Bioelectrochemical process for simultaneous removal of copper, ammonium and organic matter using an algae-assisted triple-chamber microbial fuel cell

Abstract

Considering the adverse effect of heavy metals (such as Cu²⁺) on biological wastewater treatment processes, an algae-assisted triple-chamber microbial fuel cell (MFC) was established to remove Cu²⁺, COD and nitrogen sequentially, and also generate electricity. About 86.2% of the Cu²⁺ was removed in the first cathodic chamber, and the remaining Cu²⁺ was largely eliminated by algal uptake, contributing to an overall Cu²⁺ removal rate of 99.9% across the whole system. The nitrogen removal rate reached 79% in the system. The majority of the ammonium was assimilated by algae, and nitrogen oxides formed during the light period were denitrified at the cathode in the dark period. The variation in electrode potentials indicated that the cathode and anode potentials not only depended on the respective substrate concentrations, but also affected each other. The influence of algae on the microbial communities was greater than that of Cu²⁺ or the system structure. Devosia, Thauera, Pseudomonas, Acinetobacter and Flavobacterium may influence nitrogen removal, while Delftia, Thauera and Pseudomonas may play an important role in power generation. The present study has developed a practical method for removing pollutants from the wastewater containing heavy metals.

Keywords: Electrode potential; Heavy metals; Microbial community; Nitrogen removal; Triple-chamber microbial fuel cell.