Computational fluid dynamics?based modeling and optimization of flow rate and radiant exitance for 1,4-dioxane degradation in a vacuum ultraviolet photoreactor

WATER RESEARCH

卷:197

Article

Shi, Gang¹  Nishizawa, Shota¹  Matsushita, Taku²  Kato, Yuna¹  Kozumi, Takahiro¹  Matsui, Yoshihiko²  Shirasaki, Nobutaka² 

[1] Hokkaido Univ, Grad Sch Engn, N13W8, Sapporo, Hokkaido 0608628, Japan

[2] Hokkaido Univ, Fac Engn, N13W8, Sapporo, Hokkaido 0608628, Japan

关键词: Advanced oxidation process;    Modeling;    Radiation efficiency;    EEO;   

DOI  :  10.1016/j.watres.2021.117086

来源: Elsevier

【 摘 要 】

1,4-Dioxane is one of the most persistent organic micropollutants in conventional drinking-water treatment processes. Vacuum ultraviolet (VUV) treatment is a promising means of removing micropollutants such as 1,4-dioxane from source water, but this approach has not yet been implemented in a fullscale water treatment plant, partly because the operating parameters for pilot and full-scale VUV photoreactors have not been optimized. Here, we developed a computational fluid dynamics-based method for optimizing VUV photoreactor performance through energy-based analyses that take into account the effects of two important operating parameters-flow rate and radiant exitance. First, we constructed a computational fluid dynamics model and determined the sole parameter required for the model, the pseudo-first-order rate constant for the reaction of 1,4-dioxane, by simple batch experiment. Then, we validated the model by using a pilot-scale flow-through annular photoreactor. Finally, we used the validated model to examine the effects of flow rate and radiant exitance on the efficiency of 1,4-dioxane degradation in a virtual annular photoreactor. Radiation efficiency, which was defined as the ratio of the logarithmic residual ratio of 1,4-dioxane to the theoretical minimum logarithmic residual ratio (best possible performance) under the given operating conditions, was calculated as an energy-based index of cost-effectiveness. Radiation efficiency was found to increase with increasing flow rate but decreasing radiant exitance. An electrical energy per order (EEO) analysis suggested that VUV treatment under laminar flow was most economical when low-power lamps and a high flow rate were used. In contrast, VUV treatment under turbulent flow was suggested to be most economical when high-power lamps were used at a high flow rate. (c) 2021 Elsevier Ltd. All rights reserved.

【 授权许可】

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