Modification of ASM3 for the determination of biomass adsorption/storage capacity in bulking sludge control

2006 ◽  
Vol 53 (3) ◽  
pp. 91-99 ◽  
Author(s):  
J. Makinia ◽  
K.-H. Rosenwinkel ◽  
L.-C. Phan
Keyword(s):  
Activated Sludge ◽  
Model Calibration ◽  
Storage Capacity ◽  
Batch Experiments ◽  
Substrate Removal ◽  
Filamentous Microorganisms ◽  
Uptake Rates ◽  
Model Predictions ◽  
Direct Growth

The selector activated sludge (SAS) systems are known to prevent excessive growth of filamentous microorganisms responsible for bulking sludge, but these systems were hardly ever modelled. This study aimed to develop a model capable of predicting rapid substrate removal in the SAS systems. For this purpose, the Activated Sludge Model No. 3 (ASM3) was extended with three processes (adsorption, direct growth on the adsorbed substrate under aerobic or anoxic conditions). The modified ASM3 was tested against the results of batch experiments with the biomass originating from two full-scale SAS systems in Germany. The endogenous biomass was mixed with various readily biodegradable substrates (acetate, peptone, glucose and wastewater) and the utilisation of substrate (expresses as COD) and oxygen uptake rates (OURs) were measured during the experiments. In general, model predictions fitted to the experimental data, but a considerable number of kinetic (5) and stoichiometric (2) parameters needed to be adjusted during model calibration. The simulation results revealed that storage was generally a dominating process compared to direct growth in terms of the adsorbed substrate utilisation. The contribution of storage ranged from 65–71% (Plant A) and 69–92% (Plant B).

Quantification of the kinetic differences between communities isolated from completely mixed activated sludge systems operated with or without a selector using a novel respirometric method

1994 ◽  
Vol 30 (11) ◽  
pp. 255-261 ◽  
Author(s):  
Barth F. Smets ◽  
Timothy G. Ellis ◽  
Stephanie Brau ◽  
Richard W. Sanders ◽  
C. P. Leslie Grady
Keyword(s):  
Oxygen Consumption ◽  
Activated Sludge ◽  
Physiological Changes ◽  
Biodegradation Kinetics ◽  
Substrate Removal ◽  
Biomass Yields ◽  
Selection For ◽  
Single Oxygen ◽  
Activated Sludge Systems

This study quantified the kinetic differences in microbial communities isolated from completely mixed activated sludge (CMAS) systems that were operated either with or without an aerobic selector preceding the main reactor. A new respirometric method was employed that allowed the determination of biodegradation kinetics from single oxygen consumption curves, thereby minimizing physiological changes to the examined communities during the assay. Results indicated that increased values for Ks and μmax for acetate, phenol, and 4-chlorophenol degradation were measured in the CMAS system operated with a selector. The biomass yields on acetate, phenol, and 4-chlorophenol were very similar in both systems. These findings indicate that the operation of CMAS systems with aerobic selectors may result in the selection for degrading populations with higher Ks and μmax values for both biogenic and xenobiotic organic compounds, and that substrate storage in the selector only partially contributes to increased substrate removal rates.

Determination of Kinetic Constants of Activated Sludge Microorganisms

1985 ◽  
Vol 17 (2-3) ◽  
pp. 259-272 ◽  
Author(s):  
J. S. Čech ◽  
J. Chudoba ◽  
P. Grau
Keyword(s):  
Activated Sludge ◽  
Mixed Culture ◽  
Removal Rate ◽  
Mixed Cultures ◽  
Kinetic Constants ◽  
Type Reactor ◽  
Substrate Removal ◽  
Velocity Coefficient ◽  
Mixed Reactor

A respirometric method for measuring kinetic constants of activated sludge microorganisms by means of a simple respirometer was developed and tested by using two types of mixed culture. It has been found that both the maximum substrate removal rate and the half-velocity coefficient are basically lower with the mixed cultures cultivated in a completely-mixed reactor /filamentous/ than with those cultivated in a selector-type reactor /nonfilamentous/.

Improvement of Sludge Settleability in Activated Sludge Plants Treating Effluent from Pulp and Paper Industries

1999 ◽  
Vol 40 (11-12) ◽  
pp. 215-221 ◽  
Author(s):  
Kjær Andreasen ◽  
Jeanette Agertved ◽  
Jens-Ove Petersen ◽  
Henrik Skaarup
Keyword(s):  
Activated Sludge ◽  
Paper Industry ◽  
Treatment Plant ◽  
Pulp And Paper ◽  
Detailed Knowledge ◽  
Effluent Quality ◽  
Pulp Industry ◽  
Substrate Removal ◽  
Filamentous Microorganisms ◽  
Pulp And Paper Industries

The main objective of many activated sludge plants treating wastewater from the pulp and paper industry is to remove COD only. These plants are often designed as high-load aerobic systems without any microbial selector system. As a consequence the sludge settling properties are normally poor due to fast growing filamentous microorganisms, which severely reduce the treatment capacity and the effluent quality. Implementation of selectors, in which the substrate concentration and the metabolic pathways can be manipulated, has in many cases reduced the bulking sludge problems in activated sludge systems. An example of a successful upgrading of a Danish pulp industry wastewater treatment plant with an anoxic selector is presented. the use of a novel technique to investigate the in situ physiology of filamentous microorganisms is discussed. It is concluded that a successful application of selectors relies on detailed knowledge about: a) physiology and substrate requirement of the filamentous microorganisms, b) wastewater composition and c) substrate removal kinetics in the selector system.

