Abstract: An acoustic treatment module stack includes a plurality of stacked pipe segments. Each pipe segment includes n ultrasound amplifier-transducers with an angular separation of (360/n)° on an outer circumference of the pipe segment, in which n is a positive integer, and a reflector unit disposed in a center of the pipe segment that includes n reflectors in which each ultrasound amplifier-transducer has a corresponding reflector positioned opposite of the ultrasound amplifier-transducer. Each acoustic treatment module is rotated (360/(n×m))° with respect to a preceding acoustic treatment module, in which m is a positive integer, and the plurality of acoustic treatment modules includes at least m pipe segments.