The anaerobic treatment of low strength wastewaters in UASB and EGSB reactors

1997 ◽  
Vol 36 (6-7) ◽  
pp. 375-382 ◽  
Author(s):  
Mario T. Kato ◽  
Jim A. Field ◽  
Gatze Lettinga
Keyword(s):  
Detrimental Effect ◽  
Granular Sludge ◽  
Anaerobic Treatment ◽  
Organic Loading ◽  
Methanogenic Activity ◽  
Loading Rates ◽  
Treatment Performance ◽  
The Media ◽  
Low Strength ◽  
Uasb Reactors

The application of the UASB and EGSB reactors for the treatment of low strength wastewaters was investigated. The effect of dissolved oxygen on the methanogenic activity of granular sludges, the low substrate levels inside reactors and lower temperatures on the treatment performance were evaluated. The results showed that methanogens located in granular sludge have a high tolerance to oxygen. The concentration to cause 50% inhibition to methanogenic activity was between 7% and 41% oxygen in the head space of flasks, corresponding to 0.05 mg/l and 6 mg/l of DO prevailing in the media, respectively. The feasibility of UASB and EGSB reactors at 30°C was demonstrated. In UASB reactors, COD removal efficiencies exceeded 95% at organic loading rates up to 6.8 g COD/l.d and influent COD concentrations ranging from 422 to 722 mg/l, during the treatment of ethanol substrate. In EGSB reactors, efficiencies were above 80% at OLRs up to 12 g COD/l.d with COD as low as 100 to 200 mg/l. The studies confirmed that in practice DO does not constitute any detrimental effect on the reactor treatment performance. Lowering the temperature down to 15°C in EGSB reactors also showed that the potentials of anaerobic technology can be further explored in the treatment of dilute wastewaters.

Anaerobic treatment for C and S removal in “zero-discharge” paper mills: effects of process design on S removal efficiencies

2001 ◽  
Vol 44 (4) ◽  
pp. 189-195 ◽  
Author(s):  
J. B. van Lier ◽  
P. N.L. Lens ◽  
L. W. Hulshoff Pol
Keyword(s):  
Loading Rate ◽  
Anaerobic Treatment ◽  
Process Water ◽  
Uasb Reactor ◽  
Organic Loading ◽  
Production Rates ◽  
Paper Mills ◽  
Loading Rates ◽  
Zero Discharge ◽  
Uasb Reactors

Stringent environmental laws in Europe and Northern America lead to the development towards closure of the process water streams in pulp and paper mills. Application of a "zero-discharge" process is already a feasible option for the board and packaging paper industry, provided in-line treatment is applied. Concomitant energy conservation inside the mill results in process water temperatures of 50-60°C. Thermophilic anaerobic treatment complemented with appropriate post-treatment is considered as the most cost-effective solution to meet re-use criteria of the process water and to keep its temperature. In the proposed closed-cycle, the anaerobic treatment step removes the largest fraction of the biodegradable COD and eliminates “S” as H2S from the process stream, without the use of additional chemicals. The anaerobic step is regarded as the only possible location to bleed "S" from the process water cycle. In laboratory experiments, the effect of upward liquid velocity (Vupw) and the specific gas loading rate (Vgas) on the S removal capacity of thermophilic anaerobic bio-reactors was investigated. Acidifying, sulphate reducing sludge bed reactors were fed with partly acidified synthetic paper mill wastewater and were operated at 55°C and pH 6. The reactors were operated at organic loading rates up to 50 g COD.l−1.day−1 at COD/SO42- ratios of 10. The effect of Vupw was researched by comparing the performance of a UASB reactor operated at 1.0 m.h−1 and an EGSB reactor, operated at 6.8 m.h−1. The Vupw had a strong effect on the fermentation patterns. In the UASB reactor, acidification yielded H2, acetate and propionate, leading to an accumulation of reducing equivalents. These were partly disposed of by the production of n-butyrate and n-valerate from propionate. In the EGSB reactor net acetate consumption was observed as well as high volumetric gas (CO2 and CH4) production rates. The higher gas production rates in the EGSB reactor resulted in higher S-stripping efficiencies. The effect of Vgas was further researched by comparing 2 UASB reactors which were sparged with N2 gas at a specific gas loading rate of 30 m3.m−2.day−1. In contrast to the regular UASB reactors, the gas-supplied UASB showed a more stable performance when the organic loading rates were increased. Also, the H2S stripping efficiency was 3-4 times higher in the gas-supplied UASB, reaching values of 67%. Higher values were not obtained owing to the relatively poor sulphate reduction efficiencies.

