• Title/Summary/Keyword: Nitrifiers

Search Result 32, Processing Time 0.026 seconds

Selective Inhibition of Ammonia Oxidation and Nitrite Oxidation Linked to $N_2O$ Emission with Activated Sludge and Enriched Nitrifiers

  • Ali, Toor Umair;Kim, Minwook;Kim, Dong-Jin
    • Journal of Microbiology and Biotechnology
    • /
    • v.23 no.5
    • /
    • pp.719-723
    • /
    • 2013
  • Nitrification in wastewater treatment emits a significant amount of nitrous oxide ($N_2O$), which is one of the major greenhouse gases. However, the actual mechanism or metabolic pathway is still largely unknown. Selective nitrification inhibitors were used to determine the nitrification steps responsible for $N_2O$ emission with activated sludge and enriched nitrifiers. Allylthiourea (86 ${\mu}M$) completely inhibited ammonia oxidation and $N_2O$ emission both in activated sludge and enriched nitrifiers. Sodium azide (24 ${\mu}M$) selectively inhibited nitrite oxidation and it led to more $N_2O$ emission than the control experiment both in activated sludge and enriched nitrifiers. The inhibition tests showed that $N_2O$ emission was mainly related to the activity of ammonia oxidizers in aerobic condition, and the inhibition of ammonia monooxygenase completely blocked $N_2O$ emission. On the other hand, $N_2O$ emission increased significantly as the nitrogen flux from nitrite to nitrate was blocked by the selective inhibition of nitrite oxidation.

Effect of a co-culture of scenedesmus dimorphus and nitrifiers on advanced wastewater treatment capacity (Scenedesmus dimorphus와 질산화 박테리아의 공배양이 하수고도처리능에 미치는 영향)

  • Choi, Kyoung-Jin;Zhang, Shan;Lee, SeokMin;Joo, Sung-Jin;Hwang, Sun-Jin
    • Journal of Korean Society of Water and Wastewater
    • /
    • v.28 no.6
    • /
    • pp.691-698
    • /
    • 2014
  • This study investigated the effect of a co-culture of Scenedesmus dimorphus and nitrifiers using artificial wastewater on the removal of ammonium, nitrate and phosphate in the advanced treatment. To test the synergistic effect of the co-culture, we compared the co-culture treatment with the cultures using S. dimorphus-only and nitrifiers-only treatment as controls. After 6 days of incubation, nitrate was removed only in the co-culture treatment and total amount of N removal was 1.3 times and 1.6 times higher in the co-culture treatment compared to those in the S. dimorphus- and nitrifiers-only treatments, respectively. In case of total amount of P, co-culture treatment removed 1.2 times and 12 times more P than the S. dimorphus -and nitrifiers-only conditions, respectively. This indicates that the co-culture improved removal rates for ammonium, nitrate, and phosphate. This further implies that there was no need for denitrification of nitrate and luxury uptake of P processes because nitrate and phosphate can be removed from the uptake by S. dimorphus. In addition, co-culture condition maintained high DO above 7 mg/L without artificial aeration, which is enough for nitrification, implying that co-culture has a potential to decrease or remove aeration cost in the wastewater treatment plants.

Effects of Initial Concentration of Ammonium Ion and Active Nitrifiers on Nitrification (암모늄 이온 및 질산화균의 초기 농도가 질산화에 미치는 영향)

  • Kim, Jung Hoon;Kim, Young Ju;Park, Hung Suck
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.26 no.4B
    • /
    • pp.421-426
    • /
    • 2006
  • The effect of initial concentration of ammonium ion ($N_0$) and active nitrifiers ($X_0$) on nitrification was examined by continuous monitoring of the ammonium removal rate. The concentration of the active nitrifiers in the culture sludge, measured by the oxygen uptake rate (OUR), was found to be 42.8% of the culture sludge. Experiments were carried out under different ratios of $N_0/X_0$, viz., 0.025 to 0.493. The results from this study show that the oxidation rate was similar under the same $N_0/X_0$ ratio despite different initial concentration of ammonium ion ($N_0$) and active nitrifiers ($X_0$). Moreover, the Contois kinetic expression which includes biomass concentration, was found to describe the mechanism behind nitrification process. The ammonium oxidation rate ($q_{Nmax}$) and half saturation constant per unit activated nitrifiers ($K_N{^{\prime}}$) were theoretically determined using the Contois expression. These values were found to be 4.32 gN/gVSS/day and 0.013 gN/gVSS respectively.

