scholarly journals Denitrification Kinetics of Nitrate by a Heterotrophic Culture in Batch and Fixed-Biofilm Reactors

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 547
Author(s):  
Yen-Hui Lin ◽  
Yi-Jie Gu
Keyword(s):  
Continuous Flow ◽  
Nitrate Concentration ◽  
Batch Reactor ◽  
Nitrate Removal ◽  
Biofilm Reactor ◽  
Experimental Results ◽  
Heterotrophic Culture ◽  
Concentration Data ◽  
Water And Wastewater Treatment ◽  
Fixed Biofilm

Herein, the progress of nitrate removal by a heterotrophic culture in a batch reactor and continuous-flow fixed-biofilm reactor was examined. Two batch experiments for nitrate reduction with acetate degradation using 250 mL batch reactors with acclimated denitrifying biomass were conducted. The experimental results indicated that the nitrate was completely reduced; however, the acetate remained at a concentration of 280 mg/L from initial nitrate concentration of 100 mg/L. However, the acetate was fully biodegraded by the denitrifying biomass at an initial nitrate concentration of 300 mg/L. To evaluate the biokinetic parameters, the concentration data of nitrate, nitrite, acetate, and denitrifying biomass from the batch kinetic experiments were compared with those of the batch kinetic model system. A continuous-flow fixed-biofilm reactor was used to verify the kinetic biofilm model. The removal efficiency of nitrate in the fixed-biofilm reactor at the steady state was 98.4% accompanied with 90.5% acetate consumption. The experimental results agreed satisfactorily with the model predictions. The modeling and experimental approaches used in this study could be applied in the design of a pilot-scale, or full-scale, fixed-biofilm reactor for nitrate removal in water and wastewater treatment plants.

Carbon tetrachloride biodegradation in a fixed-biofilm reactor and its kinetic study

1998 ◽  
Vol 38 (8-9) ◽  
pp. 155-162 ◽  
Author(s):  
G. Jin ◽  
A. J. Englande
Keyword(s):  
Carbon Tetrachloride ◽  
Continuous Flow ◽  
Model Comparison ◽  
Biofilm Reactor ◽  
Pseudomonas Cepacia ◽  
Initial Concentration ◽  
Biphasic Model ◽  
Providencia Stuartii ◽  
Kinetics Of ◽  
Fixed Biofilm

Kinetics of Carbon Tetrachloride biodegradation are evaluated in a continuous-flow fixed-biofilm reactor with controlled initial redox potential. The column was seeded with a mixed culture of indigenous microorganisms Pseudomonas cepacia and Providencia stuartii. The fixed biofilm reactor exhibited 98%–99.9% biodegradation of CT introduced into the reactor at an initial concentration of about 200 μg/l for retention times of 1 to 4 days respectively. Four models were employed to evaluate the kinetics of CT biodegradation. These included: Eckenfelder (1989), Arvin (1991), Bouwer and McCarty (1985) and a biphasic model. Comparison of calculated results with observed results between these models agreed very closely to each other (0.968 < R2 < 0.999). Predicted performance was best described by the model of Bouwer and McCarty (1985). However, the biphasic and Eckenfelder models provided excellent correlations and were much simpler to apply. The biphasic model yielded very good correlations of the data for all detention times evaluated; whereas, the Eckenfelder model effected comparable results only at the longer retention times studied.

scholarly journals Experimental Analysis and Modeling of Nitrate Removal through Zero-Valent Magnesium Particles

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1276 ◽  
Author(s):  
Siciliano ◽  
Curcio ◽  
Limonti
Keyword(s):  
Nitrate Concentration ◽  
Nitrate Removal ◽  
Experimental Results ◽  
Process Efficiency ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Nitrogen Forms ◽  
Sustainable Technologies ◽  
Batch Tests ◽  
Effects Of Ph

