The present invention relates to an ultrasonic fluid treatment device comprising a tank, at least one inlet pipe opening into said tank, at least one outlet pipe, and at leasat one ultrasound transducer within a sidewall of said tank. The transducer emits ultrasonic waves into the fluid that are not parallel to the primary flow of fluid through the tank. Ultrasonic waves emitted into the tank may treat the fluid, matter within the fluid, and/or organisms within the fluid in a variety of manners such as, but not limited to, cleaning objects within the fluid, sterilizing the fluid and/or objects within it, separating bonded matter within the fluid, segregating matter within the fluid into discrete laminas, killing or inactivating organisms within the fluid, extracting matter within the fluid, inducing chemical reactions within the fluid, and/or converting toxic matter within the fluid into a less toxic state.