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NH4-N and organic N are the predominant forms of N in urban wastewaters. NH4-N contributes to eutrophication and degradation of natural water courses, thus it must be removed from treated effluents (Kadlec and Knight, 1996). Nitrification-denitrification is the selected process for NH4-N elimination in most wastewater treatment facilities. However, this biological process requires large dissolved oxygen inputs, a well established specific bacterial biomass and large hydraulic residence times. Additionally, Advanced Oxidation Technologies (AOTs), such as TiO2-photocatalysis, O3-UV and the photo-Fenton reaction, are able to degrade and mineralize many organic and inorganic compounds in relatively short times and at moderate economic cost (Pirkanniemi and Sillanpää, 2002). In this work, NH4-N degradation (from NH4Cl in distilled water and a pond-wetland wastewater treatment pilot plant) was attempted by using different AOTs. Figure 2 illustrates the preliminary results from a 20 ppm N-NH4 solution degradation under different experimental conditions.