Influence of operating conditions on population dynamics in nitrifying biofilms

1999 ◽  
Vol 39 (7) ◽  
pp. 5-11 ◽  
Author(s):  
Valentina Lazarova ◽  
Danièle Bellahcen ◽  
Jacques Manem ◽  
David A. Stahl ◽  
Bruce E. Rittmann
Keyword(s):  
Population Dynamics ◽  
Ammonia Oxidation ◽  
Biofilm Reactor ◽  
Operating Conditions ◽  
Stable Operation ◽  
N Removal ◽  
Wide Range ◽  
Total Nitrogen Removal ◽  
Nitrite Oxidizers

TURBO N® is a circulating-bed biofilm reactor that provides stable operation and high N removal for a wide range of N and BOD loadings. This paper describes the influence of operating conditions on biofilm composition and population dynamics when the TURBO N® is operated to achieve tertiary nitrification, simultaneous carbon and ammonia oxidation and total nitrogen removal when coupled with a pre-denitrification fixed floating bed reactor. In situ specific nitrification rates and respiration tests showed that ammonium and nitrite oxidizers became less active in the biofilm once oxidation of influent BOD became important. Analyses of community structure with oligonucleotide probes targeted to the 16S rRNA showed the same general trends for nitrifiers, but also suggested shifts in the makeup of the ammonium and nitrite oxidizers that could not be detected with respirometry or specific nitrification rates.

scholarly journals Temperature response of denitrification and anammox reveals the adaptation of microbial communities to in situ temperatures in permeable marine sediments that span 50° in latitude

2013 ◽  
Vol 10 (9) ◽  
pp. 14595-14626 ◽  
Author(s):  
A. Canion ◽  
J. E. Kostka ◽  
T. M. Gihring ◽  
M. Huettel ◽  
J. E. E. van Beusekom ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Marine Sediments ◽  
Metabolic Response ◽  
Anammox Bacteria ◽  
Advective Flow ◽  
Permeable Sediments ◽  
N Removal ◽  
In Situ Conditions ◽  
Wide Range

Abstract. Despite decades of research on the physiology and biochemistry of nitrate/nitrite-respiring microorganisms, little is known regarding their metabolic response to temperature, especially under in situ conditions. The temperature regulation of microbial communities that mediate anammox and denitrification was investigated in near shore permeable sediments at polar, temperate, and subtropical sites with annual mean temperatures ranging from −5 to 23 °C. Total N2 production rates were determined using the isotope pairing technique in intact core incubations under diffusive and simulated advection conditions and ranged from 2 to 359 μmol N m−2 d−1. For the majority of sites studied, N2 removal was 2 to 7 times more rapid under advective flow conditions. Anammox comprised 6 to 14% of total N2 production at temperate and polar sites and was not detected at the subtropical site. Potential rates of denitrification and anammox were determined in anaerobic slurries in a temperature gradient block incubator across a temperature range of −1 to 42 °C. The highest optimum temperature (Topt) for denitrification was 36 °C and was observed in subtropical sediments, while the lowest Topt of 21 °C was observed at the polar site. Seasonal variation in the Topt was observed at the temperate site with values of 26 and 34 °C in winter and summer, respectively. The Topt values for anammox were 9 and 26 °C at the polar and temperate sites, respectively. The results demonstrate adaptation of denitrifying communities to in situ temperatures in permeable marine sediments across a wide range of temperatures, whereas marine anammox bacteria may be predominately psychrophilic to psychrotolerant. To our knowledge, we provide the first rates of denitrification and anammox from permeable sediments of a polar permanently cold ecosystem. The adaptation of microbial communities to in situ temperatures suggests that the relationship between temperature and rates of N removal is highly dependent on community structure.

scholarly journals Treatment performance, nitrous oxide production and microbial community under low-ammonium wastewater in a CANON process

