Measurement and modelling of ordinary heterotrophic organism active biomass concentrations in anoxic/aerobic activated sludge mixed liquor

2006 ◽  
Vol 54 (1) ◽  
pp. 1-10 ◽  
Author(s):  
B.J. Lee ◽  
M.C. Wentzel ◽  
G.A. Ekama
Keyword(s):  
Activated Sludge ◽  
Test Method ◽  
Batch Test ◽  
Active Biomass ◽  
Batch Tests ◽  
Test Conditions ◽  
Kinetic Rates ◽  
Slow Grower ◽  
Activated Sludge Systems ◽  
Key Parameter

Ordinary heterotrophic organism (OHO) active biomass (ZBH) is a key parameter in models for activated sludge systems, which defines quantitatively the kinetic rates of relevant processes. However, ZBH has not been measured directly with consistent success: a simple respirometric batch test has provided varying correspondence between measured and theoretical concentrations. In this paper, the batch test is applied to mixed liquors drawn from well defined anoxic/aerobic parent systems at 10 and 20 d sludge ages, with consistent but poor correspondence between measured and theoretical values. In contrast, aerobic digestion batch tests on the same mixed liquors give good correspondences. It is concluded that the differences between theoretical and batch test measured values are due to the batch test method itself and its interpretation. It is found that the batch test conditions (particularly the substrate/ZBH ratio) influence the kinetic constants derived from the data, and hence the ZBH estimate. Two kinetic models with two competing OHO populations, a fast and a slow grower, are developed and applied to the batch tests and parent systems. The first model is based on kinetic selection only, while the second includes additional metabolic selection. Both models can account for the observations in the batch tests, but the second provides greater consistency between simulations of the parent systems and batch tests.

Heterotrophic active biomass component of activated sludge mixed liquor

1998 ◽  
Vol 37 (4-5) ◽  
pp. 79-87 ◽  
Author(s):  
M. C. Wentzel ◽  
M. F. Ubisi ◽  
G. A. Ekama
Keyword(s):  
Activated Sludge ◽  
Direct Evidence ◽  
Test Procedure ◽  
Simulation Models ◽  
Good Correspondence ◽  
Active Biomass ◽  
Mixed Liquor ◽  
Biomass Component ◽  
Activated Sludge Systems ◽  
Key Parameter

In the current steady state design and kinetic simulation models for activated sludge systems, the heterotrophic active biomass (XH) is a key parameter. However, this parameter remains hypothetical within the structure of the models; it has not been measured directly, primarily due to the lack of suitable simple experimental techniques. In this paper a simple batch test procedure is used to quantify XH in mixed liquor samples drawn from a well-defined parent anoxic/aerobic activated sludge system operated at sludge ages 12d and 20d. The measured XH concentrations are in close agreement with those calculated theoretically for the parent system at 12d sludge age, but are about 1/2 the theoretical values for the system at 20d sludge age. While the good correspondence at 12d sludge age provides substantive direct evidence supporting both the models and the experimental method, reasons for the poor correspondence at 20d sludge age need to be found.

Verification of anoxic phosphate uptake as the main biochemical mechanism of the “dephanox” process

1997 ◽  
Vol 35 (10) ◽  
pp. 87-94 ◽  
Author(s):  
R. Sorm ◽  
J. Wanner ◽  
R. Saltarelli ◽  
G. Bortone ◽  
A. Tilche
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Uptake Rate ◽  
Phosphate Uptake ◽  
Biochemical Mechanism ◽  
Batch Experiments ◽  
Batch Tests ◽  
Genetic Probes ◽  
Activated Sludge Systems ◽  
Removal System

The phenomenon of anoxic phosphate uptake with simultaneous denitrification was studied. For this purpose kinetic batch tests have been carried out by using the activated sludge samples from three modifications of nutrient removal activated sludge systems: two based on an anaerobic-anoxic-oxic (A2/O) system and a third on an anaerobic-oxic (A/O) system. The results showed significant differences in anoxic phosphate uptake rate between activated sludge which was alternatively exposed to anoxic conditions and activated sludge from the A/O arrangement. These differences were also accompanied by different denitrification rates. Simultaneously with batch experiments the microscopic observation of activated sludge samples was carried out. Neisser and Gram stained samples showed clear differences in shape, size and distribution of polyphosphate accumulating bacteria between A2/O and A/O Processes. Moreover, experiments performed using genetic probes confirmed the differences in microbiological composition of activated sludge samples from different nutrient removal system arrangements.

