Enhanced anaerobic digestion of linoleic acid containing piggery wastewater

摘要

Linoleic acid, a major derivative of lipid hydrolysis, caused serious problems on biological anaerobic digestion of piggery wastewater. The effect of linoleic acid on anaerobic digestion of piggery wastewater was evaluated, and the reversal of linoleic acid inhibition was explored and optimized. Both methanogens and acidogens were found to be susceptible to linoleic acid inhibition, with IC50 (50% inhibitory concentration) of 376 mg/L of linoleic acid for methanogenesis. Among tested cations (Na~+, Mg~(2+), Ca~(2+), Fe~(3+) and Al~(3+)), only Ca~(2+) reversed the inhibition of linoleic acid on anaerobic digestion of piggery wastewater, where 0.4 g/L of CaCl_2 completely recovered the inhibition of linoleic acid. It was thought that protective adsorption of calcium ions by biomass played an important role in reversal of linoleic acid inhibition. With respect of detoxification of linoleic acid, as indicated by resuming methane generation and VFAs consumption after re-inoculation, this study suggested the application of multi-phase anaerobic system to treat oil containing piggery wastewater.