Determination of the optimum dose of activated sludge in the aeration tank-mixer system in biological purification of wastewaters

1997 ◽  
Vol 29 (4) ◽  
pp. 265-268
Author(s):  
I. M. Maslyakov ◽  
L. L. Zhuravleva
Keyword(s):  
Activated Sludge ◽  
Optimum Dose ◽  
Aeration Tank ◽  
Biological Purification

Denitrification kinetics in an activated sludge system

1995 ◽  
Vol 32 (9-10) ◽  
pp. 323-330
Author(s):  
M. Roš
Keyword(s):  
Activated Sludge ◽  
Closed System ◽  
Open Systems ◽  
Aeration Tank ◽  
Activated Sludge System ◽  
Denitrification Kinetics ◽  
Closed Systems ◽  
Nitrate And Nitrite ◽  
Sludge Concentration

For all water bodies especially for sea, lakes, and ground waters it is very important that nutrient pollution is the least possible (minimal). From municipal and industrial waste waters where considerable amount of nutrients is expected it is possible to remove nutrients with biological treatment. The first step is usually aerobic activated sludge treatment and the second step is combined anaerobic-anoxic-aerobic step in different combinations. A very effective process for nitrogen removal is anoxic activated sludge system. It is very important that in the first aerobic step complete nitrification is achieved. In our laboratory denitrification kinetics was studied. The objective of this study was determination of denitrification velocity and attendance of different parallel phenomena such as nitrite, disappearance of nitrate and nitrite, sulphide formation, etc. Denitrification process was studied in two systems, in closed system (such as in closed reactors for denitrification) and in open systems (such as in open denitrification tanks). We found out that denitrification rate in closed systems was from about 8 to 52 mg/l.h and was dependent on activated sludge type, sludge concentration, and temperature of the system. In open system (such as in an anoxic aeration tank) the rate of denitrification was lower than in closed system; it was from 4 to 15 mg/l.h dependent on activated sludge type, sludge concentration, and temperature of the system. Experiments were carried out in the range of temperature from 20° to 30°C.

scholarly journals Determination of methyl mercury in a pilot-scale activated sludge wastewater treatment plant

2013 ◽  
Vol 8 (1) ◽  
pp. 61-67 ◽  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Methyl Mercury ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Photochemical Reactions ◽  
Synthetic Wastewater ◽  
Aeration Tank

The methylation of mercury has been investigated and documented mainly in sediments, fish and microorganisms, while limited number of relevant studies is available for wastewater. The procedure of mercury methylation can occur via biological pathway (by microorganisms) and via chemical or photochemical reactions. Methylation of mercury occurs mainly under anaerobic conditions, but some studies have shown its existence also under aerobic conditions. The resulting concentration of methyl mercury, which is a highly toxic compound, depends on the specific rates of methylation/demethylation of mercury. The factors affecting these procedures are the availability of inorganic mercury, pH, organic matter concentration, microbial activity, redox potential and temperature. Bacteria which can methylate mercury are often present in wastewater, and, therefore, the formation of methyl mercury during wastewater treatment is possible. The objective of the present investigation was the determination of methyl mercury in a pilotscale activated sludge wastewater treatment plant supplied with synthetic wastewater enriched with mercury. For this purpose, a Liquid-Liquid Extraction / Simultaneous Derivatization - GC/MS method was developed and applied for the analysis of samples from the aeration tank, from the treatment plant effluent and from the sludge. Methyl mercury was not detected in the samples (detection limit 0.07 μg l-1), leading to the conclusion that mercury is not methylated under the particular experimental conditions of the pilot-scale water treatment plant.

Respirometry for determination of the influents SS-concentration

1996 ◽  
Vol 33 (1) ◽  
pp. 311-323 ◽  
Author(s):  
A. Witteborg ◽  
A. van der Last ◽  
R. Hamming ◽  
I. Hemmers
Keyword(s):  
Experimental Design ◽  
Activated Sludge ◽  
Substrate Concentration ◽  
Full Scale ◽  
Activated Sludge Process ◽  
Respiration Rates ◽  
On Line ◽  
Large Measurement ◽  
Set Up

A method is presented for determining influent readily biodegradable substrate concentration (SS). The method is based on three different respiration rates, which can be measured with a continuous respiration meter which is operated in a cyclic way. Within the respiration meter nitrification is inhibited through the addition of ATU. Simulations were used to develop the respirometry set-up and decide upon the experimental design. The method was tested as part of a large measurement programme executed at a full-scale plant. The proposed respirometry set-up has been shown to be suitable for a semi-on-line determination of an influent SS which is fully based on the IAWQ #1 vision of the activated sludge process. The YH and the KS play a major role in the principle, and should be measured directly from the process.

