Enhanced degradation of pharmaceutical in real wastewater via peroxydisulphate addition in a pulsed corona discharge process

Removal of pharmaceuticals from water is a major challenge for water and chemical engineers worldwide. Low detected levels of these emerging pollutants require application of advanced treatment processes. Among them, pulsed corona discharge (PCD) is a promising solution. In this study, performance of gas-phase pilot scale PCD with addition of potassium peroxydisulphate (PS) was investigated. The effluents from municipal wastewater treatment plant – containing 24 native pharmaceuticals at the total concentration of approximately 10 μg L −1 – were treated. PCD was evaluated at two pulse frequencies–low (200 pulses per second, (pps)) and high (833 pps)–under three PS concentrations (0, 1 and 10 mg L −1 ) to determine the removal efficiency of pharmaceuticals. Low-frequency (LF) PCD showed 36% higher total removal of pharmaceuticals than the high-frequency PCD, at the same delivered energy (340 Whm −3 ). Addition of 10 mg L −1 of PS increased removal efficiency of both low- and high-frequency PCD by around 20%. A 94% removal of pharmaceuticals was achieved using LF PCD combined with PS addition at 400 Whm −3 . PS addition led to an increased energy yield for 50% removal of pharmaceuticals. In LF PCD, it increased from 26.4·10 −3 g kW −1 h −1 to 44.1·10 −3 g kW −1 h −1 when 10.7 mg L −1 of PS was added. We compered operational costs for low-frequency PCD alone and with PS addition under two electricity price scenarios. At a high electricity price 0.2 € kW −1 h −1 , addition of PS cuts LF PCD effluent treatment costs from ~0.08 € m −3 to ~0.06 € m −3 , leading to annual savings of 147 k€. • PCD effectively removes pharmaceuticals present in effluents from WWTP • 10 mg L −1 of peroxydisulphate (PS) increased removal of pharmaceuticals by 20% • PS addition in low-frequency PCD increased energy yield by c.a. 40% • Adding PS cuts PCD effluent treatment costs from ~0.08 € m −3 to ~0.06 € m −3 • At the energy price of 0.2 €/kWh, LF PCD/PS process yields annual savings of 147 k€