Thermophilic anaerobic digestion of methanol in UASB reactor

2001 ◽  
Vol 44 (4) ◽  
pp. 129-136 ◽  
Author(s):  
P. L. Paulo ◽  
B. Jiang ◽  
S. Rebac ◽  
L. Hulshoff Pol ◽  
G. Lettinga
Keyword(s):  
Temperature Drop ◽  
Oxygen Demand ◽  
Granular Sludge ◽  
Methanol Conversion ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Reactor Performance ◽  
Thermophilic Conditions ◽  
Main Components ◽  
Main Component

A 5.1 L laboratory scale upflow anaerobic sludge bed (UASB) reactor was operated at 55°C over 130 days in order to investigate the feasibility of treating methanol-containing wastewater under thermophilic conditions, focussing on start-up and process stability. Batch assays were conducted to elucidate the most probable pathway for methanol conversion. The results demonstrated a good performance, with a chemical oxygen demand (COD) removal averaging 82% throughout the experiment. No significant VFA accumulation was detected in the effluent, even with bicarbonate concentration exceeding 20 mM. Acetate was the main component of the VFA at relatively low organic loading rates (OLR). At high OLR, the main components were propionate and butyrate. Reactor performance was hardly affected when the system was exposed to non-optimal conditions, i.e., temperature drop, overloading and no feeding. Good thermophilic granular sludge was retained in the reactor. Washout of biomass was not severe during the experiment. From the pathway analysis it could be concluded that indirect pathways play an important role in the methanol degradation by the cultivated consortia.

scholarly journals Simple estimation of granule size distribution and sludge bed porosity in a UASB reactor

2013 ◽  
Vol 10 (1) ◽  
pp. 73-79
Keyword(s):  
Size Distribution ◽  
Granular Sludge ◽  
Granule Size ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Reactor Performance ◽  
Efficient Operation ◽  
Mathematical Algorithm ◽  
Bed Porosity

Granular sludge is the key factor for an efficient operation of an upflow anaerobic sludge blanket (UASB) reactor. In order to monitor the granularity of anaerobic sludge, the determination of the granule size distribution is of vital importance. Another critical parameter for the UASB reactor performance is the sludge bed porosity. For this reason, several techniques have been proposed, however they are either tedious, imprecise or expensive and hardly applicable in full scale treatment plants. There was then the need for a simple and low cost technique. This technique involves the determination of the settling velocities of a sludge sample and of extrapolating the corresponding diameters using a mathematical algorithm. In the proposed algorithm, the granules density was calculated, the flow regime was examined and finally the granule size distribution was obtained. Some very important correlations were suggested by the experimental results. The granule density and diameter as well as the sludge bed porosity were strongly correlated with the VSS/TSS ratio.

Anaerobic treatment of crude glycerol from biodiesel production

2015 ◽  
Vol 72 (8) ◽  
pp. 1383-1389 ◽  
Author(s):  
M. M. Nakazawa ◽  
W. R. S. Silva Júnior ◽  
M. T. Kato ◽  
S. Gavazza ◽  
L. Florencio
Keyword(s):  
Crude Glycerol ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Experimental Period ◽  
Anaerobic Treatment ◽  
Biodiesel Production ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Reactor Performance

In this study, we evaluated the use of an up-flow anaerobic sludge blanket (UASB) reactor to treat crude glycerol obtained from cottonseed biodiesel production. The laboratory-scale UASB reactor (7.0 L) was operated at ambient temperature of 26.5°C with chemical oxygen demand (COD) concentrations between 0.5 and 8.0 g/L. The volatile fatty acid contents, pH, inorganic salt contents and biogas production were monitored during a 280-day experimental period. Molecular biology techniques were used to assess the microbial diversity in the bioreactor. The reactor achieved COD removal efficiencies of up to 92% except during one phase when the efficiency decreased to 81%. Biogas production remained stable throughout the experimental period, when the fraction converted to methane reached values as high as 68%. The profile of the denaturing gradient gel electrophoresis (DGGE) bands suggested slight changes in the microbial community during reactor operation. The overall results indicated that the crude glycerol from biodiesel production can serve as a suitable substrate for anaerobic degradation with a stable reactor performance and biogas production as long as the applied organic loads are up to 8.06 kg COD/m3·d.

