Theoretical and Experimental Analysis of the Role of Sludge Age on the Removal of Adsorbed Micropollutants in Activated Sludge Processes

2008 ◽  
Vol 47 (17) ◽  
pp. 6775-6782 ◽  
Author(s):  
Davide Dionisi ◽  
Lorena Bornoroni ◽  
Sara Mainelli ◽  
Mauro Majone ◽  
Francesca Pagnanelli ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Experimental Analysis ◽  
Activated Sludge Processes

The Role of Micro-Organisms Other than Acinetobacter in Biological Phosphate Removal in Activated Sludge Processes

1983 ◽  
Vol 15 (3-4) ◽  
pp. 117-125 ◽  
Author(s):  
Karin E U Brodisch ◽  
Sylvia J Joyner
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Experimental Period ◽  
Phosphate Removal ◽  
Acinetobacter Species ◽  
Micro Organisms ◽  
Activated Sludge Processes ◽  
Plant Capacity ◽  
Do So

The composition of the microflora in the anaerobic, anoxic and aerated stages was determined by means of the Analytical Profile Index (API) system for three biological phosphate removal plants (a pilot plant (capacity 100 m3/d) and two laboratory scale units (capacity 24 ℓ/d)). The plants monitored differed with respect to anaerobic retention time and configuration, but all three were removing phosphate to concentrations less than 0.2 mg/ℓ as P during the experimental period. In contrast to findings by other investigators, bacteria of the genus Acinetobacter were present in minor proportions. Organisms of the genera Aeromonas and Pseudomonas constituted more than 50 % of the total aerobic microbial population. Depending on the length of the anaerobic retention time, 40 to 50 % of the bacteria were identified as Gram-positive. These findings suggest that Acinetobacter species may not be the only bacterium to remove phosphate from an activated sludge system, but that other groups of bacteria also do so under suitable environmental conditions.

Role of Glycogen as an Intracellular Carbon Reserve of Activated Sludge in the Competitive Growth of Filamentous and Non-Filamentous Bacteria

1991 ◽  
Vol 23 (4-6) ◽  
pp. 899-905 ◽  
Author(s):  
Y. Matsuzawa ◽  
T. Mino
Keyword(s):  
Activated Sludge ◽  
Feeding Pattern ◽  
Filamentous Bacteria ◽  
Competitive Growth ◽  
Maximum Capacity ◽  
Intermittent Feeding ◽  
Feeding Type ◽  
Continuous Feeding ◽  
The Relationship

Activated sludge mixed cultures were cultivated with a glucose containing substrate in order to investigate the relationship between the feeding pattern (continuous or intermittent feeding) and the glycogen reservation capacity of activated sludge. An experimental method to measure the maximum capacity of glycogen reservation in the sludge was developed. Sludge with higher glycogen reservation capacity has an ability to synthesize glycogen faster, which ensures the higher glucose uptake. Therefore, sludge which has high glycogen reservation capacity becomes predominant in intermittently fed reactors. When the feeding pattern was changed from continuous feeding to intermittent feeding, a filamentous bacterium, Type 1701, started to decrease and a gram positive tetrad coccus became predominant. When the feeding pattern was returned to continuous feeding, Type 1701 re-appeared. Type 1701 has lower glycogen reservation capacity than the tetrad coccus. Therefore, the former cannot dominate over the latter in intermittently fed reactors.

Activated Sludge Treatment of Kraft Mill Effluents from Conventional and Oxygen Bleaching

1991 ◽  
Vol 24 (3-4) ◽  
pp. 427-430 ◽  
Author(s):  
J. Nevalainen ◽  
P.-R. Rantala ◽  
J. Junna ◽  
R. Lammi
Keyword(s):  
Activated Sludge ◽  
Kraft Pulp ◽  
Activated Sludge Process ◽  
Chlorinated Phenols ◽  
Pulp Mills ◽  
Main Interest ◽  
Sludge Treatment ◽  
Kraft Pulp Mills ◽  
Activated Sludge Processes ◽  
Oxygen Bleaching

