Effect of Aeration Rate on Nutrient Removal from Slaughterhouse Wastewater in Intermittently Aerated Sequencing Batch Reactors

Abstract

The effect of aeration rate on nutrient removal from slaughterhouse wastewater was examined in two 10-L laboratory-scale sequencing batch reactors (SBRs-SBR1 and SBR2) operated at ambient temperature. The contaminants in the slaughterhouse wastewater had average concentrations of 4,000 mg chemical oxygen demand (COD) L −1 , 350 mg total nitrogen (TN) L −1 and 26 mg total phosphorus (TP) L −1 . The duration of a complete SBR operation cycle was 8 h and comprised four operational phases: fill (7 min), react (393 min), settle (30 min) and draw/idle (50 min). During the react phase, the reactors were intermittently aerated four times at 50-min intervals, 50 min each time. DO, pH and oxidation-reduction potential (ORP) in the reactors were real-time monitored. Four aeration rates-0.2 L air min −1 in SBR1 for 70 days, 0.4 L air min −1 in SBR1 for 50 days, 0.8 L air min −1 in SBR2 for 120 days and 1.2 L air min −1 in SBR1 for 110 days-were tested. When the aeration rate was 0.2 L air min −1 , the SBR was continuously anaerobic. When the aeration rate was 0.4 L air min −1 , COD and TP removals were 90% but TN removal was only 34%. When the aeration rates were 0.8 and 1.2 L air min −1 , average effluent concentrations were 115 mg COD L −1 , 19 mg TN L −1 and 0.7 mg TP L −1 , giving COD, TN and TP removals of 97%, 95% and 97%, respectively. It was found that partial nitrification followed by denitrification occurred in the intermittently aerated SBR systems.

Partial nitrification and nutrient removal in intermittently aerated sequencing batch reactors treating separated digestate liquid after anaerobic digestion of pig manure

“…This indicates end of nitrification. If aeration would be terminated before the sharp increase, the energy input would be saved [15]. In addition, since the AOR:NOR ratios at DO of 4 mg/L were higher than those at DO of 1.2 mg/L, maintaining the operation of the IASBR reactors at lower DO levels would benefit partial nitrification.…”

“…Efficient partial nitrification has been observed in intermittently aerated sequencing batch reactors (IASBRs) treating wastewater [13,14]. It is reported that IASBRs treating slaughterhouse wastewater achieved a NO 2 --N level of up to 96% of the total oxidized nitrogen (TON, NO 2 --N and NO 3 --N), in addition to COD and total nitrogen (TN) removals from wastewater of more than 94 and 92%, respectively [15,16].…”

Remoción de nutrientes en aguas residuales de un matadero de reses usando un reactor biológico secuencial

“…Los parámetros medidos a la entrada, salida de cada una de las fases de la etapa de reacción y al finalizar el tratamiento de cada ciclo fueron los siguientes: pH (4500-B), DBO [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] (SM 5210), DQO T y DQO S (5220-C), NTK (4500-Norg-B), N-NH 4 + (4500-NH 3 -B), N-NO 2 -(4500-NO2 2 --B), N-NO 3 -(4500-NO 3 --D), NT (4500-Norg-B), PT (4500-P-C), P-PO 4 -3 (4500-P-C), alcalinidad total (2320 B), SS (2540-F), SSV (2540-E) y SST (2540-D) según los procedimientos establecidos en el Método Estándar [15]. Para la determinación de la DQO S , las muestras fueron previamente filtradas por una membrana de celulosa y un tamaño de poro de 0,45 µm (Whatman).…”

“…Es por esto que en la actualidad se ha visto la necesidad de remover simultáneamente la materia orgánica, el nitrógeno y el fósforo en los efluentes provenientes de los mataderos de reses, realizándose exitosamente mediante la aplicación de tratamientos biológicos con sistemas no convencionales de lodos activados, como los reactores por carga secuencial (SBR) [7][8][9][10].…”

Nitrogen removal from slaughterhouse wastewater in a sequencing batch reactor under controlled low DO conditions

“…Li et al [10] found that, at an aeration rate of 0.8 l air/ min, after the depletion of ammonium-N (NH 4 ? -N), DO in the reactor during the aeration periods reached 70% of DO saturation.…”