Disruption of Microbial Cell Within Waste Activated Sludge by DC Corona Assisted Pulsed Electric Field

Disruption of microbial cell within waste activated sludge is a key step to the treatment of the sludge. Pulsed electric field (PEF) has been utilized to damage the cell microstructure so as to accelerate the sludge treatment. In this paper, with the purpose of improving the cell disruption efficiency of PEF, a dc corona assisted PEF method has been proposed. Corona discharge triggered by dc voltage has been introduced to the sludge prior to the application of PEF. It was observed that by treating with the dc corona assisted PEF, the increment in soluble chemical oxygen demand tended to be enhanced obviously compared with the individual application of PEF, which indicated that the cell disruption performance of PEF was improved by the exposure of the sludge to dc corona. The influence of dc corona on the PEF performance was dependent upon the magnitude and polarity of dc voltage that induced the corona discharge. It is suggested that electric charges and electrochemical reaction products generated within the corona appear to modify the sludge and hence facilitate the treatment of PEF.