Biological degradation of a mixture of municipal wastewater and organic garbage leachate in expanded bed anaerobic reactors and a zeolite filter

2009 ◽  
Vol 59 (4) ◽  
pp. 723-728 ◽  
Author(s):  
P. Castilla ◽  
L. Aguilar ◽  
M. Escamilla ◽  
B. Silva ◽  
Z. Milán ◽  
...  
Keyword(s):  
Suspended Solids ◽  
Municipal Wastewater ◽  
Total Suspended Solids ◽  
Granular Sludge ◽  
Biological Degradation ◽  
Organic Loading ◽  
Methanogenic Activity ◽  
Loading Rates ◽  
Anaerobic Reactors ◽  
Removal Efficiencies

Municipal wastewater was amended with organic garbage leachates at a concentration around 700 mgCODsoluble/L and fed to three different anaerobic systems to compare their performance: a down flow fluidized bed (DFFB), an expanded granular sludge bed (EGSB) and a zeolite-packed anaerobic filter reactor (ZPF). The DFFB and EGSB reactors were operated at HRT of 6 and 4 h and the ZPF reactor at 12 and 36 h. Organic loads rate for the DFFB reactor were 2.3±0.9 and 4.8±1.8 gCOD/L·d, with removal efficiencies around 40% and a methane productivity of 0.2±0.03 L/Lreactor·d. For the EGSB reactor, organic loads tested were 2.1±0.9 and 4.3±1.3 gCOD/L·d, removal efficiencies attained were of 77.6±12.7% and 84.4±4.9%, respectively at both conditions and total suspended solids were removed in 54.6±19.3%, while methane productivity at 4 h HRT was of 1.29±0.4 L/Lreactor·d. The ZPF reactor was operated at lower organic loading rates, 1.4±0.27 and 0.42±0.13 gCOD/L·d and attained removal efficiencies of 48±18% and 83±8%, respectively, reaching a methane productivity of 0.21±0.09 and 0.12±0.04 L/Lreactor·d, 83±8.0% of total suspended solids were retained in the reactor and as HRT was increased ammonium concentrations increased in 39%. Specific methanogenic activity in all systems was around 0.2 gCOD-CH4/gVSS d.

Anaerobic Treatment of Slaughterhouse Wastewater in an Expanded Granular Sludge Bed (EGSB) Reactor

1999 ◽  
Vol 40 (8) ◽  
pp. 99-106 ◽  
Author(s):  
L. A. Núñez ◽  
B. Martínez
Keyword(s):  
Suspended Solids ◽  
Hydraulic Retention Time ◽  
Granular Sludge ◽  
Anaerobic Treatment ◽  
Slaughterhouse Wastewater ◽  
Methanogenic Activity ◽  
Loading Rates ◽  
Feasible Option ◽  
One Year ◽  
Sludge Activity

The performance of an Expanded Granular Sludge Bed (EGSB) reactor for treating slaughterhouse wastewater under mesophilic conditions (35°C), was investigated. The reactor was inoculated with granular sludge from an anaerobic reactor of a brewery factory. The averaged COD removal percentages were 67% for total organic loading rates (BV.TCOD) up to 15 kg COD m−3 d−1 and a hydraulic retention time (HRT) of 5 h. Total suspended solids (TSS) were 90% removed for total solids loads of 6 kg TSS m−3 d−1. Fats were 85% removed and no accumulation of fats on the sludge was observed. The specific methanogenic activity of the sludge, after 140 days, was about three times higher than the sludge inoculated into the reactor. The sludge activity did not significantly change after one year of work. These findings indicate that the anaerobic treatment of slaughterhouse wastewater in an EGSB system appears to be a feasible option.

