Self-rotation induced regeneration of filter media to enhance the oil-water separation in a microchannel filter

Abstract

The regeneration of filter media was crucial to the filtration performance of the oily wastewater. Herein, a novel hydrocyclone-induce approach was proposed for filter media regeneration, followed by an exploration of oil desorption feasibility and mechanism. The effect of structural and operation parameters of a hydrocyclone on the particle self-rotation was extensively analyzed by numerical simulation, and its feasibility for oil desorption from the filter media was subsequently investigated. A hydrocyclone-intensified filtration method that combined by the unit of filtration and hydrocyclone self-rotation regeneration was proposed, and the effect of hydrocyclone-induced filter media regeneration on the subsequent oily wastewater filtration was also explored. The ideal specifications of the hydrocyclone were concluded to be an overflow pipe insertion of 120 mm, and a cone angle of 60° for the optimal self-rotation velocity. The hydrocyclone-induced regeneration presents a remarkable oil desorption efficiency, and the oil concentration of filter media reduced from 9.43 % to 6.94 %, 4.33 %, and 3.43 % as the flowrate increased from 1.8 × 105 L·m−2·h−1 to 5.4 × 105 L·m−2·h−1. The adhered oil was exfoliated due to the centrifugal force caused by the revolution and self-rotation of the media particles, while the filter media spun in a hydrocyclone. The average effluent oil concentration in the raw oily wastewater was reduced to 12.2 mg/L during the pilot-scale test, indicating that the hydrocyclone regeneration benefits the continuous oil-water separation. It is believed that this work might provide a unique and efficient method for oily wastewater treatment with the integration of filtration and hydrocyclone regeneration.