Anaerobic Microbial Activity Under Electric Fields

The impact of electric fields on some environmental conditions and on the activity of anaerobic microorganisms was investigated in this study. Experiments were conducted in plexiglass chambers with coated titanium mesh electrodes mounted on either end. Electric fields of 1.5V/cm through 6V/cm were applied. Anaerobic cultures (primarily a consortium with methane producing bacteria)obtained from a mesophilic digester from the Redhook Wastewater Treatment Plant, Brooklyn, were used in these experiments. Results indicated that the pH decreased to as low as 4.5 even under completely mixed conditions in fed-batch reactors, if pH-control measures were not in place. Microbial activity, measured as a function of the ability of the anaerobic microorganisms to consume readily degradable acetate, generally decreased as expected if the pH and dissolved oxygen were not controlled. Using sodium sulfite slightly in excess of the stoichiometric amount and sodium bicarbonate, both pH variation as well as oxygen generation were adequately controlled. Microbial activity initially decreased under exposure to electric current but recovered after a period of several hours of exposur