2017 ◽  
Vol 76 (12) ◽  
pp. 3468-3477 ◽  
Author(s):  
Weixing Mi ◽  
Jianqiang Zhao ◽  
Xiaoqian Ding ◽  
Guanghuan Ge ◽  
Rixiang Zhao
Keyword(s):  
Nitrous Oxide ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Ammonia Oxidation ◽  
Removal Rate ◽  
Biofilm Reactor ◽  
Ammonium Concentration ◽  
Nitrous Oxide Production ◽  
Total Nitrogen Removal ◽  
Canon Process

Abstract To investigate the characteristics of anaerobic ammonia oxidation for treating low-ammonium wastewater, a continuous-flow completely autotrophic nitrogen removal over nitrite (CANON) biofilm reactor was studied. At a temperature of 32 ± 1 °C and a pH between 7.5 and 8.2, two operational experiments were performed: the first one fixed the hydraulic retention time (HRT) at 10 h and gradually reduced the influent ammonium concentrations from 210 to 50 mg L−1; the second one fixed the influent ammonium concentration at 30 mg L−1 and gradually decreased the HRT from 10 to 3 h. The results revealed that the total nitrogen removal efficiency exceeded 80%, with a corresponding total nitrogen removal rate of 0.26 ± 0.01 kg N m−3 d−1 at the final low ammonium concentration of 30 mg L−1. Small amounts of nitrous oxide (N2O) up to 0.015 ± 0.004 kg m−3 d−1 at the ammonium concentration of 210 mg L−1 were produced in the CANON process and decreased with the decrease in the influent ammonium loads. High-throughput pyrosequencing analysis indicated that the dominant functional bacteria ‘Candidatus Kuenenia’ under high influent ammonium levels were gradually succeeded by Armatimonadetes_gp5 under low influent ammonium levels.

scholarly journals Nitrogen removal via a single-stage PN–Anammox process in a novel combined biofilm reactor

2017 ◽  
Vol 77 (6) ◽  
pp. 1483-1492 ◽  
Author(s):  
Yue-mei Han ◽  
Feng-xia Liu ◽  
Xiao-fei Xu ◽  
Zhuo Yan ◽  
Zhi-jun Liu
Keyword(s):  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Ammonia Oxidation ◽  
Biofilm Reactor ◽  
Nitrifying Bacteria ◽  
Anammox Bacteria ◽  
Ammonia Oxidizing Bacteria ◽  
High Ammonia ◽  
Total Nitrogen Removal ◽  
Anammox Process

Abstract This study developed a partial nitrification (PN) and anaerobic ammonia oxidation (Anammox) process for treating high-ammonia wastewater using an innovative biofilm system in which ammonia oxidizing bacteria grew on fluidized Kaldnes (K1) carriers and Anammox bacteria grew on fixed acryl resin carriers. The airlift loop biofilm reactor (ALBR) was stably operated for more than 4 months under the following conditions: 35 ± 2 °C, pH 7.5–8.0 and dissolved oxygen (DO) of 0.5–3.5 mg/L. The results showed that the total nitrogen removal efficiency reached a maximum of 75% and the total nitrogen removal loading rate was above 0.4 kg/(d·m3). DO was the most efficient control parameter in the mixed biofilm system, and values below 1.5 mg/L were observed in the riser zone for the PN reaction, while values below 0.8 mg/L were observed in the downer zone for the Anammox reaction. Scanning electron microscopy and Fluorescence In Situ Hybridization images showed that most of the nitrifying bacteria were distributed on the K1 carriers and most of the Anammox bacteria were distributed within the acryl resin carriers. Therefore, the results indicate that the proposed combined biofilm system is easy to operate and efficient for the treatment of high-ammonia wastewater.

