• Journal of Korean Society of Environmental Engineers
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• v.31 no.10
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• pp.919-926
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• 2009

Enrichment of anaerobic ammonium oxidation (ANAMMOX) bacteria is the essential step for operating full-scale ANAMMOX bioreactor because adding a significant amount of seeding sludge is required to stabilize the ANAMMOX reactor. In this study, the enrichment of ANAMMOX bacteria from an activated sludge using sequencing batch reactor was conducted and verified by analyzing changes in the microbial community structure. ANAMMOX bacteria were successfully enriched for 70 days and the substrate removal efficiencies showed 98.5% and 90.7% for $NH_4\;^+$ and $NO_2\;^-$ in the activity test, respectively. The phylogenetic trees of Planctomycetes phylum showed that the diverse microbial community structure of an activated sludge was remarkably simplified after the enrichment. All 36 clones, obtained after the enrichment, were affiliated with ANAMMOX bacteria of Candidatus Brocadia (36%) and Candidatus Anammoxoglobus (64%) genera. The quantification using real-time quantitative PCR (RTQ-PCR) revea ed that the 16S rDNA concentration of ANAMMOX bacteria was 74.8% compared to the granular ANAMMOX sludge obtained from an upflow ANAMMOX sludge bed reactor which had been operated for more than one year. The results of molecular analysis supported that the enriched sludge could be used as a seeding sludge for a full-scale ANAMMOX bioreactor.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4B
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• pp.427-432
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• 2006

The effects of free ammonia (FA) concentration and temperature on nitrite accumulation were studied. To estimate the most effective ammonium oxidation and nitrite build-up condition, nitrification tests were conducted in batch conditions at various FA concentrations, and at different ammonium concentration and temperature. The activation energies of ammonium oxidizer were 81.7 KJ/mol below $20^{\circ}C$, and 32.5 KJ/mol over $20^{\circ}C$, while that of nitrite oxidizer was 35.5 KJ/mol irrespective of temperature variations. The results of nitrification tests conducted at different FA concentrations and temperatures showed that temperature strongly affects nitrite accumulation, while effects due to FA concentrations were found negligible.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.4
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• pp.294-300
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• 2013

In this study, major parameter of partial nitritation was investigated for the stable operation. In order to establish partial nitritation system, prevailing parameters such as temperature, BA (bicarbonate alkalinity) and pH were evaluated. As a result, it is inferred that appropriate bicarbonate alkalinity ratio (mg $NaHCO_3{\cdot}L^{-1}/mg$ Inf. $NH_4{^+}-N{\cdot}L^{-1}$) drives stable 50% partial nitritation at $32^{\circ}C$ and ambient temperature, respectively. Alkalinity ratio was proposed as new strategy for 50% partial nitritation without pH control in both temperature regimes. Because of the results, it was added amound of BA required only for 50% nitritation to inhibit nitratation. The effluent $NO_2{^-}-N/NH_4{^+}-N$ ratio reached almost 100% when initial bicarbonate alkalinity ratios (mg $NaHCO_3{\cdot}L^{-1}/mg$ Inf. $NH_4{^+}-N{\cdot}L^{-1}$) were 6.8 (R1) and 6.7 (R2), respectively. Polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) results demonstrated that AOB was the dominant nitrifying bacteria and NOB was negligible after adopting process control.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.1
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• pp.57-63
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• 2013

