Performance of a Trickling-Bed Biocathode Microbial Electrochemical System Treating Domestic Wastewater and Functional Microbial Community Characteristics

Abstract

Biocathode microbial electrochemical systems (MESs) that remove nitrogen compounds out of wastewater are of special interest for practice. High energy-input for aeration is one of the barriers that hinder their application on a wider scope. A trickling-bed biocathode MES (TB-MES) was developed by integrating biotrickling filters with a biocathode MES. By recirculating the catholyte and sprinkling it through a spray nozzle, the system was able to achieve a reoxygenation process, which could facilitate the creation of an aerobic and anoxic environment. At an optimal recirculation rate of 200 mL min−1, the TB-MES removed 87.2 ± 2.7% of ammonium nitrogen and 79.7 ± 2.5% of total nitrogen (TN), and simultaneously achieved a maximum power density of 3.8 ± 0.3 Wm−3. Comparable performances were achieved when treating domestic wastewater, which were 84.6 ± 2.4%, 70.1 ± 4.2%, and 3.2 ± 0.2 W m−3 for ammonium nitrogen removal, TN removal, and maximum power density. Pyrosequencing analysis revealed Nitrosomonas was more abundant in the upper portion of the carbon fiber brush biocathode (CFBup, 20.4%) and Azoarcus was more abundant in the lower portion (CFBbottom, 12.6%), which was probably caused by the difference in dissolved oxygen concentration in different parts of the biocathode. The TB-MES shows great promise for domestic wastewater treatment by employing biotrickling filters for oxygen supply in biocathode MES.

An overview of microbial electrolysis cell configuration: Challenges and prospects on biohydrogen production

“…At an optimum condition, the system removed 79.7% of total nitrogen and achieved a maximum power density of 3.8 W/m 3. 118 A hollow trickling‐bed MFC (TB‐MFC) was developed for enhancing the removal efficiency of isopropyl alcohol. The effects of shock load and shutdown on the performance of TB‐MFC were evaluated.…”