A liquid treatment system comprising at least one ultra-violet light treatment lamp arranged within an elongated protective UV-transparent sleeve provided along a central longitudinal axis A, said sleeve having an outer surface and an essentially circular cross-sectional shape; and an elongated reactor configured to receive said sleeve, whereby an elongated liquid treatment chamber for receiving liquid to be treated, is provided between an inner surface of the reactor and the outer surface of the sleeve; wherein said liquid treatment system further comprises at least one cleaning arrangement comprising at least one cleaning device, wherein said cleaning arrangement is configured to compress said cleaning device towards the outer surface of the sleeve and to transfer the cleaning device over the sleeve surface for cleaning the outer surface of the sleeve, wherein the at least one cleaning device comprises at least one metal braid.