In the present study, the volatile fatty acids (VFA) and non-volatile free fatty acids (NV-FA) of two separate anaerobic digesters (one for acetogenesis and the other one for methanogenesis) fed with municipal wastewater sludges, were characterized by using head-space solid phase microextraction coupled with gas-chromatography-mass spectrometry (HSSPME-GC-MS) and gas-chromatography-flame ionization detector (GC-FID), respectively. VFA mainly consisted of acetic (C2), propionic (C3), iso-butyric, (C4), butyric (C4), iso-valeric (C5), valeric (C5) and caproic (C6) and they prevailed in acetogenesis. This implies that homoacetogenic and acetate/butyrate fermentations were predominant in this process. In methanogenesis, acetate and n-butyrate were completely degraded, while propionate degradation seemed to be time-dependent. No negative effect of propionate was observed during methanogenesis. NV-FA were mainly constituted by saturated fatty acids (SFA) from C12:0 to C24:0 and only few unsaturated fatty acids (UFA) (from C18:1 to C22:1) were observed in both processes. A considerable amount of branched NV-FFA was found in both fermentation processes and this result confirmed the microbial origin of these compounds
LIPID CHARACTERIZATION IN TWO-PHASES ANAEROBIC DIGESTION FROM MUNICIPAL WASTEWATER SLUDGES
FRANCIOSO, ORNELLA;SAVIOLI, STEFANO;RODRIGUEZ ESTRADA, MARIA TERESA;PALENZONA, DOMENICO
2009
Abstract
In the present study, the volatile fatty acids (VFA) and non-volatile free fatty acids (NV-FA) of two separate anaerobic digesters (one for acetogenesis and the other one for methanogenesis) fed with municipal wastewater sludges, were characterized by using head-space solid phase microextraction coupled with gas-chromatography-mass spectrometry (HSSPME-GC-MS) and gas-chromatography-flame ionization detector (GC-FID), respectively. VFA mainly consisted of acetic (C2), propionic (C3), iso-butyric, (C4), butyric (C4), iso-valeric (C5), valeric (C5) and caproic (C6) and they prevailed in acetogenesis. This implies that homoacetogenic and acetate/butyrate fermentations were predominant in this process. In methanogenesis, acetate and n-butyrate were completely degraded, while propionate degradation seemed to be time-dependent. No negative effect of propionate was observed during methanogenesis. NV-FA were mainly constituted by saturated fatty acids (SFA) from C12:0 to C24:0 and only few unsaturated fatty acids (UFA) (from C18:1 to C22:1) were observed in both processes. A considerable amount of branched NV-FFA was found in both fermentation processes and this result confirmed the microbial origin of these compoundsI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
