Impact of multi-air plasma jets on nitrogen concentration variance in effluent of membrane bioreactor pilot-plant

Abstract

An investigation of an atmospheric non-thermal air plasma effect on the modification of nitrogen concentration in the effluent of membrane bioreactor (MBR) pilot-plant has been proposed in this paper. The plasma treatment system has been a vertical liquid circulating system with horizontal multi-air plasma jets generated by a 125 W neon power supply. It has been found out that the variation trend of nitrogen concentration in air plasma-treated MBR effluent and deionized water (DI water) with different electrical conductivity (EC), ranging from 361.3  21.3 to 2,153.3  83.1 S/cm, has been similar. The trend has been a positively skewed bell-like curve. The highest nitrogen concentration in the plasma-treated effluent has been found out at 15 min plasma treatment, which has been almost two times higher than that of the untreated effluent. The experimental results show that the EC of treated media had not significantly influenced the nitrogen concentration variance. However, considerably low EC (less than 1 S/cm) of liquid media affects the difficulty of plasma generation. Regarding the experimental results, the atmospheric non-thermal air plasma has shown a positive impact on the nitrogen enhancement of MBR effluent, which could provide information in water reuse applications.

Keywords

• air discharge
• wastewater treatment
• membrane bioreactor (mbr)
• circulating system
• water reuse