Improvement of biological total phosphorus release and uptake by low electrical current application in lab-scale bio-electrochemical reactors

The overall process enhancement by different electrical current application on the biological phosphorus release and uptake have been investigated. Five reactors were constructed for three experiments and activated sludge was used as inoculums. In Exp.1 by comparing the control and the bio-electrochemical reactors, it was found that the overall phosphorus removal efficiency could be enhanced at lower electrical current applications of 5 mA and 10 mA, but were restrained at higher than 20 mA, although 20 mA could be a sensitive turning point. Moreover, the electrochemical effects of the cathodic and the anodic reactions on the phosphorus release and uptake, respectively, have been further evaluated separately under an electrical current application of 10 mA in Exp.2 and Exp.3, respectively. As observed, both of the biological release and uptake were improved by the cathodic reactions in the cathode reactor, but not by the anodic reactions in the anode reactor, and thus indicated that the cathodic reactions play an important role in the improvement of the biological phosphorus release and uptake.

► In this study the electrochemical influences on biological phosphorus release and uptake is evaluated.
► The overall bio-electrochemical removal of phosphorus can be stimulated by electrical current below 10 mA.
► The cathodic reactions play an important role in the improvement of both the phosphorus release and uptake.
► The anodic reactions have little or even negative effects on the phosphorus release and uptake.
► The low electrical current possibly stimulates the bacteria metabolism during the biological phosphorus release and uptake.