Removal of Sulfamethoxazole from Wastewater Treatment Plant Effluents by a Boron-doped Diamond Electrode

Abstract

The high inflow of pharmaceutical pollutants from wastewater into the aquatic environment requires new technologies for effective wastewater treatment. The current research focusses on the application of borondoped diamond (BDD) electrodes for the removal of the persistent antibiotic sulfamethoxazole (SMX) from wastewater effluent. Tests were performed with real secondary effluents from a wastewater treatment plant spiked with SMX at the initial concentration of 5.5 µM. The BDD electrode was operated at two different current densities (208 and 333 mA/cm²). The results showed a very good degradation of SMX. Four previously reported transformation products (TPs) were detected. These intermediates disappeared gradually with the extension of treatment time. SMX was removed during the first 5 to 10 minutes, depending on the current density applied to the electrode. However, much more time was required to remove the majority of the detected TPs. The hazardousness of the TPs is not known and in case it is negligible, the treatment time could be shortened. This will be reflected in less energy consumption and consequently lower costs.