Fluidized bed reactor operation for groundwater denitrification

1994 ◽  
Vol 29 (10-11) ◽  
pp. 509-515 ◽  
Author(s):  
M. Green ◽  
M. Shnitzer ◽  
S. Tarre ◽  
B. Bogdan ◽  
G. Shelef ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Loading Rate ◽  
Fluidized Bed Reactor ◽  
Reactor Operation ◽  
Biofilm Thickness ◽  
Loading Rates ◽  
Nitrite Removal ◽  
Sand Particles ◽  
Nitrate And Nitrite ◽  
Very High

Groundwater denitrification was carried out in a laboratory scale fluidized bed reactor using sand particles as the biomass carrier. This paper is concentrated on the fluidized bed reactor operation at very high nitrate loading rates (between 30 to 100 kg.NO3/m3 reactor/day) with corresponding short retention times (5 to 1.5 minutes). The effects of nitrate loading rate on nitrate and nitrite removal, as well as on reactor biomass profiles and biofilm characteristics, are presented in this article. The results of the present study indicate that this type of reactor can operate efficiently at retention times shorter than 3 minutes and at nitrate loading rates higher than 70 kg.NO3/m3/day. However, this system requires careful control of the biofilm thickness to achieve a reliable reactor operation.

Phosphate removal in real anaerobic supernatants: modelling and performance of a fluidized bed reactor

1998 ◽  
Vol 38 (1) ◽  
pp. 275-283 ◽  
Author(s):  
P. Battistoni ◽  
P. Pavan ◽  
F. Cecchi ◽  
J. Mata-Alvarez
Keyword(s):  
Fluidized Bed ◽  
Contact Time ◽  
Fluidized Bed Reactor ◽  
Phosphate Removal ◽  
Plant Design ◽  
Air Stripping ◽  
And Performance ◽  
Ph Range ◽  
Very High ◽  
A2o Process

Phosphate removal in anaerobic supernatant coming from a centrifugation sludge station of an A2O process is studied. A fluidized bed reactor is employed to crystallize phosphate as hydroxyapatite or struvite using only air stripping to reach the supersaturation pH. The classic composition of supernatant (alkalinity 3550 mgCaCO3/l, PO4 139 mg/l, Mg 24 mg/l) does not require any addition of chemicals for phosphate removal. Seventeen runs are performed in a bench scale FBR obtaining very high conversion and removal efficiency and phosphate loss in the effluent ≤3.5%. The use of Ca or Mg enriched supernatant has no meaningful influence on efficiency, but it determines the prevalent salt formed between MAP or HAP. Efficiency can be related to pH and sand contact time in a double saturational model. The half efficiency constants: 0.075 h for t and 7.75 pH, have an important role in the process knowledge and optimization of plant design. Exhaust sand analysis indicates the same composition at the top, bottom and mean of the sand bed (39% mol MAP and 61% mol HAP). This result together with the high half efficiency constant for contact time indicate that the phosphate growth on the bed is not competitive. Finally, the phosphate release from the plant is studied. Results show a weak release rate, equivalent to 2.8-10% d−1 phosphate as MAP, obtained at an operative pH range of 8.1-8.4.

Kinetics of an anaerobic fluidized bed reactor using biolite carrier

1996 ◽  
Vol 23 (6) ◽  
pp. 1305-1315 ◽  
Author(s):  
R. Prakash ◽  
K. J. Kennedy
Keyword(s):  
Steady State ◽  
Fluidized Bed ◽  
Loading Rate ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Loading Rates ◽  
Start Up ◽  
Removal Efficiencies ◽  
Biofilm Development ◽  
Kinetics Of

