Performance characterization of anaerobic sequencing batch reactor process for digestion of night soil

2001 ◽  
Vol 43 (1) ◽  
pp. 27-34 ◽  
Author(s):  
J. G. Lee ◽  
J. M. Hur ◽  
D. Chang ◽  
T. H. Chung

Laboratory experiments were conducted to investigate the performance of an anaerobic sequencing batch reactor (ASBR) process for night soil treatment. Performances of the reactors were evaluated at an equivalent hydraulic retention time (HRT) of 10 days with an equivalent loading rate of 2.6 kgVS/m3/d (3.1 kgCOD/m3/day) at 35°C. Digestion of a night soil was possible using the ASBR at an HRT of 10 days in spite of high concentration of ammonia nitrogen and settleable solids. Solids were accumulated rapidly in the ASBRs, and their concentrations were 2.3∼2.4 times higher than that in a completely mixed control reactor. Remarkable increases in gas production were observed in the ASBRs compared with the control reactor. Average increases in equivalent daily gas production from the ASBRs were 205∼220% compared with that from the control run. The ASBR with reaction period/thickening period ratio (R/T ratio) of 1 showed a little higher gas production and organic removal efficiency than that with R/T ratio of 3. Volatile solids removals based on supernatant of the ASBRs were 12∼14% higher than that of the control reactor. Thus, the ASBR was a stable and effective process for the treatment of night soil having high concentration of settleable organics and ammonia nitrogen.

1994 ◽  
Vol 30 (12) ◽  
pp. 161-170 ◽  
Author(s):  
Duk Chang ◽  
Joon Moo Hur ◽  
Tai Hak Chung

Laboratory experiments were conducted to investigate the performance of the anaerobic sequencing batch reactor (ASBR) for digestion of a municipal sludge. The reactors were operated at an HRT of 10 days with an equivalent loading rate of 0.8-1.5 g VS 1−1 d−1 at 35°C. Solids were accumulated rapidly in the ASBR during start-up period. Flotation thickening occurred in the ASBRs, and its efficiency was comparable to that of additional thickening of the completely mixed control reactor. Solids concentrations in the ASBRs were 2.6 times higher than that in the control. The dehydrogenase activity had a strong correlation with the solids concentration. The ASBRs with 3- and 4-day cycle showed almost identical high digestion performances without adverse effect on digestion stability. The organics removals based on subnatant of the ASBRs were consistently above 90%. Remarkable increase in equivalent gas production of 52% was observed at the ASBRs compared with the control though the control and ASBRs showed similar effluent quality. Thus, digestion of a municipal sludge was possible using the ASBR in spite of high concentration of settleable solids in the sludge.


2013 ◽  
Vol 67 (5) ◽  
pp. 1068-1074 ◽  
Author(s):  
Elena Cristina Rada ◽  
Marco Ragazzi ◽  
Vincenzo Torretta

This work describes batch anaerobic digestion tests carried out on stillages, the residue of the distillation process on fruit, in order to contribute to the setting of design parameters for a planned plant. The experimental apparatus was characterized by three reactors, each with a useful volume of 5 L. The different phases of the work carried out were: determining the basic components of the chemical oxygen demand (COD) of the stillages; determining the specific production of biogas; and estimating the rapidly biodegradable COD contained in the stillages. In particular, the main goal of the anaerobic digestion tests on stillages was to measure the parameters of specific gas production (SGP) and gas production rate (GPR) in reactors in which stillages were being digested using ASBR (anaerobic sequencing batch reactor) technology. Runs were developed with increasing concentrations of the feed. The optimal loads for obtaining the maximum SGP and GPR values were 8–9 gCOD L−1 and 0.9 gCOD g−1 volatile solids.


2004 ◽  
Vol 49 (5-6) ◽  
pp. 47-55 ◽  
Author(s):  
C.S. Gee ◽  
J.S. Kim

Biological ammonia-nitrogen removal utilizes two distinct processes, nitrification and denitrification. In nitrification, ammonia oxidizes to nitrite then to nitrate. In this study, elimination of nitrite oxidation to nitrate step was attempted in order to directly remove nitrite to nitrogen gas by denitrification. For this study the supernatant from an anaerobic digester was used as an ammonia source and a sequencing batch reactor (SBR) was employed. Emphasis was given to the evaluation of the operational factors affecting nitrite accumulation and the elucidation of kinetics for biological nitrification and denitrification. Accumulation of nitrite in the nitrification process was achieved by suppressing the growth of Nitrobacter, a nitrite oxidizer, by loading high concentration ammonia supernatant immediately after all ammonia in the previous loading was oxidized to nitrite. Nitrite oxidation was taking place as the solid retention time (SRT) was increased from 2.5 days to 3.0 days in a continuously aerated SBR mode with daily feeding. However, nitrite accumulation was achieved even at longer SRT of 5 days when the aeration and non-aeration periods were appropriately combined and the non-aeration period can be used for denitrification of the accumulated nitrite with a carbon source supplied.


