AWWA WQTC65844

The number of water treatment facilities using ozone as a primary disinfectant isgrowing in places where surface waters are used as a source. Ozone disinfection in drinkingwater treatment facilities is often carried out in an ozone contactor that consists of multiplevertical or horizontal chambers to which ozone is fed by fine bubble diffusers (FBD). Thehydrodynamics of an ozone contactor strongly affect the overall conversion of all the chemicaland biological reactions (Roustan, et al, 1993; Henry & Freeman, 1995; Do-Quang, et al, 2000).Its effect is more pronounced for reactions with a relatively higher conversion (e.g., inactivationof C. parvum oocysts up to 99 to 99.9 percent) compared to reactions with a lower conversion(e.g., bromate formation from bromide is typically below 30 percent). Consequently, thereactor hydrodynamics could be optimized to minimize bromate formation while achievingtarget inactivation efficiency for C. parvum oocysts (Tang, et al, 2005; Kim, et al, 2006; Kim, etal, 2007).The impact of hydrodynamic conditions determined by such design variables oninactivation efficiency, which is a primary concern in ozone contactor design, was investigated.In particular, a three-dimensional laser-induced fluorescence (3D-LIF) was developed in thisstudy to visualize the mixing condition inside the ozone contactor by quantifying the entireinstantaneous tracer concentration field at very high resolution in three-dimensional space (Tian& Roberts, 2003) without disturbing the flow conditions (i.e. due to sampling). Varioushydrodynamic conditions within an ozone contactor including the non-ideal flow pattern, theeffects of flow rate, and the baffle opening size, were examined. Includes 9 references, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2007

Number of Pages:

7

File Size:

1 file , 780 KB