Effect of operational variables on sand filter efficiency for separation of oil-in-water emulsions

Producing oily wastewater in different industries particularly petroleum industry, is one of the major environmental concerns. In this study a sand filter was used to remove oil from the oil/water emulsion and its performance was investigated. The Design-Expert ۱۲ software was applied in order to design experiments and investigate the effect of flow rate and bed height on removal efficiency of experimental setup. The statistical analysis showed that the response of process (removal efficiency) was well defined by the second-order equation. Base on the statistical results, the actual and the predicted results were well fitted. The results of optimization showed that the removal efficiency of sand filtration under optimal condition: flowrate of ۲۰ ml/min, bed height of ۷۰cm reached to ۸۸%. It demonstrated that the filtration column operated better in lower flowrates and higher bed heights. The result showed that the sand filter can be an effective method for the removal of oil from oil in water emulsion.