Acidogenic Fermentation of Grape Marc with Sewage Sludge to Produce Volatile Fatty Acids

Abstract

In the present study a laboratory-scale reactor experiment was carried out to determine the feasibility of the acidogenic fermentation of grape marc with sewage sludge. The effect of temperature, hydraulic retention time (HRT) and pH on the volatile fatty acids (VFA) production was explored. The experiment was conducted at two different working temperatures (37 and 50 ºC), different HRT (10, 15 and 20 days) and two ranges of pH (acidic pH and alkaline pH). The optimal conditions considered for VFA production were 50 ºC, 10 days HRT and acidic pH. Under these conditions, the degree of acidification was 25% and the VFA profile was dominated by acetic and butyric acids. Moreover, under this conditions Thermoanaerobacterium sp . (34%) was the genus most abundant confirming a highly enriched microbiome.

Keywords: Acidogenic fermentation, Grape marc, microbial community, Sewage sludge, Volatile fatty acids