A combined process consisted of a biofilm reactor and a continuously stirred-tank reactor (CSTR) was investigated for highly loaded ammonium wastewater treatment via nitrite accumulation. To enhance ammonium oxidizing bacteria over nitrite oxidizing bacteria on the surface of carriers, the biofilm reactor was operated at temperature of $35^{\circ}C$ for more than three months but the influent ammonium (500 mg-N/L) was partially oxidized to nitrite (240 mg-N/L). As pH was increased from 7.5 to 8.0, nitrite accumulation was fully achieved due to the inhibition of nitrite oxidizing bacteria under high free ammonia concentration. The biofilm reactor performance was severely deteriorated at the hydraulic retention time of 12 hr, at which incomplete nitrification of ammonia was observed. Various solubilization methods were applied to sewage sludge for enhancing its biodegradability and the combined method, alkaline followed by ultrasonic, gave the highest solubilization efficiency (58%); the solubilized solution was used as the external carbon source for denitrification reaction in CSTR. FISH analysis showed that the dominant microorganisms on the carriers were ammonium oxidizing bacteria such as Nitrosomonas spp. and Nitrospirar spp. but low amounts of nitrite oxidizing bacteria as Nitrobacter spp. was also detected.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.7
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• pp.700-704
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• 2008

Nitrite and free ammonia have been known as substrate inhibitors in anaerobic ammonium oxidation. To reduce inhibitory effect of these substrates, the NH$_3$-N/NO$_2$-N ratio in the influent could be properly controlled in anaerobic ammonium oxidation process. Five kinds of NH$_3$-N/NO$_2$-N ratio were assayed in batch to find optimum NH$_3$-N/NO$_2$-N ratio, curtailing substrate inhibition. As the results of batch test, the highest T-N removal efficiency of 88% was obtained at 1.00 : 1.30 of NH$_3$-N/NO$_2$-N ratio. In addition, rate constants for ammonium and nitrite in zero-order kinetics were found to be the highest values as 7.66 mg/L$\cdot$hr and 11.89 mg/L$\cdot$hr at 1.00 : 1.30 ratio, respectively. However, as for the specific anammox activity, the ratio of NH$_3$-N/NO$_2$-N ratio was recommended as 1 : 1.15 which can maintain the highest SAA during continuous operation and preclude the accumulation of nitrite in the reactor.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.2
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• pp.135-142
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• 2021

The activity of anaerobic ammonium oxidation (ANAMMOX) immobilized in synthetic media (Poly Ethylene Glycol, PEG) and granular form was evaluated comparatively to investigate the effect of influent nitrogen concentration and exposure of oxygen. In ANAMMOX granule reactor, when concentration of influent total nitrogen increased to 500mg/L, removal efficiency of ammonium, nitrite and nitrate were shown to 90.5±6.5, 96.6±4.9, and 93.2±6.1%, respectively. In the case of the PEG gel, it showed lower nitrogen removal performance, resulting in that the removal efficiency of ammonium, nitrite and nitrate were shown to 83.3±13.0, 96.4±6.1, and 90.3±7.5%, respectively. In second step, when exposed to oxygen, the nitrogen removal performance in the ANAMMOX granule reactor also remained stable, but the activity of PEG gel ANAMMOX was found to be inhibited. Consequently, the PEG gel ANAMMOX was a higher sensitivity than that of granular ANAMMOX with two variables applied in this study.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.2
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• pp.195-206
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• 2014

Immobilization of anaerobic ammonium oxidizing bacteria has been studied to enhance the biomass retention of the slowly growing bacteria and the process stability. The purpose of this study was to compare the nitrogen removal efficiency of granular and immobilized anammox bacteria with poly vinyl alcohol and alginate. The specific anammox activity of the granular, homoginized and immobilized anammox bacteria were $0.016{\pm}0.0002gN/gVSS/d$, $0.011{\pm}0.001gN/gVSS/d$ and $0.007{\pm}0.0005gN/gVSS/d$, respectively. Although the activity decreased to 43.7 % of the original one due to low pH and $O_2$ exposure during the homogination and the immobilization, it was rapidly recovered within 7 days in the following continuous culture. When synthetic T-N concentrations of 100, 200, 400, 800 mg/L were fed, the immobilized anammox bacteria showed higher nitrogen removal efficiencies at all operational conditions than those of granular anammox bacteria. When the sludge retention time was shorten below 30.7 days and the reject water was fed, the nitrite removal efficiency of the granular anammox bacteria dropped to 8 % of the initial value, while that of the immobilized anammox bacteria was maintained over 95 % of the initial one. The immobilization with poly vinyl alcohol and alginate would be a feasible method to improve the performance and stability of the anammox process.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1055-1064
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• 2006