Dynamic digital image analysis: emerging technology for particle characterization

2004 ◽  
Vol 50 (12) ◽  
pp. 19-26 ◽  
Author(s):  
G. Rabinski ◽  
D. Thomas
Keyword(s):  
Real Time ◽  
Digital Image Analysis ◽  
Visual Analysis ◽  
Dynamic Imaging ◽  
Operating Conditions ◽  
Particle Sizes ◽  
Particle Characterization ◽  
Imaging Analysis ◽  
Wide Range

The feasibility of applying dynamic imaging analysis technology to particle characterization has been evaluated for application in the water sector. A system has been developed which captures in-situ images of suspended particles in a flowing sample stream and analyzes these images in real time to determine particle size and concentration. The technology can measure samples having a wide range of particle sizes (∼1.5 to 1,000 μm equivalent circular diameter) and concentrations (<1 to >1 million/ml). The system also provides magnified images of particles for visual analysis of properties such as size, shape and grayscale level. There are no sample preparation requirements and statistically accurate results are produced in less than three minutes per sample. The overall system architecture is described. The major design challenges in developing a practical system include obtaining adequate contrast for the range of particle materials found in typical water samples and achieving this under operating conditions permitting an adequate sample processing rate for real time feedback of results. Performance of the instrument is reported in reference to industry accepted particle standards and applications as an analytical tool for the water industries are considered.

Vibration Characteristics of a 75kW Turbo Machine With Air Foil Bearings

2006 ◽  
Vol 129 (3) ◽  
pp. 843-849 ◽  
Author(s):  
Kyeong-Su Kim ◽  
In Lee
Keyword(s):  
High Speed ◽  
Performance Test ◽  
Pressure Ratio ◽  
Vibration Characteristics ◽  
Operating Conditions ◽  
Maximum Pressure ◽  
Stable Operation ◽  
Foil Bearings ◽  
Wide Range ◽  
Free Environment

Air foil bearings are very attractive bearing systems for turbomachinery because they have several advantages over conventional bearings in terms of oil-free environment, low power loss, long life, and no maintenance. However, most of the developed machines using air foil bearings are limited to small and high-speed rotors of 60,000–120,000 rpm, since the increase in power of turbomachinery requires lower rotor speed and greater loading in bearings, which makes it difficult to use air foil bearings for large machines. In this paper, a 75 kW turboblower using air foil bearings is introduced, and the vibration characteristics of the machine have been investigated experimentally under a wide range of operating conditions, including compressor surge in the performance test. The machine is designed to be fully air lubricated and air cooled, and its operating speed is 20,000–26,000 rpm with maximum pressure ratio of 1.8. The results show that the air foil bearings offer adequate damping to ensure dynamically stable operation in the whole range.

scholarly journals Intermittent Aeration in a Hybrid Moving Bed Biofilm Reactor for Carbon and Nutrient Biological Removal

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 492 ◽  
Author(s):  
Gaetano Di Bella ◽  
Giorgio Mannina
Keyword(s):  
Loading Rate ◽  
Nitrogen Loading ◽  
Biofilm Reactor ◽  
Operating Conditions ◽  
Organic Loading Rate ◽  
Intermittent Aeration ◽  
Moving Bed Biofilm Reactor ◽  
Moving Bed ◽  
Operational Conditions ◽  
N Removal

The paper presents an experimental study on a lab scale hybrid moving bed biofilm reactor with intermittent aeration. Specifically, a comparison between two different operating conditions was analyzed: continuous and intermittent aeration. Both continuous and intermittent aeration were monitored and compared in order to get the best operational conditions. The intermittent aeration campaign was sub-divided in three phases with different duration of alternation of aerobic and anoxic times and organic and nitrogen loading rates. The efficiency of N-removal improved by 70% during the intermittent aeration. The best condition was observed with 40 min of aeration and 20 min of no-aeration, an organic loading rate of 2.2 kgCODm−3day−1 and a nitrogen loading rate of 0.25 kgNm−3day−1: under these operational conditions the removal efficiencies for carbon and nitrogen were 93% and 90%, respectively. The derived results provide the basis for WWTP upgrade in order to meet stricter effluent limits at low energy requirements.

scholarly journals Temperature response of denitrification and anammox reveals the adaptation of microbial communities to in situ temperatures in permeable marine sediments that span 50° in latitude

2014 ◽  
Vol 11 (2) ◽  
pp. 309-320 ◽  
Author(s):  
A. Canion ◽  
J. E. Kostka ◽  
T. M. Gihring ◽  
M. Huettel ◽  
J. E. E. van Beusekom ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Marine Sediments ◽  
Metabolic Response ◽  
Temperature Response ◽  
Anammox Bacteria ◽  
Advective Flow ◽  
N Removal ◽  
In Situ Conditions ◽  
Wide Range