The pollution of water by nitrates represents an important environmental and health issue. The development of sustainable technologies that are able to efficiently remove this contaminant is a key challenge in the field of wastewater treatment. Chemical denitrification by means of zero-valent metallic elements is an interesting method to reduce the oxidized forms of nitrogen. Compared to other metallic reactants, zero-valent magnesium (ZVM) has many profitable aspects, but its use for nitrate removal has scarcely been investigated. In the present work, several batch tests were conducted to examine the concurrent effects of pH, initial nitrate concentration and Mg0 quantity on process performance. The experimental results proved that at pH 3, for a given initial nitrate concentration, the dose of ZVM largely influences process efficiency. In particular, with a ratio between Mg0 and initial N-NO3− amount (Mg/NNi) of 0.33 g/mg, it is possible to obtain complete denitrification within 30 min. Beyond this ratio, no further improvement of treatment was observed. The experiments allowed us to identify the nitrogen forms produced during the treatment. Nitrogen gas was generally the main reaction product, but the trends of the different compounds (NO3−, NO2−, NH4+ and N2) notably changed in response to the modification of operating parameters. Moreover, the results demonstrated that, in a highly acidic environment, when treating solutions with a low nitrate concentration, process performances are unsatisfactory even when using a high Mg/NNi ratio. By increasing the process pH to 5 and 7, a significant denitrification decline occurred. Furthermore, at these pH levels, the enhancement of nitrate concentration caused a progressive process deterioration. Through detailed analysis of experimental results, reactions kinetics and new mathematical equations, able to describe the trends of different nitrogen forms, have been defined. Moreover, reactions pathways have been proposed. Finally, the characterization of exhausted material allowed us to identify the corrosion products formed during the treatment.

Modeling response of nitrifying biofilm to inhibitory shock loads

2004 ◽  
Vol 50 (6) ◽  
pp. 53-60 ◽  
Author(s):  
B.K. Rajbhandari ◽  
A.P. Annachhatre
Keyword(s):  
Experimental Observation ◽  
Exposure Time ◽  
Close Agreement ◽  
Nitrate Concentration ◽  
Recovery Phase ◽  
Biofilm Reactor ◽  
Experimental Results ◽  
Ambient Conditions ◽  
Shock Loads ◽  
Inhibitory Compound

To study the response of nitrifying biofilm to inhibitory shock loads, a lab-scale nitrifying biofilm reactor was operated in ambient conditions. Shock loads of various concentrations of inhibitory compound were applied to the biofilm. Aniline was used as an inhibitory compound. The experimental results were utilized to develop a model for predicting the variation of effluent nitrate concentration from the biofilm reactor for given shock loads of aniline concentration and exposure time both in exposure as well as in recovery phase. Close agreement between model and experimental observation of bulk aniline concentration and effluent nitrate concentration was obtained which indicates the usefulness of the model to estimate bulk aniline concentration and to predict the response of inhibitory shock loads on nitrifying biofilm.

Nitrate removal by nitrate-dependent Fe(II) oxidation in an upflow denitrifying biofilm reactor

2015 ◽  
Vol 72 (3) ◽  
pp. 377-383 ◽  
Author(s):  
Jun Zhou ◽  
Hongyu Wang ◽  
Kai Yang ◽  
Yuchong Sun ◽  
Jun Tian
Keyword(s):  
Removal Efficiency ◽  
Hydraulic Retention Time ◽  
Nitrate Concentration ◽  
Nitrate Removal ◽  
Biofilm Reactor ◽  
Nitrite Accumulation ◽  
Pseudomonas Sp ◽  
Reaction Parameters ◽  
Optimum Reaction ◽  
Maximum Removal

A continuous upflow biofilm reactor packed with ceramsite was constructed for nitrate removal under an anaerobic atmosphere without an organic carbon source. Denitrifying bacteria, Pseudomonas sp. W1, Pseudomonas sp. W2 and Microbacterium sp. W5, were added to the bioreactor as inocula. Nitrate concentration, nitrite accumulation and nitrogen removal efficiency in the effluent were investigated under various conditions set by several parameters including pH, hydraulic retention time (HRT), ratios of carbon to nitrogen (C/N) and temperature. The results illustrated that the maximum removal efficiency of nitrogen was 85.39%, under optimum reaction parameters, approximately pH 6.5–7, HRT = 48 hours and C/N = 13.1:1 at temperature of 30 °C, which were determined by experiment.

scholarly journals Evaluation of a pilot plant for removal of nitrate from groundwater using ion exchange and recycled regenerant

2017 ◽  
Vol 12 (3) ◽  
pp. 541-548
Author(s):  
Sheldon Tarre ◽  
Michael Beliavski ◽  
Michal Green
Keyword(s):  
Ion Exchange ◽  
Batch Reactor ◽  
Nitrate Removal ◽  
Bacterial Count ◽  
Water Volume ◽  
Foam Fractionation ◽  
Well Water ◽  
Combined System ◽  
Blow Down ◽  
Product Water

