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. The layer comprises hydroxide radicals and oxygen species reacting with the contaminating component thereby transforming the component into radical form and oxidizing the component thereby causing binding of the component into insoluble aggregates which are precipitated within the sludge fluid. In addition, the apparatus comprises a filter unit disposed within the housing in a flow of the pre-filtered fluid from the layer to the outlet port.