Dissolved oxygen as a factor influencing nitrogen removal rates in a one-stage system with partial nitritation and Anammox process

2011 ◽  
Vol 64 (5) ◽  
pp. 1009-1015 ◽  
Author(s):  
G. Cema ◽  
E. Płaza ◽  
J. Trela ◽  
J. Surmacz-Górska

A biofilm system with Kaldnes biofilm carrier was used in these studies to cultivate bacteria responsible for both partial nitritation and Anammox processes. Due to co-existence of oxygen and oxygen-free zones within the biofilm depth, both processes can occur in a single reactor. Oxygen that inhibits the Anammox process is consumed in the outer layer of the biofilm and in this way Anammox bacteria are protected from oxygen. The impact of oxygen concentration on nitrogen removal rates was investigated in the pilot plant (2.1 m3), supplied with reject water from the Himmerfjärden Waste Water Treatment Plant. The results of batch tests showed that the highest nitrogen removal rates were obtained for a dissolved oxygen (DO) concentration around 3 g O2 m−3. At a DO concentration of 4 g O2 m−3, an increase of nitrite and nitrate nitrogen concentrations in the batch reactor were observed. The average nitrogen removal rate in the pilot plant during a whole operating period oscillated around 1.3 g N m−2d−1 (0.3 ± 0.1 kg N m−3d−1) at the average dissolved oxygen concentration of 2.3 g O2 m−3. The maximum value of a nitrogen removal rate amounted to 1.9 g N m−2d−1 (0.47 kg N m−3d−1) and was observed for a DO concentration equal to 2.5 g O2 m−3. It was observed that increase of biofilm thickness during the operational period, had no influence on nitrogen removal rates in the pilot plant.

2007 ◽  
Vol 55 (8-9) ◽  
pp. 19-26 ◽  
Author(s):  
B. Szatkowska ◽  
G. Cema ◽  
E. Plaza ◽  
J. Trela ◽  
B. Hultman

The ability of bacterial cultures to create biofilm brings a possibility to enhance biological wastewater treatment efficiency. Moreover, the ability of Anammox and Nitrosomonas species to grow within the same biofilm layer enabled a one-stage system for nitrogen removal to be designed. Such a system, with Kaldnes rings as carriers for biofilm growth, was tested in a technical pilot plant scale (2.1 m3) at the Himmerfjärden Waste Water Treatment Plant (WWTP) in the Stockholm region. The system was directly supplied with supernatant originating from dewatering of digested sludge containing high ammonium concentrations. Nearly 1-year of operational data showed that during the partial nitritation/Anammox process, alkalinity was utilised parallel to ammonium removal. The process resulted in a small pH drop, and its relationship with conductivity was found. The nitrogen removal rate for the whole period oscillated around 1.5 g N m−2d−1 with a maximum value equal to 1.9 g N m−2d−1. Parallel to the pilot plant experiment, a series of batch tests were run to investigate the influence on removal rates of different dissolved oxygen conditions and addition of nitrite. The highest nitrogen removal rate (5.2 g N m−2d−1) in batch tests was obtained when the Anammox process was stimulated by the addition of nitrite. In the simultaneous partial nitritation and Anammox process, the partial nitritation was the rate-limiting step.


2006 ◽  
Vol 54 (8) ◽  
pp. 209-217 ◽  
Author(s):  
G. Cema ◽  
B. Szatkowska ◽  
E. Plaza ◽  
J. Trela ◽  
J. Surmacz-Górska

Traditional nitrification/denitrification is not suitable for nitrogen removal when wastewater contains high concentrations of ammonium nitrogen and low concentrations of biodegradable carbon. Recently, a deammonification process was developed and proposed as a new technology for treatment of such streams. This process relies on a stable interaction between aerobic bacteria Nitrosomonas, that accomplish partial nitritation and anaerobic bacteria Planctomycetales, which conduct the Anammox reaction. Simultaneous performance of these two processes can lead to a complete autotrophic nitrogen removal in one single reactor. The experiments where nitrogen was removed in one reactor were performed at a technical-scale moving-bed pilot plant, filled with Kaldnes rings and supplied with supernatant after dewatering of digested sludge. It was found that a nitrogen removal rate obtained at the pilot plant was 1.9 g m−2d−1. Parallel to the pilot plant run, a series of batch tests were carried out under anoxic and aerobic conditions. Within the batch tests, where the pilot plant's conditions were simulated, removal rates reached up to 3 g N m−2d−1. Moreover, the batch tests with inhibition of Nitrosomonas showed that only the Anammox bacteria (not anoxic removal by Nitrosomonas) are responsible for nitrogen removal.


2010 ◽  
Vol 113-116 ◽  
pp. 662-665
Author(s):  
Wen De Tian ◽  
Kyoung Jin An ◽  
Zhi Wei Li

This study focused on the feasibility of autotrophic nitrogen removal to treat high ammonia leachate, using combined partial Nitritation and Anammox process. In partial nitritation reactor, the optimal operation condition was found with influent ammonium concentration of 1200 mg/L, DO about 3 mg/L, HRT 3 days and temperature about 31°C at the ratio of NO2-N / NH4-N effluent kept at 1.1, which is a prerequisite for the application of Anammox. In Anammox reactor, more than 85% ammonium is removed at HRT 8 days, temperature 28±1°C, and pH 8. The removal rate of nitrogen and COD in combined partial Nitritation and Anammox process are 90% and 74%, respectively. Thus, a combined process of partial nitritation and a subsequent Anammox could be an alternative solution for ammonium removal for leachate.


