Water treatment device

A disinfection device including a pipe, an ultraviolet (UV) laser, a beam steering device and a transparent layer, the pipe including a tapered section, an inlet and an outlet, wherein:

• the UV laser is located at a smaller diameter end of the pipe and is adapted to project a laser beam towards a larger diameter end of the pipe;
• the laser beam is adapted to project through and/or off the beam steering device and through the transparent layer at a plurality of angles in a cycle;
• the beam steering device is adapted to steer the laser beam at the angles such that a profile of the laser beam projects through part or all of an inner profile of a point along the tapered section in the cycle;
• the pipe is adapted to receive a fluid that enters the inlet, passes through the pipe and exits through the outlet;
• the UV laser is adapted to move in a pattern that achieves statistically full coverage or full exposure of the fluid that flows through the pipe;
• and
• one of the inlet or outlet is located at the smaller diameter end of the pipe and the other of the inlet or the outlet is located at the larger diameter end of the pipe.