scholarly journals Hydrodynamics of Uasb Reactor Treating Domestic Wastewater: A Three-Dimensional Numerical Study

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 279 ◽  
Author(s):  
Maria G. S. L. Brito ◽  
Flávio C. B. Nunes ◽  
Hortência L. F. Magalhães ◽  
Wanderson M. P. B. Lima ◽  
Flávia L. C. Moura ◽  
...  
Keyword(s):  
Numerical Study ◽  
Three Dimensional ◽  
Domestic Wastewater ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Reactor Outlet ◽  
Ansys Cfx ◽  
Anaerobic Sludge Blanket ◽  
The Mathematical Model

This work performed a three-dimensional numerical study to describe the hydrodynamics of upflow anaerobic sludge blanket reactor treating domestic wastewater. The simulations were made in the commercial software Ansys CFX®. Different inclinations of the gas deflector were considered, to assess its influence on the velocity field inside the reactor. In order to validate the numerical study, we used experimental data regarding the inflow, the inlet and outlet concentrations of the organic matter, the concentration of solids at the liquid-gas interface and at the reactor outlet, and the pressure field inside it. The comparison between the numerical and experimental results demonstrated small differences. The mathematical model used to describe the hydrodynamics flow in the UASB reactor was quite satisfactory since it adequately has reproduced the physical behavior inside the reactor.

Mathematical modeling of upflow anaerobic sludge blanket (UASB) reactor treating domestic wastewater

2013 ◽  
Vol 67 (1) ◽  
pp. 24-32 ◽  
Author(s):  
Tarek Elmitwalli
Keyword(s):  
Chemical Oxygen Demand ◽  
Dynamic Model ◽  
Empirical Model ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Model Based ◽  
Anaerobic Sludge Blanket

Although the upflow anaerobic sludge blanket (UASB) reactor has been widely applied for domestic wastewater treatment in many developing countries, there is no sufficient mathematical model for proper design and operation of the reactor. An empirical model based on non-linear regression was developed to represent the physical and chemical removal of suspended solids (SS) in the reactor. Moreover, a simplified dynamic model based on ADM1 and the empirical model for SS removal was developed for anaerobic digestion of the entrapped SS and dissolved matter in the wastewater. The empirical model showed that effluent suspended chemical oxygen demand (CODss) concentration is directly proportional to the influent CODss concentration and inversely proportional to both the hydraulic retention time (HRT) of the reactor and wastewater temperature. For obtaining sufficient CODss removal, the HRT of the UASB reactor must be higher than 4 h, and higher HRT than 12 h slightly improved CODss removal. The dynamic model results showed that the required time for filling the reactor with sludge mainly depends on influent total chemical oxygen demand (CODt) concentration and HRT. The influent CODt concentration, HRT and temperature play a crucial role on the performance of the reactor. The results indicated that shorter HRT is needed for optimization of CODt removal, as compared with optimization of CODt conversion to methane. Based on the model results, the design HRT of the UASB reactor should be selected based on the optimization of wastewater conversion and minimization of biodegradable SS accumulation in the sludge bed, not only based on COD removal, to guarantee a stable reactor performance.

Theoretical/Experimental Study of an Upflow Anaerobic Sludge Blanket Reactor Treating Domestic Wastewater

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Maria Gorethe Sousa Lima ◽  
Severino Rodrigues de Farias Neto ◽  
Antonio Gilson Barbosa de Lima ◽  
Flávio César Brito Nunes ◽  
Luciano de Andrade Gomes
Keyword(s):  
Experimental Study ◽  
Suspended Solids ◽  
Fluid Dynamic ◽  
Total Concentration ◽  
Domestic Wastewater ◽  
Pilot Scale ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Ansys Cfx ◽  
Anaerobic Sludge Blanket

This work reports a theoretical and experimental study to evaluate the fluid dynamic of an Upflow Anaerobic Sludge Blanket reactor (UASB), treating domestic wastewater in a pilot scale. Simulations were developed using the Ansys CFX 10.0. For validating the numerical results, an experimental study was conducted by monitoring the total concentration of suspended solids in the effluent and pressure along the reactor. The comparative analysis between the numerical and experimental results of the pressure and sludge concentration in the outlet of the reactor presented few differences, being considered satisfactory.

