The present invention provides a system, method and apparatus for treating a liquid by providing a santitary type stainless steel hydrocyclone, flowing the liquid through the hydrocyclone, and turning on a plasma torch attached to the hydrocyclone such that a plasma arc irradiates the liquid. The hydrocyclone can be a forward flow hydrocyclone, a reverse flow hydrocyclone, a through flow hydrocyclone, a hydrocyclone pump or a volute.