LAUSR

A novel process ‘coalescence-airflotation-carrier preferential adsorption’ utilising an oil-water separation flotation column with a unique structure was used in the oil-water separation field. The oil-water separation flotation column contains the cyclonic separation and airflotation separation which has advantages in oily sewage treatment, especially in polymer-flooding-drive oily sewage treatment. In this paper, different dimensions of flotation column with 1 m 3 d −1 , 30 m 3 d −1 and 2,000 m 3 d −1 oil-water separation systems were investigated. In addition, several operating parameters which impact separation, such as feeding speed, aeration rate, circulating pressure, adsorbents consumption and frother consumption were also investigated. The optimum operating parameters determined for 1 m 3 d −1 the oil-water separation flotation column were a feeding speed of 0.042 m 3 h −1 , an aeration rate of 0.10 m 3 h −1 , a coal consumption of 4 (g coal)·(g oil) −1 , a frother consumption of 10 mg L −1 , and a circulating pressure of 0.12 MPa. The novel process cost reduced 55.8% than conventional two-stage air flotation process. In the 2,000 m 3 d −1 oil-water separation experiment, the oil concentration and the oil removal efficiency of outlet are 23.39 mgL −1 , 97.70%, respectively. Sediment is not produced during the oily sewage treatment using the novel process and flotation column.