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.

Operational Determination of the Activated Sludge Process Using Neural Networks

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2461-2464 ◽  
Author(s):  
R. D. Tyagi ◽  
Y. G. Du
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Steady State ◽  
Activated Sludge ◽  
Feedforward Neural Network ◽  
Training Data ◽  
Activated Sludge Process

A steady-statemathematical model of an activated sludgeprocess with a secondary settler was developed. With a limited number of training data samples obtained from the simulation at steady state, a feedforward neural network was established which exhibits an excellent capability for the operational prediction and determination.

An investigation into studying of the activated sludge foaming potential by using physicochemical parameters

2002 ◽  
Vol 46 (1-2) ◽  
pp. 525-528 ◽  
Author(s):  
K. Hladikova ◽  
I. Ruzickova ◽  
P. Klucova ◽  
J. Wanner
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Physicochemical Parameters ◽  
Wastewater Treatment Plants ◽  
Physicochemical Characteristics ◽  
Full Scale ◽  
Aeration Tank ◽  
Foam Formation ◽  
Individual Parameter

This paper examines how the physicochemical characteristics of the solids are related to foam formation and describes how the foaming potential of full-scale plants can be assessed. The relations among activated sludge and biological foam hydrophobicity, scum index, aeration tank cover and filamentous population are evaluated. Individual parameter comparison reveals the scumming intensity can be estimated only on the assumption that foams is already established. None of the above mentioned characteristics can be reliably used to predict the foaming episodes at wastewater treatment plants.

Effect of important operational parameters on performance of coarse pore filtration activated sludge process

2002 ◽  
Vol 46 (9) ◽  
pp. 229-236 ◽  
Author(s):  
M.R. Alavi Moghaddam ◽  
H. Satoh ◽  
T. Mino
Keyword(s):  
Activated Sludge ◽  
Aeration Tank ◽  
Activated Sludge Process ◽  
Operational Parameters ◽  
Solid Retention Time ◽  
Effluent Quality ◽  
Membrane Pores ◽  
Filtration Membrane ◽  
Operation Pressure ◽  
Filter Clogging

A coarse pore filter can be applied inside the aeration tank instead of sedimentation tank for liquid separation from the sludge. It has pores, which are irregular in shape, and much bigger than micro-filtration membrane pores in size. The objective of the study was to investigate the effect of important operational parameters such as flux, aeration intensity, and solid retention time (SRT) on the performance of the coarse pore filtration activated sludge process. The effect of these parameters was studied in laboratory scale experiments. It was found that the flux had a significant role in the effluent quality of this system. The effluent SS and turbidity were not changed significantly at different aeration intensities. Three SRTs, 10, 30 and longer days (without excess sludge) were used for three reactors to check the effect of this parameter on the system performance. The results of the reactors with SRTs about 10 and 30 days have shown very good effluent quality without any filter clogging for more than 4 months operation. For the reactor with long SRT, the filter clogging was observed after about 80 days of operation, which caused the increase of the operation pressure and deterioration in the effluent quality for a few days.

Evaluation of ozonation and cryptic growth for biosolids management in wastewater treatment

1999 ◽  
Vol 39 (10-11) ◽  
pp. 155-158 ◽  
Author(s):  
E. Egemen ◽  
J. Corpening ◽  
J. Padilla ◽  
R. Brennan ◽  
N. Nirmalakhandan
Keyword(s):  
Activated Sludge ◽  
Continuous Flow ◽  
Growth Conditions ◽  
Aeration Tank ◽  
Biomass Growth ◽  
Waste Sludge ◽  
Process Configuration ◽  
Activated Sludge System ◽  
Expensive Problems ◽  
Cryptic Growth

The ultimate disposal of biosolids has been and continues to be one of the most expensive problems faced by wastewater utilities. The objective of this research is to develop a process configuration for reducing the waste sludge generation in an activated sludge plant by promoting cryptic growth conditions (i.e., biomass growth on intracellular products). For this purpose, excess biosolids from a continuous flow activated sludge system were solubilized using ozone as the cell lysis agent, and then returned to the aeration tank. It is hypothesized that growth under such cryptic conditions will result in low net microbial yields, and hence, minimal net solids wastage. The results of these preliminary studies indicate that the proposed process configuration has the potential to reduce the waste sludge production by 40% to 60%.

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