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.

The effect of reactor configuration and operational mode on Microthrix parvicella bulking and foaming in nutrient removal activated sludge systems

2002 ◽  
Vol 46 (1-2) ◽  
pp. 61-64 ◽  
Author(s):  
C. Noutsopoulos ◽  
D. Mamais ◽  
A.D. Andreadakis
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Plug Flow ◽  
Selective Advantage ◽  
Operational Mode ◽  
Intermittent Aeration ◽  
Reactor Configuration ◽  
Microthrix Parvicella ◽  
Activated Sludge Systems ◽  
Removal System

Three bench-scale nutrient removal activated sludge units were used to examine the effect of the reactor configuration and the intermittent aeration mode on the growth of Microthrix parvicella. According to the results, the plug flow configuration seems to achieve satisfactory Microthrix parvicella control. The imposed concentration gradient for both RBCOD and SBCOD creates a selective advantage for the floc forming bacteria throughout the system (both the anoxic and oxic zones) and limits Microthrix parvicella growth. In terms of the operational mode, the intermittent aeration CSTR nutrient removal system promotes the growth of M.parvicella and deteriorates the settling characteristics of the activated sludge.

Interaction of Different Groups of Micro-Organisms in Biological Phosphate Removal

1985 ◽  
Vol 17 (11-12) ◽  
pp. 89-97 ◽  
Author(s):  
Karin E. U. Brodisch
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Continuous Flow ◽  
Phosphate Uptake ◽  
Phosphate Removal ◽  
Batch Experiments ◽  
Flow Conditions ◽  
End Products ◽  
Pure Cultures ◽  
Micro Organisms

Observations under continuous flow conditions in a bench-scale activated sludge unit and in full-scale nutrient removal activated sludge plants indicated that, despite relatively high numbers of Aoinetobaoter oalooaoetious, no enhanced biological phosphate removal was achieved. Total bacteriological analyses of the mixed liquor of these plants indicated that in all cases Aeromonas spp. were present in low numbers, particularly Aeromonas punotata. This bacterium is described as being able to produce acetate as one of its major fermentation end products. Phosphate uptake batch experiments using pure cultures showed that Aeromonas punotata enhances the phosphate uptake capability of Aoinetobaoter calooaoetious by converting carbohydrates present in the sewage to a substrate required for phosphate removal. It was shown that the anaerobic zone in a phosphate removing activated sludge plant is a fermentation reactor, where suitable substrates are generated rather than stress conditions imposed on the bacteria, a condition which was previously believed to be essential for enhanced phosphate uptake.

Modeling the biotransformation of trimethoprim in biological nutrient removal system

2018 ◽  
Vol 2017 (1) ◽  
pp. 144-155
Author(s):  
Olumuyiwa O. Ogunlaja ◽  
Wayne J. Parker
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Pilot Scale ◽  
Biological Nutrient Removal ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrification Inhibition ◽  
Batch Tests ◽  
Microbial Groups ◽  
Polyphosphate Accumulating Organisms ◽  
Removal System

Abstract A pilot scale biological nutrient removal (BNR) process, batch experiments and modeling exercises were employed to investigate the removal and biotransformation of trimethoprim (TMP) in a BNR activated sludge process. The concentrations of the active microbial groups – ammonia oxidizing bacteria (AOB), ordinary heterotrophic organisms (OHOs) and polyphosphate accumulating organisms (PAOs) – in the BNR bioreactor were quantified through modeling of the pilot bioreactor. The overall TMP removal efficiency for the pilot BNR process was 64 ± 14% while the TMP biotransformation efficiencies in the anaerobic, anoxic and aerobic zones were 22 ± 20%, 27 ± 8% and 36 ± 5% respectively. Batch tests with and without nitrification inhibition showed that AOB played a role in the biotransformation of TMP in BNR activated sludge. A pseudo first order model which incorporated the contributions of PAOs, OHOs and AOB to the overall biodegradation of TMP was found to describe the biodegradation of TMP in batch tests with and without nitrification inhibition. This model showed that PAOs, OHOs and AOB contributed towards the biotransformation of TMP in aerobic BNR activated sludge with the biotransformation rate constants following the trend of kAOB > kOHOs > kPAOs.

A hypothesis for the cause of low F/M filament bulking in nutrient removal activated sludge systems

1992 ◽  
Vol 26 (6) ◽  
pp. 867-869 ◽  
Author(s):  
T.G. Casey ◽  
M.C. Wentzel ◽  
R.E. Loewenthal ◽  
G.A. Ekama ◽  
G.v.R. Marais
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Activated Sludge Systems

Difficulties and developments in biological nutrient removal technology and modelling

1999 ◽  
Vol 39 (6) ◽  
pp. 1-11 ◽  
Author(s):  
George A. Ekama ◽  
Mark C. Wentzel
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
P Uptake ◽  
Biological Nutrient Removal ◽  
Filamentous Bulking ◽  
Recent Developments ◽  
Removal Technology ◽  
Hydrolysis Of ◽  
Activated Sludge Systems ◽  
P Removal

Filamentous bulking and the long sludge age required for nitrification are two important factors that limit the wastewater treatment capacity of biological nutrient removal (BNR) activated sludge systems. A growing body of observations from full-scale plants indicate support for the hypothesis that a significant stimulus for filamentous bulking in BNR systems in alternating anoxic-aerobic conditions with the presence of oxidized nitrogen at the transition from anoxic to aerobic. In the DEPHANOX system, nitrification takes place externally allowing sludge age and filamentous bulking to be reduced and increases treatment capacity. Anoxic P uptake is exploited in this system but it appears that this form of biological excess P removal (BEPR) is significantly reduced compared with aerobic P uptake in conventional BNR systems. Developments in the understanding of the BEPR processes of (i) phosphate accumulating organism (PAO) denitrification and anoxic P uptake, (ii) fermentation of influent readily biodegradable (RB)COD and (iii) anaerobic hydrolysis of slowly biodegradable (SB)COD are evaluated in relation to the IAWQ Activated Sludge Model (ASM) No.2. Recent developments in BEPR research do not yet allow a significant improvement to be made to ASM No. 2 that will increase its predictive power and reliability and therefore it remains essentially as a framework to guide further research.

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.

Design of nutrient removal activated sludge systems

2003 ◽  
Vol 47 (11) ◽  
pp. 115-122 ◽  
Author(s):  
J. Manga ◽  
J. Ferrer ◽  
A. Seco ◽  
F. Garcia-Usach
Keyword(s):  
Mathematical Model ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Pilot Plant ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
User Friendly ◽  
Biological Phosphorus ◽  
Activated Sludge Systems

A mechanistic mathematical model for nutrient and organic matter removal was used to describe the behavior of a nitrification denitrification enhanced biological phosphorus removal (NDEBPR) system. This model was implemented in a user-friendly software DESASS (design and simulation of activated sludge systems). A 484-L pilot plant was operated to verify the model results. The pilot plant was operated for three years over three different sludge ages. The validity of the model was confirmed with data from the pilot plant. Also, the utility of DESASS as a valuable tool for designing NDEBPR systems was confirmed.

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