scholarly journals Effects of carbon sources, COD/NO2−-N ratios and temperature on the nitrogen removal performance of the simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm

2017 ◽  
Vol 75 (7) ◽  
pp. 1712-1721 ◽  
Author(s):  
Zhaoming Zheng ◽  
Yun Li ◽  
Jun Li ◽  
Yanzhuo Zhang ◽  
Wei Bian ◽  
...  

The aim of the present work was to evaluate the effects of carbon sources and chemical oxygen demand (COD)/NO2−-N ratios on the anammox–denitrification coupling process of the simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm. Also, the anammox activities of the SNAD biofilm were investigated under different temperature. Kaldnes rings taken from the SNAD biofilm reactor were operated in batch tests to determine the nitrogen removal rates. As a result, with the carbon source of sodium acetate, the appropriate COD/NO2−-N ratios for the anammox–denitrification coupling process were 1 and 2. With the COD/NO2−-N ratios of 1, 2, 3, 4 and 5, the corresponding NO2−-N consumption via anammox was 87.1%, 52.2%, 29.3%, 23.7% and 16.3%, respectively. However, with the carbon source of sodium propionate and glucose, the anammox bacteria was found to perform higher nitrite competitive ability than denitrifiers at the COD/NO2−-N ratio of 5. Also, the SNAD biofilm could perform anammox activity at 15 °C with the nitrogen removal rate of 0.071 kg total inorganic nitrogen per kg volatile suspended solids per day. These results indicated that the SNAD biofilm process might be feasible for the treatment of municipal wastewater at normal temperature.

2020 ◽  
Vol 81 (5) ◽  
pp. 1071-1079
Author(s):  
Caimeng Wang ◽  
Lirong Lei ◽  
Fangrui Cai ◽  
Youming Li

Abstract In this study, the completely autotrophic nitrogen removal over nitrite (CANON) process was initiated in a sequencing batch biofilm reactor (SBBR). Then the reactor was operated under different IC/N ratios. The total inorganic nitrogen removal efficiency (TINRE) at IC/N ratios of 0.75, 1.0, 1.25, 1.5 and 2.0 were 37.0 ± 11.0%, 58.9 ± 10.2%, 73.9 ± 3.2%, 73.6 ± 1.8% and 72.6 ± 2.0%, respectively. The suitable range of IC/N ratio in this research is 1.25–2.0. The poor nitrogen removal performance at IC/N ratio of 0.75 was due to the lack of growth substrate for AnAOB and low pH simultaneously; at IC/N ratio of 1.0 this was because the substrate concentration was insufficient for fully recovering the AnAOB activities. Microbial analysis indicated that Nitrosomonas, Nitrospira and Candidatus Brocadia were the main ammonium oxidation bacteria (AOB), nitrite oxidation bacteria (NOB) and anammox bacteria (AnAOB), respectively. In addition, at IC ratios of 1.25 or higher, denitrification was promoted with the rise of IC/N ratio, which might be because the change of IC concentrations caused cell lysis of microorganisms and provided organic matter for denitrification.


2017 ◽  
pp. 655-664
Author(s):  
Andrii Butkovskyi ◽  
Karin Jönsson

The efficiency of nitrogen removal from leachate by different chemical and biological methods was explored. The leachate was derived from Filborna landfill (NSR AB, Helsingborg, Sweden) and was characterized as an old leachate with pH = 8.0 and comparatively low concentrations of nitrogen and organic compounds (ca. 150 mg/l NH4-N and 500 mg/l COD). Three treatment processes were tested in lab-scale experiments; combined nitrification and denitrification in a sequencing-batch reactor (SBR), one-reactor nitritation-anammox process in a moving-bed biofilm reactor (MBBR) in sequencing-batch configuration and nitrogen precipitation in the form of magnesium-ammonium-phosphate (MAP). State-of-the-art of these processes is described. The conventional combined nitrification/denitrification process allowed 99% removal of inorganic nitrogen with 23 mg NH4-N/(l·h) being the highest nitrification rate achieved. Aeration during nitrification step and addition of carbon source according to the stoichiometric ratio for denitrification was required, accounting for the operational costs. The nitritation-anammox process also allowed 99% removal of inorganic nitrogen with 3.7 g NH4- N/(m2·d) being the highest process rate achieved while running the reactor at 25°C and pH 8.0. The process is advantageous in comparison with the conventional biological removal process, as oxygen consumption is lower and addition of carbon source is not required. With MAP precipitation at the optimal Mg:N:P ratio (1.2:1:1) only 78% removal of inorganic nitrogen was achieved. The precipitation process led to a significant increase of phosphorous concentrations in the effluent, while external magnesium and phosphorous sources to be added resulted in high process costs. Detailed descriptions of the processes and obtainedresults are given in the article. Comparing the three processes, conclusions are drawn that it is possible to achieve effluent nitrogen requirements (15 mg N/l) by treatment of leachate with both tested biological processes, but not with MAP precipitation. One-reactor nitritation-anammox would require the lowest operational costs, while MAP precipitation – the highest.


Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 346
Author(s):  
Keugtae Kim ◽  
Yong-Gyun Park

Conventional biological nutrient removal processes in municipal wastewater treatment plants are energy-consuming, with oxygen supply accounting for 45–75% of the energy expenditure. Many recent studies examined the implications of the anammox process in sidestream wastewater treatment to reduce energy consumption, however, the process did not successfully remove nitrogen in mainstream wastewater treatment with relatively low ammonia concentrations. In this study, blue light was applied as an inhibitor of nitrite-oxidizing bacteria (NOB) in a photo sequencing batch reactor (PSBR) containing raw wastewater. This simulated a biological nitrogen removal system for the investigation of its application potential in nitrite accumulation and nitrogen removal. It was found that blue light illumination effectively inhibited NOB rather than ammonia-oxidizing bacteria due to their different sensitivity to light, resulting in partial nitrification. It was also observed that the NOB inhibition rates were affected by other operational parameters like mixed liquor suspended solids (MLSS) concentration and sludge retention time (SRT). According to the obtained results, it was concluded that the process efficiency of partial nitrification and anammox (PN/A) could be significantly enhanced by blue light illumination with appropriate MLSS concentration and SRT conditions.


2018 ◽  
Vol 78 (7) ◽  
pp. 1566-1575 ◽  
Author(s):  
S. S. Rathnaweera ◽  
B. Rusten ◽  
K. Korczyk ◽  
B. Helland ◽  
E. Rismyhr

Abstract A pilot-scale CFIC® (continuous flow intermittent cleaning) reactor was run in anoxic conditions to study denitrification of wastewater. The CFIC process has already proven its capabilities for biological oxygen demand removal with a small footprint, less energy consumption and low cost. The present study focused on the applicability for denitrification. Both pre-denitrification (pre-DN) and post-denitrification (post-DN) were tested. A mixture of primary treated wastewater and nitrified wastewater was used for pre-DN and nitrified wastewater with ethanol as a carbon source was used for post-DN. The pre-DN process was carbon limited and removal rates of only 0.16 to 0.74 g NOx-N/m²-d were obtained. With post-DN and an external carbon source, 0.68 to 2.2 g NO3-Neq/m²-d removal rates were obtained. The carrier bed functioned as a good filter for both the larger particles coming with influent water and the bio-solids produced in the reactor. Total suspended solids removal in the reactor varied from 20% to 78% (average 45%) during post-DN testing period and 9% to 70% (average 29%) for pre-DN. The results showed that the forward flow washing improves both the DN function and filtration ability of the reactor.


2020 ◽  
Author(s):  
Robert Niederdorfer ◽  
Damian Hausherr ◽  
Alejandro Palomo ◽  
Jing Wei ◽  
Paul Magyar ◽  
...  

AbstractAutotrophic nitrogen removal by anaerobic ammonium oxidizing (anammox) bacteria is an energy-efficient nitrogen removal process in wastewater treatment. However, full-scale deployment under mainstream conditions remains challenging for practitioners due to the high stress susceptibility of anammox bacteria towards fluctuations in dissolved oxygen and temperature. Here, we investigated the response of microbial biofilms with verified anammox activity to oxygen shocks under favorable and cold temperature regimes. Genome-centric metagenomics and metatranscriptomics were used to investigate the stress response on various biological levels. We show that temperature regime and strength of oxygen perturbations induced divergent responses from the process level down to the transcriptional profile of individual taxa. Temperature induced distinct transcriptional states in compositionally identical communities and transient pulses of dissolved oxygen resulted in the upregulation of stress-response only under favorable temperatures. Anammox species and other key biofilm taxa display different transcriptional responses to the induced stress regimes.