Removal efficiency and methanogenic activity profiles in a pilot-scale UASB reactor treating settled sewage at moderate temperatures

2002 ◽  
Vol 45 (10) ◽  
pp. 243-248 ◽  
Author(s):  
L. Seghezzo ◽  
R.G. Guerra ◽  
S.M. González ◽  
A.P. Trupiano ◽  
M.E. Figueroa ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Retention Time ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
Granular Sludge ◽  
Pilot Scale ◽  
Cod Removal ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Methanogenic Activity

The performance of a sewage treatment system consisting of a settler followed by an Upflow Anaerobic Sludge Bed (UASB) reactor is described. Mean ambient and sewage temperature were 16.5 and 21.6°C, respectively. Total Chemical Oxygen Demand (CODt) concentration averaged 224.2 and 152.6 mg/L, for raw and settled sewage, respectively. The effluent concentration was 68.5 mgCODt/L. Total and suspended COD removal efficiencies of approximately 70 and 80%, respectively, have been observed in the system at a mean Hydraulic Retention Time (HRT) of 2 + 5 h. Maximum COD removal efficiency was achieved in the UASB reactor when upflow velocity (Vup) was 0.43 m/h (HRT = 6 h). Mean Specific Methanogenic Activity (SMA) and Volatile Suspended Solids (VSS) concentration in the granular sludge bed were 0.11 gCOD-CH4/gVSS.d and 30.0 gVSS/Lsludge, respectively. SMA was inversely related to VSS concentration, and both parameters varied along the sludge bed height. The Solids Retention Time (SRT) in the reactor was 450 days. Sludge characteristics have not been affected by changes of up to one month in Vup in the range 0.28–0.85 m/h (HRT 3–9 h). This system or two UASB reactors in series could be an alternative for sewage treatment under moderate temperature conditions.

Herbal pharmaceutical wastewater treatment by a pilot scale upflow anaerobic sludge blanket (UASB) reactor

2009 ◽  
Vol 59 (11) ◽  
pp. 2265-2272 ◽  
Author(s):  
S. Satyanarayan ◽  
A. Karambe ◽  
A. P. Vanerkar
Keyword(s):  
Biogas Production ◽  
Oxygen Demand ◽  
High Strength ◽  
Cost Effective ◽  
Pilot Scale ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Reactor Performance ◽  
Anaerobic Sludge Blanket

Herbal pharmaceutical industry has grown tremendously in the last few decades. As such, literature on the treatment of this wastewater is scarce. Water pollution control problems in the developing countries need to be solved through application of cost effective aerobic/anaerobic biological systems. One such system—the upflow anaerobic sludge blanket (UASB) process which is known to be cost effective and where by-product recovery was also feasible was applied for treatment of a high strength wastewater for a period of six months in a pilot scale upflow anaerobic sludge blanket (UASB) reactor with a capacity of 27.44 m3. Studies were carried out at various organic loading rates varying between 6.26 and 10.33 kg COD/m3/day and hydraulic retention time (HRT) fluctuating between 33 and 43 hours. This resulted in chemical oxygen demand (COD), biochemical oxygen demand (BOD) and suspended solids (SS) removal in the range of 86.2%–91.6%, 90.0%–95.2% and 62.6%–68.0% respectively. The biogas production varied between 0.32–0.47 m3/kg COD added. Sludge from different heights of UASB reactor was collected and subjected to scanning electron microscopy (SEM). The results indicated good granulation with efficient UASB reactor performance.

Impact of ozone pre-treatment on the performance of upflow anaerobic sludge blanket treating pre-treated grain distillery wastewater

2014 ◽  
Vol 70 (10) ◽  
pp. 1702-1708 ◽  
Author(s):  
L. Robertson ◽  
T. J. Britz ◽  
G. O. Sigge
Keyword(s):  
Unsaturated Fatty Acids ◽  
Oxygen Demand ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Reactor Performance ◽  
Distillery Wastewater ◽  
Pre Treatment ◽  
Anaerobic Sludge Blanket ◽  
Performance Results

Two 2 L laboratory-scale upflow anaerobic sludge blanket (UASB) reactors were operated for 277 days. The substrate of the control reactor (Rc) contained grain distillery wastewater (GDWW) that had undergone coagulant pre-treatment, and the substrate of the second UASB reactor consisted of GDWW that had undergone coagulant pre-treatment and ozone pre-treatment (Ro). Both reactors treated pre-treated GDWW successfully at ca. 9 kgCOD m−3 d−1. Chemical oxygen demand (COD) reductions of ca. 96% for Rc and 93% for Ro were achieved. Fats, oils and grease (FOG) reductions (%) showed variations throughout the study, and reductions of ca. 88 and 92% were achieved for Rc and Ro, respectively. Rc produced more biogas, and the methane percentage was similar in both reactors. UASB granule washout in Rc suggested possible toxicity of unsaturated fatty acids present in non-ozonated substrate. The feasibility of FOG removal was demonstrated as both reactors successfully treated pre-treated GDWW. Better results were obtained for Ro effluent during post-ozonation. The ozone pre-treatment possibly led to easier degradable wastewater, and better results could potentially be obtained when other post-treatment steps are applied. Ozone pre-treatment did not, however, show an added benefit in the reactor performance results.

