Simultaneous nitrification and denitrification by controlling vertical and horizontal microenvironment in a membrane-aerated biofilm reactor

Hibiya, Kazuaki; Terada, Akihiko; Tsuneda, Satoshi; Hirata, Akira

doi:10.1016/s0168-1656(02)00227-4

Cited by 183 publications

(99 citation statements)

References 24 publications

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“…Our study, however, is the first to simultaneously detect AOB and denitrifying bacteria within a single MAB. Our results are also consistent with previous studies that reported complete nitrogenous pollutant removal in MAB reactors (16,26,33,36). In contrast, AOB and denitrifying bacterial populations did not coexist in MABs grown under conditions of low fluid velocity (2 cm s Ϫ1 ).…”

Section: Discussionsupporting

confidence: 93%

“…Previous studies have used fluorescent in situ hybridization to detect AOB near the membrane of MABs (16,32,36). Our study, however, is the first to simultaneously detect AOB and denitrifying bacteria within a single MAB.…”

Section: Discussionmentioning

confidence: 87%

“…Numerous researchers have previously reported that ammonia-oxidizing bacteria (AOB) are concentrated near the membrane in MABs (16,32,36). Additional research, however, is needed to understand the stratification of the denitrifying bacterial populations as well as the pertinent factors (e.g., nutrient loading, fluid shear, etc.)…”

mentioning

confidence: 99%

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Stratification of Activity and Bacterial Community Structure in Biofilms Grown on Membranes Transferring Oxygen

Cole

Semmens

LaPara

2004

Appl Environ Microbiol

124

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Previous studies have shown that membrane-aerated biofilm (MAB) reactors can simultaneously remove carbonaceous and nitrogenous pollutants from wastewater in a single reactor. Oxygen is provided to MABs through gas-permeable membranes such that the region nearest the membrane is rich in oxygen but low in organic carbon, whereas the outer region of the biofilm is void of oxygen but rich in organic carbon. In this study, MABs were grown under similar conditions but at two different fluid velocities (2 and 14 cm s ؊1 ) across the biofilm. MABs were analyzed for changes in biomass density, respiratory activity, and bacterial community structure as functions of biofilm depth. Biomass density was generally highest near the membrane and declined with distance from the membrane. Respiratory activity exhibited a hump-shaped profile, with the highest activity occurring in the middle of the biofilm. Community analysis by PCR cloning and PCR-denaturing gradient gel electrophoresis of 16S rRNA genes demonstrated substantial stratification of the community structure across the biofilm. Population profiles were also generated by competitive quantitative PCR of gene fragments specific for ammonia-oxidizing bacteria (AOB) (amoA) and denitrifying bacteria (nirK and nirS). At a flow velocity of 14 cm s ؊1 , AOB were found only near the membrane, whereas denitrifying bacteria proliferated in the anoxic outer regions of the biofilm. In contrast, at a flow velocity of 2 cm s ؊1 , AOB were either not detected or detected at a concentration near the detection limit. This study suggests that, under the appropriate conditions, both AOB and denitrifying bacteria can coexist within an MAB.The aeration of bioreactors is one of the most significant operating costs incurred during the treatment of municipal and industrial wastewaters. One technological alternative to conventional coarse and fine bubble diffusers is the use of microporous membranes that contain small (Ͻ0.1 m) hydrophobic pores for bubbleless oxygen transfer to the wastewater (1). Biofilms actively grow on these membranes, such that membrane-aerated biofilm (MAB) reactors can treat wastewater at rates comparable to conventional suspended-growth processes (6,33,37). MAB reactors have lower operating costs, because oxygen transfer efficiency approaches 100% (5, 26) and because expensive air compression is no longer required (9). In addition, MAB reactors generate fewer odors, because volatile pollutants are not released into the atmosphere (5, 6).MABs are unique compared to biofilms grown on inert substrata. Nutrient concentrations in MABs are highest at the biofilm-liquid boundary and decrease with depth into the biofilm; in contrast, oxygen concentrations are highest at the membrane and decrease toward the outside of the biofilm (Fig. 1). In thick MABs, oxygen partially penetrates the biofilm, generating an anoxic zone at the biofilm-liquid boundary (6). In such biofilms, the region of greatest microbial activity is variable and depends on the relative availability of oxygen a...

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 87%

See 1 more Smart Citation

Stratification of Activity and Bacterial Community Structure in Biofilms Grown on Membranes Transferring Oxygen

Cole

Semmens

LaPara

2004

Appl Environ Microbiol

124

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“…Many consider the performance of a simultaneous nitrification/denitrification advantages that can be mentioned as (1) nitrification produces nitrite or nitrate, which is a reactant in denitrification, (2) nitrification re-duces the pH raised in denitrification, and (3) denitrification generates the alkalinity required in nitrification (7). The advantage of simultaneous nitrification and denitrification for biofilm systems such as integrated fixed-film activated sludge (IFAS) can be described as (1) accumulation of bacteria enhanced by chemical modification of the membrane surface, and (2) the amount of supplied oxygen controlled by intramembrane pressure.…”

