Fouling of UV lamp sleeves : exploring inconsistencies in the role of iron

This paper investigates the effects of water quality parameters on fouling rates of UV lamp sleeves, through the results of various published studies performed by different groups as well as by the author.As part of this study, a pilot UV system was installed at the effluent line of two different biological wastewater treatment plants. The first plant included biofilters supplemented by alum addition during the summer for phosphorus removal. The second plant used an oxidation ditch and no coagulants were added. Iron was added to the UV pilot system influent in both cases to simulate post-coagulation of phosphorus. The Trojan UV System 3000 pilot consisted of three separate channels each containing 2 lamps. Two channels were used as controls by having just the sleeves (without UV lamps) in one of them and non-UV lamps (i.e. lamps with visible light output only) in the other. The third channel contained sleeves with two low-pressure UV lamps. The flow in each channel was maintained around 1--1.5 L/s and the ferric chloride concentration was varied from 0 to 6 mg/L. (Abstract shortened by UMI.