Respirometry as a tool for rapid characterization of wastewater and activated sludge

1995 ◽  
Vol 31 (2) ◽  
pp. 105-114 ◽  
Author(s):  
Henri Spanjers ◽  
Peter Vanrolleghem
Keyword(s):  
Activated Sludge ◽  
Nitrification Inhibitor ◽  
Wastewater Sludge ◽  
Process Models ◽  
Parameter Estimates ◽  
Reliable Parameter ◽  
Autotrophic Biomass ◽  
Rapid Characterization ◽  
Biokinetic Parameters

A procedure is presented to estimate biokinetic parameters for heterotrophic and autotrophic process models and to estimate wastewater characteristics in the context of the Activated Sludge Models No. 1 and No. 2. The procedure is based on respirometric measurements at low substrate to biomass ratio (S/X). The addition of nitrification inhibitor is avoided by applying a calibrated nitrification model to the respiration rate data resulting from both heterotrophic and autotrophic degradation. Furthermore, a new procedure is developed for simultaneous assessment of decay coefficients for heterotrophic and autotrophic biomass. The results show that, for a given wastewater/sludge combination S/X can be crucial in obtaining reliable parameter estimates: at a very low ratio not all parameters could be identified. A higher ratio caused problems because of nitrification inhibition.

Enrichment and characterization of an anaerobic methyl ethyl ketoxime degrading culture from an anoxic/anaerobic/aerobic activated sludge sequencing batch reactor

1998 ◽  
Vol 37 (4-5) ◽  
pp. 95-98 ◽  
Author(s):  
Nancy G. Love ◽  
Mary E. Rust ◽  
Kathy C. Terlesky
Keyword(s):  
Energy Source ◽  
Activated Sludge ◽  
Electron Acceptor ◽  
Sequencing Batch Reactor ◽  
Enrichment Culture ◽  
Batch Reactor ◽  
Nitrification Inhibitor ◽  
Time Frame ◽  
Methyl Ethyl

An anaerobic enrichment culture was developed from an anoxic/anaerobic/aerobic activated sludge sequencing batch reactor using methyl ethyl ketoxime (MEKO), a potent nitrification inhibitor, as the sole carbon and energy source in the absence of molecular oxygen and nitrate. The enrichment culture was gradually fed decreasing amounts of biogenic organic compounds and increasing concentrations of MEKO over 23 days until the cultures metabolized the oxime as the sole carbon source; the cultures were maintained for an additional 41 days on MEKO alone. Turbidity stabilized at approximately 100 mg/l total suspended solids. Growth on selective media plates confirmed that the microorganisms were utilizing the MEKO as the sole carbon and energy source. The time frame required for growth indicated that the kinetics for MEKO degradation are slow. A batch test indicated that dissolved organic carbon decreased at a rate comparable to MEKO consumption, while sulfate was not consumed. The nature of the electron acceptor in anaerobic MEKO metabolism is unclear, but it is hypothesized that the MEKO is hydrolyzed intracellularly to form methyl ethyl ketone and hydroxylamine which serve as electron donor and electron acceptor, respectively.

Simultaneous Biokinetic Characterization of Heterotrophic and Nitrifying Populations of Activated Sludge with an On-Line Respirographic Biosensor

1993 ◽  
Vol 28 (11-12) ◽  
pp. 377-387 ◽  
Author(s):  
P. A. Vanrolleghem ◽  
W. Verstraete
Keyword(s):  
Activated Sludge ◽  
Model Identification ◽  
Normal Operation ◽  
Conversion Rates ◽  
On Line ◽  
Increasing Demand ◽  
Wastewater Samples ◽  
Biokinetic Parameters ◽  
Bod Removal