Start-up and steady state operation of anaerobic fluidized bed reactors (AFBRs) with biolite as the inert carrier material was studied. Start-up and concomitant biofilm development of AFBRs was performed using two common start-up techniques, the maximum efficiency profile (MEP) technique and the maximum load profile (MLP) technique. The MEP start-up technique increases the volumetric organic loading rates to the reactor gradually and is tied to the removal efficiency of the process. The MLP start-up technique maintains a moderately high but constant volumetric organic loading rate irrespective of reactor performance. Using sucrose-based wastewater as feed, both start-up techniques led to equally fast biofilm development and start-up times of approximately 5 weeks. However, the MEP technique resulted in more stable controlled reactor operation during the start-up period. The quick start-up confirms the high compatibility of biolite for bio-adhesion and the development of a healthy active biofilm.High concentrations of biofilm biomass achieved in AFBRs (69 g volatile biofilm solids (VBS)/L of expanded bed volume at an organic loading rate of 25 g COD/(Lùd)) allowed the successful treatment of wastewaters at high organic loading rates and organic removal efficiencies. During steady state experiments, organic removal efficiencies over 80% were obtained for organic loading rates as high as 20 g COD/(L∙d). It was found that the dependence of removal efficiency on hydraulic retention time is influenced by substrate concentration. Total biofilm yield was determined to be 0.08 g VBS/g COD removed, demonstrating the low net synthesis of solids in the AFBR. AFBRs had an average solids retention time of 150 days, corresponding to a washout factor of 0.01. Extrinsic kinetics of the AFBRs was determined to be zero order with a maximum specific utilization rate of 0.48 g COD/(g VBS∙d).AFBRs used to treat municipal landfill leachate with a BOD5:COD ratio of 0.86 achieved steady state COD removal efficiencies that ranged from 70% to 87%, depending on the reactor organic loading rate and the concentration of the leachate being treated. During leachate treatment, biofilm biomass gradually became "mineralized" as a result of precipitation of metal sulfides and carbonates. This eventually resulted in a decrease in biofilm microbial activity and the need for higher pumping rates to maintain the same degree of bed expansion. Key words: anaerobic, biological fluidized bed reactor, biolite, landfill leachate, sucrose, modeling, start-up, steady state kinetics.

Nitrification of high-strength ammonium wastewater by a fluidized-bed reactor

2004 ◽  
Vol 49 (5-6) ◽  
pp. 65-71 ◽  
Author(s):  
A.E.F. Botrous ◽  
M.F. Dahab ◽  
P. Mihaltz
Keyword(s):  
Fluidized Bed ◽  
High Strength ◽  
Fluidized Bed Reactor ◽  
Removal Rates ◽  
Ammonium Removal ◽  
Loading Rates ◽  
Conventional Activated Sludge ◽  
Nitrite Nitrogen ◽  
Order Of Magnitude ◽  
Activated Sludge Systems

A laboratory-scale fluidized-bed reactor with an external aeration loop was used for nitrification of high-strength ammonium wastewater (up to 500 mg NH4-N/L). The results demonstrated that the system is capable of handling ammonium removal rates of up to 2.5 kg NH4-N/m3·d, while removal efficiencies were as high as 98% and independent of the applied ammonium loading rates. Ammonium loading rates higher than 2.5 kg NH4-N/m3·d resulted in decreased ammonium removal efficiency. The data show that near complete ammonium removal occurred at DO concentrations as low as 0.3-0.5 mg/L. However, the nitrite-nitrogen fraction in the effluent increased from 3.5% to 23.2% when the DO dropped from 1.0 mg/L to approximately 0.4 mg/L, respectively. The high specific removal rates in this system are one order of magnitude higher than that of suspended-growth systems. This can reduce the supplementary reactor volumes required for nitrification to less than 10% of that needed in conventional activated sludge systems. These results clearly indicate the potential economic gains that could be achieved through implementation of this technology.

APLIKASI PROSES BIOLOGI ANAEROBIK PADA PENGOLAHAN AIR LIMBAH ORGANIK BERKONSENTRASI GARAM TINGGI “STUDI KASUS INDUSTRI UME BOSHI”

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Ikbal Mahmud
Keyword(s):  
Fluidized Bed ◽  
Removal Efficiency ◽  
Loading Rate ◽  
Salt Content ◽  
Fluidized Bed Reactor ◽  
Anaerobic Treatment ◽  
Evolved Gas ◽  
Toc Removal ◽  
Anaerobic Fluidized Bed Reactor ◽  
Organic Carbon Loading

Anaerobic treatment of wastewater with high organic and salt content but low pH (TOC, 14 g/l; salt, 150 g/l; pH,2.7) generated during an “ume boshi” manufacturing process was investigated. Five-fold-diluted “ume boshi” effluent was treated by a draw-and-fill method at a volumetric TOC (total organic carbon) loading rate of 3.0  g/l/d with a TOC removal efficiency of 75%. Five-fold-diluted “ome boshi” effluent was also treated in an anaerobic fluidized-bed reactor (AFBR) at a maximum volumetric TOC loading rate of 3.0 g/l/d, which gave almost the same results as the draw-and-fill method. However, ten-fold-diluted “ome boshi” effluent could be treated in the AFBR at a maximum volumetric TOC loading rate of 11 g/l/d with a TOC removal efficiency of 85%. The methane content in the evolved gas was high, being 70%. The red pigment in the “ome boshi” effluent was completely decolorized by the anaerobic treatment.  Key words :, Anaerobic fluidized-bed reactor, “Ume boshi”Co2+ and Ni2+ ions, decolorization