Performance and Modeling of a Pilot-Scale Up-Flow Anaerobic Sludge Blanket (UASB) Treating Pharmaceutical Wastewater Containing Berberine

2012 ◽  
Vol 518-523 ◽  
pp. 2625-2630 ◽  
Author(s):  
Ya Dong Guo ◽  
Cui Ting Fu ◽  
Guo Rong Liu ◽  
Chun Shuang Liu
Keyword(s):  
Scale Up ◽  
Back Propagation ◽  
Oxygen Demand ◽  
Granular Sludge ◽  
Pilot Scale ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Pharmaceutical Wastewater ◽  
Average Percentage ◽  
Anaerobic Sludge Blanket

A pilot-scale test was conducted with an up-flow anaerobic sludge blanket (UASB) treating pharmaceutical wastewater containing berberine. The aim of this study was to investigate the performance of UASB in the condition of a high chemical oxygen demand (COD) loading rate from 4.64 to 8.68 kg/m3d and a wide berberine concentration from 254 to 536 mg/L, in order to provide a reference for treating the similar pharmaceutical wastewater containing berberine. The results demonstrated that the UASB average percentage reduction in COD and berberine 68.14% and 57.39%, respectively. Granular sludge was formed during this process. In addition, a model, built on the back propagation neural network (BPNN) theory and linear regression techniques was developed for the simulation of the UASB system performance in the biodegradation of pharmaceutical wastewater containing berberine. The average errors of COD and berberine were -0.55% and 0.24%, respectively. The results indicated that this model built on the BPNN theory was well-fitted to the detected data, and was able to simulate and predict the removal of COD and berberine by UASB reactor.

scholarly journals Modification of UASB reactor by using CFD simulations for enhanced treatment of municipal sewage

2017 ◽  
Vol 77 (3) ◽  
pp. 766-776 ◽  
Author(s):  
Suprotim Das ◽  
Supriya Sarkar ◽  
Sanjeev Chaudhari
Keyword(s):  
Cfd Simulation ◽  
Biogas Production ◽  
Research Work ◽  
Vertical Wall ◽  
Oxygen Demand ◽  
Uasb Reactor ◽  
Municipal Sewage ◽  
Anaerobic Sludge ◽  
Reactor Performance ◽  
And Performance

Abstract Up-flow anaerobic sludge blanket (UASB) has been in use since last few decades for the treatment of organic wastewaters. However, the performance of UASB reactor is quite low for treatment of low strength wastewaters (LSWs) due to less biogas production leading to poor mixing. In the present research work, a modification was done in the design of UASB to improve mixing of reactor liquid which is important to enhance the reactor performance. The modified UASB (MUASB) reactor was designed by providing a slanted baffle along the height of the reactor having an angle of 5.7° with the vertical wall. A two-dimensional computational fluid dynamics (CFD) simulation of three phase gas-liquid-solid flow in MUASB reactor was performed and compared with conventional UASB reactor. The CFD study indicated better mixing in terms of vorticity magnitude in MUASB reactor as compared to conventional UASB, which was reflected in the reactor performance. The performance of MUASB was compared with conventional UASB reactor for the onsite treatment of domestic sewage as LSW. Around 16% higher total chemical oxygen demand removal efficiency was observed in MUASB reactor as compared to conventional UASB during this study. Therefore, this MUASB model demonstrates a qualitative relationship between mixing and performance during the treatment of LSW. From the study, it seems that MUASB holds promise for field applications.

The operation of two EGSB reactors under the application of different loads of oxytetracycline and florfenicol

2012 ◽  
Vol 66 (12) ◽  
pp. 2578-2585 ◽  
Author(s):  
Yudy Andrea Londoño ◽  
Diana Catalina Rodríguez ◽  
Gustavo Peñuela
Keyword(s):  
Bacterial Population ◽  
Oxygen Demand ◽  
Dairy Farm ◽  
Granular Sludge ◽  
Inhibitory Effect ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Pellet Size ◽  
Anaerobic Sludge Blanket

