Application of magnetic enhanced bio-effect on nitrification: a comparative study of magnetic and non-magnetic carriers

2013 ◽  
Vol 67 (6) ◽  
pp. 1280-1287 ◽  
Author(s):  
Chuang Yao ◽  
Heng-Yi Lei ◽  
Qiang Yu ◽  
Shu-Ping Li ◽  
Hua-Liang Li ◽  
...  
Keyword(s):  
Oxidation Rate ◽  
Magnetic Carrier ◽  
Ammonium Oxidation ◽  
Nitrite Oxidation ◽  
Surface Magnetic Field ◽  
Biofilm Reactors ◽  
Rate Analysis ◽  
Magnetic Carriers ◽  
N Concentration ◽  
Time Required

A novel magnetic carrier with surface magnetic field of 4 mT was developed for studying the magnetic enhanced bio-effect on nitrification. The bio-effect on nitrificaton induced by the magnetic carrier was studied by comparing the performance of sequencing batch biofilm reactors filled with magnetic (MC) and non-magnetic (NMC) carriers. The result showed that the bioreactor with MC had better performance for nitrification than bioreactor with NMC. During the biofilm culturing period, the time required for nitrification formation in biofilm of the MC reactor was 25% less than that for the NMC reactor. The results also showed that the ammonium oxidation rate of the MC reactor was 1.6-fold faster than that in the NMC reactor at high influent NH4-N concentration, while nitrite oxidation rate was always accelerated regardless of influent NH4-N concentration. The specific oxygen uptake rate analysis revealed that ammonia and nitrite oxidation activities in biofilm of the MC reactor were 1.65 and 1.98 times greater than those of the NMC reactor, respectively.

scholarly journals Effects of the chemical characteristics and concentration of inorganic suspended solids on nitrification in freshwater

2017 ◽  
Vol 76 (11) ◽  
pp. 3101-3113
Author(s):  
Quynh Nga Le ◽  
Chihiro Yoshimura ◽  
Manabu Fujii
Keyword(s):  
Clay Minerals ◽  
Rate Constants ◽  
Oxidation Rate ◽  
Suspended Solids ◽  
Nitrification Rate ◽  
Chemical Characteristics ◽  
Ammonium Oxidation ◽  
Nitrite Oxidation ◽  
Oxidation Rate Constant ◽  
Positive Effect

Abstract The effect of inorganic suspended solids (ISS) on nitrification in freshwater samples has been described inconsistently and remains unclear. This study therefore investigated the effects of the chemical characteristics and concentration of ISS on the nitrification rate by focusing on Nitrosomonas europaea and Nitrobacter winogradskyi as the two most dominant nitrification species in freshwater. Batch-wise experiments were conducted using three chemically well-characterized ISS (i.e. the clay minerals montmorillonite, sericite, and kaolinite in the concentration range 0–1,000 mg L−1). The results show that the ammonium oxidation rate constant (kNH4) was significantly affected by the ISS type, whereas changes in the ISS concentration had an insignificant effect on kNH4, except for kaolinite. The highest kNH4 was observed in samples containing sericite (kNH4, 0.067 L mg−1 day−1), followed by samples containing montmorillonite (kNH4, 0.044 L mg−1 day−1). The ammonium oxidation rate was low in the control and kaolinite samples. Nitrite oxidation was enhanced in the presence of all types of ISS. The rate constants of ISS-mediated nitrite oxidation (kNO2, 0.13–0.21 L mg−1 day−1) were not significantly different among the three types of ISS, but kNO2 was significantly affected by ISS concentration. Overall, our study indicated various effects of the ISS type and concentration on nitrification and, in particular, a notable positive effect of sericite.

Single-disc investigations on nitrogen removal of higher loads in sequencing batch and continuously operated RDR systems

2000 ◽  
Vol 41 (4-5) ◽  
pp. 77-84 ◽  
Author(s):  
J. Lindemann ◽  
U. Wiesmann
Keyword(s):  
Nitrogen Removal ◽  
Oxidation Rate ◽  
C:N Ratio ◽  
Treatment Phase ◽  
Synthetic Wastewater ◽  
Ammonium Oxidation ◽  
Nitrite Oxidation ◽  
Rotating Disc ◽  
Hydraulic Residence Time ◽  
First Results

