An apparatus (100) for purifying liquid comprises an irradiation chamber (102) upon which are disposed a plurality of UV-LEDs (112) which irradiate a flow (110) of liquid as it passes therethrough a coolant conduit (104) is disposed about said irradiation chamber (102) and UV-LEDs (112), which conducts a flow (126) of a coolant fluid through it thereby cooling the flow (110) of liquid and the plurality of UV-LEDs (112).