2001 ◽  
Vol 43 (3) ◽  
pp. 147-150 ◽  
Author(s):  
K. Y. Park ◽  
J. W. Lee ◽  
Y. Inamori ◽  
M. Mizuochi ◽  
K. H. Ahn

Nitrous oxide (N2O) gas is emitted as an intermediate in the biological nitrogen removal process. A track study was performed to investigate the characteristics of N2O emission depending on the cyclic mode of a sequencing batch reactor (SBR). A major emission of N2O took place at the aerobic phase, while N2O emission at the anoxic phase was insignificant. Especially, the highest N2O emission rate was observed at the initial stage of aerobic phase under the limited dissolved oxygen (DO) condition. Under such a condition, nitrite (NO2-) was transiently accumulated along with significant N2O emission due to incomplete nitrification. In addition, N2O production at the aerobic phase was strongly related with incomplete denitrification by nitrifiers. N2O emission could be reduced by change in fill modes in the SBR. A significant conversion to N2O took place in the SBR with the anoxic fill mode, while only small amount of N2O was conversed in the SBR with the aerobic fill mode. Relatively high concentration of ammonia nitrogen (NH4+) accelerated N2O production at the aerobic phase in the SBR with the anoxic fill compared to the aerobic fill. For control of N2O emission in the SBR, the aerobic fill mode could be an effective method even if denitrification efficiency may be reduced at the anoxic phase.


2002 ◽  
Vol 45 (10) ◽  
pp. 219-224 ◽  
Author(s):  
C. Ruíz ◽  
M. Torrijos ◽  
P. Sousbie ◽  
J. Lebrato Martínez ◽  
R. Moletta ◽  
...  

Treatment of winery wastewater was investigated using an anaerobic sequencing batch reactor (ASBR). Biogas production rate was monitored and permitted the automation of the bioreactor by a simple control system. The reactor was operated at an organic loading rate (ORL) around 8.6 gCOD/L.d with soluble chemical oxygen demand (COD) removal efficiency greater than 98%, hydraulic retention time (HRT) of 2.2 d and a specific organic loading rate (SOLR) of 0.96 gCOD/gVSS.d. The kinetics of COD and VFA removal were investigated for winery wastewater and for simple compounds such as ethanol, which is a major component of winery effluent, and acetate, which is the main volatile fatty acid (VFA) produced. The comparison of the profiles obtained with the 3 substrates shows that, overall, the acidification of the organic matter and the methanisation of the VFA follow zero order reactions, in the operating conditions of our study. The effect on the gas production rate resulted in two level periods separated by a sharp break when the acidification stage was finished and only the breaking down of the VFA continued.


1998 ◽  
Vol 37 (4-5) ◽  
pp. 95-98 ◽  
Author(s):  
Nancy G. Love ◽  
Mary E. Rust ◽  
Kathy C. Terlesky

An anaerobic enrichment culture was developed from an anoxic/anaerobic/aerobic activated sludge sequencing batch reactor using methyl ethyl ketoxime (MEKO), a potent nitrification inhibitor, as the sole carbon and energy source in the absence of molecular oxygen and nitrate. The enrichment culture was gradually fed decreasing amounts of biogenic organic compounds and increasing concentrations of MEKO over 23 days until the cultures metabolized the oxime as the sole carbon source; the cultures were maintained for an additional 41 days on MEKO alone. Turbidity stabilized at approximately 100 mg/l total suspended solids. Growth on selective media plates confirmed that the microorganisms were utilizing the MEKO as the sole carbon and energy source. The time frame required for growth indicated that the kinetics for MEKO degradation are slow. A batch test indicated that dissolved organic carbon decreased at a rate comparable to MEKO consumption, while sulfate was not consumed. The nature of the electron acceptor in anaerobic MEKO metabolism is unclear, but it is hypothesized that the MEKO is hydrolyzed intracellularly to form methyl ethyl ketone and hydroxylamine which serve as electron donor and electron acceptor, respectively.


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