Multi-tube parallel surface discharge plasma reactor for wastewater treatment

A multi-tube parallel surface discharge plasma reactor has been designed to investigate its mineralization potential for organic wastewater. p-Nitrophenol (PNP) was used as the target pollutant. The effects of some operational parameters such as solution pH value, discharge voltage, air flow rate and air moisture on COD removal were investigated. Ozone utilization and biodegradability (BOD5/COD) of wastewater were evaluated. The results indicated that this discharge system presented a great potential for COD removal. For 40 L of PNP wastewater, complete PNP removal and 97% of COD removal efficiency were achieved after 1 h of discharge treatment with energy yield of 27.4 gCOD kW h−1, and correspondingly, the ozone consumption and ozone utilization efficiency were 80% and 1.3 gCOD gO3−1. Increasing solution pH value and increasing discharge voltage were both beneficial for COD removal. The optimal air flow rate was observed as 1.5 m3 h−1. Dry air contributed to a greater COD removal efficiency, due to more O3 generation. The biodegradability of PNP wastewater increased up to 0.42 after 1 h of treatment.

► A multi-tube parallel surface discharge reactor is designed to treat wastewater.
► Complete p-nitrophenol removal and 97% COD removal are achieved.
► Biodegradability of p-nitrophenol wastewater is enhanced greatly after treatment.