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(184) Biological degradation of swine manure in anaerobic fluidized bed reactors (AFBR). Hidalgo, MªDolores1, Hernández, Marta1,2, del Alamo, Josué1,2, Núñez, Yolanda1,2, Irusta, Rubén1,2, 1 2 ABSTRACT- A study of the swine manure degradation and biofilm development under mesophilic conditions was carried out on two pilot lab scale anaerobic fluidized bed reactors (AFBR). Biolite and activate carbon was used as supports. The soluble total organic carbon (TOC) reduction in the treated waste was 40% of the feed waste TOC for both reactors, working with an organic loading rate of 10 Kg TOC.m3.d-1 and an hydraulic retention time (HRT) of 35 hours. By gas chromatography volatile fatty acids were analyzed in the effluents. The study shows an imperceptible content in acetic, propionic and butyric acids in the treated manure, whereas fatty acids of longer chain are detected. Microbial population develops inside reactors seems unable to degrade these long chain acids in short periods of time because of the biofilm is thinly populated by acidogenic bacterias. On the contrary, it seems to be large acetogenic and methanogenic population that carries out short chain fatty acid removal. Kinetic studies reveal the existence of a remaining organic fraction in the anaerobic swine waste degradation that shows the low number of hydrolytic microorganisms presents in the media. Scanning Electron Microscopy did not revealed important differences on the biofilm structure, microbial colonization and bacterial morphotypes development in each reactor depend on the type of support media used. In all experiments the studies show a wide variety of microcolonies of different trophic populations which are located in crevices and other regions sheltered from hydraulic shear forces. Experimental observations revealed the non-uniform spatial distributions of bacteria populations within the biofilm however substrate composition results in biofilm structure with dominant populations. Key words: anaerobic , biodegradation, biofilm, manure |
