Abstract: A non-destructive method for the early detection of the formation of orga deposits or a biofilm on the internal surface of a conduit through which a fluid passes comprises allowing the fluid to flow through a conduit, passing a light beam, e.g., IR or UV light, through the fluid and the deposits in a direction transversal to the surface thereof, detecting and measuring the transmitted portion of the light beam after it has emerged from the fluid and the deposits, conducting these measurements at least twice at a set time interval, the first time before any materials deposit, and calculating % variation absorbed light during the time interval, which value is proportional to the organic materials or biofilm deposited and a method of removing at least a portion of organic deposits or a biofilm deposited on the internal surface of a conduit through which a fluid flows comprises allowing the fluid to flow through a conduit having a deposited organic layer or biofilm, passing a light beam, e.g.