Validation of a multisubstrate mathematical model for the simulation of the denitrification process in fluidized bed biofilm reactors

1994 ◽  
Vol 29 (10-11) ◽  
pp. 401-408 ◽  
Author(s):  
B. Eramo ◽  
R. Gavasci ◽  
A. Misiti ◽  
P. Viotti

The present paper compares the experimental results obtained from a research programme developed on a pilot-scale fluidized bed biofilm reactor and the outputs of a numeric simulation model; the mathematical model can determine the substrate concentration profile within the reactor. The experimental campaign investigated heterotrophic biological denitrification in anoxic conditions. The model is based on multi-substrate Michaelis-Menten kinetics and considers mass transport resistancephenomena within and outside bioparticles. A monodimensional model of the reactor taking into consideration, in steady-state condition, phenomena due to convective transport and turbulent diffusion has been used. The fluidization model applied to describe the behaviour of the biofilm-covered rigid particle bed is based on the Wen and Yu correlation.

2010 ◽  
Vol 62 (12) ◽  
pp. 2801-2810 ◽  
Author(s):  
Yen-Hui Lin

A pilot-scale fixed-biofilm reactor (FBR) was established to treat textile wastewater to evaluate the feasibility of replacing conventional treatment processes that involve activated sludge and coagulation units. A kinetic model was developed to describe the biodegradation of textile wastewater by FBR. Batch kinetic tests were performed to evaluate the biokinetic parameters that are used in the model. FBR column test was fed with a mean COD of 692 mg/L of textile wastewater from flow equalization unit. The influent flow rate was maintained at 48.4 L/h for FBR column test. Experimental data and model-predicted data for substrate effluent concentration (as COD), concentration of suspended biomass in effluent and the amount of carbon dioxide (CO2) produced in the effluent agree closely with each other. Microscopic observations demonstrated that the biofilm exhibited a uniform distribution on the surface of polyurethane foam sponge. Under a steady-state condition, the effluent COD from FBR was about 14.7 mg COD/L (0.0213 Sb0), meeting the discharge standard (COD < 100 mg/L) that has been set by the government of Taiwan for textile wastewater effluent. The amount of biofilm and suspended biomass reached a maximal value in the steady state when the substrate flux reached a constant value and remained maximal. Approximately 33% of the substrate concentration (as COD) was converted to CO2 during biodegradation in the FBR test. The experimental and modeling schemes proposed in this study could be employed to design a full-scale FBR to treat textile wastewater.


1994 ◽  
Vol 30 (11) ◽  
pp. 101-110
Author(s):  
Toshiaki Tsubone ◽  
Seiichi Kanamori ◽  
Tatsuo Takechi ◽  
Masahiro Takahashi

A pilot scale study was conducted using an Air-Fluidized-Bed Biofilm Reactor (AFBBR) system with a Multi Media Filter (MMF). Soluble BOD (S-BOD) concentration in the effluent of the AFBBR had a correlation with total BOD (T-BOD) and Suspended Solids (SS) concentration in the effluent of the MMF. The lower the S-BOD in the effluent of the AFBBR was, the lower was not only T-BOD but also SS in the effluent of the MMF. It was found that as treatment proceeded, S-BOD was removed and the particle size of SS increased in the AFBBR. These results suggested that the mechanism of BOD removal in this system was: S-BOD was removed and a part of the S-BOD was changed to SS and the particle size of the SS increased in the AFBBR, and then the SS was removed by the MMF. Thus not only the T-BOD but also the SS in the effluent of MMF was lower when the S-BOD in the effluent of the AFBBR was lower. When the S-BOD in the effluent of the AFBBR was 8mg/L, T-BOD and the SS in the effluent of the MMF were 10mg/L and 4mg/L, respectively. In order to have an average S-BOD value in the effluent of the AFBBR of about 8mg/L, the T-BOD loading and the S-BOD loading needed to be less than 1.3kg/m3/day and 0.45 kg/m3/day, respectively. Even when the BOD loading was high, nitrification still occurred in this system.


1987 ◽  
Vol 19 (1-2) ◽  
pp. 1-10 ◽  
Author(s):  
Chun T. Li ◽  
Wen K. Shieh ◽  
Chun S. Wu ◽  
Ju S. Huang

The oxygenic fluidized bed biofilm reactor(FBBR) was evaluated in a laboratory investigation for treatment of pig slaughtering wastewater (slaughterhouse wastewater). Because the slaughterhouse wastewater contains a high concentration of grease, chemical coagulation/flocculation was adopted as the pretreatment step prior to FBBR treatment. The performance of the FBBR was evaluated at BOD loadings of between 8.5 to 98.5 kg/m3-day, hydraulic retention times of between 8.8 to 30.8 minutes, recirculation ratios of between 1 to 6, and feed BOD concentrations of between 305 to 602 mg/L. Under these operating conditions, removal efficiencies of BOD, grease, and NH3-N were in the range of 71 to 94%, 29 to 84%, and 20 to 73%, respectively. Both BOD and grease of the slaughterhouse wastewater used could be lowered to 40 and 10 mg/L, respectively, at a BOD loading of 20 kg/m3-day in order to meet effluent requirements to be enforced in Taiwan in 1990. Because the maximum amount of oxygen that could be dissolved in the oxygenation device used in this investigation was 40 mg/L, the FBBR would become anaerobic when the BOD loading applied exceeded 50 kg/m3-day. Relatively constant biomass holdups (10,000 mg TVS/L) could be maintained in FBBRs over the BOD loadings applied via the practice of regular biofilm separation and biomass wasting. The combined chemical coagulation/flocculation-FBBR process provides a feasible and cost-effective alternative for treatment of slaughterhouse wastewater.


