Experimental study on oily wastewater treatment with low energy consumption based on effervescent atomizer

Abstract

The low energy consumption and efficient treatment of oily wastewater using microbubble flotation technology is a current research hotspot. A low-energy microbubble jet flotation system for treating oily wastewater was established using an effervescent atomizer as a microbubble generator. The effects of air-liquid mass flow ratio(ALR) and working pressure (p) on the size distribution characteristics of microbubbles and de-oiling capacity were discussed, and the energy consumption of effervescent atomizer was analyzed. The experimental results showed that a large number of microbubbles could be generated by using the effervescent atomizer to organize submerged jet, the number of microbubbles with diameters less than 150 μm accounted for more than 55%, and the number of microbubbles with diameters less than 600 μm accounted for more than 98%. The number of microbubbles increased first and then decreased with the increase of ALR, and the optimum ALR was 0.15. When p was 0.2 MPa and ALR was 0.15, the Sauter mean diameter of microbubbles could be as low as 238 μm, the oil concentration in wastewater was 29.73 mg/L, the power consumed by the microbubble jet flotation was only 6.53×10-4 kW·h per kilogram of wastewater , which was more than 35% lower than dissolved air flotation.

Keywords

• low energy consumption
• microbubble
• jet floatation
• oily wastewater
• effervescent atomizer