Assessment on activated sludge models for acetate biodegradation under aerobic conditions

2009 ◽  
Vol 60 (4) ◽  
pp. 983-994 ◽  
Author(s):  
M. A. Hoque ◽  
V. Aravinthan ◽  
N. M. Pradhan
Keyword(s):  
Parameter Estimation ◽  
Activated Sludge ◽  
Model Calibration ◽  
Aerobic Biodegradation ◽  
Batch Experiments ◽  
Storage Model ◽  
Biodegradation Process ◽  
Ammonia Degradation ◽  
And Storage ◽  
Activated Sludge Models

A comparison of four different established models along with parameter estimation was carried out in order to explain the aerobic biodegradation of acetate in an activated sludge system. These models were investigated using experimental OUR data from batch experiments of three different concentration studies. Model calibration reveals that ASM1 model is not suitable to explain the observed experimental OUR during the famine phase implying storage compounds could play an important role during that stage. Besides, the model corresponds to the accumulation concept and is not well fitted for all concentrations studies though it includes the storage phenomena. Both the ASM3 model and the model for simultaneous storage and growth on substrate can well describe the acetate biodegradation process, however the OUR data alone is not sufficient to justify the suitability of those models. Simulated profiles using the model outputs demonstrate that storage is overestimated while ammonia degradation is underestimated in ASM3 compared to simultaneous growth and storage model. The current study also gives reasonable outcomes related to parameter estimation as compared with previous study which is statistically interpreted in this paper.

Substrate removal and sludge production in a batch activated-sludge process with blending

1982 ◽  
Vol 9 (3) ◽  
pp. 558-566 ◽  
Author(s):  
Ronald L. Droste ◽  
Jatinder K. Bewtra
Keyword(s):  
Oxygen Uptake ◽  
Activated Sludge ◽  
Oxygen Uptake Rate ◽  
Oxygen Demand ◽  
Effluent Quality ◽  
Mixed Liquor ◽  
Substrate Removal ◽  
Uptake Rates ◽  
Absorption Phenomenon ◽  
Similar Unit

Bench-scale studies were conducted on a batch-operated, activated-sludge system in which the mixed liquor was blended periodically in an Osterizer blender. A similar unit without mechanical blending was operated as a control. Synthetic organic feed of known characteristics was used as a substrate. Tests were conducted for mixed liquor volatile suspended solids (MLVSS), effluent chemical oxygen demand (COD), settleability, and oxygen uptake rate under steady-state conditions.Substrate uptake in both units was observed to be a rapid adsorption–absorption phenomenon. The nonremovable COD was significantly lower in the blended unit. Also, the oxygen uptake rates showed significant increases due to floc breakup. Settleability was good in the blended unit and the overall effluent quality had improved considerably.

Application of Batch Kinetic Data to the Sizing of Continuous-Flow Activated Sludge Reactors

1987 ◽  
Vol 19 (3-4) ◽  
pp. 505-516 ◽  
Author(s):  
André van Niekerk ◽  
David Jenkins ◽  
M. G. Richard
Keyword(s):  
Activated Sludge ◽  
Continuous Flow ◽  
Kinetic Data ◽  
Substrate Uptake ◽  
Flow Reactors ◽  
Linear Rate ◽  
Substrate Removal ◽  
Uptake Rates ◽  
Non Linear ◽  
Continuous Flow Reactors

The removal of substrates from wastewaters by activated sludge is commonly expressed in terms of a collective substrate parameter such as COD, BOD5 or TOC. Several different linear and non-linear rate expressions are employed to describe complex substrate removal in the literature. The indiscriminate application of batch substrate uptake rates to the analysis or design of continuous-flow reactors can introduce errors. These potential errors have particular significance in the design of aerobic selectors used to control low F/M bulking.

Feedforward control of nitrification by manipulating the aerobic volume in activated sludge plants

1998 ◽  
Vol 38 (3) ◽  
pp. 245-254 ◽  
Author(s):  
Harry Brouwer ◽  
Michiel Bloemen ◽  
Bram Klapwijk ◽  
Henri Spanjers
Keyword(s):  
Activated Sludge ◽  
Model Calibration ◽  
Ammonia Oxidation ◽  
Feedforward Control ◽  
Plug Flow ◽  
Pilot Scale ◽  
Ammonia Nitrogen ◽  
Batch Experiments ◽  
Aerobic Nitrification ◽  
Ammonia Oxidation Rate

A procedure was developed to manipulate the aerobic nitrification volume by means of model based respirometry. The objective was to oxidise all ammonia nitrogen. The required aerobic volume was calculated from the influent flow rate, the influent concentration nitrifiable nitrogen and maximum ammonia oxidation rate which were obtained from respirometric batch-experiments using model calibration and state estimation techniques. Automation of the procedure resulted in the development of the RESCUE (REspirometric activated Sludge and wastewater Characterisation Unit). The procedure was tested for a pilot scale plug-flow activated sludge plant with satisfactory results.

