scholarly journals Rethinking growth and decay kinetics in activated sludge – towards a new adaptive kinetics approach

2016 ◽  
Vol 75 (3) ◽  
pp. 501-506 ◽  
Author(s):  
Michael Friedrich ◽  
Jose Jimenez ◽  
Amy Pruden ◽  
Jennifer H. Miller ◽  
Jacob Metch ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Decay Rates ◽  
Molecular Techniques ◽  
Physiological Adaptation ◽  
Ammonia Oxidizing Bacteria ◽  
Decay Kinetics ◽  
Active Biomass ◽  
Decay Properties ◽  
Nitrite Oxidizing Bacteria ◽  
Solids Retention

Growth kinetics in activated sludge modelling (ASM) are typically assumed to be the result of intrinsic growth and decay properties and thus process parameters are deemed to be constant. The activity change in a microbial population is expressed in terms of variance of the active biomass fraction and not actual shifts in bacterial cellular activities. This approach is limited, in that it does not recognise the reality that active biomass is highly physiologically adaptive. Here, a strong correlation between maximum specific growth rate (μmax) and decay rate (be) of ordinary heterotrophic organisms was revealed in both low solids retention times (SRT) and high SRT activated sludge systems. This relationship is indicative of physiological adaptation either for growth (high μmax and be) or survival optimization (low μmax and be). Further, the nitrifier decay process was investigated using molecular techniques to measure decay rates of ammonia oxidizing bacteria and nitrite oxidizing bacteria over a range of temperatures. This approach revealed decay rates 10–12% lower than values previously accepted and used in ASM. These findings highlight potential benefits of incorporating physiological adaptation of heterotrophic and nitrifying populations in future ASM.

scholarly journals Nitrification mainly driven by ammonia-oxidizing bacteria and nitrite-oxidizing bacteria in an anammox-inoculated wastewater treatment system

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jing Lu ◽  
Yiguo Hong ◽  
Ying Wei ◽  
Ji-Dong Gu ◽  
Jiapeng Wu ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
High Throughput Sequencing ◽  
High Efficiency ◽  
Ammonia Oxidation ◽  
Ammonia Oxidizing Bacteria ◽  
Ammonium Oxidation ◽  
Strong Activity ◽  
Nitrite Oxidizing Bacteria

AbstractAnaerobic ammonium oxidation (anammox) process has been acknowledged as an environmentally friendly and time-saving technique capable of achieving efficient nitrogen removal. However, the community of nitrification process in anammox-inoculated wastewater treatment plants (WWTPs) has not been elucidated. In this study, ammonia oxidation (AO) and nitrite oxidation (NO) rates were analyzed with the incubation of activated sludge from Xinfeng WWTPs (Taiwan, China), and the community composition of nitrification communities were investigated by high-throughput sequencing. Results showed that both AO and NO had strong activity in the activated sludge. The average rates of AO and NO in sample A were 6.51 µmol L−1 h−1 and 6.52 µmol L−1 h−1, respectively, while the rates in sample B were 14.48 µmol L−1 h−1 and 14.59 µmol L−1 h−1, respectively. The abundance of the nitrite-oxidizing bacteria (NOB) Nitrospira was 0.89–4.95 × 1011 copies/g in both samples A and B, the abundance of ammonia-oxidizing bacteria (AOB) was 1.01–9.74 × 109 copies/g. In contrast, the abundance of ammonia-oxidizing archaea (AOA) was much lower than AOB, only with 1.28–1.53 × 105 copies/g in samples A and B. The AOA community was dominated by Nitrosotenuis, Nitrosocosmicus, and Nitrososphaera, while the AOB community mainly consisted of Nitrosomonas and Nitrosococcus. The dominant species of Nitrospira were Candidatus Nitrospira defluvii, Candidatus Nitrospira Ecomare2 and Nitrospira inopinata. In summary, the strong nitrification activity was mainly catalyzed by AOB and Nitrospira, maintaining high efficiency in nitrogen removal in the anammox-inoculated WWTPs by providing the substrates required for denitrification and anammox processes.

