Improving Wastewater Nitrogen Removal and Reducing Effluent NOx - -N by an Oxygen-Limited Process Consisting of a Sequencing Batch Reactor and a Sequencing Batch Biofilm Reactor

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 %.

2018 ◽  
Vol 44 ◽  
pp. 00179 ◽  
Author(s):  
Mariusz Tomaszewski ◽  
Grzegorz Cema ◽  
Tomasz Twardowski ◽  
Aleksandra Ziembińska-Buczyńska

The anaerobic ammonium oxidation (anammox) process is one of the most energy efficient and environmentally-friendly bioprocess for the treatment of the wastewater with high nitrogen concentration. The aim of this work was to study the influence of the high nitrogen loading rate (NLR) on the nitrogen removal in the laboratory-scale anammox sequencing batch reactor (SBR), during the shift from the synthetic wastewater to landfill leachate. In both cases with the increase of NLR from 0.5 to 1.1 – 1.2 kg N/m3d, the nitrogen removal rate (NRR) increases to about 1 kg N/m3d, but higher NLR caused substrates accumulation and affects anammox process efficiency. Maximum specific anammox activity was determined as 0.638 g N/g VSSd (NRR 1.023 kg N/m3d) and 0.594 g N/g VSSd (NRR 1.241 kg N/m3d) during synthetic and real wastewater treatment, respectively. Both values are similar and this is probably the nitrogen removal capacity of the used anammox biomass. This indicates, that landfill leachate did not influence the nitrogen removal capacity of the anammox process.


2009 ◽  
Vol 59 (3) ◽  
pp. 573-582 ◽  
Author(s):  
Xiao-ming Li ◽  
Dong-bo Wang ◽  
Qi Yang ◽  
Wei Zheng ◽  
Jian-bin Cao ◽  
...  

It was occasionally found that a significant nitrogen loss in solution under neutral pH value in a sequencing batch reactor with a single-stage oxic process using synthetic wastewater, and then further studies were to verify the phenomenon of nitrogen loss and to investigate the pathway of nitrogen removal. The result showed that good performance of nitrogen removal was obtained in system. 0–7.28 mg L−1 ammonia, 0.08–0.38 mg L−1 nitrite and 0.94–2.12 mg L−1 nitrate were determined in effluent, respectively, when 29.85–35.65 mg L−1 ammonia was feeding as the sole nitrogen source in influent. Furthermore, a substantial nitrogen loss in solution (95% of nitrogen influent) coupled with a little gaseous nitrogen increase in off-gas (7% of nitrogen influent) was determined during a typical aerobic phase. In addition, about 322 mg nitrogen accumulation (84% of nitrogen influent) was detected in activated sludge. Based on nitrogen mass balance calculation, the unaccounted nitrogen fraction and the ratio of nitrogen accumulation in sludge/nitrogen loss in solution were 14.6 mg (3.7% of nitrogen influent) and 0.89, respectively. The facts indicated that the essential pathway of nitrogen loss in solution in this study was excess nitrogen accumulation in activated sludge.


2010 ◽  
Vol 62 (11) ◽  
pp. 2599-2606 ◽  
Author(s):  
Hong Xiao ◽  
Ping Yang ◽  
Hong Peng ◽  
Yanzong Zhang ◽  
Shihuai Deng ◽  
...  

A study was conducted regarding the biological nitrogen removal from the livestock and poultry breeding wastewater (LPBWs) using a novel sequencing batch biofilm reactor (SBBR). Nitrogen removal process was studied under three aeration strategies/modes, referred to as MODE 1, 2, and 3. The results showed that MODE 2 (one operation period: instant fill of LPBWs, 3.0 h aeration, 1.5 h non-aeration, 1.5 h aeration, 1.0 h non-aeration and rapid drain of treated LPBWs) performed the best in nitrogen removal. Under MODE 2, the removal efficiencies were as high as 96.1 and 92.1% for NH3-N and TN, respectively. Simultaneous nitrification and denitrification (SND), as well as shortcut nitrification and denitrification are likely to be the two main mechanisms for the nitrogen removal in this study. Nitrifying bateria were not inhibited by heterotrophic bacteria with C/N ratios ranging from 18.1 to 21.4 and DO concentration of 2.0 mg/l. Alternation between aeration and non-aeration played an important role in NO2−-N accumulation.


2016 ◽  
Vol 74 (11) ◽  
pp. 2666-2674 ◽  
Author(s):  
A. Sarti ◽  
A. W. Lamon ◽  
A. Ono ◽  
E. Foresti

This study proposes a new approach to selecting a biofilm carrier for immobilization using dissolved oxygen (DO) microsensors to measure the thickness of aerobic and anaerobic layers in biofilm. The biofilm carriers tested were polyurethane foam, mineral coal (MC), basaltic gravel, and low-density polyethylene. Development of layers in the biofilm carrier surface was evaluated using a flow cell device, and DO profiles were conducted to determine the size of the layers (aerobic and anaerobic). MC was the biofilm carrier selected due to allowing the development of larger aerobic and anaerobic layers in the biofilm (896 and 1,058 μm, respectively). This ability is supposed to improve simultaneous nitrogen removal by nitrification and denitrification biological processes. Thus, as a biofilm carrier, MC was used in a fixed-bed sequencing batch biofilm reactor (FB-SBBR) for treatment of wastewater with a high ammonia concentration (100–400 mgNH4+-N L−1). The FB-SBBR (15.0 L) was filled with matrices of the carrier and operated under alternating aeration and non-aeration periods of 6 h each. At a mean nitrogen loading rate of 0.55 ± 0.10 kgNH4+-N m−3 d−1, the reactor attained a mean nitrification efficiency of 95 ± 9% with nitrite as the main product (aerobic period). Mean denitrification efficiency during the anoxic period was 72 ± 13%.


2009 ◽  
Vol 59 (12) ◽  
pp. 2371-2377 ◽  
Author(s):  
Q. Yang ◽  
X. H. Liu ◽  
Y. Z. Peng ◽  
S. Y. Wang ◽  
H. W. Sun ◽  
...  

To obtain economically sustainable wastewater treatment, advanced nitrogen removal from municipal wastewater and the feasibility of achieving and stabilizing short-cut nitrification and denitrification were investigated in a pilot-plant sequencing batch reactor (SBR) with a working volume of 54 m3. Advanced nitrogen removal, from summer to winter, with effluent TN lower than 3 mg/L and nitrogen removal efficiency above 98% was successfully achieved in pulsed-feed SBR. Through long-term application of process control in pulsed-feed SBR, nitrite accumulation reached above 95% at normal temperature of 25°C. Even in winter, at the lowest temperature of 13°C, nitrite was still the end production of nitrification and nitrite accumulation was higher than 90%. On the basis of achieving advanced nitrogen removal, short-cut nitrification and denitrification was also successfully achieved. Compare to the pulse-feed SBR with fixed time control, the dosage of carbon source and energy consumption in pulsed-feed SBR with process control were saved about 30% and 15% respectively. In pulsed-feed SBR with process control, nitrogen removal efficiency was greatly improved. Moreover, consumption of power and carbon source was further saved.


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.


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