A combined system of ion exchange (IX) and advanced biophysical treatment of a recirculating regenerant was tested for nitrate removal from groundwater with minimal brine discharge and chloride addition to the product water. Using well water containing 21.5 ± 1.4 mg NO3−-N/L, optimal IX operation was found at a service cycle of 500 bed volumes (BV). Product water nitrate concentrations (7.4 ± 1.4 mg/L as N) met regulations while minimizing both Cl− addition to the treated water (1.03 meq Cl− added per meq NO3−-N removed) and waste brine production (0.2% of the water volume treated). The total organic carbon in the product water was slightly higher (1.5 ± 0.5 vs. 1.3 ± 0.4 mg/L) than the well water and before disinfection the bacterial count was 10–700 cfu/ml. Brine used to regenerate the IX columns was treated first in a sequential batch reactor (SBR) for biological denitrification followed by ozonation for polishing. The SBR was operated at 8 hour cycles and achieved complete nitrate removal. An ozone dose of 3 to 5 mg/L brine allowed for efficient recycling of the denitrified regenerant by removing suspended solids by foam fractionation. In spite of the low brine blow-down, DOC in the recycled regenerant brine after a year of continuous operation was maintained at relatively low levels of 61.0 ± 11.6 mg/L.

Degradation of chlorophenols by biofilms on semi-permeable membranes in two types of fixed bed reactors

1995 ◽  
Vol 32 (8) ◽  
pp. 205-212 ◽  
Author(s):  
A. Wobus ◽  
S. Ulrich ◽  
I. Röske
Keyword(s):  
Continuous Flow ◽  
Plug Flow ◽  
Fixed Bed ◽  
Biofilm Reactor ◽  
Flow Conditions ◽  
Concentration Gradients ◽  
Batch Mode ◽  
Sequencing Batch Biofilm Reactor ◽  
Fixed Bed Reactors ◽  
Protozoan Community

Two identical fixed bed reactors containing gas-permeable tubings as carrier material were compared for the elimination of chlorophenols. Under plug flow conditions, the continuous flow operation resulted in a stratification of biomass due to concentration gradients. To achieve a homogeneous colonization, the sequencing batch mode has been applicated to one biofilm reactor (Sequencing Batch Biofilm Reactor - SBBR). Concentration gradients after filling, probably due to sorption phenomena, caused an uneven distribution of biomass in the SBBR. However, the colonization of the SBBR was more homogeneous as compared to the continuously operated reactor (CFBR). As to the elimination of a trichlorophenol (2,4,5-trichlorophenol - TCP), no significant differences between the SBBR and the CFBR were observed with regard to its sensitivity against load surges. It is to be supposed that sorption to the biofilm was included in the elimination of chlorophenols. A higher diversity of protozoan community and meiofauna is obviously to be attributed to continuous flow.

Biological Phosphorus Removal in a Sequencing Batch Moving Bed Biofilm Reactor

1999 ◽  
Vol 40 (4-5) ◽  
pp. 161-168 ◽  
Author(s):  
H. Helness ◽  
H. Ødegaard
Keyword(s):  
Phosphorus Removal ◽  
Batch Reactor ◽  
Complete Removal ◽  
Biofilm Reactor ◽  
Biological Phosphorus Removal ◽  
Moving Bed Biofilm Reactor ◽  
Moving Bed ◽  
Biofilm Carrier ◽  
Biofilm Process ◽  
Biological Phosphorus

Experiments have been carried out with biological phosphorus removal in a sequencing batch moving bed biofilm reactor (SBMBBR) with a plastic biofilm carrier (Kaldnes) suspended in the wastewater. The aim of the research leading to this paper was to evaluate biological phosphorus removal in this type of biofilm process. Biological phosphorus removal can be achieved in a moving bed biofilm reactor operated as a sequencing batch reactor. In order to achieve good and stable phosphorus removal over time, the length of the anaerobic period should be tuned to achieve near complete removal of easily biodegradable COD in the anaerobic period. The total COD-loading rate must at the same time be kept high enough to achieve a net growth of biomass in the reactor. Use of multivariate models based on UV-absorption spectra and measurements of the redox potential show potential for control of such a process.

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