Conventional and oxygen bleaching effluents from hardwood kraft pulp mills were treated in laboratory-scale activated sludge processes. The main interest was the fate of organochlorine compounds in the activated sludge process. In the treatment of conventional bleaching wastewaters the BOD7-reduction was 80-91 % and in oxygen bleaching wastewaters 86-93 %. The respective CODCr removals were about 40 % and about 50 %. The AOX reductions were on average 22 % and 40 % in the treatment of conventional and oxygen bleaching effluents, respectively. The reductions of chlorinated phenols, guajacols and catecols were usually more than 50 % in both reactors. Very little accumulation of AOX into the sludge was observed. The stripping of AOX from aeration unit was insignificant.

Design and Operational Analyses of Activated Sludge Processes Using Respirometrically Calibrated Models

1992 ◽  
Vol 26 (3-4) ◽  
pp. 753-762 ◽  
Author(s):  
A. F. Rozich
Keyword(s):  
Activated Sludge ◽  
Model Calibration ◽  
Process Model ◽  
Process Analysis ◽  
Case Histories ◽  
Model Case ◽  
Operational Strategies ◽  
Analysis Methodology ◽  
Technical Basis ◽  
Activated Sludge Processes

The purpose of this paper is to present the background and examples of methodology which enable environmental engineers and scientists to analyze activated sludge processes much more effectively than is otherwise possible with conventional approaches. Good process analyses are key for devising optimal design and operational strategies. The key features to the technique presented herein are the field-proven predictability of the model and the methodology for collecting data needed for calibrating the process model. Case histories prove the predictability of the model that is associated with the process analysis approach. The advantage of the approach advocated herein is the use of respirometric techniques to calibrate the model. These methods enable the process analyst to collect the requisite data for model calibration in twenty-four hours or less. This feature enables one to use this process analysis methodology for both design and operational applications. The paper will present the technical basis for the process model and how respirometric methods are utilized to compute biokinetic constants in a manner which is consistent with kinetic theory. Case histories will be discussed that demonstrate the predictability of the modeling approach and demonstrate the utility of this tool for process analysis.

Automatic monitoring of denitrification rates and capacities in activated sludge processes using fluorescence or redox potential

1998 ◽  
Vol 37 (12) ◽  
pp. 121-129 ◽  
Author(s):  
S. Isaacs ◽  
Terry Mah ◽  
S. K. Maneshin
Keyword(s):  
Biological Activity ◽  
Activated Sludge ◽  
Redox Potential ◽  
Treatment Plant ◽  
Automatic Monitoring ◽  
Organic Substrate ◽  
Anoxic Zone ◽  
Optimal Dosing ◽  
Denitrifying Microorganisms ◽  
Activated Sludge Processes

A novel method is described to automatically estimate several key parameters affecting denitrification in activated sludge processes: the nitrate concentration, the denitrification capacity, and the maximum (substrate unlimited) and actual denitrification rates. From these, the concentration of active denitrifying microorganisms and the quality of available organic substrate pool can be estimated. Additionally, a modification of the method allows the determination of the efficacy of various carbon substrates to enhance denitrification, and this can be used to determine optimal dosing rates of an external carbon source. The method is based on measurements of either fluorescence or redox potential (ORP) in an isolated mini-reactor, the Biological Activity Meter (BAM), situated in the anoxic zone of the wastewater treatment plant. Advantages of the method are that it is in situ, operating at the same temperature as in the measured anoxic zone, requires no pumps or pipes for mixed liquor sampling, consumes little or no reagents, and uses measurement signals which are instantaneous and low maintenance, one of which provides a direct measure of biological activity.