2017 ◽  
Vol 75 (11) ◽  
pp. 2580-2585 ◽  
Author(s):  
Jun Cheng ◽  
Liang Zhang ◽  
Yandong Yang ◽  
Shujun Zhang ◽  
Xiaoyu Han ◽  
...  

For enhancing the partial nitritation-anammox (PN/A) process, the effects of granule fraction on system performance were investigated in this study. Two sequencing batch reactors (SBRs) were inoculated with PN/A biomass with a floc mass fraction of 53%. In SBR1, when the nitrogen removal rate (NRR) was stable, flocculent sludge was gradually discharged from the reactor using a screen, and the granule fraction was therefore increased. However, nitrogen removal was not improved and finally deteriorated due to the loss of nitritation activity. In SBR2, most flocculent sludge was eliminated and granular proportion was maintained at over 90% by controlling a short settling and decanting time. NRR was low initially but gradually improved to 1.23 kg N/(m3·d), which was 54% higher than SBR1. Ammonium oxidation activities of flocs and granules were respectively measured. Results suggested that the increase of nitritation activity in the granules was the main reason for the improvement of nitrogen removal in SBR2.


2018 ◽  
Vol 78 (3) ◽  
pp. 634-643 ◽  
Author(s):  
Yeshi Cao ◽  
Bee Hong Kwok ◽  
Mark C. M. van Loosdrecht ◽  
Glen Daigger ◽  
Hui Yi Png ◽  
...  

Abstract Mainstream partial nitritation/anammox (PN/A), coupled with excess biological phosphorus removal, in a 200,000 m3/d step-feed activated sludge process (Train 2) in the Changi Water Reclamation Plant (WRP), Singapore, has been studied and reported. This paper presents an overview of process performance and the microbial community during the period from 2011 to 2016. The site data showed that, along with the reduction of dissolved oxygen (DO) from 1.7 to 1.0 mg O2/L in the aeration zones, the concentrations of ammonium and nitrate of the final effluent increased, while nitrite decreased, resulting in an increase of 2.4 mg N/L of total inorganic nitrogen. Autotrophic nitrogen removal was higher than heterotrophic biological nitrogen removal under higher DO concentration conditions, but decreased under low DO operating condition. These macro-scale changes were caused by shifts of the nitrogen-converting microbial community. The ammonia oxidizing bacteria (AOB) population abundance was reduced by 30 times, while the nitrite oxidizing bacteria (NOB) population abundance and specific activity increased significantly with a shift of dominant genus from Nitrobacter to Nitrospira. The ratio of AOB and NOB specific activities were reduced from 12.8 to 1.6, and the ex situ nitrite accumulation ratio reduced from 76% to 29%. Changes in the microbial community and overall process performance illustrated that, compared to the excellent NOB suppression under high DO conditions, NOB were more active after the DO concentration reduction despite still being partly suppressed. This case study demonstrated, for the first time, the influence of DO reduction on the nitrogen conversion microbial community and PN/A process performance for a suspended growth system. Its relevance to biofilm and hybrid PN/A processes is also discussed.


1998 ◽  
Vol 38 (8-9) ◽  
pp. 213-221 ◽  
Author(s):  
Mohamed F. Hamoda ◽  
Ibrahim A. Al-Ghusain

Performance data from a pilot-plant employing the four-stage aerated submerged fixed film (ASFF) process treating domestic wastewater were analyzed to examine the organic removal rates. The process has shown high BOD removal efficiencies (> 90%) over a wide range of hydraulic loading rates (0.04 to 0.68 m3/m2·d). It could also cope with high hydraulic and organic loadings with minimal loss in efficiency due to the large amount of immobilized biomass attained. The organic (BOD and COD) removal rate was influenced by the hydraulic loadings applied, but organic removal rates of up to 104 kg BOD/ m2·d were obtained at a hydraulic loading rate of 0.68 m3/m2·d. A Semi-empirical model for the bio-oxidation of organics in the ASFF process has been formulated and rate constants were calculated based on statistical analysis of pilot-plant data. The relationships obtained are very useful for analyzing the design and performance of the ASFF process and a variety of attached growth processes.


2021 ◽  
Vol 26 (1) ◽  
pp. 25
Author(s):  
Zulkarnaini Zulkarnaini ◽  
Puti Sri Komala ◽  
Arief Almi

The anaerobic ammonium oxidation (anammox) biofilm process commonly uses various inorganic carriers to enhance nitrogen removal under anaerobic conditions. This study aims to analyze the performance of nitrogen removal in anammox process using sugarcane bagasse as an organic carrier. The experiment was carried out by using an up‐flow anaerobic sludge blanket (UASB) reactor for treating artificial wastewater at room temperature. The reactor was fed with ammonium and nitrite with the concentrations of 70‐150 mg–N/L and variations in the hydraulic retention time of 24 and 12 h. The granular anammox belongs to the genus Candidatus Brocadia sinica that was added as an inoculum of the reactor operation. The experimental stoichiometric of anammox for ΔNO2‐–N: ΔNH4+–N and ΔNO3‐: ΔNH4+ were 1.24 and 0.18, respectively, which is similar to anammox stoichiometry. The maximum Nitrogen Removal Rate (NRR) has achieved 0.29 kg–N/m3.d at Nitrogen Loading Rate (NLR) 0.6 kg–N/m3.d. The highest ammonium conversion efficiency (ACE) and nitrogen removal efficiency (NRE) were 88% and 85%, respectively. Based on this results, it indicated that sugarcane bagasse as organic carriers could increase the amount of total nitrogen removal by provided of denitrification process but inhibited the anammox process at a certain COD concentration.


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