Long-term performance of side-stream deammonification in a continuous flow granular-activated sludge process for nitrogen removal from high ammonium wastewater

2015 ◽  
Vol 71 (8) ◽  
pp. 1241-1248 ◽  
Author(s):  
Babak Rezania ◽  
Donald S. Mavinic ◽  
Harlan G. Kelly
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Biomass Concentration ◽  
Granular Sludge ◽  
Operating Conditions ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
Wide Range ◽  
Nitrite Oxidizing Bacteria ◽  
Solids Retention

An innovative granular sludge deammonification system was incorporated into a conventional-activated sludge process. The process incorporated an internal baffle in the bioreactor for continuous separation of granular biomass from flocculent biomass, which allowed for controlling the solids retention time of flocculent sludge. The process was evaluated for ammonium removal from municipal digested sludge dewatering centrate under various operating conditions lasting over 450 days. The process successfully removed, on average, 90% of the ammonium from centrate at various ammonium loading reaching 1.4 kg/m3d at 20 hours hydraulic retention time. Controlling the retention time of the flocculent biomass and maintaining low nitrite concentration were both found to be effective for nitrite oxidizing bacteria management, resulting in a low nitrate concentration (below 50 mg/L) over a wide range of flocculent biomass concentration in the bioreactor.

scholarly journals Density-Based Separation of Microbial Functional Groups in Activated Sludge

2020 ◽  
Vol 17 (1) ◽  
pp. 376
Author(s):  
Lin Li ◽  
Yaqi You ◽  
Krishna Pagilla
Keyword(s):  
Activated Sludge ◽  
Functional Groups ◽  
Ammonia Oxidizing Bacteria ◽  
Biological Phosphorus Removal ◽  
Domestic Water ◽  
Microbial Functional Groups ◽  
Nitrite Oxidizing Bacteria ◽  
And Performance ◽  
Microbial Groups ◽  
Polyphosphate Accumulating Organisms

Mechanistic understanding of how activated sludge (AS) solids density influences wastewater treatment processing is limited. Because microbial groups often generate and store intracellular inclusions during certain metabolic processes, it is hypothesized that some microorganisms, like polyphosphate-accumulating organisms (PAOs), would have higher biomass densities. The present study developed a density-based separation approach and applied it to suspended growth AS in two full-scale domestic water resource recovery facilities (WRRFs). Incorporating quantitative real-time PCR (qPCR) and fluorescence in situ hybridization (FISH) analyses, the research demonstrated the effectiveness of density-based separation in enriching key microbial functional groups, including ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB) and PAOs, by up to 90-fold in target biomass fractions. It was observed that WRRF process functionalities have significant influence on density-based enrichment, such that maximum enrichments were achieved in the sludge fraction denser than 1.036 g/cm3 for the enhanced biological phosphorus removal (EBPR) facility and in the sludge fraction lighter than 1.030 g/cm3 for the non-EBPR facility. Our results provide important information on the relationship between biomass density and enrichment of microbial functional groups in AS, contributing to future designs of enhanced biological treatment processes for improved AS settleability and performance.

In situ analysis of nitrifying bacteria in sewage treatment plants

1996 ◽  
Vol 34 (1-2) ◽  
pp. 237-244 ◽  
Author(s):  
Michael Wagner ◽  
Gabriele Rath ◽  
Hans-Peter Koops ◽  
Janine Flood ◽  
Rudolf Amann
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Nitrifying Bacteria ◽  
Ammonia Oxidizing Bacteria ◽  
Microbiological Methods ◽  
Nitrite Oxidizing Bacteria ◽  
Identification Technique ◽  
Engineered Systems ◽  
Simultaneous Identification

Autotrophic microbial nitrification is the key process in the removal of ammonia from wastewater. To avoid the limitations of traditional microbiological methods an in situ identification technique for ammonia- and nitrite-oxidizing bacteria was developed. Based on comparative sequence analyses we designed a collection of 16S ribosomal RNA-targeted oligonucleotide probes for all validly described members of the genusNitrobacter . Whole cell hybridizations of target and reference cells with fluorescent probe derivatives were used to determine the optimal hybridization stringency for each of the probes. These probes were applied together with a recently developed probe for important members of the genus Nitrosomonas for simultaneous identification of ammonia- and nitrite-oxidizing bacteria in natural and engineered systems. Ammonia-oxidizing bacteria were identified in situ in river water, epiphytic biofilms from eutrophic wetlands, oligotrophic biofilms, a nitrifying trickling filter biofilm as well as in all analyzed nitrifying activated sludge samples. In none of these samples could Nitrobacter cells be detected in situ. However, all hitherto describedNitrobacter species and a strain of Nitrobacter sp. isolated from one of the analyzed nitrifying activated sludge samples showed bright hybridization signals with all Nitrobacter specific probes. Possible reasons for the absence of in situ detectable Nitrobacter cells are discussed.

