining for the manufacturing of microfluidic devices

Biomachining has been investigated as a sustainable and effective alternative to conventional prototyping techniques for molding polymeric materials for their subsequent use as microfluidic devices. A novel and simple process based on the combination of a Pressure Sensitive Adhesive mask and a varnish has been proposed for preparing metal workpieces as an alternative to photolithography, with the latter being the most widely used technique for protecting workpieces. As far as the bioprocess is concerned, it has been applied in successive mold-etching and oxidant bio-regeneration stages. Metal solubilization has proven to be repeatable in several consecutive mold-etching stages when using the regenerated oxidant solution. As a result, the lifespan of the biomachining medium has been prolonged, contributing to process sustainability. An equation with two restrictions has been proposed to predict the time required to obtain a mold with a fixed height, as metal solubilization evolves differently between the first and subsequent hours. Finally, the bio-engraved copper pieces have acted as effective molds in the fabrication of self-powered polydimethylsiloxane microfluidic devices. This new biomachining application is therefore an effective and ecofriendly process for producing microfluidic devices.This work was supported by the State Agency for Research (AEI) of the Spanish Government-European Regional Development Fund (FEDER-ERDF, EU) [grant number: CTM2016-77212-P], Spain’s Ministry of Science and Education [grant number: PID2020-120313 GB-I00/AIE/10.13039/501100011033], and the Basque Government’s Department of Education for the consolidation of research groups [grant number: IT1633-22]. Professor L. N. López de la Calle is acknowledged for his assistance with the copper samples

Metal Extraction and Recovery from Mobile Phone PCBs by a Combination of Bioleaching and Precipitation Processes

Bearing in mind the metal rich composition of printed circuit boards (PCBs), this material represents a secondary source of valuable metals and offers an entrepreneurial opportunity in the metal sales market. Based on the ability of microorganisms to regenerate and produce the chemical oxidants that are responsible for metal leaching, bioleaching has become an efficient and affordable alternative to conventional metal recycling technologies, although further research is still necessary before industrial implementation. This study focuses on the recovery of metals contained in mobile phone PCBs through a combined process. Two different PCB pre-treatments were evaluated: grinding the whole piece and removing the epoxy cover from the piece without grinding. The benefit of A. ferrooxidans activity on the metal solubilization rate was analyzed. Additional chemical leaching assays were also conducted for comparison purposes and the reagents ferric iron (Fe3+) and sulfuric acid (H2SO4) were selected for these experiments. The copper extraction results obtained in Fe3+ experiments with and without bacteria (A. ferrooxidans) were similar after 260 h of operation, indicating the need for alternative strategies to ensure a controlled and continuous metal biodissolution rate. The contribution of H2SO4 to the leaching processes for copper and nickel was almost negligible during the first 50 h, and more significant thereafter. The recovered metals were precipitated from a synthetic solution simulating a real ferric leaching by adding sodium hydroxide (NaOH) and sodium sulfide (Na2S). The combination of both precipitants allowed an effective removal of metals from the leachate.The authors wish to acknowledge the financial support received from the State Agency for Research (AEI) of the Spanish Government and the European Regional Development Fund (ERDF, EU) [Project CTM2016-77212-P]. The University of the Basque Country UPV/EHU (Spain) [GIU18/118] is also acknowledged