A fluid treatment system includes a reactor chamber fluidly coupled with a fluid inlet and a fluid outlet. The reactor chamber is defined by one or more chamber walls. The system includes a UV LED, and a light pipe. The light pipe extends into the reactor chamber through at least one of the chamber walls. The light pipe has a proximal end disposed outside of the reactor chamber. The proximal end is coupled with the UV LED to transmit UV light into the reactor chamber through the light pipe. To that end, the light pipe also has a distal end, opposite the proximal end, that is disposed within an interior volume of the reactor chamber. The light pipe includes a central section disposed between the proximal end and the distal end. The central section is configured to transmit the UV light from UV LED to the distal end.