Nitrification of ammonium-rich synthetic wastewater was studied in a continuously operated rotating disc reactor (RDR) with additional aeration. For a wastewater with 500 mg L−1 NH4−N a nearly complete oxidation to nitrate could be demonstrated for a hydraulic residence time of 27 h (HRT). The reactor was nearly completely mixed. Nevertheless, the biofilm covering the first discs was remarkably thicker than that of the last discs. In order to study the bioactivity of selected discs, single-disc reactors were used. The determined ammonium oxidation rate was nearly independent of the thickness and location of the disc. In contrast, the nitrite oxidation rate increased from the first to the last discs. Some results from experiments on nitrogen removal in sequencing batch single-disc reactors (SBSDR) are discussed. The SBSDR was operated with 2 phases, a partially submerged phase for nitrification and a completely submerged anoxic phase in which acetate was added for denitrification. It was advantageous to operate without additional aeration and thus produce more nitrite and saving carbon and energy. First results of the treatment of a synthetic wastewater with a C:N ratio of 1 in a 5-phase SBBR process providing 2 nitrification, 2 anoxic and a final aerobic post-treatment phase showed average specific rates.

Effect of Acclimation Strategy on the Biological Nitrification in the Saline Wastewater

2011 ◽  
Vol 183-185 ◽  
pp. 522-526 ◽  
Author(s):  
Ling Ling Li ◽  
Bo Yang ◽  
Peng Zhou
Keyword(s):  
Oxidation Rate ◽  
Nitrifying Bacteria ◽  
Ammonia Oxidizing Bacteria ◽  
Ammonium Oxidation ◽  
Salt Tolerant ◽  
Nitrite Oxidation ◽  
Saline Wastewater ◽  
Nacl Concentration ◽  
Nitrite Oxidizing Bacteria ◽  
Fresh Culture

During the process of cultivation of salt-tolerant nitrifying bacteria, the increase in NaCl concentrations was carried out in two different manners. The NaCl concentration in reactor A was increased by increment of 5 g/L, while the NaCl concentration in reactor B was increased by increment of 2.5 g/L. The impacts of NaCl content on the fresh culture and two acclimated cultures were investigated, which focused upon the changes of the specific ammonium oxidation rate (SAOR) and specific nitrite oxidation rate (SNOR). The results indicated that fresh nitrifiers were severely inhibited by high salinity. At NaCl concentration of 25 g/L, ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) completely lost the nitrification capability. After 46 days of acclimation, the nitrifying bacteria could be adapted to the saline wastewater. The average SAOR and SNOR in reactor B were slightly higher than those in reactor A, which meant that low increment in salt concentration may be in favor of the development of salt-tolerant nitrifiers. But the two NaCl increasing approaches did not affect the SAOR and SNOR too much. Salt-tolerant nitrifiers could be well developed with the two acclimation manners.

Oxidation Rate Analysis of Carbon Nanoparticles for a Small Particle Heat Exchange Receiver

2014 ◽  
Author(s):  
Mario Leoni ◽  
Lee Frederickson ◽  
Fletcher Miller
Keyword(s):  
Heat Exchange ◽  
Small Particle ◽  
Oxidation Rate ◽  
Flow Behavior ◽  
Average Diameter ◽  
Index Of Refraction ◽  
Spherical Particles ◽  
Extinction Cross Section ◽  
Carbon Particles ◽  
Rate Analysis

A new experimental set-up has been introduced at San Diego State University’s Combustion and Solar Energy Lab to study the thermal oxidation characteristics of in-situ generated carbon particles in air at high pressure. The study is part of a project developing a Small Particle Heat Exchange Receiver (SPHER) utilizing concentrated solar power to run a Brayton cycle. The oxidation data obtained will further be used in different existing and planned computer models in order to accurately predict reactor temperatures and flow behavior in the SPHER. The carbon black particles were produced by thermal decomposition of natural gas at 1250 °C and a pressure of 5.65 bar (82 psi). Particles were analyzed using a Diesel Particle Scatterometer (DPS) and scanning electron microscopy (SEM) and found to have a 310 nm average diameter. The size distribution and the complex index of refraction were measured and the data were used to calculate the specific extinction cross section γ of the spherical particles. The oxidation rate was determined using 2 extinction tubes and a tube furnace and the values were compared to literature. The activation energy of the carbon particles was determined to be 295.02 kJ/mole which is higher than in comparable studies. However, the oxidation of carbon particles bigger than 100 nm is hardly studied and almost no previous data is available at these conditions.

