UV radiation and ozonation were investigated as disinfection alternatives for the wastewater treatment plant. The inactivation of total and fecal coliforms using ozone and ultraviolet radiation as separate treatments was evaluated. Different ozone concentrations (3 to 40 mg O 3 /L) were applied and UV fluencies ranging from 8.5 to 12 mJ/cm 2 at different pH values (from 5 to 9) were tested. Best results were obtained for ozone doses near 20 mg/min with removals of 72 % and 78% of fecal and total coliforms, respectively. The ozone also was capable of oxidizing organic matter in the effluent measured as COD (the highest removal obtained was 36% for 20 mg O 3 /min). Maximum bacterial resistance was observed at pH 7 in both cases. The UV light offered a high bacterial inactivation (over 80%) and the lowest bacterial inactivation was observed at pH 7. Finally, we obtained the electric energy per order (E EO , kWh/m 3 /order), defined as the electric energy (kW-h) required to degrade a contaminant by one order of magnitude in a unit volume of contaminated water, being noteworthy that E EO values for the UV process resulted were lower than those determined for the process with ozone in all the water flow tested.
N. A. Beltran and B. Jimenez, “Faecal Coliforms, Faecal enterococci, Salmonella typhi and Acanthamoeba spp. UV Inactivation in Three Different Biological Effluents,” Water SA, Vol. 32, No. 2, 2008, pp. 261-270.
M. Guo, H. Hu, J. R. Bolton and M. G. El-Din, “Comparison of Low- and Medium-Pressure Ultraviolet Lamps: Photoreactivation of Escherichia coli and Total Coliforms in Secondary Effluents of Municipal Wastewater Treatment Plants,” Water Research, Vol. 43, No. 3, 2009, pp. 815-821. http://dx.doi.org/10.1016/j.watres.2008.11.028
S. Gelover, E. R. Bandala, M. T. Leal, S. Pérez and M. Martinez, “GC-MS Determination of Volatile Organic Compounds in Drinking Water Supplies in Mexico,” Environmental Toxicology, Vol. 15, No. 2, 2000, pp. 131-139. http://dx.doi.org/10.1002/(SICI)1522-7278(2000)15:2 3.0.CO;2-Q
L. Liberti, M. Notarnicola and D. Petruzzeli, “Advanced Treatment for Municipal Wastewater Reuse in Agriculture. UV Disinfection: Parasite Removal and By-Product Formation,” Desalination, Vol. 152, No. 1-3, 2002, pp. 315-324. http://dx.doi.org/10.1016/S0011-9164(02)01079-2
R. Cantwell and R. Hofmann, “Inactivation of Indigenous Coliform Bacteria in Unfiltered Surface Water by Ultraviolet Light,” Water Research, Vol. 42, No. 10-11, 2009, pp. 2729-2735. http://dx.doi.org/10.1016/j.watres.2008.02.002
I. Salcedo, J. A. Andrade, J. M. Quiroga and E. Nebot, “Pilot Plant Protocol for Optimization of UV Dose Required to Obtain an Appropriate Municipal Wastewater Disinfection,” Journal of Water Supply: Research and Technology, Vol. 57, No. 1, 2008, pp. 57-63. http://dx.doi.org/10.2166/aqua.2008.072
D. D. Drury, S. A. Snyder and E. Wert, “Using Ozone Disinfection for EDC Removal,” Proceedings of the Water Environmental Foundation Conference (WEFTEC), Vol. 10, 2006, pp. 1249-1258.
A. Salveson, C. Ishida, K. Robinson, R. Bowman and S. Snyder, “Ozone Disinfection with the HiPOX Reactor: Streamlining and Old Technology for Wastewater Reuse,” Proceedings of the Water Environmental Federation, (WEFTEC), Session 11-20, 2008, pp. 1194-1206.
E. C. Wert, F. L. Rosado-Ortiz and S. A. Snyder, “Effect of Ozone Exposure on the Oxidation of Trace Organic Contaminants in Wastewater,” Water Research, Vol. 43, No. 4, 2009, pp. 1005-1014. http://dx.doi.org/10.1016/j.watres.2008.11.050
NOM-001-SEMARNAT, “Maximum Permissible Limits for Contaminants in Wastewater Releasing to Natural Streams,” Ministry of Environment, Mexico, 1996. http://es.scribd.com/doc/20808014/NOM-001-SEMARNAT-1996
APHA, AWWA, and WEF, “Standard Methods for the Examination of Water and Wastewater,” APHA, AWWA, and WEF, Washington DC, 1995.
