Aerobic Denitrification: A Review of Important Advances of the Last 30 Years

Bin Ji,Kai Yang,Lei Zhu,Yu Jiang,Hongyu Wang,Jun Zhou,Huining Zhang 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.4

Understanding aerobic denitrification has become an important focus of environmental microbiology. Aerobic denitrification can be performed by various genera of microorganisms and describes the use of nitrate (NO3 −) as oxidizing agents under an aerobic atmosphere. Isolation of aerobic denitrifiers, enzymes involved in aerobic denitrifiers, phylogenetic distribution of aerobic denitrifiers, factors affecting the performance of aerobic denitrifiers, attempts of applications and possible future trends are depicted. The periplasmic nitrate reductase is vital for aerobic denitrifiers and NapA gene may be the proof of aerobic denitrification. Phylogenetic analysis revealed that aerobic denitrifiers mainly belong to α-, β- and γ-Proteobacteria. Aerobic denitrifiers tend to work efficiently at 25 ~ 37°C and pH 7 ~ 8, when dissolved oxygen concentration is 3 ~ 5 mg/L and C/N load ratio is 5 ~ 10. In addition, recent progresses and applications on aerobic denitrifiers are described, including single aerobic reactors, sequencing batch reactor and biofilm reactors. The review attempts to shed light on the fundamental understanding in aerobic denitrification.

Predictive capability of response surface methodology and cybernetic models for cyanogenic simultaneous nitrification and aerobic denitrification facilitated by cyanide-resistant bacteria

Ncumisa Mpongwana,Seteno Karabo Obed Ntwampe,Lovasoa Christine Razanamahandry,Boredi Silas Chidi,Elizabeth Ife Omodanisi 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.6

Free cyanide (CN−) is a threat to metabolic functions of the microbial population used for the treatment of wastewater, particularly, total nitrogen removal (TN) consortia which gets inhibited by CN− in wastewater treatment plants (WWTPs). Many other methods are used to treat CN− prior to the TN removal stages; however, these methods increase the operational cost of the WWTPs. The capability of a microbial population to use multiple substrates is critical in WWTP and in eliminating inhibition associated with CN−. Previously, cyanide resistant bacteria were used to eliminate the inhibitory effect of CN− towards simultaneous nitrification and aerobic denitrification (SNaD). However, a study to predict the degradation efficiency of the microorganism was required. In this study, response surface methodology (RSM) and cybernetic models were used to predict and optimize SNaD performance for TN removal under CN− conditions. Physiological parameters influencing the SNaD were pH 6.5 and 36.5°C, with TN and CN− degradation efficiency of 78.6 and 80.2%, respectively. These results show a complete elimination of the CN− inhibitory effect towards SNaD and show the prediction ability of both RSM and the cybernetic models used. These results exhibited a promising solution in the control, management, and optimization of SNaD.

Aerobic Denitrification by a Heterotrophic Nitrifying-aerobic Denitrifying (HN-AD) Culture Enriched Activated Sludge

최경진,Shan Zhang,송지현,황선진 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.6

Heterotrophic nitrifying bacteria capable of denitrification under aerobic conditions, which are known as HN-AD species, were investigated. Instead of the isolation and subsequent cultivation of a pure HN-AD strain, the activated sludge obtained from the domestic wastewater treatment plant was enriched to enhance the fraction and activity of the indigenous HN-AD species by adding ammonium and organic carbon. The enriched culture showed both rapid ammonium removal at a rate of 13.3 mg-N/L/hr and nitrate removal at a rate of 12.3 mg-N/L/hr, which was higher than those for the pure HN-AD bacteria reported in the literature. On the contrary, the activated sludge that was not enriched showed insignificant nitrification and aerobic denitrification. These results implied that the selective enrichment procedure improved the fraction and/or activity of the HN-AD culture in the mixed biomass. Consequently, the enriched HN-AD culture from activated sludge could be a feasible alternative over the conventional BNR process.

