[en] Due to the limitations associated with fossil fuels it is necessary to promote energy sources that are renewable as well as eco-friendly, such as biogas generated in anaerobic digesters. The biogas, composed principally of methane and CO2, is the result of the biodegradation of organic matter under anaerobic conditions. Its use as fuel is limited by the presence of minority compounds such as hydrogen sulphide (H2S); therefore, its pre-treatment is necessary. Currently there are various technologies for the removal of H2S from a gas stream, but most of them are based on physic-chemical treatments which have a number of drawbacks as reactive consumption, generation of secondary flows, etc. Biofiltration has been used as an efficient and low cost alternative to conventional purification processes, and excellent results for the degradation of H2S have been obtained. However process can be limited due to the progressive ageing of the support material, along with the loss of nutrients and other specific characteristics necessary for the good development of biomass. The purpose of this project is to develop a mixed support consisting of a mixture of an organic material and an inorganic support for its application in the removal of the H2S from biogas. This support material helps to optimize the characteristics of the bed and extend its lifespan. The development of such material will contribute to the implementation of biofiltration for treating biogas from anaerobic digesters for its use as biofuel. The inorganic material used is electric arc furnace (EAF) black slag, a by-product generated in large quantities in the production of steel in the Basque Country. Although traditionally the slag has been used in civil engineering, its physicochemical characteristics make it suitable for reuse as a filter medium in biofiltration. The main conclusion drawn from the experimental results is that EAF black slag is a suitable co-packing material in organic biofilters treating H2S-polluted gaseous streams. High pollutant removal rates have been achieved during the whole experimental period. The removal capacity recorded in biofilters with less inorganic material was higher than in those with higher slag portion. Nevertheless, all the biofilters have shown a satisfactory response even at high inlet loads (48 g·m-3·h-1), where the RE has not decreased over 82%.

[eu] Erregai fosilek dakarten mugak direla eta, beharrezkoa da izaera energetiko berriztagarri eta, aldi berean, ingurugiroarekiko errespetuzkoak diren energi iturri berriak garatzea; honen adibide bat digestore anaerobietan garatutako biogasaren erabilera da. Biogasa, gehien bat metanoz eta CO2 osatua, baldintza anaerobiotan burutako materia organikoaren biodegradazioaren ondorioz sortzen da. Biogasaren erabilera erregai bezala mugatua da, hidrogeno sulfuroa sortzen baita tartean. Badira zenbait teknologia hidrogeno sulfuroa gas korronte batetik ezabatzea ahalbidetzen dutenak; hala ere, gehiengoek oinarri kimikoa dutenez zenbait eragozpen ekar ditzakete, erreaktiboen kontsumoa edo korronte sekundarioen sorkuntza, besteak beste. Bioirgazketa, efizientzia altua eta kostu murriztua duena, prozesu konbentzionalen ordezko bezala aurkeztu da, H2S ren degradazioan izandako emaitza egokiengaitik. Hala ere, errendimendu altua izateko kontuan hartu beharreko zenbait muga azal daitezke, euskarriaren higadura eta biomasa ondo garatzeko zenbait propietateen galera kasu. Lanaren helburu nagusia euskarri organiko eta inorganikoen arteko konbinazioz lortutako euskarri bat garatzea da. Aipatutako nahasketa, ohantzearen propietateak hobetu eta honen erabilpena luzatzeaz gain, biogasak daukan H2S degradatzeko gai izan behar da. Bi material desberdinen konbinazioaz sortutako material honen erabilpena, bioiragazketa digestore anaerobioetna sortutako biogasa erregai bezala erabiltzeko tratamendu bezala indartzen du. Erabilitako material inorganikoa labe elektrikoko zepa beltza izan da, Euskadin altzairuaren industrian kantitate handietan sortutako hondakina dena. Luzaroan obra zibiletan erabili bada ere, dituen ezaugarri bereizgarriak direla eta, azken aldian materialaren bererabilera iragazki gisa bioiragazketan bideratu ahalbidetu da. Lortutako emaitzek zepa beltzen berabilpena euskarri bezala bioiragazketan indartzen dute, izan ere, H2S deuseztazeko efikatzia altuak lortu baitira. Nahiz eta, euskarri organiko gehien duten biofiltroen emaitzak hobeak izan, zepa proportzio altuetan duten biofiltroen erantzuna kutsatzailearekiko ona izan da. Izan ere, biofiltro hauen eliminazio efikatzia ez da 82% gehitsi, karga masiko altuetan (48 g·m-3·h-1) erabilita ere.