Calibration and validation of an ASM3-based steady-state model for activated sludge systems—part I:

Koch, Gerhard; Kühni, Martin; Siegrist, Hansruedi

doi:10.1016/s0043-1354(00)00514-5

Cited by 37 publications

(18 citation statements)

References 9 publications

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“…Such an estimate, while highly conservative relative to WWTP performance design, can substantially increase capital and operation costs due to overcapacity. In contrast, a more recent model estimated that the autotrophic biomass was negligible, accounting for only 2 to 3% of the total activated sludge mass in municipal wastewater (21). Our values suggest that the amount of autotrophic biomass in municipal WWTP may be even smaller.…”

Section: Discussioncontrasting

confidence: 69%

Quantification of Nitrosomonas oligotropha -Like Ammonia-Oxidizing Bacteria and Nitrospira spp. from Full-Scale Wastewater Treatment Plants by Competitive PCR

Dionisi¹,

Layton²,

Harms³

et al. 2002

Appl Environ Microbiol

387

229

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Utilizing the principle of competitive PCR, we developed two assays to enumerate Nitrosomonas oligotrophalike ammonia-oxidizing bacteria and nitrite-oxidizing bacteria belonging to the genus Nitrospira. The specificities of two primer sets, which were designed for two target regions, the amoA gene and Nitrospira 16S ribosomal DNA (rDNA), were verified by DNA sequencing. Both assays were optimized and applied to full-scale, activated sludge wastewater treatment plant (WWTP) samples. If it was assumed that there was an average of 3.6 copies of 16S rDNA per cell in the total population and two copies of the amoA gene per ammonia-oxidizing bacterial cell, the ammonia oxidizers examined represented 0.0033% ؎ 0.0022% of the total bacterial population in a municipal WWTP. N. oligotropha-like ammonia-oxidizing bacteria were not detected in an industrial WWTP. If it was assumed that there was one copy of the 16S rDNA gene per nitrite-oxidizing bacterial cell, Nitrospira spp. represented 0.39% ؎ 0.28% of the biosludge population in the municipal WWTP and 0.37% ؎ 0.23% of the population in the industrial WWTP. The number of Nitrospira sp. cells in the municipal WWTP was more than 62 times greater than the number of N. oligotropha-like cells, based on a competitive PCR analysis. The results of this study extended our knowledge of the comparative compositions of nitrifying bacterial populations in wastewater treatment systems. Importantly, they also demonstrated that we were able to quantify these populations, which ultimately will be required for accurate prediction of process performance and stability for cost-effective design and operation of WWTPs.Nitrification, the bio-oxidation of ammonia (NH 3 ) to nitrate (NO 3 Ϫ ), is a key process in the removal of ammonia from wastewater, which alleviates problems of aquatic toxicity, high oxygen demand in receiving waters, and nutrient contributions to eutrophication (3, 13). The number and physiological activity of nitrifying bacteria in wastewater treatment reactors are considered the rate-limiting parameters for the bioconversion of nitrogen in sewage (48). The slow growth rate of nitrifying bacteria and the sensitivity of these organisms to several environmental factors (e.g., pH, O 2 , temperature, substrate concentration, and the presence of toxic substances) influence the minimum sludge age during wastewater treatment required to establish stable nitrification (34). Consequently, early detection of a decline in the nitrifying population by rapid and reliable molecular methods may improve process control and prevent washout of these organisms from a wastewater treatment system.Chemolithotrophic nitrification is a two-step biochemical process involving sequential transformation of NH 3 to NO 3 Ϫ via NO 2 Ϫ (6). In wastewater treatment plants (WWTPs), the reactions are catalyzed by two phylogenetically distinct groups of bacteria, the ammonia-oxidizing bacteria (AOB) belonging to the ␤ subclass of the class Proteobacteria and nitrite-oxidizing bacteria (NOB). In AOB, oxidatio...