Abstract. Despite decades of research on the physiology and biochemistry of nitrate/nitrite-respiring microorganisms, little is known regarding their metabolic response to temperature, especially under in situ conditions. The temperature regulation of microbial communities that mediate anammox and denitrification was investigated in near shore permeable sediments at polar, temperate, and subtropical sites with annual mean temperatures ranging from −5 to 23 °C. Total N2 production rates were determined using the isotope pairing technique in intact core incubations under diffusive and simulated advection conditions and ranged from 2 to 359 μmol N m−2 d−1. For the majority of sites studied, N2 removal was 2–7 times more rapid under simulated advective flow conditions. Anammox comprised 6–14% of total N2 production at temperate and polar sites and was not detected at the subtropical site. Potential rates of denitrification and anammox were determined in anaerobic slurries in a temperature gradient block incubator across a temperature range of −1 °C to 42 °C. The highest optimum temperature (Topt) for denitrification was 36 °C and was observed in subtropical sediments, while the lowest Topt of 21 °C was observed at the polar site. Seasonal variation in the Topt was observed at the temperate site with values of 26 and 34 °C in winter and summer, respectively. The Topt values for anammox were 9 and 26 °C at the polar and temperate sites, respectively. The results demonstrate adaptation of denitrifying communities to in situ temperatures in permeable marine sediments across a wide range of temperatures, whereas marine anammox bacteria may be predominately psychrophilic to psychrotolerant. The adaptation of microbial communities to in situ temperatures suggests that the relationship between temperature and rates of N removal is highly dependent on community structure.

scholarly journals Simultaneous Partial Nitrification and Denitrification Maintained in Membrane Bioreactor for Nitrogen Removal and Hydrogen Autotrophic Denitrification for Further Treatment

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 911
Author(s):  
Kun Dong ◽  
Xinghui Feng ◽  
Wubin Wang ◽  
Yuchao Chen ◽  
Wei Hu ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Dominant Role ◽  
Domestic Sewage ◽  
Biofilm Reactor ◽  
Partial Nitrification ◽  
Ammonia Oxidizing Bacteria ◽  
Autotrophic Denitrification ◽  
Membrane Biofilm Reactor ◽  
N Removal ◽  
Wide Range

Low C/N wastewater results from a wide range of factors that significantly harm the environment. They include insufficient carbon sources, low denitrification efficiency, and NH4+-N concentrations in low C/N wastewater that are too high to be treated. In this research, the membrane biofilm reactor and hydrogen-based membrane biofilm reactor (MBR-MBfR) were optimized and regulated under different operating parameters: the simulated domestic sewage with low C/N was domesticated and the domestic sewage was then denitrified. The results of the MBR-MBfR experiments indicated that a C/N ratio of two was suitable for NH4+-N, NO2−-N, NO3−-N, and chemical oxygen demand (COD) removal in partial nitrification-denitrification (PN-D) and hydrogen autotrophic denitrification for further treatment. The steady state for domestic wastewater was reached when the MBR-MBfR in the experimental conditions of HRT = 15 h, SRT = 20 d, 0.04 Mpa for H2 pressure in MBfR, 0.4–0.8 mg/L DO in MBR, MLSS = 2500 mg/L(MBR) and 2800 mg/L(MBfR), and effluent concentrations of NH4+-N, NO3−-N, and NO2−-N were 4.3 ± 0.5, 1.95 ± 0.04, and 2.05 ± 0.15 mg/L, respectively. High-throughput sequencing results revealed the following: (1) The genus Nitrosomonas as the ammonia oxidizing bacteria (AOB) and Denitratisoma as potential denitrifiers were simultaneously enriched in the MBR; (2) at the genus level, Meiothermus,Lentimicrobium, Thauera,Hydrogenophaga, and Desulfotomaculum played a dominant role in leading to NO3−-N and NO2−-N removal in the MBfR.