무산소-호기 유동상에 의한 질소제거

안송엽 ( Ahn Song-yeob ),김환홍 ( Kim Hwan-hong ),권희태 ( Kweon Hee-tae ) 한국환경기술학회 2000 한국환경기술학회지 Vol.1 No.1

본 연구는 유동상의 원리를 이용하여 무산소-호기조의 유기물과 질소제거에 미치는 영향을 분석 연구하였다. 두 개의 반응조는 질산화와 탈질화를 하기 위하여 생물학적 유동상을 설계에 이용하였다. 실험 결과 순환비는 무산소조 30과 호기조 40이 최적조건이 되는데, 순환비가 DO 농도의 증감과 관련되어 유기물이 제거됨을 보여주었다. 무산소조의 알카리도 생성량 80mg/ ℓ, 호기조의 카리도 소비량 160mg/ ℓ 에서 좋은 처리효율이 나타났다. 이것은 무산소조에서 탈질화 반응이 원활히 일어나게 되는데, 이는 질산화 반응보다 일반적으로 pH에 덜 민감하기 때문인 것으로 판단되었다. The study is analyzed to effecy organic matter and nitrogen removal of anoxic-aerobic reactor by using principle of fluidized bed. Two cases are presented which can be used in the design of biological fluidized bed for the nitrification and the denitrification. The results obtained through the experiments were as follows. Recycle ratio are condition of optimum at Anoxic reactor 30 and Aerobic reactor 40 respectively. Recycle ratio is showed to removal of organic matter that is relatively more or less of DO concentration. Treatment efficiency is showed a good alkalinity production 80mg/ℓ of Anoxic and alkalinity Consumption 160 mg ℓ of Aerobic. Nitrification reaction become to harmonious in aerobic Reactor. It is less sensitive to pH then denitrification reaction.

SBR 을 이용한 하수와 생활폐수로 구성된 혼합폐수의 영양소 제거

김홍태 한국환경과학회 1999 한국환경과학회지 Vol.8 No.5

This study was carried out to obtain the optimal operating parameter on organic matters and nutrient removal of mixed wastewater which was composed of sewage and stable wastewater using SBR. A laboratory scale SBR was operated with An/Ae(Anaerobic/ Aerobic) ratio of 3/3, 2/4 and 4/2(3.5/2.5) at organic loading rate of 0.14 to 0.27 ㎏BOD/㎥/d. TCOD/SCOD ratio of mixed wastewater was 3, so the important operating factor depended upon the resolving the particulate parts of wastewater. Conclusions of this study were as follows: 1) For mixed wastewater, BOD and COD removal efficiencies were 93-96% and 85-89%, respectively. It was not related to each organic loading rate, whereas depended on An/Ae ratio. During Anaerobic period, the amount of SCOD consumption was very little, because ICOD in influent was converted to SCOD by hydrolysis of insoluble matter. 2) T-N removal efficiencies of mixed wastewater were 55-62% for Exp. 1, 66-76% for Exp. 2, and 67-81% for Exp. 3, respectively. It was found that nitrification rate was increased according to organic concentration in influent increased. Therefore, the nitrification rate seemed to be achieved by heterotrophs. During anoxic period, denitrification rate depended on SCOD concentration in aerobic period and thus, was not resulted by endogenous denitrification. However, the amount of denitrification during anaerobic period were 3.5-14.1㎎/cycle, and that of BOD consumed were 10-40㎎/cycle. 3) For P removal of mixed wastewater, EBPR appeared only Mode 3(3^*). It was found that the time in which ICOD was converted to VFA should be sufficient. For mode 3 in each Exp., P removal efficiencies were 74, 87, and 81%, respectively. But for 45-48 of COD/TP ratio in influent, P concentration in effluent was over 1 ㎎/L. It was caused to a large amount of ICOD in influent. However, as P concentration in influent was increased, the amounts of P release and uptake were increased linearly.

Efficient aerobic denitrification in the treatment of leather industry wastewater containing high nitrogen concentration

Kyeong Hwan Kang,Geon Lee,Joong Kyun Kim 대한환경공학회 2015 Environmental Engineering Research Vol.20 No.1

To treat leather industry wastewater (LIW) containing high nitrogen concentration, eight aerobic denitrifiers were isolated from sludge existing in an LIW-treatment aeration tank. Among them, one strain named as KH8 had showed the great ability in denitrification under an aerobic condition, and it was identified as Pseudomonas aeruginosa R12. The aerobic denitrification ability of the strain KH8 was almost comparable to its anaerobic denitrification ability. In lab-scale aerobic denitrifications performed in 1-L five-neck flasks for 48 hr, denitrification efficiency was found to be much improved as the strain KH8 held a great majority in the seeded cells. From the nitrogen balance at the cell-combination ratio of 10:1 (the strain KH8 to the other seven isolates) within the seeded cells, the percentage of nitrogen loss during the aerobic denitrification process was estimated to be 58.4, which was presumed to be converted to N2 gas. When these seeded cells with lactose were applied to plant-scale aeration tank for 56 day to treat high-strength nitrogen in LIW, the removal efficiencies of CODCr and TN were achieved to be 97.0% and 89.8%, respectively. Under this treatment, the final water quality of the effluent leaving the treatment plant was good enough to meet the water-quality standards. Consequently, the isolated aerobic denitrifiers could be suitable for the additional requirement of nitrogen removal in a limited aeration-tank capacity. To the best of our knowledge, this is the first report of aerobic denitrifiers applied to plant-scale LIW treatment.