1987 ◽  
Vol 19 (1-2) ◽  
pp. 151-162 ◽  
Author(s):  
H. Harada ◽  
H. Ando ◽  
K. Momonoi

A mathematical model is proposed herein to describe the dynamic behavior of the denitrification process in a fluidized bed biofilm reactor. The model basically consists of the following four submodels: bioparticles fluidization, bulk liquid flow pattern, substrate conversion within biofilm and biofilm thickness development. As for intrinsic denitrification reaction, a consecutive two-step reaction kinetics with nitrite as an intermediate product is adopted. All parameters needed for simulation were experimentally determined. Verification of the model was obtained in a dynamic state using a laboratory-scale fluidized bed denitrification reactor under well defined conditions.


1999 ◽  
Vol 4 (1) ◽  
pp. 51-58 ◽  
Author(s):  
Jeong-Woo Choi ◽  
Juhong Min ◽  
Won-Hong Lee ◽  
Sang Back Lee

2011 ◽  
Vol 64 (1) ◽  
pp. 293-299 ◽  
Author(s):  
D. Puyol ◽  
H. Rajhi ◽  
A. F. Mohedano ◽  
J. J. Rodríguez ◽  
J. L. Sanz

The biodegradation of 2,4,6-trichlorophenol (246TCP) was studied using expanded granular sludge bed (EGSB) reactors and a fluidized bed biofilm reactor (FBBR) filled with activated carbon. One of the EGSB reactor and the FBBR were bioaugmented with Desulfitobacterium strains. 246TCP loading rate was gradually incremented from 10 to 250 mg L−1 day−1. The main pathway of dechlorination was in ortho-position, generating 4-chlorophenol and 2,4-dichlorophenol. The maintenance of both COD degradation efficiency (higher than 80%) and methanogenic efficiency (between 0.3 and 0.6 g CH4–COD g−1 COD consumed) in EGSB reactor implies a great stability of the process. Through isotherm studies in FBBR, it could be deduced that around 52% of 246TCP was completely dechlorinated, whereas the adsorption involved around 16%. By means of FISH studies it was proved that the methanogenic Archaea community was maintained in the bioaugmented EGSB reactor, whereas in the FBBR this community was gradually developed until reaching stability. Desulfitobacterium community was also maintained in the reactors, although D. chlororespirans proportion rise in the FBBR at the higher 246TCP loading rates, implying that this species can withstand the 246TCP toxicity better than D. hafniense.


1999 ◽  
Vol 4 (1) ◽  
pp. 58-58
Author(s):  
Jeong-Woo Choi ◽  
Juhong Min ◽  
Won-Hong Lee ◽  
Sang Back Lee

2005 ◽  
Vol 52 (10-11) ◽  
pp. 117-127 ◽  
Author(s):  
H. Helness ◽  
E. Melin ◽  
Y. Ulgenes ◽  
P. Järvinen ◽  
V. Rasmussen ◽  
...  

Many cities around the world are looking for compact wastewater treatment alternatives since space for treatment plants is becoming scarce. In this paper development of a new compact, high-rate treatment concept with results from experiments in lab-scale and pilot-scale are presented. The idea behind the treatment concept is that coagulation/floc separation may be used to separate suspended and colloidal matter (resulting in >70% organic matter removal in normal wastewater) while a high-rate biofilm process (based on Moving Bed™ biofilm reactors) may be used for removing low molecular weight, easily biodegradable, soluble organic matter. By using flotation for floc/biomass separation, the total residence time for a plant according to this concept will normally be <1 hour. A cationic polymer combined with iron is used as coagulant at low dosages (i.e. 1–2mg polymer/l, 5–10mg Fe/l) resulting in low sludge production (compared to conventional chemical treatment) and sufficient P-removal.


2013 ◽  
Vol 67 (5) ◽  
pp. 1083-1091 ◽  
Author(s):  
X. M. Hu ◽  
Y. W. Chen ◽  
Y. G. Liao ◽  
W. F. Yan ◽  
S. M. Zhu ◽  
...  

In this experiment, a rapid mass-transfer inner loop fluidized bed biofilm reactor (ILFBBR) was employed to treat synthetic high ammonia nitrogen-containing (NH4+-N) wastewater by shortcut nitrification–denitrification. The reactor operation was stable after a short start-up period. Ammonia oxidizing bacteria (AOB) were predominant and 65% nitrite (NO2−-N/NOx−-N) levels were achieved. During the nitrification–denitrification period, the removal rates of NH4+-N and total nitrogen (TN) reached 94 and 82%, respectively. From the material balance, it was indicated that 87% of NH4+-N was removed by shortcut nitrification. The features of ILFBBR and the benefits of shortcut nitrification were combined in this experiment, and showed an excellent removal of NH4+-N from high-concentration NH4+-N wastewater.


1982 ◽  
Vol 4 (4) ◽  
pp. 269-275 ◽  
Author(s):  
Wen K. Shieh ◽  
Leo T. Mulcahy ◽  
Enrique J. LaMotta

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