Abstract: An apparatus and method for controllable separation of a purified fluid from a process water-based fluid containing at least one contaminating component are described. The apparatus comprises a housing having an inlet port for receiving the process water-based fluid through a controllable inlet valve, an outlet port for discharge of the purified fluid and a sludge port for discharge of a sludge fluid. The apparatus also includes an acoustic vibrator configured for generating a controllable acoustic wave having at least one adjustable parameter selected from frequency, amplitude and intensity. This acoustic vibrator creates at least one layer in the process water-based fluid dividing the process water-based fluid into a pre-filtered fluid and a sludge fluid. This layer is substantially perpendicular to a flow direction of said process water-based fluid.