Feasibility of expanded granular sludge bed reactors for the anaerobic treatment of low-strength soluble wastewaters

1994 ◽  
Vol 44 (4) ◽  
pp. 469-479 ◽  
Author(s):  
Mario T. Kato ◽  
Jim A. Field ◽  
Paul Versteeg ◽  
Gatze Lettinga
Keyword(s):  
Granular Sludge ◽  
Anaerobic Treatment ◽  
Low Strength

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.

scholarly journals Psychrophilic anaerobic treatment of low strength wastewaters

1999 ◽  
Vol 39 (5) ◽  
pp. 203-210 ◽  
Author(s):  
Salih Rebac ◽  
Jules B. van Lier ◽  
Piet Lens ◽  
Alfons J. M. Stams ◽  
Freddy Dekkers ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Oxygen Demand ◽  
Granular Sludge ◽  
Anaerobic Treatment ◽  
Cod Removal ◽  
High Rate ◽  
Organic Loading Rate ◽  
Substrate Conversion ◽  
Low Strength

Psychrophilic (2 to 20°C) anaerobic treatment of low strength synthetic and malting wastewater was investigated using a single and two module expanded granular sludge bed (EGSB) reactor system. The chemical oxygen demand (COD) removal efficiencies found in the experiments exceeded 90 % in the single module reactor at an organic loading rate up to 12 g COD dm−3 day−1 and a HRT of 1.6 h at 10-12°C ambient temperature using influent concentrations ranging from 500 to 800 mg COD dm−3. When a two module EGSB system was used at the temperature range 10-15°C, soluble COD removal and volatile fatty acids removal of 67-78% and 90-96% were achieved, respectively, and an OLR between 2.8-12.3 kg COD m−3 day−1 and a HRT of 3.5 h. The second module serves mainly as a scavenger of non-degraded volatile fatty acids (VFA) from the first module. The optimal temperatures for substrate conversion of reactor sludge, after it has been exposed to long term psychrophilic conditions, were similar to those of the original mesophilic inoculum. The specific activities of the sludge in the reactor increased in time by a factor 3, indicating enrichment of methanogens and acetogens even at low temperatures. By adapting the process design to the expected prevailing conditions inside the reactor, the loading potentials and overall stability of the anaerobic high-rate process may be distinctly improved under psychrophilic conditions. The results obtained clearly reveal the big potentials of anaerobic wastewater treatment under low ambient (10-12°C) temperature conditions for low strength wastewaters, very likely including domestic sewage.

Treatment of Sugar Containing-Low Strength Wastewater at 20°C by Anaerobic Granular Sludge Bed Reactor

2010 ◽  
Vol 5 (3) ◽  
Author(s):  
W. Yoochatchaval ◽  
K. Kubota ◽  
T. Kawai ◽  
T. Yamaguchi ◽  
K. Syutsubo
Keyword(s):  
Stable Process ◽  
Growth Yield ◽  
High Growth ◽  
Granular Sludge ◽  
Post Treatment ◽  
Cod Removal ◽  
Synthetic Wastewater ◽  
Anaerobic Granular Sludge ◽  
Treatment Technology ◽  
Low Strength

To investigate the feasibility of anaerobic wastewater treatment technology for low strength sugar refinery wastewater (0.4 - 0.5 g COD/L), an 8.8 L volume of anaerobic granular sludge bed reactor was operated at 20°C for 400 days. The operation mode was combination of one pass flow (UASB, 50 min) and effluent-recirculation (EGSB, 10 min) mode. The aerobic down-flow hanging sponge (DHS) reactor was installed as a post-treatment. During the started-up period, reactors were fed with synthetic wastewater at overall HRT of 3 hours (anaerobic 2 hours, aerobic 1 hour). After day 85, feed was changed to real wastewater together with supplement of nutrients, trace elements and NaHCO3. The sufficient COD removal efficiency (85% SD±6.2) and stable process performance were elicited from the granular sludge bed reactor.Also, post-treatment (DHS reactor) offered good quality of effluent (45 mg COD/L, 7 mg BOD/L) and it achieved the discharge standard. Increasing of sulfate concentration of wastewater caused higher contribution of sulfate reducing bacteria for COD removal. The sludge concentration and settleability were well maintained thoroughly. However, floatation of large size granule was observed in the later part of experiment. This phenomenon may attribute to the high growth yield of retained sludge at 20°C.