Physical modelling of an upflow anaerobic sludge blanket reactor: near-field study

2002 ◽  
Vol 45 (10) ◽  
pp. 157-162
Author(s):  
J.R. Gimenez ◽  
S.C. Nassr ◽  
R.D. Maestri ◽  
L.O. Monteggia
Keyword(s):  
Distribution System ◽  
Near Field ◽  
Three Dimensional ◽  
Physical Modelling ◽  
Upflow Anaerobic Sludge Blanket ◽  
Scale Model ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Anaerobic Sludge Blanket ◽  
Reduced Scale

This paper presents a physical evaluation of an upflow anaerobic sludge blanket reactor. Specifically, the study contemplates the region influenced by the wastewater inlet jets at the bottom of the reactor, here termed the near-field area. A three-dimensional physical model of a UASB reactor in reduced scale, geometrically and dynamically correlated to a full-scale prototype was used in the evaluation. From the analysis of the major forces acting and of the physical properties investigated in the prototype, it was possible to establish non-dimensional relations that were applied to the reduced scale model, allowing the investigation of the phenomenon of interest. Tests were developed on the model to visualise the inlet flows under the buoyant effect at the bottom of the reactor, through the injection of a tracer fluid in the area with higher density, simulating the effects of the sludge bed. Based on the experimental results, it was possible to provide dimensioning criteria for the jet distribution system in UASB reactors.

Temperature effect on UASB reactor operation for domestic wastewater treatment in temperate climate regions

2003 ◽  
Vol 48 (3) ◽  
pp. 25-30 ◽  
Author(s):  
B. Lew ◽  
M. Belavski ◽  
S. Admon ◽  
S. Tarre ◽  
M. Green
Keyword(s):  
Methane Production ◽  
Domestic Wastewater ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Temperate Climate ◽  
Anaerobic Sludge ◽  
Biological Degradation ◽  
Domestic Wastewater Treatment ◽  
Anaerobic Sludge Blanket

The performance of an upflow anaerobic sludge blanket (UASB) reactor was investigated for the treatment of domestic wastewater at different operational temperatures (28, 20, 14 and 10°C) and loading rates. For each temperature studied a constant CODt removal was observed as long as the upflow velocity was lower than 0.35 m/h: 82% at 28°C, 68% at 14°C and 44% at 10°C. At 20°C the COD removal increased with the HRT, reaching similar values as at 28°C for long HRT. At upflow velocities higher than 0.35 m/h, a reduction in total COD removal was observed due to washout of influent TSS. At 28°C, a constant 200 g sludge mass was observed and COD removal was attributed to biological degradation only. At lower temperatures, COD removal resulted from degradation and solids accumulation in the reactor. The increase in reactor sludge was greater as the temperature decreased and explains the similar overall COD removal efficiency at 28°C, 20°C and 14°C. During the transition from winter to summer conditions (10°C to 28°C), methane production initially increased due to the degradation of accumulated solids. Afterwards, methane production gradually declined and an increase in COD removal was observed, indicating that the TSS accumulated during the winter was exhausted and influent degradation remained.

UASB reactor for domestic wastewater treatment at low temperatures: a comparison between a classical UASB and hybrid UASB-filter reactor

2004 ◽  
Vol 49 (11-12) ◽  
pp. 295-301 ◽  
Author(s):  
B. Lew ◽  
S. Tarre ◽  
M. Belavski ◽  
M. Green
Keyword(s):  
Domestic Wastewater ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Hybrid Reactor ◽  
Anaerobic Sludge ◽  
Biological Degradation ◽  
Domestic Wastewater Treatment ◽  
Reactor Types ◽  
Anaerobic Sludge Blanket

The performance of an upflow anaerobic sludge blanket (UASB) reactor and a hybrid UASB-filter reactor was investigated and compared for the treatment of domestic wastewater at different operational temperatures (28, 20, 14 and 10¡C) and loading rates. For each temperature studied a constant CODt removal was observed as long as the upflow velocity was lower than 0.35 m/h. At these upflow velocities similar removals were observed for both reactor types at 28 and 20¡C, 82 and 72% respectively. However, at 14 and 10¡C the UASB reactor showed a better COD removal (70% and 48%, respectively) than the hybrid reactor (60% and 38%). COD removal resulted from biological degradation and solids accumulation in the reactors. At 28°C, a constant 200 g sludge mass was observed in both reactors and COD removal was attributed to biological degradation only. At lower temperatures, solids accumulation was observed in addition to biological degradation with an increase in reactor sludge as the temperature decreased. The decrease in biological degradation at lower temperatures was offset by solids accumulation and explains the similar overall COD removal efficiency observed at 28°C, 20°C and 14°C. The decrease in temperature was also followed by an increase in the effluent TSS concentration in both reactors. At 14 and 10°C a lower effluent TSS concentration and better performance was observed in the UASB reactor.

scholarly journals Microbial Removal of Pb(II) Using an Upflow Anaerobic Sludge Blanket (UASB) Reactor

