Lipid Degradation in a Two-Phase Anaerobic SBR and Upflow Anaerobic Sludge Blanket
LCFAs, the intermediate products in lipid biodegradation are known to inhibit microorganisms by their toxicity and floatation. To reduce LCFA inhibition, two-phase anaerobic system, consisting of anaerobic sequencing batch reactor (ASBR) and upflow anaerobic sludge blanket (UASB) reactor, was applied to synthetic dairy wastewater. During 153 days of continuous operation, two-phase system showed stable performance in lipid degradation. In ASBR performance, failure due to high organic loading (19.2 g COD/L/day) was observed. Except failure period, 13% of lipid removal efficiency and 10% of double bond removal efficiency were maintained. In UASB performance, COD, lipid and VFA removal efficiencies up to organic loading rate 6.5 g COD/L/day were more than 80%, 70%, 95%, respectively. There was no operational problem like serious scum formation and sludge washout. Protein degradation was more favorable for microorganisms rather than lipid degradation.