A passive fluid treatment assembly is provided including a passive treatment body defining a primary flow path and a liquid treatment path. The liquid treatment path bypasses a portion of the primary flow path and enters a treatment enclosure through a high pressure port. The fluid entering the high pressure port is treated by a treatment media in the treatment enclosure and exits through a low pressure port into a mixing chamber where it is remixed with the fluid in the primary flow path. A one-way valve is operably coupled to an outlet of the high pressure port for preventing the flow of treated fluid from exiting the treatment enclosure through the high pressure port.