Effects of temperature and volatile fatty acids on nitrification-denitrification activity in small-scale anaerobic-aerobic recirculation biofilm process

1997 ◽  
Vol 35 (6) ◽  
pp. 101-108 ◽  
Author(s):  
T. Takai ◽  
A. Hirata ◽  
K. Yamauchi ◽  
Y. Inamori
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Nitrifying Bacteria ◽  
Small Scale ◽  
Ammonium Oxidation ◽  
Nitrite Oxidation ◽  
Nitrification Activity ◽  
Denitrification Activity ◽  
Effects Of Temperature ◽  
Biofilm Process

The purpose of this study is to clarify effects of temperature, volatile fatty acids (VFAs) and recirculation on nitrification-denitrification activity and biota such as nitrifying bacteria in a small-scale domestic wastewater treatment process. Effects of VFAs produced in anaerobic biofilm reactors under various flow-rates and recirculation ratios on nitrifying bacteria were also investigated with laboratory-scale plants on a long-term stable conditions. As a result, at a temperature of 10°C, nitrification activity could be increased about 65% by recirculation and nitrogen removal efficiency was also surely raised. Temperature coefficients of nitrification rate at recirculation ratios of 0 and 4.0 were 1.039 and 1.090, respectively, and that of denitrification was 1.065 at recirculation ratio of 4.0. High concentrations of VFAs were found in anaerobically treated effluent, especially at 10°C without recirculation, and inhibition of nitrite oxidation and nitrite accumulation were observed in the aerobic biofilm reactor. From batch experiments, VFAs' inhibition constants γ in nitrification activity of aerobic biofilm was calculated, and consumption rates of each VFA was investigated on the condition that denitrification was progressed or not. It was clarified that each VFA did not inhibit ammonium oxidation in observed concentration, but slightly inhibited nitrite oxidation. Acetic acid was used as a carbon source of denitrification at the rate of 17.3mg/mg-SS/hr. On the other hand, propionic acid was not used effectively and denitrification did not occur. It was concluded that the recirculation was indispensable to promote nitrification-denitrification activity and biodegradation of VFAs in the small-scale anaerobic-aerobic biofilm process.

scholarly journals Effect of pH and nitrite concentration on nitrite oxidation rate

2011 ◽  
Vol 102 (19) ◽  
pp. 8741-8747 ◽  
Author(s):  
E. Jiménez ◽  
J.B. Giménez ◽  
M.V. Ruano ◽  
J. Ferrer ◽  
J. Serralta
Keyword(s):  
Oxidation Rate ◽  
Nitrite Oxidation ◽  
Nitrite Concentration ◽  
Effect Of Ph

Effect of pH, substrate and free nitrous acid concentrations on ammonium oxidation rate

2012 ◽  
Vol 124 ◽  
pp. 478-484 ◽  
Author(s):  
E. Jiménez ◽  
J.B. Giménez ◽  
A. Seco ◽  
J. Ferrer ◽  
J. Serralta
Keyword(s):  
Oxidation Rate ◽  
Nitrous Acid ◽  
Ammonium Oxidation ◽  
Free Nitrous Acid ◽  
Effect Of Ph

Nitrite oxidation inhibition by hydroxylamine: experimental and model evaluation

2004 ◽  
Vol 50 (6) ◽  
pp. 295-304 ◽  
Author(s):  
P. (Lek) Noophan ◽  
L.A. Figueroa ◽  
J. Munakata-Marr
Keyword(s):  
Oxidation Rate ◽  
Biological Nitrogen Removal ◽  
Ammonia Oxidizers ◽  
Batch Experiments ◽  
Nitrite Oxidation ◽  
Ph Values ◽  
Initial Ph ◽  
Nitrogen Concentrations ◽  
Biological Nitrogen ◽  
Nitrite Oxidizers

A proposed approach for biological nitrogen removal significantly reduces cost by reducing biomass production and carbon requirements via inhibition of nitrite oxidation (NO2− to NO3−). Batch experiments were conducted to examine the effect of hydroxylamine (HM) on nitrite oxidizers, ammonia oxidizers, and nitrite reducers. Hydroxylamine effect experiments were done at initial pH values of 7.4-8.4, nitrogen concentrations of 100 mg N/L, biomass concentrations of 100-400 mg VSS/L and HM dosages up to 43 mg/L. Nitrite oxidizer activity was completely inhibited by HM at dosages of 7.0 and 8.9 mg/L for pH values of 8.4 and 7.6, respectively. Relatively low HM concentrations (0.35-5.5 mg/L) can be used to completely inhibit nitrite oxidation, but do not significantly affect ammonia oxidizers and nitrite reducers. A model developed to describe the effect of pH on nitrite oxidation rate fits the data well (R2 = 0.89) with values for Vmax of 0.372 (mg N/mg VSS-hr), pH* of 7.72, and the inhibition constant Kh of 0.154. Incorporation of HM inhibition into the model provided a good fit to relative nitrite oxidation rate as a function of undissociated HM concentration (R2 = 0.80, Vmax = 0.028 mg N/mg VSS-hr, pH* = 7.89, Kh * 0.302, a * 0.195, and Ki = 0.277 mg/L).

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