scholarly journals The HyEnD stern hybrid sounding rocket project

2019 ◽  
Author(s):  
M. Kobald ◽  
C. Schmierer ◽  
U. Fischer ◽  
K. Tomilin ◽  
A. Petrarolo ◽  
...  
Keyword(s):  
Rocket Engine ◽  
Operating Conditions ◽  
Chamber Pressure ◽  
Sounding Rocket ◽  
Small Scale ◽  
Stable Operation ◽  
Hybrid Rocket ◽  
Wide Range ◽  
Hybrid Rocket Engine

The student team Hybrid Engine Development (HyEnD) of the University of Stuttgart is taking part with the Institute of Space Systems (IRS) in the DLR educational program STERN (Studentische Experimentalraketen). This program supports students at German universities to design, build, and launch an experimental rocket within a 3-year project time frame. HyEnD is developing a hybrid rocket called HEROS (Hybrid Experimental Rocket Stuttgart) with a design thrust of 10 kN, a total impulse of over 100 kN·s, and an expected liftoff weight up to 175 kg. HEROS is planned to be launched in October 2015 from Esrange in Sweden to an expected flight altitude of 40 to 50 km. The current altitude record for amateur rockets in Europe is at approximately 21 km. The propulsion system of HEROS is called HyRES (Hybrid Rocket Engine Stuttgart) and uses a paraffin-based solid fuel and nitrous oxide (N2O) as a liquid oxidizer. The development and the test campaign of HyRES is described in detail. The main goals of the test campaign are to achieve a combustion efficiency higher than 90% and provide stable operation with low combustion chamber pressure fluctuations. The successful design and testing of the HyRES engine was enabled by the evaluation and characterization of a small-scale demonstrator engine. The 500-newton hybrid rocket engine, called MIRAS (MIcro RAkete Stuttgart), has also been developed in the course of the STERN project as a technology demonstrator. During this test campaign, a ballistic characterization of paraffin-based hybrid rocket fuels with different additives in combination with N2O and a performance evaluation were carried out. A wide range of operating conditions, fuel compositions, injector geometries, and engine configurations were evaluated with this engine. Effects of different injector geometries and postcombustion chamber designs on the engine performance were analyzed. Additionally, the appearance of combustion instabilities under certain conditions, their effects, and possible mitigation techniques were also investigated. Concluding, the development and construction of an advanced, lightweight hybrid sounding rocket for the given requirements and budget within the DLR STERN program are described herein. The most important parts include a high thrust hybrid rocket engine, the development of a light weight oxidizer tank, pyrotechnical valves, carbon fiber rocket structure, recovery systems, and onboard electronics.

Total nitrogen removal in an aerobic/anoxic membrane biofilm reactor system

2005 ◽  
Vol 52 (7) ◽  
pp. 115-120 ◽  
Author(s):  
J. Cowman ◽  
C.I. Torres ◽  
B.E. Rittmann
Keyword(s):  
Nitrogen Removal ◽  
Hydrogen Pressure ◽  
Biofilm Reactor ◽  
Total N ◽  
Nitrate N ◽  
Membrane Biofilm Reactor ◽  
N Removal ◽  
Ammonium N ◽  
High O2 ◽  
Total Nitrogen Removal

The hydrogen-based membrane biofilm reactor (MBfR) is effective for reducing nitrate-N to N2 gas, but most wastewaters contain ammonium-N. Here, we document that an aerobic/anoxic MBfR system achieves nearly total N removal (<2 mgN/L) when the influent N is ammonium. The aerobic/anoxic MBfR couples two MBfR modules. The aerobic MBfR is supplied O2 and brings about nitrification of ammonium to nitrate or nitrite. The anoxic MBfR is supplied H2 and brings about denitrification to N2 gas. Total N removal is most strongly influenced by the O2 pressure in the aerobic module: too low O2 caused poor nitrification, while too high O2 inhibited denitrification in the anoxic module. Hydrogen pressure does not strongly affect total-N removal, and the best total-N removal occurs when the H2 and O2 pressures are similar.

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