Enhanced Lipid Degradation in an Upflow Anaerobic Sludge Blanket Reactor by Integration with an Acidogenic Reactor

Abstract

Lipids inhibition and their degradation in dairy wastewater treatment were investigated in this study. A two-phase system, composed of an acidogenic continuously stirred tank reactor (CSTR) and a methanogenic upflow anaerobic sludge blanket (UASB) reactor, was compared with the single-phase system of a conventional UASB reactor. The systems were operated up to an organic loading rate of 8.09 g chemical oxygen demand (COD)/L x d at a lipid loading rate of 2.94 g COD/L x d. The two-phase system showed better performance in COD removal (1.19 times), lipids removal (1.92 times), and methane production (1.42 times) compared with the single-phase system. The degradation of lipids and the saturation of the double-bonded lipids in the CSTR enhanced the performance of the system. In serum bottle tests at different lipids concentrations, a high lipids concentration resulted in a long lag-phase time for methane production. However, 69.5% of COD eventually was converted to methane within 50 days at 6.1 g lipid-COD/L.