Papers Published

1. Rosenfeldt, Erik J. and Linden, Karl G. and Canonica, Silvio and von Gunten, Urs, Comparison of the efficiency of ^{{radical dot}}OH radical formation during ozonation and the advanced oxidation processes O₃/H₂O₂ and UV/H₂O₂, Water Research, vol. 40 no. 20 (2006), pp. 3695 - 3704 [008] .
   (last updated on 2007/04/09)

   Abstract:
   Comparison of advanced oxidation processes (AOPs) can be difficult due to physical and chemical differences in the fundamental processes used to produce ^{{radical dot}}OH radicals. This study compares the ability of several AOPs, including ozone, ozone+H₂O₂, low pressure UV (LP)+H₂O₂, and medium pressure UV (MP)+H₂O₂ in terms of energy required to produce ^{{radical dot}}OH radicals. Bench scale ^{{radical dot}}OH radical formation data was generated for each AOP using para-chlorobenzoic acid (pCBA) as an ^{{radical dot}}OH radical probe compound in three waters, Lake Greifensee water, Lake Zurich water, and a simulated groundwater. Ozone-based AOPs were found to be more energy efficient than the UV/H₂O₂ process at all H₂O₂ levels, and the addition of H₂O₂ in equimolar concentration resulted in 35% greater energy consumption over the ozone only process. Interestingly, the relatively high UV/AOP operational costs were due almost exclusively to the cost of hydrogen peroxide while the UV portion of the UV/AOP process typically accounted for less than 10 percent of the UV/AOP cost and was always less than the ozone energy cost. As the ^{{radical dot}}OH radical exposure increased, the energy gap between UV/H₂O₂ AOP and ozone processes decreased, becoming negligible in some water quality scenarios. © 2006 Elsevier Ltd. All rights reserved.

   Keywords:
   Ozonization;Ultraviolet radiation;Lakes;Energy utilization;Costs;