Evaluation of UV/H2O2 for the disinfection and treatment of municipal secondary effluents for water reuse

BACKGROUND In this work, photochemical treatment (UV/H2O2) of a municipal secondary effluent was studied to assess its suitability for preparing water for reuse. Ten water reuse criteria obtained from the legislation of eight countries were used as indicators of water quality. Effluents from the municipal wastewater treatment plant (WWTP) of Gava-Viladecans (Barcelona, Spain) were subjected to UV/H2O2 treatment with low H2O2 concentration ([H2O2]o = 5 mg L−1 and UV fluence = 8.04 mW cm−2) and the most common water reuse parameters, such as disinfection indicators, turbidity, total suspended solids and microcontaminant removal (atrazine), were monitored. RESULTS Treatment inactivated 100% of the disinfection indicators after 5 min. Afterwards, three levels of treatment corresponding to different reuse applications were defined according to the legislation used. In addition, according to the LuminoTox® bioassay, oxidative treatment of the secondary effluent favoured the formation of less toxic intermediates. Finally, a study was performed to determine the costs of each reuse condition. CONCLUSIONS Findings suggest that UV/H2O2 is a suitable method to obtain water of sufficient quality for further reuse. © 2012 Society of Chemical Industry