Volatile fatty acids production from separately collected municipal biowaste through mixed cultures fermentation

Abstract

Substituting the conventional crude oil-based products, such as volatile fatty acids (VFAs) derived from oil refineries by adequate substances produced in biowaste refineries triggers a lot of attention. There is also interest in combining wastewater treatment and biowaste treatment and focus it on bio-products production, other than the currently established methane fermentation. This paper summarizes investigations of VFAs generation from separately collected municipal biowaste, inoculated with anaerobic digestion plant wastewater, in a batch laboratory bioreactor with 20 L volume under varying conditions. The production of VFAs within 72 h from batch with 7.5 % TS and OLR of 21.5 g/(L·d) amounted to 11.5 g/L; 13.5 g/L and 20.5 g/L for pH 5.0; 5.5 and 6.0, respectively. The highest yield of VFAs production (0.310 g VFAs/g VSfed) was determined for pH 6.0 and OLR of 21.5 g/(L·d). Moreover, at pH 6.0 the dominating products were higher chain acids, in form of valeric and butyric acids, constituting 53 % and 41 % of the total mass of VFAs produced, which distinguishes this study from existing literature.