Aerobic Denitrification of Pseudomonas putida AD-21 at Different C/N Ratios

Kim, M.,Jeong, S.Y.,Yoon, S.J.,Cho, S.J.,Kim, Y.H.,Kim, M.J.,Ryu, E.Y.,Lee, S.J. Society for Bioscience and Bioengineering, Japan ; 2008 Journal of bioscience and bioengineering Vol.106 No.5

An aerobic denitrifier was newly isolated from soil and its denitrification activity under different C/N (carbon/nitrogen) ratios was investigated. The isolate was identified as Pseudomonas putida AD-21 by biochemical studies and 16s rDNA sequencing analysis. P. putida AD-21 tolerated oxygen levels of 5.0-6.0 mg/l. An <SUP>15</SUP>NH<SUB>4</SUB>/<SUP>14</SUP>NO<SUB>3</SUB> analysis indicated that the nitrogen of NH<SUB>4</SUB> was preferentially assimilated into the cell mass and that the nitrate removed could be considered an indication of bacterial denitrification efficiency. Increasing the C/N ratio increased the nitrate removal rates, whereas nitrogen assimilation into the cell mass was not affected. The optimal C/N ratio was 8 with a maximum nitrate removal rate of 254.6 mg/l/h and a nitrate removal efficiency of 95.9%. The results suggest that P. putida AD-21 may be a good candidate for aerobic wastewater treatment.

Predictive capability of response surface methodology and cybernetic models for cyanogenic simultaneous nitrification and aerobic denitrification facilitated by cyanide-resistant bacteria

Ncumisa Mpongwana,Seteno Karabo Obed Ntwampe,Lovasoa Christine Razanamahand,Boredi Silas Chidi,Elizabeth Ife Omodanisi 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.6

Free cyanide (CN<SUP>-</SUP>) is a threat to metabolic functions of the microbial population used for the treatment of wastewater, particularly, total nitrogen removal (TN) consortia which gets inhibited by CN<SUP>-</SUP> in wastewater treatment plants (WWTPs). Many other methods are used to treat CN<SUP>-</SUP> prior to the TN removal stages; however, these methods increase the operational cost of the WWTPs. The capability of a microbial population to use multiple substrates is critical in WWTP and in eliminating inhibition associated with CN<SUP>-</SUP>. Previously, cyanide resistant bacteria were used to eliminate the inhibitory effect of CN<SUP>-</SUP> towards simultaneous nitrification and aerobic denitrification (SNaD). However, a study to predict the degradation efficiency of the microorganism was required. In this study, response surface methodology (RSM) and cybernetic models were used to predict and optimize SNaD performance for TN removal under CN<SUP>-</SUP> conditions. Physiological parameters influencing the SNaD were pH 6.5 and 36.5℃, with TN and CN<SUP>-</SUP> degradation efficiency of 78.6 and 80.2%, respectively. These results show a complete elimination of the CN<SUP>-</SUP>inhibitory effect towards SNaD and show the prediction ability of both RSM and the cybernetic models used. These results exhibited a promising solution in the control, management, and optimization of SNaD.

Heterotrophic nitrification-aerobic denitrification potential of cyanide and thiocyanate degrading microbial communities under cyanogenic conditions

Lukhanyo Mekuto,Young Mo Kim,Seteno K. O. Ntwampe,Maxwell Mewa-Ngongang,John Baptist N. Mudumbi,Nkosikho Dlangamandla,Elie Fereche Itoba-Tombo,E. A. Akinpelu 대한환경공학회 2019 Environmental Engineering Research Vol.24 No.2

