Abstract: A method and an apparatus for separating a water/organic/solid emulsion, wherein the solid comprises particles having a length of about 50 .mu.m or less, are disclosed. The method comprises the steps of (1) directing the water/organic/solid emulsion from an emulsion source through a first hydrocyclone; (2) inverting the phase of the overflow emulsion from the first hydrocyclone; (3) directing the overflow emulsion through one or more subsequent hydrocyclones arranged in series; and (4) collecting the aqueous phase and the organic phase. The solid can be a biocatalyst, such as an intact bacterial, fungal or yeast cell. The organic phase is a liquid material substantially comprising carbon, which is substantially immiscible with water, such as petroleum.