The technical and economical assessment of the different electrode materials for pH recovery in the anaerobic baffled reactor on a lab-scale

摘要

This research focuses on the optimization of employed electrode material for pH recovery in a lab-scale anaerobic baffled reactor (ABR). Five types of material included iron, stainless steel, copper, aluminium, and brass were examined for pH revival with the least electricity consumption. The main characteristics including the distance and the contact surface of electrodes, current intensity, voltage, electrolysis time, and consumed electrical energy were investigated. The results showed that the iron electrode can recover a pH unit within a shorter time, and its consuming energy cost in proportion to stainless steel, copper, aluminium, and brass was 0.26, 0.56, 0.43 and 0.82, respectively. For the iron electrode, by augmenting the current density from 3.33 to 10 mA/cm(2), the electrolysis time was reduced from 51.6 to 20.6 min in constant current. While the time variation for stainless steel electrode was more pronounced and decreased from 215.3 to 69.3 min. From the perspective of by-products, copper and brass electrodes would have negative effects on reactor performance by releasing copper with the amounts of 34.6 and 58.3 mg/L, respectively. While the iron electrode will be beneficial for anaerobic bacteria growth with the release of 76.4 mg/L of iron by providing them soluble nutrients. In terms of initial investment and operating cost, the iron electrode is the most optimum option, because its procurement cost in proportion to stainless steel, copper, aluminium, and brass was 0.17, 0.05, 0.29 and 0.07, respectively. According to the obtained results, the application of an electrolysis system using iron electrodes in the clinging state to the baffles at the maximum distance would show the best performance in order to revive the pH in an anaerobic baffled reactor.