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 512
Author(s):  
Jeremiah Chimhundi ◽  
Carla Hörstmann ◽  
Evans M. N. Chirwa ◽  
Hendrik G. Brink
Keyword(s):  
Treatment Process ◽  
Removal Rate ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Reduction Potentials ◽  
Oxidation Reduction ◽  
Anaerobic Sludge Blanket ◽  
Microbial Removal ◽  
Maximum Removal

The main objective of this study was to achieve the continuous biorecovery and bioreduction of Pb(II) using an industrially obtained consortia as a biocatalyst. An upflow anaerobic sludge blanket reactor was used in the treatment process. The bioremediation technique that was applied made use of a yeast extract as the microbial substrate and Pb(NO3)2 as the source of Pb(II). The UASB reactor exhibited removal efficiencies of between 90 and 100% for the inlet Pb concentrations from 80 to 2000 ppm and a maximum removal rate of 1948.4 mg/(L·d) was measured. XRD and XPS analyses of the precipitate revealed the presence of Pb0, PbO, PbS and PbSO4. Supporting experimental work carried out included growth measurements, pH, oxidation–reduction potentials and nitrate levels.

KINETIC MODELS FOR PREDICTION OF COD EFFLUENT FROM UPFLOW ANAEROBIC SLUDGE BLANKET (UASB) REACTOR FOR CANNERY SEAFOOD WASTEWATER TREATMENT

2016 ◽  
Vol 78 (5-6) ◽  
Author(s):  
Sunwanee Jijai ◽  
Chairat Siripatana ◽  
Sompong O-Thong ◽  
Norli Ismail
Keyword(s):  
Palm Oil ◽  
Kinetic Models ◽  
Second Order ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Substrate Removal ◽  
Reactor Kinetic ◽  
Palm Oil Mill ◽  
Anaerobic Sludge Blanket

The three identical lab-scale upflow anaerobic sludge blanket (UASB) reactors were operated continuously for treating cannery seafood wastewater at seven hydraulic retention times (HRTs) of 5, 4, 3, 2, 1, 0.5 and 0.25 days. The different of granule sizes from three sources: a cassava factory (CS), a seafood factory (SS), and a palm oil mill (PS), average sizes in the range 1.5-1.7, 0.7-1.0 and 0.1-0.2 mm respectively were used as inocula for anaerobic digestion. The UASB-R1 used only granules from seafood factory (R1-SS), the UASB-R2 used mixed granules from seafood with cassava factory (R2-SS+CS) and the UASB-R3 used mixed granules from seafood factory with palm oil mill (R3-SS+PS). In this study selected mathematical models including Monod, Contois, Grau second-order and modified Stover-Kicannon kinetic models were applied to determine the substrate removal kinetics of UASB reactor. Kinetic parameters were determined through linear regression using experimental data obtained from the steady-state experiment and subsequently used to predict effluent COD. The results showed that Grau second-order and modified Stover-Kicannon kinetic models were more suitable than that of others for predicting the effluent COD, with high the correlation coefficient (R2). In addition, the UASB-R2 from mixed granules with cassava factory (SS+CS) gave the best performance and highest coefficient value.

Nitrite reduction and methanogenesis in a single-stage UASB reactor

2015 ◽  
Vol 72 (12) ◽  
pp. 2236-2242 ◽  
Author(s):  
L. I. Borges ◽  
C. M. López-Vazquez ◽  
H. García ◽  
J. B. van Lier
Keyword(s):  
Domestic Wastewater ◽  
High Strength ◽  
Single Stage ◽  
Nitrite Reduction ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
N Removal

In this study, nitrite reduction and methanogenesis in a single-stage upflow anaerobic sludge blanket (UASB) reactor was investigated, using high-strength synthetic domestic wastewater as substrate. To assess long-term effects and evaluate the mechanisms that allow successful nitrite reduction and methanogenesis in a single-stage UASB, sludge was exposed to relatively high nitrite loading rates (315 ± 13 mgNO2−-N/(l.d)), using a chemical oxygen demand (COD) to nitrogen ratio of 18 gCOD/gNO2−-N, and an organic loading rate of 5.4 ± 0.2 gCOD/(l.d). In parallel, the effects of sludge morphology on methanogenesis inhibition were studied by performing short-term batch activity tests at different COD/NO2−-N ratios with anaerobic sludge samples. In long-term tests, denitrification was practically complete and COD removal efficiency did not change significantly after nitrite addition. Furthermore, methane production only decreased by 13%, agreeing with the reducing equivalents requirement for complete NO2− reduction to N2. Apparently, the spatial separation of denitrification and methanogenesis zones inside the UASB reactor allowed nitrite reduction and methanogenesis to occur at the same moment. Batch tests showed that granules seem to protect methanogens from nitrite inhibition, probably due to transport limitations. Combined COD and N removal via nitrite in a single-stage UASB reactor could be a feasible technology to treat high-strength domestic wastewater.

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