Virus elimination in activated sludge systems: from batch tests to mathematical modeling

2014 ◽  
Vol 70 (6) ◽  
pp. 1115-1121 ◽  
Author(s):  
Emma Haun ◽  
Katharina Ulbricht ◽  
Regina Nogueira ◽  
Karl-Heinz Rosenwinkel
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Virus Concentration ◽  
Extended Model ◽  
Municipal Wastewater Treatment ◽  
Virus Elimination ◽  
Somatic Coliphages ◽  
Batch Tests ◽  
Activated Sludge Systems

A virus tool based on Activated Sludge Model No. 3 for modeling virus elimination in activated sludge systems was developed and calibrated with the results from laboratory-scale batch tests and from measurements in a municipal wastewater treatment plant (WWTP). The somatic coliphages were used as an indicator for human pathogenic enteric viruses. The extended model was used to simulate the virus concentration in batch tests and in a municipal full-scale WWTP under steady-state and dynamic conditions. The experimental and modeling results suggest that both adsorption and inactivation processes, modeled as reversible first-order reactions, contribute to virus elimination in activated sludge systems. The model should be a useful tool to estimate the number of viruses entering water bodies from the discharge of treated effluents.

Influence of microbial activity on polar xenobiotic degradation in activated sludge systems

2010 ◽  
Vol 62 (3) ◽  
pp. 701-707 ◽  
Author(s):  
M. Majewsky ◽  
T. Gallé ◽  
L. Zwank ◽  
K. Fischer
Keyword(s):  
Activated Sludge ◽  
Microbial Activity ◽  
Suspended Solids ◽  
Sewage Treatment ◽  
Total Suspended Solids ◽  
Active Biomass ◽  
Sewage Treatment Plants ◽  
Degradation Rates ◽  
Xenobiotic Degradation ◽  
Activated Sludge Systems

The influence of activated sludge quality on the co-metabolic biodegradation of three aminopolycarboxyl acids was investigated for a variety of Luxembourg sewage treatment plants. A combination of biodegradation experiments and respirometric techniques are presented as a reliable approach for the estimation of biokinetics and biological xenobiotic degradation rates that allow for identification of governing parameters such as microbial activity and active biomass. Results showed that biokinetics and degradation rates vary greatly between different plants. The fraction of active biomass on the total suspended solids ranged between 16.9 and 53.7%. Xenobiotic biodegradation rates correlated with microbial activity suggesting a relationship with WWTP performance for carbon and nutrient removal. The biokinetic information can be used to increase the prediction accuracy of xenobiotics removal by individual WWTPs.

Ozonation of endogenous residue and active biomass from a synthetic activated sludge

2011 ◽  
Vol 63 (2) ◽  
pp. 297-302 ◽  
Author(s):  
M. -A. Labelle ◽  
A. Ramdani ◽  
S. Deleris ◽  
A. Gadbois ◽  
P. Dold ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Microbial Activity ◽  
Sludge Reduction ◽  
Digested Sludge ◽  
Active Biomass ◽  
Batch Tests ◽  
Coupled Process ◽  
Synthetic Sludge ◽  
Aerobically Digested

Coupling the activated sludge and the ozonation processes is an efficient, although expensive, solution for sludge reduction. A better knowledge of the mechanisms involved in the degradation of various sludge fractions by ozone is needed to optimize the coupled process. The objectives of this study were to determine the biodegradability of ozone-solubilized endogenous residue, the action of ozone on the active biomass and the solubilization yield of these two main sludge fractions. Batch tests were conducted with slug input of ozone stock solution into fresh or aerobically digested synthetic sludge. Biodegradability of the solubilized endogenous residue was increased by ozonation by up to 0.27 g BOD5/g CODi. Ozone caused biomass lysis, as opposed to an increase in maintenance needs, as shown by a correlation between the decrease in microbial activity and viability. Lysis caused by ozonation was associated with a solubilization of 20% of the lyzed cell COD mass. Solubilization yields were of 9.6 and of 1.9 to 3.6 g COD/g O3 for fresh and aerobically digested sludge, respectively. Design of sludge ozonation processes should account for the variability between the solubilization yield and biodegradability of the various sludge fractions.

