Effect of Sludge Loading on the Simultaneous Nitrification and Denitrification by Using a Sequencing Batch Bioreactor

2011 ◽  
Vol 183-185 ◽  
pp. 231-235
Author(s):  
Yan Ping Jia ◽  
Lan He Zhang ◽  
Zhi Ling Zhao ◽  
Tao Yang

In this study, a sequencing batch reactor (SBR) was used to treat synthetic wastewater when dissolved oxygen (DO) concentration and temperature were 0.5-1.0mg/L and 30±1°C, respectively. Effect of sludge loading(Ns) on simultaneous nitrification and denitrification (SND) was investigated. The results indicated that removal efficiencies of ammonia nitrogen (NH4+-N), COD and total nitrogen (TN) were all higher than 90%, respectively, when influent NH4+-N and Ns were 35-45mg/L, 0.15kgCOD/(kgMLSS•d) under 7 hours of aeration time and 1 hour of idle time, respectively. Therefore, the SBR has obviously achieved simultaneous nitrification and denitrification.

2013 ◽  
Vol 39 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Katarzyna Bernat

Abstract In this study, the dependence between volumetric exchange rate (n) in an SBR (Sequencing Batch Reactor) with a modified cycle and simultaneous nitrification and denitrification (SND) efficiency during the treatment of anaerobic sludge digester supernatant was determined. In the SBR cycle alternating three aeration phases (with limited dissolved oxygen (DO) concentration up to 0.7 mg O2/L) and two mixing phases were applied. The lengths of each aeration and mixing phases were 4 and 5.5 h, respectively. Independently of n, a total removal of ammonium was achieved. However, at n = 0.1 d-1 and n = 0.3 d-1 nitrates were the main product of nitrification, while at n = 0.5 d-1, both nitrates and nitrites occurred in the effluent. Under these operational conditions, despite low COD/N (ca. 4) ratio in the influent, denitrification in activated sludge was observed. A higher denitrification efficiency at n = 0.5 d-1 (51.3%) than at n = 0.1 d-1 (7.8%) indicated that n was a crucial factor influencing SND via nitrite and nitrate in the SBR with a low oxygen concentration in aeration phases.


1994 ◽  
Vol 29 (10-11) ◽  
pp. 431-438 ◽  
Author(s):  
Y. Watanabe ◽  
D. Y. Bang ◽  
K. Itoh ◽  
K. Matsui

This paper concerns simultaneous nitrification and denitrification in a completely mixed bio-reactor with partially and fully submerged rotating biological contactors. The bio-reactor is designed to cause the nitrification and denitrification in partially and fully submerged biofilms, respectively. An experimental investigation was made into the effect of organic material and ratio of influent organic carbon to ammonia nitrogen concentrations(C/N ratio) on the efficiency of simultaneous nitrification and denitrification in the bio-reactor. Settled municipal wastewater and synthetic wastewater containing ammonia nitrogen and organic material such as acetate, ethylene-glycol, phenol and poly-vinyl-alcohol(PVA) were fed into the experimental units. A biofilm dominated by nitrifiers developed on the partially submerged contactors, while a biofilm dominated by heterotrophs developed on the fully submerged contactors. A micro-aerobic environment was formed and biological denitrification occurred in the submerged biofilm. In the municipal wastewater treatment where the influent C/N ratio was around 3.5, the maximum nitrogen removal efficiency was about 60 %. Acetate and ethlene-glycol were effectively used as the organic source of the denitrification. The ability to aerobically degrade PVA was induced by phenol. Once the bacteria inhibiting the biofilm gained the ability to degrade PVA, PVA became an effective organic source of the denitrification.


2020 ◽  
Vol 17 (2) ◽  
pp. 946-949
Author(s):  
Samaneh Alijantabar Aghouzi ◽  
Thomas S. Y. Choong ◽  
M. I. Aida Isma

This study elucidates the performance of sequencing batch reactor for nutrient removal from municipal wastewater. The removal of COD, ammonia nitrogen and phosphorus were investigated. The SBR with a working volume of 5 L was operated for 6 hours, with 5 min fill, 30 min settle and 5 min effluent withdrawal. The remaining time in each cycle was 90 min anaerobic phase, 130 min anoxic phase and 110 min aerobic phase. The experiment was repeated with a longer aeration time of 180 min resulting to prolong the duration cycle. In the aerobic phase, dissolved oxygen was kept in the range of more than 2 mg/L. During batch operation, the system attained stability and had a removal efficiency for ammonia nitrogen, COD and phosphorus of 51.36%, 83.33% and 99.53%, respectively. Extending the aeration period improved ammonia nitrogen removal to 54.27%. It should be noted that the stability of the granular biomass agglomerates highly depending on the bacterial consortia. The particle size of sludge reduced from 60.26 μm to 39.00 μm in 60 days. It was observed that degranulation process and biomass loss was unavoidable.