The more stringent requirements imposed on wastewater treatment systems result in an increasing demand for on-line monitoring equipment for these processes. The paper presents the modification of a fully operational respirographic biosensor to allow simultaneous and on-line biokinetic characterization of both BOD-removal and nitrification capacities of activated sludge. For this characterization, advantage is taken of the calibration measurements that are performed regularly (every 2-3 h) during normal operation of this biosensor. The injection of a well chosen calibration mixture of readily biodegradable BOD and ammonia to a small activated sludge filled bioreactor results in oxygen uptake rate profiles that are interpreted in the framework of a mathematical model that describes the combined oxygen consumption for BOD removal and nitrification. Model identification gives rise to biokinetic parameters (max. conversion rates and affinity constants) that are indicative of the different metabolic capacities of the activated sludge. It is shown that this information can be used to assess the effect of injected wastewater samples on the sludge condition, e.g. adaptation or inhibition, and allows one to follow the change in relative abundance of heterotrophic and nitrifying populations. Special attention is paid to the proper composition of the calibration solution. Especially the ratio between NOD and BOD is found to be critical. With the aid of simulation, sub-optimal experimental designs are proposed that allow reliable estimation of the biokinetic parameters. Finally, validation of the proposed design is given with experimental data.

A hybrid respirometric method for more reliable assessment of activated sludge model parameter

1998 ◽  
Vol 37 (12) ◽  
pp. 237-246 ◽  
Author(s):  
Peter A. Vanrolleghem ◽  
Henri Spanjers
Keyword(s):  
Activated Sludge ◽  
Process Model ◽  
Process Models ◽  
Estimation Accuracy ◽  
Parameter Estimates ◽  
Respiration Rates ◽  
Reliable Assessment ◽  
Measuring Frequency ◽  
Oxygen Probes ◽  
Combined Sensor

A novel hybrid respirometric principle is proposed that is particularly suited to sludge and wastewater characterisation in the context of activated sludge process models. Advantages of two respirometric principles are combined and their disadvantages eliminated to increase measuring frequency and precision. Emphasis is put on decreasing the bias in parameter estimates that results from the use of unreliable sensor constants in the calculation of respiration rates. To this end checks for dissolved oxygen probes, aeration systems and pumps are built into the respirometer's operation. Checks are to be run while the respirometric batch experiment is conducted so that between-experiment variation is eliminated and within-experiment variation is minimised. It is also stressed that a combined sensor/process model should be used to estimate the process parameters rather than a sequential procedure in which the sensor constants are first used to calculate respiration rates, that are subsequently used for sludge and wastewater characterisation. Finally, three possible practical implementations of the new principle are discussed in relation to maximising parameter estimation accuracy.

Evaluation of the information content of long-term wastewater characteristics data in relation to activated sludge model parameters

2017 ◽  
Vol 75 (6) ◽  
pp. 1370-1389 ◽  
Author(s):  
Jamal Alikhani ◽  
Imre Takacs ◽  
Ahmed Al-Omari ◽  
Sudhir Murthy ◽  
Arash Massoudieh
Keyword(s):  
Activated Sludge ◽  
Hybrid Genetic Algorithm ◽  
Parameter Estimates ◽  
Model Parameters ◽  
Main Role ◽  
Activated Sludge Model ◽  
Parameter Estimations ◽  
Reliable Parameter ◽  
Denitrification Bioreactor ◽  
Sensitive Parameters

A parameter estimation framework was used to evaluate the ability of observed data from a full-scale nitrification–denitrification bioreactor to reduce the uncertainty associated with the bio-kinetic and stoichiometric parameters of an activated sludge model (ASM). Samples collected over a period of 150 days from the effluent as well as from the reactor tanks were used. A hybrid genetic algorithm and Bayesian inference were used to perform deterministic and parameter estimations, respectively. The main goal was to assess the ability of the data to obtain reliable parameter estimates for a modified version of the ASM. The modified ASM model includes methylotrophic processes which play the main role in methanol-fed denitrification. Sensitivity analysis was also used to explain the ability of the data to provide information about each of the parameters. The results showed that the uncertainty in the estimates of the most sensitive parameters (including growth rate, decay rate, and yield coefficients) decreased with respect to the prior information.

Model based evaluation of plant improvement strategies for biological nutrient removal

1999 ◽  
Vol 39 (4) ◽  
pp. 45-53 ◽  
Author(s):  
H. M. van Veldhuizen ◽  
M. C. M. van Loosdrecht ◽  
F. A. Brandse
Keyword(s):  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
P Uptake ◽  
Biological Nutrient Removal ◽  
Adequate Description ◽  
Control Scheme ◽  
Detailed Simulation ◽  
High Fraction ◽  
Biokinetic Parameters ◽  
P Removal