The impact of slowly biodegradable organic compounds on the oxygen uptake rate in activated sludge systems

2013 ◽  
Vol 69 (6) ◽  
pp. 1136-1144 ◽  
Author(s):  
J. Drewnowski
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Oxygen Utilization ◽  
Batch Tests ◽  
Hydrolysis Process ◽  
Major Discrepancy ◽  
The Impact ◽  
Activated Sludge Systems

The hydrolysis process of slowly biodegradable substrate (XS) has an impact on the efficiencies of nutrient removal in activated sludge systems. Measurement of oxygen utilization rates (OURs) and corresponding chemical oxygen demand (COD) is accepted as a very useful tool to reflect the consumption of biodegradable substrates. The influence of the SS fraction in biological wastewater treatment systems has been extensively investigated, but little information is known about the effects of XS on OUR. The aim of this study was to determine the immediate effects of particulate and colloidal (XS) biodegradable compounds on oxygen utilization for a full-scale process mixed liquor from a large wastewater treatment plant located in northern Poland. Since it is difficult to distinguish XS in a direct way, a novel procedure, based on the standard batch tests, was developed and run in parallel reactors with settled wastewater (SWW) and pretreated SWW samples. Two types of aerobic OUR experiments with low and high substrate/biomass (S0/X0 ratio) concentration, were carried out with the SWW without pretreatment, and pretreated with a coagulation–flocculation (C–F) method. The removal of colloidal and particulate fractions by C–F resulted in reduced process rates. The major discrepancy in the rate reductions (over 300% referred to the OURmax) was observed during the OUR batch test with high S0/X0 ratio.

Estimation of maximum specific growth rate of heterotrophic and autotrophic biomass: a combined technique of mathematical modelling and batch cultivations

1994 ◽  
Vol 30 (11) ◽  
pp. 171-180 ◽  
Author(s):  
Libor Novák ◽  
Luis Larrea ◽  
Jiri Wanner
Keyword(s):  
Mathematical Modelling ◽  
Growth Rates ◽  
Specific Growth ◽  
Maximum Growth ◽  
Batch Cultivation ◽  
Test Method ◽  
Batch Test ◽  
Batch Tests ◽  
Autotrophic Biomass ◽  
Specific Growth Rates

Present methods for determination of kinetic and stoichiometric parameters are mostly based on simple and rapid batch cultivation. An alternative technique of mathematical simulation and a batch cultivation was proposed for estimation of maximum specific growth rates of heterotrophic and autotrophic microorganisms in activated sludge. Estimation of heterotrophic and autotrophic fractions in the biomass is based on mathematical model calibration of continuously operated system. Maximum growth rates are then calculated from the maximum OUR measured in batch tests. The proposed method was compared with a batch test cultivation based on an exponential growth of microorganisms when a proportion of filtered wastewater is mixed together with a small proportion of biomass and aerated in time. Comparing both methods, a disproportion between obtained results was found (μH,max = 4 d−1 from the proposed, and μH,max = 10 d−1 from the batch test method). An explanation of this observation was based on a hypothesis that under batch test conditions (higher S0/X0 ratio) faster-growing microorganisms can be favoured in their growth. This phenomenon was mathematically simulated with a simplified model and confirmed. Therefore, it is recommended that some constants for mathematical modelling obtained from batch tests should be applied on continuously operated systems only with care.

Nitrate versus Oxygen Utilization Rates in Wastewater and Activated Sludge Systems

1986 ◽  
Vol 18 (6) ◽  
pp. 115-122 ◽  
Author(s):  
Mogens Henze
Keyword(s):  
Activated Sludge ◽  
Oxygen Activity ◽  
Oxygen Utilization ◽  
Active Biomass ◽  
Respiration Rates ◽  
Activated Sludge Processes ◽  
Activated Sludge Systems ◽  
Raw Wastewater

Respiration rates for nitrate and oxygen are compared. Raw wastewaters vary much in these rates and the same holds for activated sludge systems. The denitrifying activity may range from 0-80 per cent of the oxygen activity. It is important to take these variations into consideration, when modelling complex activated sludge processes. Of similar importance are the amounts of active biomass in raw wastewater, as these amounts can exceed those produced in the activated sludge plant itself, and thus significantly can influence the overall composition of the active biomass.

Upgrading of activated sludge systems for nitrogen removal by application of the LINPOR®-CN process

1994 ◽  
Vol 29 (12) ◽  
pp. 167-176 ◽  
Author(s):  
M. R. Morper
Keyword(s):  
Activated Sludge ◽  
Performance Improvement ◽  
Plastic Foam ◽  
Active Biomass ◽  
Conventional Activated Sludge ◽  
Porous Plastic ◽  
Nitrogen Pollutants ◽  
Highly Porous ◽  
Activated Sludge Systems ◽  
Simultaneous Elimination

LINPOR®-systems are modified activated sludge plants, where the aeration tanks contain a certain quantity of highly porous plastic foam particles, which serve as a carrier material for active biomass. Thus a substantial performance improvement is achieved as compared to conventional activated sludge systems without having to renounce the well proven elements of the activated sludge technology. The LINPOR®-CN process for the simultaneous elimination of organic and nitrogen pollutants is particularly suitable for upgrading existing plants, because it can be made to fit into existing tanks with no or only little change of the once installed facilities.

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