Author(s):  
Mehdi Hajsardar ◽  
Seyed Mehdi Borghei ◽  
Amir Hessam Hassani ◽  
Afshin Takdastan

Abstract A series of reactors including a sequencing batch reactor (SBR) and a sequencing batch biofilm reactor (SBBR) were used for nitrogen removal. The aim of this study was simultaneous removal of NH4+-N and NOx–-N from synthetic wastewater. In the novel proposed method, the effluent from SBR was sequentially introduced into SBBR, which contained 0.030 m3 biofilm carriers, so the system operated under a paired sequence of aerobic-anoxic conditions. The effects of different carbon sources and aeration conditions were investigated. A low dissolved oxygen (DO) level in the biofilm depth of the fixed-bed process (SBBR) simulated the anoxic phase conditions. Accordingly, a portion of NH4+-N that was not converted to NO3–-N by the SBR process was converted to NO3–-N in the outer layer of the biofilm in the SBBR process. Further, simultaneous nitrification and denitrification (SND) was achieved in the SBBR where NO2–-N was converted to N2 directly, before NO3–-N conversion (partial nitrification). The level of mixed liquid suspended solids (MLSS) was 2740 mg/l at the start of the experiments. The required carbon source (C: N ratio of 4) was provided by adding an internal carbon source (through step feeding) or ethanol. Firstly, as part of the system (SBR and SBBR), SBR operated at a DO level of 1 mg/l while SBBR operated at a DO concentration of 0.3 mg/l during Run-1. During Run-2, the system operated at the low DO concentration of 0.3 mg/l. When the source of carbon was ethanol, the nitrogen removal rate (RN) was higher than the operation with an internal carbon source. When the reactors were operated at the same DO concentration of 0.3 mg/l, 99.1 % of the ammonium was removed. The NO3–-N produced during the aerobic SBR operation of the novel method was removed in SBBR reactor by 8.3 %. The concentrations of NO3--N and NO2–-N in the SBBR effluent were reduced to 2.5 and 5.5 mg/l, respectively. Also, the total nitrogen (TN) removal efficiency was 97.5 % by adding ethanol at the DO level of 0.3 mg/l. When C:N adjustment was carried out SND efficiency at C:N ratio of 6.5 reached to 99 %. The increasing nitrogen loading rate (NLR) to 0.554 kg N/m3 d decreased SND efficiency to 80.7 %.


2004 ◽  
Vol 49 (5-6) ◽  
pp. 47-55 ◽  
Author(s):  
C.S. Gee ◽  
J.S. Kim

Biological ammonia-nitrogen removal utilizes two distinct processes, nitrification and denitrification. In nitrification, ammonia oxidizes to nitrite then to nitrate. In this study, elimination of nitrite oxidation to nitrate step was attempted in order to directly remove nitrite to nitrogen gas by denitrification. For this study the supernatant from an anaerobic digester was used as an ammonia source and a sequencing batch reactor (SBR) was employed. Emphasis was given to the evaluation of the operational factors affecting nitrite accumulation and the elucidation of kinetics for biological nitrification and denitrification. Accumulation of nitrite in the nitrification process was achieved by suppressing the growth of Nitrobacter, a nitrite oxidizer, by loading high concentration ammonia supernatant immediately after all ammonia in the previous loading was oxidized to nitrite. Nitrite oxidation was taking place as the solid retention time (SRT) was increased from 2.5 days to 3.0 days in a continuously aerated SBR mode with daily feeding. However, nitrite accumulation was achieved even at longer SRT of 5 days when the aeration and non-aeration periods were appropriately combined and the non-aeration period can be used for denitrification of the accumulated nitrite with a carbon source supplied.


2011 ◽  
Vol 233-235 ◽  
pp. 600-603
Author(s):  
Gao Shun Qiu ◽  
Ling Feng Qiu ◽  
Yi Ming Chen

The influences of HRT, C/N ratio on simultaneous nitrification and denitrification (SND) and the rule of pH in a sequencing batch reactor (SBR) were investigated while treating low C/N synthetic municipal wastewater. The results showed that the function of SND became more outstanding and the removal rate of TN, NH4+-N was improved greatly by lengthening HRT appropriately; when the C/N increased, the denitrification effect of the simultaneous nitrification and denitrification would be improved; .At the same time, the variation of pH value was well related to ammonia oxidation. So that judgment on the ending of nitrification and denitrification could be based on the inflection point on the varied curve of pH, and thus reducing aeration and mixing time for the purpose of energy saving.


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