The use of the biochar-based catalyst for the improvement of bioelectrochemical cleanup of NO3 and NH3 in water environment

Abstract

A bioelectrochemical system is a form of bioengineering technology that has been popularly employed in treating wastewater and energy recovery. However, most of the recent studies in the field of bioelectrochemical technology have mainly focused on scalable architectural designs of the system, while research on the selection of a suitable biocatalyst for the improvement of bioelectrochemical cleanup of pollutants has been given insufficient consideration. The three major limitations of improving bioelectrochemical cleanup technology are time consumption, high cost, and non-nature-based catalyst. In this study, a new bioelectrochemical compartment (BC) incorporating a biochar-based catalyst was fabricated to determine the upscaling effect on the cleanup of nitrate (NO₃) and ammonia (NH₃) from an aqueous solution. The two different bioelectrochemical reactors used in this experiment were denoted as System 1 (control), and System 2 (experimental), which were later expressed as S1 and S2, and the wastewater sample used was activated sludge. The highest cleanup efficiency of NO₃ (99%) was achieved in S2 when the BC was operated with a biochar-based catalyst compared to that of the which was 95%. However, the cleanup efficiencies of NH₃ were 96% and 67% in S1 and S2, respectively. This outcome indicated that the highest cleanup efficiency of NH₃ was achieved in S1. In addition, we monitored biogas generation in each BC and recovered a significant quantity of CO_2, N₂O, and CH₄. Sporosarcina, Tissierala from the species of Firmicutes, and Pseudomonas of phylum Proteobacteria were the most abundant bacteria that supported the cleanup of pollutants in this study.