I. George, P. Crop and P. Servais, “Fecal Coliform Removal in Wastewater Treatment Plants Studied by Plate Counts and Enzymatic Methods,” Water Research, Vol. 36, No. 10, 2002, pp. 2607-2617. http://dx.doi.org/10.1016/S0043-1354(01)00475-4
J. A. Morgan, A. E. Hoet, T. E. Wittum, C. M. Monahan and J. F. Martin “Reduction of Pathogen Indicator Organisms in Dairy Wastewater Using an Ecological Treatment System,” Journal of Environmental Quality, Vol. 37, 2008, pp. 272-279. http://dx.doi.org/10.2134/jeq2007.0120
M. A. Belmont, E. Castellano, S. Thompson, M. Williamson, A. Sanchez and C. Metcalf, “Treatment of Domestic Wastewater in a Pilot-Scale Natural Treatment System in Central Mexico,” Ecological Engineering, Vol. 23, No. 4-5, 2004, pp. 299-311. http://dx.doi.org/10.1016/j.ecoleng.2004.11.003
H. Hernández, H. López, J. F. Rodríguez and R. Enríquez, “Preliminary Study of the Disinfection of Secondary Wastewater Using a Solar Photolytic-Fotocatalytic Reactor,” Journal of Solar Energy Engineering, Vol. 130, No. 4, 2008, pp. 35-39.
K. Tosa and T. Hirata, “Photoreactivation of Entherohemorragic Escherichia coli Following UV Disinfection,” Water Research, Vol. 33, No. 2, 2004, pp. 361-366. http://dx.doi.org/10.1016/S0043-1354(98)00226-7
V. Lazarova, M. L. Janex, L. Fiskdal, C. Oberg, I. Barcina and M. Pommepuy, “Advanced Wastewater Disinfection Technologies: Short and Long Term Efficiency,” Water Science and Technology, Vol. 38, No. 12, 1998, pp. 109-117. http://dx.doi.org/10.1016/S0273-1223(98)00810-5
R. T. Irving, T. J. Macalister and J. W. Costerton, “Tris (Hydroxymethyl)amino-Methane Buffer Modification of Escherichia coli Outer Membrane Permeability,” Journal of Bacteriology, Vol. 145, No. 3, 1981, pp. 1397-1403.
L. Shabala and T. Ross, “Cyclopropane Fatty Acids Improves Escherichia coli Survival in Acidified Media by Reducing Membrane Permeability to H+ and Enhance Ability to Extrude H+,” Research in Microbiology, Vol. 159, No. 6, 2008, pp. 458-461. http://dx.doi.org/10.1016/j.resmic.2008.04.011
H. Nikaido, “Molecular Basis of Bacterial Outer Membrane Permeability Revisited,” Microbiology and Molecular Biology Reviews, Vol. 67, 2003, pp. 593-656. http://dx.doi.org/10.1128/MMBR.67.4.593-656.2003
P. Savoye, M. L. Janex and V. Lazarova, “Wastewater Disinfection by Low-Pressure and Ozone: A Design Approach Based on Water Quality,” Water Science and Technology, Vol. 43, No. 10, 2001, pp. 163-171.
P. Xu, M. L. Janex, P. Savoye, A. Cockx and V. Lazarova, “Wastewater Disinfection by Ozone: Main Parameters for Process Design,” Water Research, Vol. 36, No. 4, 2002, pp. 1043-1055. http://dx.doi.org/10.1016/S0043-1354(01)00298-6
J. R. Bolton, K. G. Bircher, W. Tumas and C. A. Tolman, “Figures-of-Merit for the Technical Development and Application of Advanced Oxidation Technologies for Both Electric and Solar-Driven Systems,” Pure and Applied Chemistry, Vol. 73, No. 4, 2001, pp. 627-637. http://dx.doi.org/10.1351/pac200173040627
E. R. Bandala, B. Corona-Vásquez, R. Guisar and M. Uscanga, “Deactivation of Highly Resistant Microorganisms in Water Using Solar Driven Photocatalytic Processes,” International Journal of Chemical Reactor Engineering, Vol. 7, No. A7, 2009, pp. 1-16.