THE EFFECT OF PORE-SIZE ON TRANSFER CAPABILITIES, FOULING TENDENCIES,AND CLEANING OF CERAMIC AIR DIFFUSERS

A study of the effect of fouling on the standard oxygen transfer effic iency (SOTE) of ceramic diffusers of four different pore sizes was con ducted at the Monroe, Wis. wastewater treatment plant over a 2-year pe riod. Four pilot test headers were installed in the plant aeration tan ks each containing four diffusers of one pore size. Only minor changes in SOTE, bubble release vacuum (BRV), and dynamic wet pressure (DWP) were observed indicating that the fouling phenomenon at Monroe was not progressive. The adverse effects of fouling with respect to back pres sure and SOTE were found to be less than might have been predicted fro m the literature. The cleaning procedure used in the study, involving a combination of high pressure water spraying with liquid acid treatme nt, followed by additional spraying, resulted in nearly complete resto ration of the diffusers' original characteristics.