The impact of free cyanide (CN⁻) and thiocyanate (SCN⁻) on the CN⁻ (CDO) and SCN⁻ degraders (TDO) to nitrify and denitrify aerobically was evaluated under alkaline conditions. The CDO’s were able to nitrify under cyanogenic conditions, achieving NH₄⁺-N removal rates above 1.66 mg NH₄⁺-N.L<SUP>-1</SUP>.h<SUP>-1</SUP>, except when CN⁻ and SCN⁻ loading was 15 mg CN⁻/L and 50 mg SCN⁻.L<SUP>-1</SUP>, respectively, which slightly inhibited nitrification. The TDO’s were able to achieve a nitrification rate of 1.59 mg NH₄⁺-N.L<SUP>-1</SUP>.h<SUP>-1</SUP> in the absence of both CN⁻ and SCN⁻, while the presence of CN⁻ and SCN⁻ was inhibitory, with a nitrification rates of 1.14 mg NH₄⁺-N.L<SUP>-1</SUP>.h<SUP>-1</SUP>. The CDO’s and TDO’s were able to denitrify aerobically, with the CDO’s obtaining NO₃⁻-N removal rates above 0.67 mg NO₃⁻-N.L<SUP>-1</SUP>.h<SUP>-1</SUP>, irrespective of the tested CN⁻ and SCN⁻ concentration range. Denitrification by the TDO’s was inhibited by CN⁻, achieving a removal rate of 0.46 mg NO₃⁻-N.L<SUP>-1</SUP>.h<SUP>-1</SUP> and 0.22 mg NO₃⁻-N.L<SUP>-1</SUP>.h<SUP>-1</SUP> when CNconcentration was 10 and 15 mg CN⁻.L<SUP>-1</SUP>, respectively. However, when the CDO’s and TDO’s were co-cultured, the nitrification and aerobic denitrification removal rates were 1.78 mg NH₄⁺-N.L<SUP>-1</SUP>.h<SUP>-1</SUP> and 0.63 mg NO₃⁻-N.L<SUP>-1</SUP>.h<SUP>-1</SUP> irrespective of CN⁻ and SCN⁻ concentrations.

Alcaligenes faecalis NS13에 의한 호기성 종속영양 질산화 및 탈질화

정택경,라창식,조기성,송홍규,Jung, Taeck-Kyung,Ra, Chang-Six,Joh, Ki-Seong,Song, Hong-Gyu 한국미생물학회 2016 미생물학회지 Vol.52 No.2

호기적 조건에서 질산화와 탈질화를 동시에 진행하는 Alcaligenes faecalis NS13 균주를 분리하여 다양한 특성을 파악하였다. 이 균주는 $15-37^{\circ}C$ 온도에서 생장할 수 있으며 암모니움 산화율이 높고 고농도의 암모니움 환경에서도 생장이 저해되지 않고 초기 암모니움 농도 증가에 따라 제거량이 증가하였다. pH와 염분농도에 대해서도 내성 범위가 넓어 암모니움 산화가 영향을 받지 않았다. 질산화에 이어진 탈질화로 인해 질산염의 축적이 일어나지 않았으며 탈질화의 중간산물인 아산화질소는 미량 검출되었지만 배양 후 모든 질소 화합물을 측정한 결과 약 42.8%가 $N_2$로 전환된 것으로 추정되었다. 탈질화는 PCR 증폭을 통해서 탈질화에 관여하는 유전자 nitrate reductase gene, napA과 nitrous oxide reductase gene, nosZ의 존재로 뒷받침되었다. 또한 배지 내 질소의 46.4%가 NS13 균주로 동화되었기 때문에 폐수처리 시 질산화 및 탈질화 후에 슬러지로 처분한다면 실질적으로 89% 이상의 우수한 암모니움의 제거효과를 거둘 수 있을 것이다. In order to find an efficient bacterial strain that can carry out nitrification and denitrification simultaneously, we isolated many heterotrophic nitrifying bacteria from wastewater treatment plant. One of isolates NS13 showed high removal rate of ammonium and was identified as Alcaligenes faecalis by analysis of its 16S rDNA sequence, carbon source utilization and fatty acids composition. This bacterium could remove over 99% of ammonium in a heterotrophic medium containing 140 mg/L of ammonium at pH 6-9, $25-37^{\circ}C$ and 0-4% of salt concentrations within 2 days. It showed even higher ammonium removal at higher initial ammonium concentration in the medium. A. faecalis NS13 could also reduce nitrate and nitrous oxide by nitrate reductase and nitrous oxide reductase, respectively, which was confirmed by detection of nitrate reductase gene, napA, and nitrous oxide reducase gene, nosZ, by PCR. One of metabolic intermediate of denitrification, $N_2O$ was detected from headspace of bacterial culture. Based on analysis of all nitrogen compounds in the bacterial culture, 42.8% of initial nitrogen seemed to be lost as nitrogen gas, and 46.4% of nitrogen was assimilated into bacterial biomass which can be removed as sludge in treatment processes. This bacterium was speculated to perform heterotrophic nitrification and aerobic denitrification simultaneously, and may be utilized for N removal in wastewater treatment processes.