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Comparison of Simultaneous Nitrification and Denitrification for Three Different Reactors.

Khanitchaidecha W, Nakaruk A, Koshy P, Futaba K - Biomed Res Int (2015)

Bottom Line: Discharge of high NH4-N containing wastewater into water bodies has become a critical and serious issue due to its negative impact on water and environmental quality.Under intermittent aeration, nitrification and denitrification occurred simultaneously in the aerobic and anaerobic periods.Moreover, internal carbon was consumed efficiently for denitrification.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil Engineering, Faculty of Engineering, Naresuan University, Thailand ; Centre of Excellence for Innovation and Technology for Water Treatment, Naresuan University, Thailand.

ABSTRACT
Discharge of high NH4-N containing wastewater into water bodies has become a critical and serious issue due to its negative impact on water and environmental quality. In this research, the performance of three different reactors was assessed and compared with regard to the removal of NH4-N from wastewater. The highest nitrogen removal efficiency of 98.3% was found when the entrapped sludge reactor (ESR), in which the sludge was entrapped in polyethylene glycol polymer, was used. Under intermittent aeration, nitrification and denitrification occurred simultaneously in the aerobic and anaerobic periods. Moreover, internal carbon was consumed efficiently for denitrification. On the other hand, internal carbon consumption was not found to occur in the suspended sludge reactor (SSR) and the mixed sludge reactor (MSR) and this resulted in nitrogen removal efficiencies of SSR and MSR being 64.7 and 45.1%, respectively. Nitrification and denitrification were the main nitrogen removal processes in the aerobic and anaerobic periods, respectively. However, due to the absence of sufficient organic carbon, denitrification was uncompleted resulting in high NO3-N contents in the effluent.

No MeSH data available.


Related in: MedlinePlus

(a) Nitrogen removal efficiency and (b) nitrogen profile of SSR.
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fig2: (a) Nitrogen removal efficiency and (b) nitrogen profile of SSR.

Mentions: The SSR was operated under intermittent aeration for two hours. In aerobic conditions, a low air flow rate of 0.5 L/min was used and the DO was ~4-5 mg/L. In the anaerobic setup, the air was not supplied and this caused the DO to drop immediately to ~0.5 mg/L within 30 min. The nitrogen removal efficiency and nitrogen concentrations during operation are presented in Figure 2(a) (for days 1–20). The nitrogen removal efficiency was 64.7% and the 15 mg/L of NO3-N remained in the effluent. These results reveal that the nitrification process to change NH4-N to NO2-N and NO3-N occurred to completion. However, the denitrification process to change NO3-N to N2 was ineffective. From previous studies [14, 17], it is suggested that the ineffective denitrification occurs due to high oxygen, high NO2-N, and low organic carbon contents. The nitrogen profile during the three cycles of intermittent aeration (including aerobic 1, anaerobic 1, aerobic 2, anaerobic 2, aerobic 3, and anaerobic 3) was determined to identify the main cause of ineffective denitrification (Figure 2(b)). After addition of the acetate during anaerobic 1 step, the NO3-N level decreased from 16 mg/L to zero and the COD concentration also decreased from 200 to 8 mg/L. The COD concentration was stable at ~5–8 mg/L till the end of the operation and there was no NO3-N reduction in anaerobic 2 and 3 stages. Since the NO2-N was not detected and the DO was also low as 0.5 mg/L in the anaerobic stage, thus the incomplete denitrification in the SSR resulted from insufficient acetate addition (C/N of 1.5).


Comparison of Simultaneous Nitrification and Denitrification for Three Different Reactors.

Khanitchaidecha W, Nakaruk A, Koshy P, Futaba K - Biomed Res Int (2015)

(a) Nitrogen removal efficiency and (b) nitrogen profile of SSR.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4562362&req=5

fig2: (a) Nitrogen removal efficiency and (b) nitrogen profile of SSR.
Mentions: The SSR was operated under intermittent aeration for two hours. In aerobic conditions, a low air flow rate of 0.5 L/min was used and the DO was ~4-5 mg/L. In the anaerobic setup, the air was not supplied and this caused the DO to drop immediately to ~0.5 mg/L within 30 min. The nitrogen removal efficiency and nitrogen concentrations during operation are presented in Figure 2(a) (for days 1–20). The nitrogen removal efficiency was 64.7% and the 15 mg/L of NO3-N remained in the effluent. These results reveal that the nitrification process to change NH4-N to NO2-N and NO3-N occurred to completion. However, the denitrification process to change NO3-N to N2 was ineffective. From previous studies [14, 17], it is suggested that the ineffective denitrification occurs due to high oxygen, high NO2-N, and low organic carbon contents. The nitrogen profile during the three cycles of intermittent aeration (including aerobic 1, anaerobic 1, aerobic 2, anaerobic 2, aerobic 3, and anaerobic 3) was determined to identify the main cause of ineffective denitrification (Figure 2(b)). After addition of the acetate during anaerobic 1 step, the NO3-N level decreased from 16 mg/L to zero and the COD concentration also decreased from 200 to 8 mg/L. The COD concentration was stable at ~5–8 mg/L till the end of the operation and there was no NO3-N reduction in anaerobic 2 and 3 stages. Since the NO2-N was not detected and the DO was also low as 0.5 mg/L in the anaerobic stage, thus the incomplete denitrification in the SSR resulted from insufficient acetate addition (C/N of 1.5).

Bottom Line: Discharge of high NH4-N containing wastewater into water bodies has become a critical and serious issue due to its negative impact on water and environmental quality.Under intermittent aeration, nitrification and denitrification occurred simultaneously in the aerobic and anaerobic periods.Moreover, internal carbon was consumed efficiently for denitrification.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil Engineering, Faculty of Engineering, Naresuan University, Thailand ; Centre of Excellence for Innovation and Technology for Water Treatment, Naresuan University, Thailand.

ABSTRACT
Discharge of high NH4-N containing wastewater into water bodies has become a critical and serious issue due to its negative impact on water and environmental quality. In this research, the performance of three different reactors was assessed and compared with regard to the removal of NH4-N from wastewater. The highest nitrogen removal efficiency of 98.3% was found when the entrapped sludge reactor (ESR), in which the sludge was entrapped in polyethylene glycol polymer, was used. Under intermittent aeration, nitrification and denitrification occurred simultaneously in the aerobic and anaerobic periods. Moreover, internal carbon was consumed efficiently for denitrification. On the other hand, internal carbon consumption was not found to occur in the suspended sludge reactor (SSR) and the mixed sludge reactor (MSR) and this resulted in nitrogen removal efficiencies of SSR and MSR being 64.7 and 45.1%, respectively. Nitrification and denitrification were the main nitrogen removal processes in the aerobic and anaerobic periods, respectively. However, due to the absence of sufficient organic carbon, denitrification was uncompleted resulting in high NO3-N contents in the effluent.

No MeSH data available.


Related in: MedlinePlus