Improvement of the properties of granular sludge in UASB reactors by flow pulsation

2003 ◽  
Vol 48 (6) ◽  
pp. 51-56 ◽  
Author(s):  
A. Franco ◽  
E. Roca ◽  
J.M. Lema
Keyword(s):  
Specific Activity ◽  
Granular Sludge ◽  
Organic Loading ◽  
Flow Pulsation ◽  
High Increase ◽  
Loading Rates ◽  
Removal Capacity ◽  
Through Flow ◽  
Pulsing Flow ◽  
Uasb Reactors

The objective of this work is to improve the characteristics of granular sludge by modification of the hydraulics of the bed through flow pulsation. Three UASB reactors, two operated with pulsing flow (P1 and P2) and a third without pulsation (NP), were started-up. Both recycling and feeding flow were pulsed in the reactor P1, while in reactor P2, only the feeding was pulsed. A high increase in the removal capacity and stability were achieved by applying pulsation in reactors P1 and P2 when compared to the non-pulsed one. Besides, pulsation promotes the formation of particles of smaller size and higher porosity, thus increasing the specific surface of the bed and consequently, the specific activity. In fact, while reactors P1 and P2 had a 95% COD removal when working at high organic loading rates (12 kg COD/m3·d), reactor NP only reached 6 kg COD/m3·d with 85% of removal capacity.

The effect of extreme temperatures (70–80°C) on the effluent quality and sludge characteristics of UASB reactors

1997 ◽  
Vol 36 (6-7) ◽  
pp. 325-332 ◽  
Author(s):  
Raghida Lepistö ◽  
Jukka Rintala
Keyword(s):  
Volatile Fatty Acids ◽  
Granular Sludge ◽  
Anaerobic Sludge ◽  
Methanogenic Activity ◽  
Sludge Characteristics ◽  
Effluent Quality ◽  
Start Up ◽  
Thermomechanical Pulping ◽  
Increasing Temperature ◽  
Uasb Reactors

The study focused on the effluent quality and sludge characteristics during the start-up and operation of extreme thermophilic (70 to 80°C) upflow anaerobic sludge bed (UASB) reactors, inoculated with mesophilic and thermophilic granular sludge and fed with acetate, volatile fatty acids (VFA), and thermomechanical pulping (TMP) whitewater. Low effluent quality and long start-up periods were observed during the start-up of the 70 to 76°C, VFA-fed UASB reactors inoculated with mesophilic granulae, while better effluent quality and considerably shorter start-up periods were observed when thermophilic (55/70°C) inocula were used. With VFA feed, a significant amount of acetate was removed at 70°C and even at 80°C, while propionate removal was negligible. With TMP whitewater feed, low VFA effluent concentration was obtained at 70°C. The volatile solids (VS) and the VS/total solids (TS) content of the sludge decreased significantly during the first 2–3 months of operation when mesophilic inocula were used. The initial specific methanogenic activity (ISMA) of the extreme thermophilic sludge decreased with increasing temperature and was slightly higher on glucose than on acetate. At 70 to 80°C, various rod-like bacteria were dispersed through the granulae in either individual or in low density micro colonies surrounded with a varying degree of precipitates.

scholarly journals Anaerobic treatment of glycerol for methane and hydrogen production

2013 ◽  
Vol 14 (2) ◽  
pp. 149-156 ◽  
Keyword(s):  
Hydrogen Production ◽  
Ph Value ◽  
Anaerobic Treatment ◽  
Microbial Culture ◽  
Batch Reactors ◽  
Continuous Stirred Tank Reactor ◽  
Organic Loading ◽  
Loading Rates ◽  
Fermentative Hydrogen Production ◽  
Initial Ph

