water ice dispenser 214 the water flowing in the pipe 213 passes through the uv led reactor 212 for treatment prior to entering the water ice dispenser 214 the refrigerator is illustrated as an example of appliances the general fluid flow directions are shown by the arrows referring now to fig1 there is shown partially diagrammatic perspective view of a hemodialysis machine containing a uv led reactor 220 having a body 221 a uv led reactor 222 and a pipe 223 the water flowing in the pipe 223 passes through the uv led reactor 222 for treatment prior to use in the hemodialysis machine the hemodialysis machine is illustrated as an example of healthcare devices the construction details of the invention as shown in fig2 to fig1 are that the uv led reactor housing may be made of aluminum stainless steel or of any other sufficiently and strong material such as metal alloy high strength plastic or the like the various components of the uv led reactor may also be made of different materials further uv leds of different peak wavelengths may be used to cause synergistic effects to enhance the photoreaction efficiency further a combination of different configuration concepts which include the concepts presented in fig2 to fig1 may be used for example static mixers may be used with photocatalysts the advantages of the present invention include without limitation that it is an efficient compact uv led reactor that can be applied to any uv activated photoreaction or photocatalytic reaction one of these applications is water purification by uv inactivation of microorganisms and uv based degradation of chemical contaminants further the reactor concept presented in this invention which can be optimized based on a combination of uv led radiation patterns and the flow.