Extremely slow growing anammox(anaerobic ammonium oxidation) bacteria were cultivated using a combination of UASB(Upflow Anaerobic Sludge Blanket) reactor seeded with anaerobic granular sludge and carbon-fiber cultivating reactor. After 180 days of continuous cultivation, average nitrogen removal rate showed 0.54 kg $N/m^3-day$ when 0.6 kg $N/m^3-day$ of nitrogen loading was applied. The black granule was changed to brown and red granule as continuous operation, and the red granule was highly dependant on the high anammox activity. Microbial community structure of red granule in the UASB reactor was analyzed by molecular methods such as gene cloning, phylogenetic tree analysis, and FISH(Fluorescence In Situ Hybridization) method. As a result of gene cloning and phylogenetic tree analysis, 5 kinds of phylum were found to be Planctomycetes, Proteobacteria, Acidobacteria, Chlorobi and Chloroflexi. 13 clones were matched to anammox bacteria among 51 clones in the red anammox granule. In-silico test which used cloning information and FISH probe of the AMX368 was conducted to detect the presence of anammox bacteria in the red anammox granule. As a result of in-silico test only one clone was exactly matched to AMX368 but 11 clones was mutated one base among 18 bases representing all 12 clones are anammox bacteria. A filamentous Chloroflexi might be related to the granulation of anammox bacteria. As a result of FISH analysis, anammox bacteria was abundant in the red anammox granule.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.5
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• pp.371-379
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• 2018

The lack of seed sludges for Ammonium Oxidizing Bacteria (AOB) and slow-growing ANaerobic AMMonium OXidation (ANAMMOX) bacteria is one of the major problem for large-scale application. In this study, $24m^3$ of single-stage SBR (Sequencing Batch Reactor) was operated to remove nitrogen from reject water using AOB and ANAMMOX bacteria cultivated from activated sludge in the field. The ANAMMOX activity was found after 44 days of cultivation in the ANAMMOX cultivation reactor, and then $0.66kg\;N/m^3/d$ of the nitrogen removal rate was achieved at $0.78kg\;N/m^3/d$ of the nitrogen loading rate at 153 days of cultivation. The AOB cultivation reactor showed $0.2kg\;N/m^3/d$ of nitrite production rate at $0.4kg\;N/m^3/d$ of nitrogen loading rate after 36 days of operation. The cultivated ANAMMOX bacteria and AOB was mixed into the single-stage SBR. The feed distribution was applied to remove total nitrogen stably in the single-stage SBR. The nitrogen removal rate in the single-stage SBR was gradually enhanced with an increase of specific activities of both AOB and ANAMMOX bacteria by showing $0.49kg\;N/m^3/d$ of the nitrogen removal rate at $0.56kg\;N/m^3/d$ of the nitrogen loading rate at 54 days of operation.

• Journal of Korean Society on Water Environment
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• v.29 no.3
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• pp.377-382
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• 2013

Enriching anammox bacteria (AMX) in a lab-scale granular sequencing batch reactor using local digester centrate, we observed the significant enrichment of the filamentous-like bacterial population. These bacteria were revealed as novel bacterial species (termed CHL) belonging to Chlorobi/Bacteroidetes phyla via Denaturing Gradient Gel Electrophoresis (DGGE). Further, niche differentiation of AMX and CHL quantification was observed in granule and filament biomass, suggesting AMX was dominant in the granule and CHL was dominant in the filament. Therefore, it was confirmed the structural role of CHL was indeed to aid the granule formation of the AMX. In parallel, the physiological role of CHL was suspected to degrade biopolymers in the digester centrate using nitrate as an electron acceptor.