Molecular assessment of ammonia- and nitrite-oxidizing bacteria in full-scale activated sludge wastewater treatment plants

2003 ◽  
Vol 48 (8) ◽  
pp. 119-126 ◽  
Author(s):  
K.G. Robinson ◽  
H.M. Dionisi ◽  
G. Harms ◽  
A.C. Layton ◽  
I.R. Gregory ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
16S Rdna ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Amoa Gene ◽  
Full Scale ◽  
Ammonia Oxidizing Bacteria ◽  
Copy Numbers ◽  
Nitrite Oxidizing Bacteria

Nitrification was assessed in two full-scale wastewater treatment plants (WWTPs) over time using molecular methods. Both WWTPs employed a complete-mix suspended growth, aerobic activated sludge process (with biomass recycle) for combined carbon and nitrogen treatment. However, one facility treated primarily municipal wastewater while the other only industrial wastewater. Real time PCR assays were developed to determine copy numbers for total 16S rDNA (a measure of biomass content), the amoA gene (a measure of ammonia-oxidizers), and the Nitrospira 16S rDNA gene (a measure of nitrite-oxidizers) in mixed liquor samples. In both the municipal and industrial WWTP samples, total 16S rDNA values were approximately 2-9 × 1013 copies/L and Nitrospira 16S rDNA values were 2-4 × 1010 copies/L. amoA gene concentrations averaged 1.73 × 109 copies/L (municipal) and 1.06 × 1010 copies/L (industrial), however, assays for two distinct ammonia oxidizing bacteria were required.

Luminescence and decay properties of the 1D2 level of Pr3+-doped YPO4

2011 ◽  
Vol 89 (3) ◽  
pp. 415-422 ◽  
Author(s):  
J. Collins ◽  
M. Bettinelli ◽  
B. Di Bartolo
Keyword(s):  
Low Temperature ◽  
Temperature Dependence ◽  
Radiative Decay ◽  
Spectroscopic Properties ◽  
Decay Rates ◽  
Decay Kinetics ◽  
Population Redistribution ◽  
Individual Crystal ◽  
Decay Properties ◽  
Kinetics Of

This investigation reports on the spectroscopic properties of trivalent Pr in YPO4. In particular, we show how the luminescence from the 1D2 level depends on the polarization of the emission and on the temperature of the sample. We also report on the decay kinetics of the 1D2 level, which show the lifetime decreasing as temperature is increased. Our observed lifetime of 440 µs is at low temperature and is significantly longer than that reported by other workers. We explain the temperature dependence of the 1D2 emission by considering the population redistribution in the 1D2 level, without invoking the existence of multiphonon relaxation. Finally, we estimate the radiative decay rates of individual crystal field levels within the 1D2 manifold.

Comparison of Yields and Decay Rates for a Biological Nutrient Removal Process and a Conventional Activated Sludge Process

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2195-2198 ◽  
Author(s):  
S. A. McClintock ◽  
V. M. Pattarkine ◽  
C. W. Randall
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Pilot Scale ◽  
Decay Rates ◽  
Growth Yields ◽  
Biological Nutrient Removal ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
Aerobic Process ◽  
Solids Retention

Two pilot-scale activated sludge reactors, one VIP (named after Virginia Initiative Plant) biological nutrient removal (BNR) process and one conventional, fully aerobic process, were operated over a range of solids retention times (SRT's) and under the same conditions so that growth yields and specific decay rates could be evaluated and compared. True growth yields (Y's) for the BNR and the conventional processes were equal and were 0.41 gVSS/gCOD. The specific decay rate, b, for the BNR process, 0.063 d, was lower than in the fully aerobic process, 0.110 d-1, indicating that decay occurs at a much lower rate in the anoxic and anaerobic zones of the BNR process.

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