Toward an operational dynamic model for tertiary nitrification by submerged biofiltration

2007 ◽  
Vol 55 (8-9) ◽  
pp. 301-308 ◽  
Author(s):  
E. Vigne ◽  
J.M. Choubert ◽  
J.P. Canler ◽  
A. Héduit ◽  
P. Lessard
Keyword(s):  
Loading Rate ◽  
Experimental Tests ◽  
Calibration Procedure ◽  
Biofilm Thickness ◽  
Loading Rates ◽  
Total Head ◽  
Model Predictions ◽  
Reduction Coefficient ◽  
The Mean ◽  
Set Up

This work deals with the methodology put in place to fit and validate the parameters of a biofiltration model (BAF) in tertiary nitrification treatment and dynamic conditions. For an average loading rate of 0.65 kg NH4-N/m3 media/d, different time loading rates are applied inside a filtration-backwash run using a semi-industrial pilot. Comparisons between predicted and observed values on the NH4-N, NO3-N and TSS in treated water and the total head loss ΔP are carried out firstly using default values of BAF parameters. Model predictions overestimate values measured but trends are well reproduced. A sensitivity analysis is carried out and the hierarchy of BAF parameters has been set up classifying them into strong and low influence on the effluent concentrations. Among parameters revealing the strongest influence are those of the filtration module and the mean density of biofilm for the TSS effluent and the total ΔP, the specific autotrophic growth rate, the maximum biofilm thickness and the reduction coefficient of diffusivity in the biofilm for the NH4-N, NO3-N effluent. Finally, this classification leads to setting a calibration procedure, thanks to specific experimental tests directly measuring some BAF parameters.

Population dynamics of methanogenic biofilm consortium during a start-up period of anaerobic fluidized bed reactor

1994 ◽  
Vol 29 (10-11) ◽  
pp. 361-368 ◽  
Author(s):  
N. Araki ◽  
H. Harada
Keyword(s):  
Fluidized Bed ◽  
Biofilm Formation ◽  
Fluidized Bed Reactor ◽  
Fluidized Bed Reactors ◽  
Microbial Activities ◽  
Acetate Production ◽  
Biofilm Thickness ◽  
Start Up ◽  
Seed Sludge ◽  
Initial Biofilm

The changes in physical properties and microbial activities were investigated during initial biofilm formation in lab-scale anaerobic fluidized bed reactors. Four different upflow velocities, i.e., 4, 7, 14 and 25 m·hr−1 were applied to four respective reactors of an equal size. The upflow velocities caused a prominent difference in the pattern of initial biofilm formation. The biofilm thickness attained eventually approximately 100 μm after 100 days of operation, independent of upflow velocity. On the contrary the biofilm density varied from 4.4 to 24.1 mg-VSS·cm−3 with an increase in the upflow velocity imposed. The activity of acetoclastic methane production increased remarkably 15 to 30 fold of seed sludge, regardless of upflow velocity. Microbial activities with respect to acetate production, H2-utilizing methanogenesis and acetate-utilizing methanogenesis increased finally up to 3-4 times as large as those of suspended grown sludge in a chemostat.

Anaerobic fluidized beds: ten years of industrial experience

1997 ◽  
Vol 36 (6-7) ◽  
pp. 415-422 ◽  
Author(s):  
T. C. Holst ◽  
A. Truc ◽  
R. Pujol
Keyword(s):  
Pilot Study ◽  
Fluidized Bed ◽  
Food Processing ◽  
Fluidized Beds ◽  
Paper Industry ◽  
Fluidized Bed Reactor ◽  
High Loading ◽  
Industrial Experience ◽  
Loading Rates ◽  
Anaerobic Fluidized Bed Reactor

The Anaflux process, an upflow anaerobic fluidized bed reactor using a mineral bacterial support, has been employed industrially for ten years treating a variety of food-processing and paper industry wastewaters. This paper describes five aspects of the design and operation of the anaerobic fluidized bed which have proven, from industrial experience, to be essential. The optimization of these factors enables a stable functioning of the process and allows the application of high loading rates. Included are the results of a semi-industrial pilot study, treating wine distillation wastewaters, which demonstrate the present capabilities (OLR=70 kg COD/m3·d) of this type of reactor.

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