Behaviour of Mechanically Blended Return-Sludge in Absence of Substrate

1970 ◽  
Vol 5 (1) ◽  
pp. 34-54
Author(s):  
Shyam D. Bokil ◽  
Jatinder K. Bewtra
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Treatment Plant ◽  
Aeration Rate ◽  
Batch Experiments ◽  
Sludge Treatment ◽  
Waring Blender ◽  
Settling Characteristics

Abstract Nine sets of batch experiments, each of ten to twelve days duration, were conducted in the laboratory on return-sludge samples collected from activated sludge treatment plant at Windsor. The thickened sludge samples were blended daily in a waring blender and were continuously aerated in twelve-litres capacity jars. Parallel runs were made on control sludge samples which were not blended. Amongst the parameters varied were the speed and frequency of blending and the aeration rate. The effects of these variables on progressive bio-degradation of volatile suspended solids and the settling characteristics of the sludge were determined. Blended sludge showed significant improvement in the rate of bio-degradation and its settling characteristics as compared to the control unblended sludge

Variation in Sludge Settleability with Temperature

1980 ◽  
Vol 15 (1) ◽  
pp. 73-82 ◽  
Author(s):  
J.G. Henry ◽  
E.E. Salenieks
Keyword(s):  
Activated Sludge ◽  
Effect Of Temperature ◽  
Organic Load ◽  
Limiting Factor ◽  
Appreciable Effect ◽  
Loading Rates ◽  
Bench Scale ◽  
Filamentous Bulking ◽  
Filamentous Microorganisms ◽  
Sludge Settleability

Abstract This study examined the effect of temperature on the settleabi1ity of activated sludge at various organic loading rates. Five completely mixed, bench-scale, activated sludge plants, operating under similar conditions at 5, 10 and 19°C, were continuously fed diluted, settled sewage supplemented with carbohydrate (sucrose). Hydraulic loading rates, MLSS and pH were maintained at constant levels during the experiments to eliminate these factors are variables. Dissolved oxygen was kept in excess of 3 mg/1 so that it would not be a limiting factor. Sludge Volume Indices (SVI ) and zone settling velocities were used to indicate changes in sludge settleability. Microscopic examination of the activated sludge indicated significant differences in the morphological features of filamentous microorganisms present at the two temperature extremes. At 19°C, the predominant forms were characterized by long curving trichomes, occasionally falsely branching, containing short cylindrical cells. At 5 °C, much smaller straight filaments, composed of long, narrow, rod-shaped cells appeared to be the principal microorganisms responsible for bulking. Various other filamentous forms were always present at each of the temperatures studied. Stirred sludge settling tests of moderately bulking sludges generally exhibited much higher settling velocities and lower SVI's than unstirred bulking samples. However, extremely filamentous bulking sludge exhibited comparable stirred and unstirred settling velocity and SVI values. The standard SVI test was found to be an inadequate indicator of the extent of bulking when trying to correlate the SVI failures from bench-scale performance with the results from continuous units. Lower temperature had no appreciable effect on COD removal efficiency as long as bulking did not cause a loss of solids in the effluent. However, results suggested that less than half the organic load could be accepted at 5°C, that could be handled at 19°C, before filamentous bulking occurred. A plot of loading versus temperature for various SVI's provided a visual indication of the safe loading limit below which bulking was unlikely to occur. The study clearly demonstrated that temperature can have a significant effect on sludge settleability.

The Use of Anoxic Selectors for the Control of Low F/M Activated Sludge Bulking

1989 ◽  
Vol 21 (6-7) ◽  
pp. 609-619 ◽  
Author(s):  
Y.-J. Shao ◽  
David Jenkins
Keyword(s):  
Organic Matter ◽  
Activated Sludge ◽  
Pilot Plant ◽  
Detention Time ◽  
Substrate Removal ◽  
Batch System ◽  
Sludge Bulking ◽  
N Removal ◽  
Soluble Substrate ◽  
Activated Sludge Systems

Laboratory and pilot plant experiments on anoxic selector activated sludge systems were conducted on two wastewaters in some cases supplemented with nitrate, acetate or glucose. To prevent bulking sufficient anoxic selector detention time and nitrate levels must be available to reduce selector effluent soluble COD to below 100 mg/l and to reduce readily metabolizable organic matter to virtually zero (< 1 mg/l). Soluble COD/NO3-N removal stoichiometry is in the range 6.0-6.7. Selector systems have elevated soluble substrate removal and denitrification rates compared to CSTR systems. These rates are not affected greatly by temperature (20-25°C) for CSTR sludges but are for selector sludges. Upon exhaustion of nitrate in a selector soluble COD leaks out of the activated sludge in significant amounts. Thiothrix sp. and type 021N denitrify only to NO2 and at much slower rates than Zoogloearamigera does to N2. A sequencing batch system provides an optimistic estimate of the SVI that can be obtained by an anoxic selector system.

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