Using a Pulsed Electric Field as a Pretreatment for Improved Biosolids Digestion and Methanogenesis

We tested the ability of a pulsed electric field (PEF) technology to enhance solubilization of organic material in waste activated sludge (WAS) and pig manure, with the goal of making it more bioavailable for methane production during subsequent anaerobic digestion. We varied PEF operating parameters across an approximately 10-fold range, showing the influence that the amount of treatment has on solubilization, as measured by soluble chemical oxygen demand (SCOD), and methane production, as gauged by the biochemical methane potential. Once PEF treatment exceeded a threshold, SCOD increased by an order of magnitude (to over 1000 mg/L), which resulted in a doubling of methane production for WAS. We obtained similar findings for pig manure, with SCOD increasing 3-fold due to PEF pretreatment and methane production increasing by 80%. These results support that PEF pretreatment before anaerobic digestion can significantly improve digester performance, resulting in added methane production and decreased residual biosolids.