Section: Introductionmentioning

confidence: 99%

Ammonium Removal by Nitrification and Denitrification in an Integrated Fixed Film Activated Sludge Process

et al. 2014

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Background: When nitrogen-containing compounds are released into the environment, they could create serious problems such as eutrophication of rivers, deterioration of water quality and potential hazard to human or animal health. Biological nitrogen removal is generally preferred over physicochemical methods due to its lower cost, lower chemical/energy requirements, and being environmental friendly. Objectives: The current study aimed to evaluate the performance of a simultaneous nitrification and denitrification in a modified integrated fixed-film activated sludge (IFAS). Materials and Methods:The ammonia and chemical oxygen demand (COD) (Ammonia 25, 40, 80, 120 and 160 mg/L and COD = 500 mg/L) removal were studied by the proposed system. Two reactors in bench scale with the capacity of 13 liters were considered. Effective parameters such as hydraulic retention time, COD consumption, and the effect of loading ammonia were evaluated. Results: Employing the BET, surface area (S a ), total pore volume (V p ), and average size of the nanostructure were 0.4026 m 2 /g, 3.808903 cm 3 /g and 44.7 nm, respectively. Results indicated that the desirable hydraulic retention time for nitrification occurred at 12. Due to higher COD consumption, there was no significant difference between the conventional IFAS and modified IFAS units. Based on the nitrification and denitrification results, the best condition for nitrifying/denitrifying performance was obtained by modified IFAS. Conclusions: Based on nitrification and denitrification data, the best condition for nitrifying/ denitrifying performance was obtained by modified-IFAS. Hence, the modification can be used to obtain the best activities of microbial and nitrogen removal improvement.

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“…Existen dos mecanismos en este tipo de proceso: físico y biológico (Robertson y Kuenen, 1984;Baumann et al, 1996;Hibiya et al, 2003). El mecanismo físico es que el proceso SND sucede como la consecuencia de los gradientes de la concentración de oxígeno disuelto (OD) dentro de los flóculos de fango activado o biofilms debido a las limitaciones en la difusión (Figura 6).…”

Section: Procesos De Nitrificación -Desnitrificación Simultáneos (Prounclassified

Modelación matemática del proceso de nitrificación en dos etapas. Desarrollo de metodologías de calibración del modelo para un reactor SHARON y un proceso de fangos activados

Douglas¹

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Cuatro años dedicados a la realización de la tesis doctoral conllevan la interacción con muchas personas. Estas primeras líneas las quiero dedicar para dar mi más sincero agradecimiento a todos aquellos que con su apoyo han hecho posible la presentación de esta memoria.En primer lugar quiero dar las gracias a José Ferrer Polo y Aurora Seco Torrecillas por darme la posibilidad de formar parte de su grupo de investigación y desarrollar mi tesis doctoral con ellos. Sin esta oportunidad hoy no estaría presentando esta memoria.Estoy profundamente agradecida a mis directores, el doctor Joaquín Serralta Sevilla y el doctor José Ferrer Polo, por la dirección, consejos e inestimable ayuda que han hecho posible la realización del presente trabajo. Deseo agradecerles también el apoyo y comprensión demostrada.A todos los compañeros del grupo de investigación que de una forma u otra han aportado su granito de arena en estos cuatro años de trabajo:A Javier Claros, mi partnet. Porque su trabajo me aportó la información necesaria para conformar los pilares de esta tesis. Junto con él y Luisa empecé mi andadura en el camino del doctorado y hemos seguido trabajando juntos durante mucho tiempo, por todo ello siempre les guardaré un especial cariño.A Vicky, Juan, Marcela y Laura Carretero por esas horas (y días) en la planta piloto y en el laboratorio compartiendo penas y alegrías. Gracias por hacer mucho más agradables las tareas más duras de este trabajo.A Freddy, Javier Eduardo y Ángel, mis compañeros de despacho. Vuestra compañía en estos años ha hecho mi vida como investigador mucho más fácil y el trabajo mucho más ameno.A Ángela, por su aportación artística y ese derroche de felicidad que anima a cualquiera.A Josep, Alberto, Paqui, Dani y Ramón porque siempre han sido un ejemplo a seguir. Gracias por los muchos comentarios y consejos aportados en estos años.A Luis, Nuria y Laura Pastor, vuestro buen humor y forma de ver la vida es siempre un regalo. Así que, simplemente, gracias por ser como sois.A Jose, Rafa, Brenda, Berta, Sara, Quique, Tatiana y Laura Segovia, porque con vosotros los momentos compartidos han sido pocos pero muy buenos.Por último, deseo expresar mi amor y agradecimiento a toda mi familia y amigos. En particular me gustaría agradecer a mis padres y hermanos porque a ellos les debo gran parte de lo que soy. Siempre encontré en sus palabras aquello que necesitaba oír en cada momento. Hemos compartido muchísimas cosas y con vuestras experiencias yo también he aprendido muchas lecciones que me han ayudado en mí día a día. Al futuro bebé de la familia porque con la noticia de tu llegada has alegrado la etapa final de esta tesis que siempre es la más difícil.También quiero dar las gracias a mi familia política, a mis suegros, cuñados y sobrinos, porque para mí siempre han sido como mis padres y mis hermanos, y me han tratado como una hija más desde el principio.A mis amigos de la infancia, Laura, Inma, Natalia,… y a todos aquellos que han ido llegando a lo largo de mi vida, en el instituto, la universidad, los via...

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Simultaneous nitrification and denitrification by controlling vertical and horizontal microenvironment in a membrane-aerated biofilm reactor

Cited by 183 publications

References 24 publications

Stratification of Activity and Bacterial Community Structure in Biofilms Grown on Membranes Transferring Oxygen

Stratification of Activity and Bacterial Community Structure in Biofilms Grown on Membranes Transferring Oxygen

Ammonium Removal by Nitrification and Denitrification in an Integrated Fixed Film Activated Sludge Process

Modelación matemática del proceso de nitrificación en dos etapas. Desarrollo de metodologías de calibración del modelo para un reactor SHARON y un proceso de fangos activados

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