Floc size distribution and bacterial activities in membrane separation activated sludge processes for small-scale wastewater treatment/reclamation

1997 ◽  
Vol 35 (6) ◽  
pp. 37-44 ◽  
Author(s):  
Boran Zhang ◽  
Kazuo Yamamoto ◽  
Shinichiro Ohgaki ◽  
Naoyuki Kamiko
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Membrane Separation ◽  
Small Scale ◽  
Nitrification Rate ◽  
Floc Size ◽  
Denitrification Activity ◽  
Concentration Changes ◽  
Activated Sludge Processes

Activated sludges taken from full-scale membrane separation processes, building wastewater reuse system (400m3/d), and two nightsoil treatment plants (50m3/d) as well as laboratory scale membrane separation bioreactor (0.062m3/d) were analyzed to characterize membrane separation activated sludge processes (MSAS). They were also compared with conventional activated sludges(CAS) taken from municipal wastewater treatment plants. Specific nitrification activity in MSAS processes averaged at 2.28gNH4-N/kgMLSS.h were higher than that in CAS processes averaged at 0.96gNH4-N/kgMLSS.h. The denitrification activity in both processes were in the range of 0.62-3.2gNO3-N/kgMLSS.h without organic addition and in the range of 4.25-6.4gNO3-N/kgMLSS.h with organic addition. The organic removal activity in nightsoil treatment process averaged at 123gCOD/kgMLSS.h which was significantly higher than others. Floc size distributions were measured by particle sedimentation technique and image analysis technique. Flocs in MSAS processes changed their sizes with MLSS concentration changes and were concentrated at small sizes at low MLSS concentration, mostly less than 60 μm. On the contrary, floc sizes in CAS processes have not much changed with MLSS concentration changes and they were distributed in large range. In addition, the effects of floc size on specific nitrification rate, denitrification rate with and without organic carbon addition were investigated. Specific nitrification rate was decreased as floc size increased. However, little effect of floc size on denitrification activity was observed.

Minimization of activated sludge production by chemically stimulated energy spilling

2000 ◽  
Vol 42 (12) ◽  
pp. 189-200 ◽  
Author(s):  
G.-H. Chen ◽  
H.-K. Mo ◽  
S. Saby ◽  
W.-k. Yip ◽  
Y. Liu
Keyword(s):  
Activated Sludge ◽  
Growth Yield ◽  
Dry Weight ◽  
Staining Technique ◽  
Microbial Culture ◽  
Dapi Staining ◽  
E Coli ◽  
Energy Spilling ◽  
Activated Sludge Processes ◽  
Sludge Production

Minimization of excess sludge production in activated sludge processes has been pursued around the world in order to meet stringent environmental regulations on sludge treatment and disposal. To achieve this goal, physical, chemical, and biological approaches have been proposed. In this paper, a chemical compound, 3,3′,4′,5-tetrachlorosalicylanilide (TCS) was tested for enhancing microbial energy spilling of the sludgeso as to minimize its growth. In order to examine this, an exploratory study was conducted using both batch and continuous activated sludge cultures. Batch experiments with these two cultures were carried out at different initial concentrations of TCS. It has been confirmed that an addition of TCS is effective in reducing the production of both the sludge cultures, particularly the continuous culture where the observed growth yield was reduced by around 70%, when the initial TCS concentration was 0.8 ppm. Meanwhile, the substrate removal activity of this culture was found not to be affected at this TCS concentration. To further evaluate the TCS effect, a pure microbial culture of E. coli was employed. Batch experiment results with this culture implied that TCS might be able to reduce the cell density of E. coli drastically when an initial TCS concentration was greater than 0.12 ppm. It was also found that TCS was not toxic to this type of bacteria. Microscopic examinations with a 4′, 6-diamidino-2-phenylindole (DAPI) staining technique revealed that TCS neither affected the cell division nor altered the cell size of E. coli. However, both the cell ATP content and the cell dry weight were reduced significantly with the addition of TCS.

Role of Acinetobacter johnsonii S35 isolate in floc-formation in activated sludge process

2010 ◽  
Vol 150 ◽  
pp. 44-44 ◽  
Author(s):  
Kimchhayarasy. Phuong ◽  
Kazuo. Kakii ◽  
Toshiyuki. Nikata
Keyword(s):  
Activated Sludge ◽  
Activated Sludge Process ◽  
Acinetobacter Johnsonii
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