Nitrification process analysis by respirometry in a sequencing batch reactor (호흡률을 이용한 연속회분식반응조의 질산화 공정 해석)

  • Kim, Donghan;Kim, Sunghong
    • Journal of Korean Society of Water and Wastewater
    • /
    • v.33 no.1
    • /
    • pp.55-62
    • /
    • 2019
  • The respirometric technique has been used to analyze the nitrification process in a sequencing batch reactor(SBR) treating municipal wastewater. Especially the profile of the respiration rate very well expressed the reaction characteristics of nitrification. As the nitrification process required a significant amount of oxygen for nitrogen oxidation, the respiration rate due to nitrification was high. The maximum nitrification respiration rate, which was about $50mg\;O_2/L{\cdot}h$ under the period of sufficient nitrification, was related directly to the nitrification reaction rate and showed the nitrifiers activity. The growth rate of nitrifiers is the most critical parameter in the design of the biological nutrient removal systems. On the basis of nitrification kinetics, the maximum specific growth rate of nitrifiers in the SBR was estimated as $0.91d^{-1}$ at $20^{\circ}C$, and the active biomass of nitrifiers was calculated as 23 mg VSS/L and it was about 2% of total biomass.

Development of Encapsulated Media for Ammonia Removal (암모니아 가스 제거를 위한 포괄고정화 담체 개발)

  • Jeong, Mi-young;Namgung, Hyeong Kyu;Song, Ji Hyeon;Hwang, Sun-Jin
    • Journal of Korean Society on Water Environment
    • /
    • v.25 no.2
    • /
    • pp.306-310
    • /
    • 2009
  • Packed-bed reactor for removing ammonia was tested at different loading rates. Nitrifiers for ammonia removing was encapsulated in gel media which consisted of polyethlene glycol, alginate and activated carbon. The removal efficiency was nearly 100% when ammonia loading was $12g/m^3/hr$, and the maximum elimination capacity (EC) achieved on this study was $18g/m^3/hr$. The initial microbial portion of nitrifiers in the media was about 82% and it was increased to more than 90% at the end of the operation. Short-term shock loading test was carried out to survey the stability of the media. The inlet loading rates were varied from 2 to $20g/m^3/hr$. The packed-bed reactor overcame the shock loading i.e. removal efficiency recovered rapidly from about 80% to almost 100% within 6 hrs. The results of Live/Dead cell test showed that nitrifiers maintained there activity in the encapsulated media during the test and also against ammonia shock load.

Effect of Ammonium Concentration on the Emission of $N_2O$ Under Oxygen-Limited Autotrophic Wastewater Nitrification

  • Kim, Dong-Jin;Kim, Yu-Ri
    • Journal of Microbiology and Biotechnology
    • /
    • v.21 no.9
    • /
    • pp.988-994
    • /
    • 2011
  • A significant amount of nitrous oxide ($N_2O$), which is one of the serious greenhouse gases, is emitted from nitrification and denitrification of wastewater. Batch wastewater nitrifications with enriched nitrifiers were carried out under oxygen-limited condition with synthetic (without organic carbon) and real wastewater (with organic carbon) in order to find out the effect of ammonium concentration on $N_2O$ emission. Cumulated $N_2O$-N emission reached 3.0, 5.7, 6.2, and 13.5 mg from 0.4 l of the synthetic wastewater with 50, 100, 200, and 500 mg/l ${NH_4}^+$-N, respectively, and 1.0 mg from the real wastewater with 125 mg/l ${NH_4}^+$-N. The results indicate that $N_2O$ emission increased with ammonium concentration and the load. The ammonium removal rate and nitrite concentration also increased $N_2O$ emission. Comparative analysis of $N_2O$ emission from synthetic and real wastewaters revealed that wastewater nitrification under oxygen-limited condition emitted more $N_2O$ than that of heterotrophic denitrification. Summarizing the results, it can be concluded that denitrification by autotrophic nitrifiers contributes significantly to the $N_2O$ emission from wastewater nitrification.

Diversity of Nitrifying and Denitrifying Bacteria in SMMIAR Process (완전침지형 회전매체공정 내 질산화 및 탈질 관련 미생물의 군집 분포)