An activated sludge model for biological N- and P-removal was developed, which describes anoxic and aerobic P-uptake based on bacterial metabolism. This model was tested in practice on two wastewater treatment plants, which are BCFS®-processes, which contain activated sludge with a high fraction of denitrifying P-removing bacteria (DPB's). The model appeared to be able to give an adequate description of the performance of these treatment plants under different conditions. If the process parameters are well defined almost no calibration of the biokinetic parameters was necessary. In the simulation of Dalfsen wwtp, which has a complex control scheme, it was possible to give an adequate simulation of the control actions and the concentration profiles in a rather simple way, showing that detailed simulation of these controllers was not necessary. With the calibrated model it was possible to analyse bottlenecks and give suggestions for upgrading of the concerned treatments plants. The simulation results were used in decisions on investments.

scholarly journals An evaluation of the InDevR FluChip-8G insight microarray assay in characterizing influenza a viruses

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Emily S. Bailey ◽  
Xinye Wang ◽  
Mai-juan Ma ◽  
Guo-lin Wang ◽  
Gregory C. Gray
Keyword(s):  
Influenza A ◽  
Influenza Viruses ◽  
Time Range ◽  
Influenza B ◽  
Influenza A Viruses ◽  
Laboratory Methods ◽  
Duke University ◽  
Multiple Viral Strains ◽  
Rapid Characterization

AbstractInfluenza viruses are an important cause of disease in both humans and animals, and their detection and characterization can take weeks. In this study, we sought to compare classical virology techniques with a new rapid microarray method for the detection and characterization of a very diverse, panel of animal, environmental, and human clinical or field specimens that were molecularly positive for influenza A alone (n = 111), influenza B alone (n = 3), both viruses (n = 13), or influenza negative (n = 2) viruses. All influenza virus positive samples in this study were first subtyped by traditional laboratory methods, and later evaluated using the FluChip-8G Insight Assay (InDevR Inc. Boulder, CO) in laboratories at Duke University (USA) or at Duke Kunshan University (China). The FluChip-8G Insight multiplexed assay agreed with classical virologic techniques 59 (54.1%) of 109 influenza A-positive, 3 (100%) of the 3 influenza B-positive, 0 (0%) of 10 both influenza A- and B-positive samples, 75% of 24 environmental samples including those positive for H1, H3, H7, H9, N1, and N9 strains, and 80% of 22 avian influenza samples. It had difficulty with avian N6 types and swine H3 and N2 influenza specimens. The FluChip-8G Insight assay performed well with most human, environmental, and animal samples, but had some difficulty with samples containing multiple viral strains and with specific animal influenza strains. As classical virology methods are often iterative and can take weeks, the FluChip-8G Insight Assay rapid results (time range 8 to 12 h) offers considerable time savings. As the FluChip-8G analysis algorithm is expected to improve over time with addition of new subtypes and sample matrices, the FluChip-8G Insight Assay has considerable promise for rapid characterization of novel influenza viruses affecting humans or animals.

scholarly journals Electrochemical Approaches for Rapid Characterization of Oxidizable Compounds in Different Oak Alternatives

Beverages ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 1
Author(s):  
Jéremie Wirth ◽  
Davide Slaghenaufi ◽  
Stéphane Vidal ◽  
Maurizio Ugliano
Keyword(s):  
Linear Sweep Voltammetry ◽  
Wine Industry ◽  
Wine Aroma ◽  
Total Current ◽  
Strong Correlations ◽  
Tannin Content ◽  
Linear Sweep ◽  
Antioxidant Characteristics ◽  
Rapid Characterization

Oak alternatives (OAs) such as chips, granulates or staves, are becoming increasingly used in the wine industry. Although they are mostly considered for their contribution to wine aroma, they are also a source of phenolic compounds to be released in the wine, in particular ellagitannins contributing to wine mouthfeel and antioxidant characteristics. In the present study, we explore the potential for a rapid analytical method based on linear sweep voltammetry (LSV) combined with disposable sensors to provide a rapid measure of the oxidizable compounds present in different OAs, as well as their characterization. Strong correlations were found between the tannin content of different OAs and the total current measures during LSV analysis, allowing a rapid quantification of the oxidizable compounds present, mostly ellagitannin. Application of derivatization to raw voltammograms allowed extraction of a number of features that can be used for classification purposes, in particular with respect to OAs types (chips or staves) and degree of toasting.

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