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Section: Discussioncontrasting

confidence: 69%

Quantification of Nitrosomonas oligotropha -Like Ammonia-Oxidizing Bacteria and Nitrospira spp. from Full-Scale Wastewater Treatment Plants by Competitive PCR

Dionisi¹,

Layton²,

Harms³

et al. 2002

Appl Environ Microbiol

387

229

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show abstract

“…The Y N obtained is 0.06 mg COD mg -1 N, which is in the same range for the NOB yield values reported in the literature (Koch et al 2001;Jubany et al 2005). …”

Section: Resultssupporting

confidence: 87%

“…10.3), because the oxygen and nitrite consumption of the NOB are accurately described by the estimated parameters. (Henze et al 1987;Koch et al 2001;Jubany et al 2005;Vadivelu, 2006). The halfsaturation constant value is greater than the most of values reported (Henze et al 1987;Gujer et al 1999;Henze et al 2000).…”

Section: Model Calibration and Validationmentioning

confidence: 61%

Microbial Products Formation in Autotrophic Granular Sludge

2012

Formation, Characterization and Mathematical Modeling of the Aerobic Granular Sludge

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The formation mechanism, characterization, and mathematical modeling of the microbial products of autotrophs in the aerobic granular sludge were systemically investigated. The heterotrophic growth on the SMP in the nitrifying sludge grown on nonorganic carbon source was also evaluated. The aerobic growth of the nitriteoxidizing bacteria (NOB) occurred at the expense of nitrite as an electron donor and resulted in the production of new biomass, UAP, EPS, and nitrate. These autotrophic microbial products could be utilized as the sole electron and carbon source for the heterotrophic growth in autotrophic systems. Growth, Maintenance, and Product Formation of Autotrophs IntroductionThe activated sludge process is the most generally applied biological wastewater treatment method. Autotrophs are widely present in activated sludge, especially in BNR processes, in which nitrification and denitrification usually occur. Nitrification is a two-step reaction: ammonium is oxidized to nitrite by ammonium-oxidizing bacteria (AOB), and later nitrite is oxidized to nitrate by nitrite-oxidizing bacteria (NOB). These processes are respectively called nitritation and nitratation. The growth rate of the autotrophs is considerably lower compared to that of the heterotrophs. Their growth rate is believed to be restricted by the limited energy generation from the oxidation of inorganic sources and also by the highly energy demanding anabolic reactions to synthesize cellular materials from inorganic carbon (Vadivelu 2006). Moreover, the nitratation rate becomes slower than the nitritation rate at higher temperatures (e.g., 30°C) (Hellinga et al. 1998). Finally, the nitratation process is the rate-limiting step when at a low dissolved oxygen B.-J. Ni, Formation, Characterization and Mathematical Modeling of the Aerobic Granular Sludge, Springer Theses,

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“…However, recent molecular studies have reported that the microbes of the Nitrospira phylum were the main NOB and they play a more active role than the Nitrobacter (Dionisi et al, 2002;Geets et al, 2007;Rysgaard and Glud, 2004;Wuchter et al, 2006). Many researchers (Araki et al, 2004;Dionisi et al, 2002;Geets et al, 2007;Harms et al, 2003;Koch et al, 2001;Kowalchuk and Stephen, 2001;Mertoglu, 2008;Robinson et al, 2003;Rotthauwe et al, 1997;Urakawa et al, 2006) have reported quantitative relationships among ammoniaand nitrite-oxidizing bacteria. Urakawa et al (2006) have studied the abundance and population structure of AOB in the marine environments.…”

Section: Resultsmentioning

confidence: 99%

“…The difference in the quantification results between the two methods is explained by the presence of g-AOB and Anammox, which are potential targets of anti-HAO antibodies. In the ASM3 model, autotrophic biomass fraction is assumed as only 2e3% of the total activated sludge mass for the proper nitrification in the municipal wastewater (Koch et al, 2001). However, in literature, this fraction extends from 0.009% to 13.8% (Araki et al, 2004), which shows that the data are very scattered in the activated sludge systems.…”

Section: Resultsmentioning

confidence: 99%

Identification and quantitative evaluation of nitrogen-converting organisms in a full-scale leachate treatment plant

Yapsakli

Aliyazicioglu

Mertoğlu

2011

Journal of Environmental Management

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Calibration and validation of an ASM3-based steady-state model for activated sludge systems—part I:

Cited by 37 publications

References 9 publications

Quantification of Nitrosomonas oligotropha -Like Ammonia-Oxidizing Bacteria and Nitrospira spp. from Full-Scale Wastewater Treatment Plants by Competitive PCR

Quantification of Nitrosomonas oligotropha -Like Ammonia-Oxidizing Bacteria and Nitrospira spp. from Full-Scale Wastewater Treatment Plants by Competitive PCR

Microbial Products Formation in Autotrophic Granular Sludge

Identification and quantitative evaluation of nitrogen-converting organisms in a full-scale leachate treatment plant

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