Degradation of pharmaceuticals from wastewater in a 20-L continuous flow bio-electro-Fenton (BEF) system

The bio-electro-Fenton (BEF) technology has proven to be an effective and energy-saving method for treating wastewaters containing a single pharmaceutical in the lab-scale. However, the continuous degradation of pharmaceuticals in a scaled-up BEF has never been reported. In this study, a 20-L dual-chamber BEF reactor was designed and tested for treating six model pharmaceuticals. The effect of key operational factors including applied voltage, cathode Fe²⁺ dosage, initial pharmaceuticals concentration and hydraulic retention time (HRT), were assessed. By implementing 0.1 V voltage, 0.3 mM Fe²⁺ and HRT of 26 h, the six selected pharmaceuticals (500 μg L^-1 for each) were removed completely. Moreover, transformation products during clofibric acid degradation, such as 4-chlororesorcinol, were detected and the relevant transformation pathway was proposed. Additionally, it successfully removed these pharmaceuticals in the real wastewater matrix. This paper contributes to scaling-up the BEF process for continuous and effective treating pharmaceuticals-contaminated wastewater.