(US5772901-A)      A method (I) of separating an emulsion comprising a water-miscible (WM) phase, a water-immiscible (WI) phase and fine solid particles into a WM phase and a WI phase comprises: (a) passing the emulsion through a hydrocyclone to form an overflow emulsion and underflow emulsion; (b) inverting the overflow emulsion; (c) passing the inverted emulsion through a further hydrocyclone (or hydrocyclones in series); and (d) collecting WM and WI phases; the particles are collected in the discontinuous phase from step (c).    USE -   The essential process is (Ia), the emulsion treated being produced in a bio:de-sulphurisation (BDS) process for treatment of sulphur-containing fossil fuels; the emulsion typically contains intact bacterial cells, and the processes directed to recovery of substantially pure oil.    (EP900113-A1)      A method (I) of separating an emulsion comprising a water-miscible (WM) phase, a water-immiscible (WI) phase and fine solid particles into a WM phase and a WI phase comprises: (a) passing the emulsion through a hydrocyclone to form an overflow emulsion and underflow emulsion; (b) inverting the overflow emulsion; (c) passing the inverted emulsion through a further hydrocyclone (or hydrocyclones in series); and (d) collecting WM and WI phases; the particles are collected in the discontinuous phase from step (c).    USE -   The essential process is (Ia), the emulsion treated being produced in a bio:de-sulphurisation (BDS) process for treatment of sulphur-containing fossil fuels; the emulsion typically contains intact bacterial cells, and the processes directed to recovery of substantially pure oil.    (CN1216478-A)      A method (I) of separating an emulsion comprising a water-miscible (WM) phase, a water-immiscible (WI) phase and fine solid particles into a WM phase and a WI phase comprises: (a) passing the emulsion through a hydrocyclone to form an overflow emulsion and underflow emulsion; (b) inverting the overflow emulsion; (c) passing the inverted emulsion through a further hydrocyclone (or hydrocyclones in series); and (d) collecting WM and WI phases; the particles are collected in the discontinuous phase from step (c).    USE -   The essential process is (Ia), the emulsion treated being produced in a bio:de-sulphurisation (BDS) process for treatment of sulphur-containing fossil fuels; the emulsion typically contains intact bacterial cells, and the processes directed to recovery of substantially pure oil.    (JP2000509325-W)      A method (I) of separating an emulsion comprising a water-miscible (WM) phase, a water-immiscible (WI) phase and fine solid particles into a WM phase and a WI phase comprises: (a) passing the emulsion through a hydrocyclone to form an overflow emulsion and underflow emulsion; (b) inverting the overflow emulsion; (c) passing the inverted emulsion through a further hydrocyclone (or hydrocyclones in series); and (d) collecting WM and WI phases; the particles are collected in the discontinuous phase from step (c).    USE -   The essential process is (Ia), the emulsion treated being produced in a bio:de-sulphurisation (BDS) process for treatment of sulphur-containing fossil fuels; the emulsion typically contains intact bacterial cells, and the processes directed to recovery of substantially pure oil.