Processes ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 109
Author(s):  
Yu Huang ◽  
Yongzhen Peng ◽  
Donghui Huang ◽  
Jiarui Fan ◽  
Rui Du

A partial-denitrification coupling with anaerobic ammonium oxidation (anammox) process (PD/A) in a continuous-flow anoxic/oxic (A/O) biofilm reactor was developed to treat carbon-limited domestic wastewater (ammonia (NH4+-N) of 55 mg/L and chemical oxygen demand (COD) of 148 mg/L in average) for about 200 days operation. Satisfactory NH4+-N oxidation efficiency above 95% was achieved with rapid biofilm formation in the aerobic zone. Notably, nitrite (NO2−-N) accumulation was observed in the anoxic zone, mainly due to the insufficient electron donor for complete nitrate (NO3−-N) reduction. The nitrate-to-nitrite transformation ratio (NTR) achieved was as high as 64.4%. After the inoculation of anammox-enriched sludge to anoxic zones, total nitrogen (TN) removal was significantly improved from 37.3% to 78.0%. Anammox bacteria were effectively retained in anoxic biofilm utilizing NO2−-N produced via the PD approach and NH4+-N in domestic wastewater, with the relative abundance of 5.83% for stable operation. Anammox pathway contributed to TN removal by a high level of 38%. Overall, this study provided a promising method for mainstream nitrogen removal with low energy consumption and organic carbon demand.


2011 ◽  
Vol 63 (4) ◽  
pp. 710-718 ◽  
Author(s):  
S. Q. Ni ◽  
J. Meng

In order to study the performance, inhibition and recovery processes of different types of anammox sludge, three up-flow anaerobic sludge blanket reactors were inoculated with flocculent sludge, granular sludge, and cultured inactive methanogenic granules. During stable period, with nitrogen loading rates of 0.9–1.1 kg/m3/d, the total nitrogen removal efficiencies of these reactors averaged at 86.5%, 90.8% and 93.5%, respectively. The kinetics study indicated that the reactor seeded with cultured inactive methanogenic granules possessed the highest nitrogen removal potential, followed by the granular anammox reactor and the flocculent anammox reactor. The study suggested that a concentration as high as 988.3 mg NH4+-N/L and 484.4 mg NO2−-N/L could totally inhibit granular anammox bacteria and result in a inhibition of 50% flocculent anammox activity. In addition, reactors seeded with flocculent sludge and anammox granules could be fully recovered by decreasing their influent substrate concentrations. However, the decrease of influent substrate concentration for the reactor with cultured inactive methanogenic granules could only restore about 75% of its bacterial activity. In this study, anammox bacteria purity was the major factor to evaluate the recovery ability in comparison with sludge type. Free ammonia was a more appropriate indicator for the anammox recovery process compared to free nitric acid.


Author(s):  
Qian Zhang ◽  
Xue Chen ◽  
Heng Wu ◽  
Wandong Luo ◽  
Xiangyang Liu ◽  
...  

In recent years, there is a trend of low C/N ratio in municipal domestic wastewater, which results in serious problems for nitrogen removal from wastewater. The addition of an external soluble carbon source has been the usual procedure to achieve denitrification. However, the disadvantage of this treatment process is the need of a closed, rather sophisticated and costly process control as well as the risk of overdosing. Solid-phase denitrification using biodegradable polymers as biofilm carrier and carbon source was considered as an attractive alternative for biological denitrification. The start-up time of the novel process using PCL (polycaprolactone) as biofilm carrier and carbon source was comparable with that of conventional process using ceramsite as biofilm carrier and acetate as carbon source. Further, the solid-phase denitrification process showed higher nitrogen removal efficiency under shorter hydraulic retention time (HRT) and low carbon to nitrogen (C/N) ratio since the biofilm was firmly attached to the clear pores on the surface of PCL carriers and in this process bacteria that could degrade PCL carriers to obtain electron donor for denitrification was found. In addition, solid-phase denitrification process had a stronger resistance of shock loading than that in conventional process. This study revealed, for the first time, that the physical properties of the biodegradable polymer played a vital role in denitrification, and the different microbial compositions of the two processes was the main reason for the different denitrification performances under low C/N ratio.


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