  • Quan, Zhe-Xue;Lim, Bong-Su;Kang, Ho;Yoon, Kyung-Yo;Yoon, Yeo-Gyo
    • Journal of Korean Society on Water Environment
    • /
    • v.22 no.6
    • /
    • pp.1014-1021
    • /
    • 2006
  • SMMIAR (Submerged Moving Media Intermittent Aeration Reactor) Process is a very efficient system which remove ammonia to nitrogen gas in one reactor. In this study, we determined the diversity of ammonia oxidizing bacteria and denitrifying bacteria using specific PCR amplification and the clone library construction. An ammonia monooxygenase gene(amoA) was analyzed to investigate the diversity of nitrifiers. Most of amoA gene fragments (27/29, 93%) were same types and they are very similar (>99%) to the sequences of Nitrosomonas europaea and other clones isolated from anoxic ammonia oxidizing reactors. ANAMMOX related bacteria have not determined by specific PCR amplification. A nitrite reductase gene(nirK) was analyzed to investigate the diversity of denitrifying bacteria. About half (9/20, 45%) of denitrifiers were clustered with Rhodobacter and most of others were clustered with Mesorhizobium (6/20, 30%) and Rhizobium (3/20, 15%). All of these nirK gene clones were clustered in alpha-Proteobacteria and this result is coincide with other system which also operate nitrification and denitrification in one reactor. The molecular monitoring of the population of nitrifiers and denitrifiers would be helpful for the system stabilization and scale-up.

Analysis on the distribution of nitrogen and phosphorus removing microorganisms and nitrifying activity in a trickling filter (살수여상에서의 질소, 인 제거 미생물 분포 및 질산화 활성 조사)

  • Kim, Dong-Jin;Yoo, Ik-Keun;Ahn, Dae-Hee
    • Journal of Environmental Science International
    • /
    • v.18 no.6
    • /
    • pp.691-698
    • /
    • 2009
  • Trickling filter has been extensively studied for the domestic wastewater treatment especially for the small scale plants in rural area. The performance of the trickling filter depends on the microbial community and their activity in the biofilms on the media. Nitrification. denitrification, and phosphorus removal of the trickling filter from the wastewater depend on the activity and the amount of the specific microorganisms responsible for the metabolism. For the estimation of the performance of a trickling filter, batch nitrification experiment and fluorescence in situ hybridization (FISH) were carried out to measure the microbial activity and its distribution on the media of the trickling filter. Batch nitrification activity measurement showed that the top part of the 1st stage trickling filter had the highest nitrification activity and the maximum activity was 0.002 g $NH_4$-N/g MLVSS${\cdot}$h. It is thought that higher substrate (ammonia) concentration yields more nitrifying bacteria in the biofilms. The dominant ammonia oxidizer and nitrite oxidizer in the biofilm were Nitrosomonas species and genus Nitrospira, respectively, by FISH analysis. Less denitrifiers were found than nitrifiers in the biofilm by the probe Rrp1088 which specifically binds to Rhodobacter, Rhodovulum, Roseobacter, and Paracoccus. Phosphorus accumulating bacteria were mostly found at the surface of the biofilm by probe Rc988 and PAO651 which specifically binds to Rhodocyclus group and their biomass was less than that of nitrifiers.

Removal of ammonia by packed bed bioreactor using immobilized nitrifiers (고정화 생물 반응기에 의한 암모니아 제거)

  • 김병진;이경범;서근학
    • Journal of Environmental Science International
    • /
    • v.8 no.2
    • /
    • pp.177-182
    • /
    • 1999
  • Nitrifier consortium entrapped in Ca-alginate bead were packed into aerated packed bed bioreactor and non aerated packed bed bioreactor and the performances of two bioreactors were evaluated for the removal of ammonia nitrogen from synthetic aquaculture water. Total ammonia nitrogen(TAN) removal rate was decrease in aerated packed bed bioreactor below 0.3hr of hydraulic residence time(HRT), but increased in non aerated packed bed bioreactor until 0.5hr of HRT. At HRT of 0.05hr, TAN removal rate of non aerated packed bed bioreactor was about 335g TAN/㎥/day and the optimum ratio of packing height and inside diameter of reactor (H/D) was 4. The performance of two bioreactors indicated that non aerated packed bed bioreactor was better than aerated packed bed bioreactor in ammonia removal from synthetic aquaculture water.

  • PDF

아질산성 질소의 축적에 대한 용존 산소와 free ammonia의 영향 연구

  • Han, Dong-U;Lee, Su-Cheol;Lee, Nam-Hui;Kim, Dong-Jin
    • 한국생물공학회:학술대회논문집
    • /
    • 2000.11a
    • /
    • pp.475-478
    • /
    • 2000
  • For an integrated nitrification-denitrification process, nitrite formation in the aerobic stage leads to big savings. Dissolved oxygen concentration, temperature, pH and free ammonia concentration have been meet for nitrite accumulation. Also their effects over the ammonia oxidizers and nitrite oxidizers have been studied. Dissolved oxygen limitation and free ammonia inhibition led to slow nitrification and nitrite build up. In this study batch kinetics of ammonium and nitrite oxidations were performed with free ammonia accumulated nitrifiers. From the results it is likely the nitrite oxidizers are inhibited by oxygen limitation rather than free ammonia.

  • PDF