This work focused on glycerol exploitation for biogas and hydrogen production. Anaerobic digestion of pure glycerol was studied in a continuous stirred tank reactor (CSTR), operated under mesophilic conditions (35oC) at various organic loading rates. The overall operation of the reactor showed that it could not withstand organic loading rates above 0.25 g COD L-1 d-1, where the maximum biogas (0.42 ± 0.05 L (g COD)-1) and methane (0.30 ± 0.04 L (g COD)-1) production were achieved. Fermentative hydrogen production was carried out in batch reactors under mesophilic conditions (35oC), using heat-pretreated anaerobic microbial culture as inoculum. The effects of initial concentration of glycerol and initial pH value on hydrogen production were studied. The highest yield obtained was 22.14 ± 0.46 mL H2 (g COD added)-1 for an initial pH of 6.5 and an initial glycerol concentration of 8.3 g COD L-1. The main metabolic product was 1.3 propanediol (PDO), while butyric and acetic acids as well as ethanol, at lower concentrations, were also determined.

Formation and properties of pure-oxygen aerobic granular sludge (POAGS) at high organic loading rates (HOLR)

2020 ◽  
Vol 179 ◽  
pp. 45-53
Author(s):  
Fanghui Pan ◽  
Youbao Wang ◽  
Yongbin Jiang ◽  
Xinxi Zhang ◽  
Kunxiao Huang ◽  
...  
Keyword(s):  
Granular Sludge ◽  
Pure Oxygen ◽  
Aerobic Granular Sludge ◽  
Organic Loading ◽  
Loading Rates

Start-Up Strategy to Achieve Excellent Efficiency of Degradation Acetate,Ethanol and Propionate in UASB

2011 ◽  
Vol 71-78 ◽  
pp. 2103-2106
Author(s):  
Ming Yue Zheng ◽  
Ming Xia Zheng ◽  
Kai Jun Wang ◽  
Hai Yan
Keyword(s):  
Loading Rate ◽  
Anaerobic Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Organic Loading ◽  
Metabolic Intermediate ◽  
Loading Rates ◽  
Start Up ◽  
Anaerobic Sludge Blanket

The performance of upflow anaerobic sludge blanket (UASB) fed with three metabolic intermediate (acetate, ethanol, and propionate) respectively was studied. The degradation of metabolic intermediate were investigated to discuss the reason for propionate inhibition problem in anaerobic treatment. The hydraulic retention time (HRT) in the reactors started with 8.0h.The yield rate of biogas were 237ml/gCOD, 242ml/gCOD, 218ml/gCOD for acetate, ethanol and propionate, respectively when finishing start-up under OLR of 5.0 kgCOD/(m3·d) (HRT=9.6h).The HRT remained constant 9.6h,and the substrate concentration was gradually increased from 1,000 to 16,000mg/L as COD,and the organic loading rates(OLR) was from 3.0 to 40.0 kgCOD/(m3·d).The maximum propionate concentration was 41.6 gHPr-COD/L at the organic loading rate of 43.9 kgCOD/(m3·d) (HRT, 9.6h) as well as acetate and ethanol.

Advanced anaerobic wastewater treatment in the near future

1997 ◽  
Vol 35 (10) ◽  
pp. 5-12 ◽  
Author(s):  
G. Lettinga ◽  
J. Field ◽  
J. van Lier ◽  
G. Zeeman ◽  
L. W. Hulshoff Pol
Keyword(s):  
Granular Sludge ◽  
Anaerobic Treatment ◽  
Loading Rates ◽  
Reactor Technology ◽  
Inhibitory Compounds ◽  
Complete Treatment ◽  
Low Costs ◽  
Biological Methods ◽  
Multi Phase ◽  
Near Future

New insights into the anaerobic degradation of very different categories of compounds, and into process and reactor technology will lead to very promising new generations of anaerobic treatment system, such as ‘Expanded Granular Sludge Bed’ (EGSB) and ‘Staged Multi-Phase Anaerobic’ (MPSA) reactor systems. These concepts will provide a higher efficiency at higher loading rates, are applicable for extreme environmental conditions (e.g. low and high temperatures) and to inhibitory compounds. Moreover, by integrating the anaerobic process with other biological methods (sulphate reduction, micro-aerophilic organisms) and with physical-chemical methods, a complete treatment of the wastewater can be accomplished at very low costs, while at the same time valuable components can be recovered for reuse.

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