Nitrobacterias en reactores biológicos rotativos de contacto (RBC) de tres cámaras bajo diferentes cargas orgánicas / Nitrobacteria in three stages rotating biological contactor (RBC) reactors under different organic loads
Palabras clave:
bacteria, carga orgánica, nitrógeno, reactor RBC, tratamiento biológico., biological treatment, nitrogen, organic load, RBC reactor.Resumen
En esta investigación se evaluó la variabilidad en la densidad de grupos bacterianos relacionados con la dinámica del nitrógeno en la biopelícula de un reactor biológico rotativo de contacto (RBC) de tres cámaras, a es- cala de laboratorio, bajo diferentes cargas orgánicas (en función de la variación del tiempo de retención hidráulico, TRH). Se estudiaron tres TRH (24, 12 y 6 h), empleando un efluente sintético que contenía sacarosa y urea como fuentes de carbono y nitrógeno, respectivamente. Se monitorearon los siguientes parámetros fisicoquímicos y for- mas de N: pH, alcalinidad total, oxígeno disuelto, demanda química de oxígeno (DQO), NO2 -, NO3 -, NH4 + y N-total (métodos estándares), así como la densidad de bacterias nitrificantes (oxidadoras de NH + y de NO -), desnitrificantes, fijadoras de N2; por la técnica de tubos múltiples con medios de cultivo selectivos, y conteo de heterótrofos. Las densidades de nitrobacterias estuvieron entre 1,2x106 y >2,5x1010 NMP/100 g peso seco. Los resultados muestran que la abundancia de bacterias estuvo afectada tanto por la carga orgánica, como por posición en las cámaras del reactor. Se evidenció la ocurrencia del proceso de nitrificación-desnitrificación simultánea, mediante la detección de ambos grupos bacterianos en la biopelícula.
Abstract
Research was undertaken to evaluate the variability in densities of bacterial groups related to ni- trogen dynamic in biofilm of a rotating biological contactor (RBC) reactor of three stages, in laboratory conditions, under different organic loads (based on the variation of hydraulic retention time, HRT). Three HTR were studied (24, 12 and 6 h), using a synthetic effluent that contained saccharose and urea, as sou- rces of carbon and nitrogen, respectively. The following physico-chemical parameters and N forms were monitored: pH, total alkalinity, dissolved oxygen, chemical oxygen demand (COD), NO2 -, NO3 -, NH4 + and N-total (standard methods), as well as the density of nitrifying (NH + and NO - oxidizing bacteria), denitrifying, N2 fixing bacteria, by multiple tubes technique with selective culture media, and heterotro- phs count. The nitrobacteria densities were between 1,2x106 and >2,5x1010 MPN/100 g dry weight. The results show that the bacteria abundance was affected so much by the organic load, as by position in the reactor stages. The occurrence of the simultaneous nitrification-denitrification process was verified, by means of the detection of both bacterial groups in the biofilm.
Descargas
Referencias
Alexander M., Clark F., Nitrifying Bacteria, Cornell University and the Soil and Water Conservation Research Division, USA, (1965), 1322-1477.
American Public Health Association (APHA), American Water Works Association (AWWA), Water Environment Federation (WEF), Standard Methods for the Examination of Water and Wastewater, 20th Edition, Washington DC, USA, (1998).
Boller M., Gujer W., Tschui M., Parameters affecting nitrifying biofilm reactors, Wat. Sci. Techol., Vol. 29, No. 10-11, (1994), 1-11.
Chen S., Ling J., Blancheton J.P., Nitrification kinetics of biofilm as affected by water quality factors, Aquacult. Eng., Vol. 34, (2006), 179-197.
Chuang S.H., Ouyang C.F., The biomass fractions of heterotrophs and phosphate-accumulating orga- nisms in a nitrogen and phosphorus removal system, Wat. Res., Vol. 34, No. 8, (2000), 2283-2290.
Cortéz S., Teixeira P., Oliveira R., Mota M., Rotating biological contactors: a review on main factors affecting performance, Rev. Environ. Sci. Biotechnol., Vol. 7, (2008), 155-172.
Garzón M., González S., Biological phosphate and nitrogen removal in a biofilm sequencing batch reactor, Wat. Sci. Technol., Vol. 43, No. 1, (1996), 1293-1301.
Garzón M., Mecanismos no convencionales de transformación y remoción del nitrógeno en sistemas de tratamiento de aguas residuales, Ingeniería Hidráulica en México, Vol. 20, No. 4, (2005), 137-149.
Guinea A., Martin M., Serrano S., Biofilm communities and operational monitoring of a rotating biological contactor system, Wat. Sci. Techol., Vol. 43, (2000), 247-253.
Gupta A., Gupta S., Simultaneous carbon and nitrogen removal in a mixed culture aerobic RBC bio- film, Wat. Res., Vol. 33, No. 2, (1999), 555-561.
Holman J.B., Wareham D.G., COD, ammonia and dissolved oxygen time profiles in the simultaneous nitrification/denitrification process, Biochem. Eng. J., Vol. 22, No. 2, (2005), 125-133.
Kindaichi T., Ito T., Okabe S., Ecophysiological interaction between nitrifiying bateria and heterotro- phic bacteria in autotrophic nitrifiying biofilms as determined by microautoradiography-fluorescence in situ hybridization, Appl. Environ. Microbiol., Vol. 70, No. 3, (2004), 1641-1650.
Liu, Y., Capdeville B., Specific activity of nitrifying biofilm in water nitrification process, Wat. Res., Vol. 30, No. 7, (1996), 1645-1650.
Okabe S., Oozawa Y., Hiratia K., Watanabe Y., Relationship between population dynamics of nitri- fiers in biofilms and reactor performance at various C:N ratios, Wat. Res., Vol. 30, No. 7, (1996), 1563-1572.
Schmidt I., Sliekers O., Schmid M., Bock E., Fuerst J., Kuenen J., Jetten M., Strous M., New con- cepts of microbial treatment processes for the nitrogen removal in wastewater, FEMS Microbiol. Rev., Vol. 27, (2003), 481-492.
Verhagen F., Duyts H., Laambroek H., Competition for ammonium between nitrifying and hetero- trofic bacteria in continuosly percolated soil columns, Appl. Environ. Microbiol., Vol. 58, No. 10, (1992), 3303-3311.
Verhagen F., Laambroek H., Competition for ammonium between nitrifying and heterotrofic bacteria in dual energy-limited chemostats, Appl. Environ. Microbiol., Vol. 57, No. 11, (1991), 3255-3263.
Yang P.Y., Zhang Z.Q., Proceedings of the UNESCO-University of Tsukuba International Seminar on Traditional Technology for Environmental Conservation and Sustainable Development in the Asian-Pacific Region, Tsukuba, Japon, (1995), 145-158.
Descargas
Publicado
Número
Sección
Licencia
Derechos de autor 2012 @copyright
Esta obra está bajo una licencia Creative Commons Reconocimiento 3.0 Unported.
Avenida 2 “El Milagro”, entrada autónoma de la 