Anaerobic treatment of thermal sludge conditioning liquor with granular sludge

1993 ◽  
Vol 65 (1) ◽  
pp. 6-14 ◽  
Author(s):  
Takashi Kimata ◽  
Takehiko Kawai ◽  
Minoru Tada ◽  
Kazuhiro Tanaka ◽  
Kazuhiro Shinabe ◽  
...  
Keyword(s):  
Granular Sludge ◽  
Anaerobic Treatment ◽  
Sludge Conditioning

Low strength wastewater treatment using emerging anaerobic treatment processes

2019 ◽  
Author(s):  
◽  
Liyuan Hou
Keyword(s):  
Electron Transfer ◽  
Municipal Wastewater ◽  
Anaerobic Treatment ◽  
Methane Yield ◽  
Extracellular Electron Transfer ◽  
Anaerobic Sludge ◽  
Treatment Processes ◽  
Anodic Chamber ◽  
Specific Affinity ◽  
Low Strength

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Anaerobic treatment is a promising and energy saving process for low-strength wastewater treatment. Roles of half saturation constant (Ks) and maximum specific growth rate (umax) in anaerobic treatment systems, however, are often overlooked. This study proposed to apply specific affinity (defined as umax/ Ks) as the key performance indicator of anaerobic processes treating low-strength wastewater. Furthermore, this study provided a new insight into the relationship between specific affinity and population of methanogens in an anaerobic membrane bioreactor (AnMBR) treating low-strength wastewater. High abundance of Methanosaeta (85.8% of total archaea) was linked to the high specific affinity (1.6 x 10[superscript -3] L/mg COD/d) in acclimated anaerobic sludge, resulting in low effluent chemical oxygen demand (COD) concentrations. Short hydraulic retention times (HRTs) are preferred for AnMBRs to treat low strength wastewater at a high volumetric organic loading rate with lower capital costs. However, short HRTs become a potential bottleneck in anaerobic treatment processes because of possible interspecies mass transfer limitations and membrane fouling in AnMBRs. Till now, little is known about how short HRTs would affect effluent water quality that is linked to the specific affinity of anaerobic sludge and their microbial community structures in AnMBRs. In current study, the overall performance, specific affinity of anaerobic sludge, and dynamics of community structures of an AnMBR treating synthetic municipal wastewater at decreasing HRTs (i.e., 24 h, 12 h, and 6 h) was investigated. A decrease in HRT resulted in sludge with high specific affinity. Correspondingly, Methanosaeta became the dominant methanogens in the AnMBR. Both the effluent water quality and methane yield were enhanced. Municipal wastewater contains complex organic constituents while multi-step biochemical processes are involved in anaerobic treatment processes. Two identical AnMBR were operated under decreasing HRTs (24 h, 12 h, and 6 h, respectively) treating low strength wastewater containing different substrate (acetate or glucose, respectively). As a result, microbial communities in the two AnMBRs diverged. The effluent quality and methane yield were enhanced in the acetate fed AnMBR while methane yield decreased in the glucose fed AnMBR as HRT decreased. Correspondingly, the abundance of Methanosaetaceae in the acetate fed AnMBR increased, but it decreased in the AnMBR fed with glucose. Interestingly, hydrogenotrophic methanogens have a higher proportion in the glucose fed AnMBR than in the acetate fed AnMBR. Overall, a minimum HRT higher than 6 h may be required to treat wastewater containing complex organic matter to ensure a successful operation. To treat the sulfate-containing low-strength wastewater, we proposed a newly designed anaerobic microbial fuel cell (MFC) system that could be used to produce electricity and remove sulfate simultaneously. A maximum voltage output of 129 mV was observed under the following feed conditions: that the ratio of lactate: sulfate was 60:20 and 0:10 in the anodic chamber and cathodic chamber, respectively. The decrease in the organic substrate/sulfate ratio in anodic chamber had a great effect on the electricity production, which could be resulted from an increasing DvH attaching on the electrode at a higher sulfate concertation contributes more electrons transfer. However, there was no significant electricity production at the ratio of two presumably because sulfate in the anodic chamber obtained all electrons produced by lactate without transferring to cathodic chamber since the stoichiometric ratio of lactate and sulfate is two. To our knowledge, this was the first time to show the electricity generation by using Desulfovibrio vulgaris Hildenborough (DvH) in such a MFC configuration. Electron microscopic analysis indicated that nanoscale filaments could enhance the extracellular electron transfer of DvH. DvH biofilm, which is necessary for extracellular electron transfer, suggesting that DvH has multiple direct electron transfer mechanisms. This could further benefit the application of DvH to enhance the power output and treat the real sulfate-containing low-strength wastewater.

Granular sludge bed anaerobic treatment systems for resource recovery

2020 ◽  
pp. 107-124
Author(s):  
Hamidreza Mojab ◽  
Eldon Raj ◽  
Santiago Pacheco-Ruiz
Keyword(s):  
Granular Sludge ◽  
Resource Recovery ◽  
Anaerobic Treatment
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