Overall evaluation of a multi-stage reverse electrodialysis reactor series system for organic wastewater treatment and power generation

Abstract

A multi-stage reverse electrodialysis reactor (REDR) series system for organic wastewater treatment and power generation is proposed in this paper. An energy evaluation method is developed for the first time by analyzing the electrical energy and oxidative degradation energy conversion efficiencies of the system. The influences of the current and feed solution velocity on the overall performances of the system are investigated by experiments. Results demonstrate that a high current can enhance the gross output power but reduce the net output power and total energy conversion efficiency. A peak value of the total COD removal can be obtained at an appropriate current. A low feed solution velocity can improve the performance of the system except for the lower net output power. Although the electrical energy conversion efficiency reduces as the serial number of REDR increases, the oxidative degradation energy conversion efficiency increases significantly, which results in the total energy conversion efficiency enhancement. Under the given experimental conditions, the maximal values of the net output power, total COD removal and total energy conversion efficiency are 1.05 W, 450.98 mg·L−1, and 11.41%, respectively.