The removal of Ibuprofen and Diclofenac in Biochar included Microbial Electrochemical Remediation (BiMER)

Abstract

Pharmaceuticals in wastewater are a growing concern in wastewater treatment. Current technologies are inadequate and there is need for a new efficient treatment technology. An approach could be integrating electroconductive materials (e.g. biochar) to microbial electrochemical technologies. Electroactive bacteria (e.g. Geobacter sulfurreducens) could remediate wastewater by respiring through electrodes/electron shuttles. In this paper it is hypothesized that ibuprofen and diclofenac are removed from wastewater by anaerobic digestion (AD) in biochar included microbial electrochemical remediation (BiMER). AD of pharmaceuticals was investigated by exposing electroactive bacteria (Geobacter sulfurreducens or a mixed culture) to diclofenac or ibuprofen. After incubation, contaminant concentration was determined with HPLC and bacterial growth with Bradford assay. In adjoining experiments, similar set-ups were used with additional electroconductive material (biochar). Additionally, the AD of acetate was investigated in BiMERs with different biochar/sand mixing ratios. Neither the pure culture, nor the mixed culture could degrade the pharmaceuticals efficient in the absence of any electro-conductive material. Biochar could improve degradation, but it was dependent on the pharmaceutical. High biochar/sand mixing ratios resulted in a lower electrochemical resistance and allowed good colonisation and growth. The analysis of further experiments together with more research is needed to acquire a better understanding of the AD process.