This study evaluated the effect of the antibiotics oxytetracycline (OTC) and florfenicol (FLO) on the operation of two EGSB (expanded granular sludge bed) reactors. The experiment was conducted for 210 d in reactor R1 and 245 d in reactor R2. The reactors were inoculated with granular sludge from a upflow anaerobic sludge blanket (UASB) reactor on a local dairy farm. The sludge had an average pellet size of 2.35 mm, good sedimentability and a high percentage of organic material. The antibiotic tolerance and the inhibitory action on the bacterial population were different for each antibiotic studied. The results showed a more severe inhibitory effect on microorganisms that were in contact with increases in loads of FLO than those that were in contact with increasing loads of OTC, a condition reflected in the chemical oxygen demand (COD) removal efficiency.

scholarly journals Up-flow vs downflow anaerobic digester reactor configurations for treatment of fats-oil-grease laden poultry slaughterhouse wastewater: a review

2020 ◽  
Vol 15 (2) ◽  
pp. 248-260
Author(s):  
M. Basitere ◽  
M. Njoya ◽  
S. K. O. Ntwampe ◽  
M. S. Sheldon
Keyword(s):  
Anaerobic Digestion ◽  
Flow Reactor ◽  
Oxygen Demand ◽  
Granular Sludge ◽  
Organic Load ◽  
Anaerobic Sludge ◽  
Reactor Performance ◽  
High Concentration ◽  
Slaughterhouse Wastewater ◽  
Reactor Configuration

Abstract The process of anaerobic digestion has been and still remains the most efficient, cost effective and environmentally benign treatment process for poultry slaughterhouse wastewater (PSW). The PSW is characterized by a high concentration in chemical oxygen demand (COD), biological oxygen demand (BOD) and fats, oil including grease (FOG). The reactor configuration influences the performance of such anaerobic systems in the treatment of such oily wastewater. The up-flow reactor configuration provided by the Up-flow Anaerobic Sludge Blanket (UASB) Bioreactor or the Expanded Granular Sludge Bioreactor (EGSB) are highly dependent on up-flow velocity, which often contributes to periodical sludge washout during the treatment of PSW with high FOG and total suspended solids (TSS) concentration, resulting in poor reactor performance in comparison with downflow reactors such as the Static Granular Bed Reactor (SGBR), which achieves high organic load removal efficiency particularly when treating PSW due to its ability to retain sludge granules and solidified residue within the reactor. The washout of the sludge results from sludge flotation, which is induced by the inhibition of the anaerobic granular biomass by the accumulation of long chain fatty acids (LCFAs) from poor hydrolysis. The aim of this review is to highlight reactor configuration deficiencies, and to elaborate on the advantages of using anaerobic digestion for the treatment of FOG-laden PSW, with a focus on reactor performance. Additionally, a comparative analysis between up-flow reactors, such as the UASB including EGSB, and downflow reactors, such as SGBR, was performed.

Kinetic evaluation and process performance of an upflow anaerobic filter reactor degrading terephthalic acid

2014 ◽  
Vol 69 (12) ◽  
pp. 2562-2569 ◽  
Author(s):  
Orkun I. Davutluoglu ◽  
Galip Seckin
Keyword(s):  
Terephthalic Acid ◽  
Anaerobic Degradation ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Reactor Performance ◽  
Kinetic Evaluation ◽  
Anaerobic Filter

The anaerobic degradation of terephthalic acid (TA) as the sole organic carbon source was studied in an upflow anaerobic filter (UAF) reactor. The reactor was seeded with biomass obtained from a full-scale upflow anaerobic sludge bed (UASB) reactor and was used to treat wastewater from a petrochemical facility producing dimethyl terephthalate. The UAF reactor was operated for 252 d with a constant hydraulic retention time of 24 h, and the organic loading rate (OLR) was gradually increased from 1 to 10 g-chemical oxygen demand (COD)/L d. After a lag period of approximately 40 d, the COD removal efficiency increased exponentially and high removal rate values (≈90%) were obtained, except for at highest OLR (10 g-COD/L d). The high removal rates and the robustness of the reactor performance could be attributed to the formation of biofilm as well as granular sludge. The methane production rates (0.22 to 2.15 L/d) correlated well with the removed OLRs (0.3 to 6.8 g-COD/L d) during the various phases of treatment, indicating that the main mechanism of TA degradation occurs via methanogenic reactions. The average methane content of the produced biogas was 70.3%. The modified Stover–Kincannon model was found to be applicable for the anaerobic degradation of TA in UAFs (Umax = 64.5, KB = 69.1 g-COD/L d and Ymax = 0.27 L-CH4/g-CODremoved). These results suggest that UAF reactors are among the most effective reactor configurations for the anaerobic degradation of TA.

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