Control of Activated Sludge Circulation and of Secondary Settling Tank Hydraulics

The directives issued by the German Waste Water Association (ABWASSERTECHNISCHE VEREINIGUNG (ATV)) and by the British WATER RESEARCH CENTRE (WRC) in respect of the rating and control of activated sludge circuits and of the loading of secondary settling tanks of biological waste water treatment plants were studied for their applicability to papermill effluents. To this end, several years' testing was carried out on an activated sludge pilot plant and on various industrial plants. These tests revealed that secondary settling tanks of papermill effluent treatment plants may safely be rated in accordance with ATV up to a sludge volume index (SVI) of 300 ml/g and a sludge return rate of 3. If SVI values are low, the WRC process permits excessive surface loadings and is thus only practicable for high SVI levels. If sedimentation properties of the activated sludge are poor, load capacity limits are indicated more correctly by the WRC method. A simplified settling velocity method derived from the WRC process gives reliable information on the load capacity of secondary settling tanks and may readily be used for sludge circulation control.

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Effect of polyphenols on activated sludge biomass during the treatment of highly diluted olive mill wastewaters: biomass dynamics and purifying performances

Water Science & Technology ◽

10.2166/wst.2020.423 ◽

2020 ◽

Vol 82 (7) ◽

pp. 1416-1429

Author(s):

T. E. Elmansour ◽

L. Mandi ◽

A. Ahmali ◽

A. Elghadraoui ◽

F. Aziz ◽

...

Keyword(s):

Waste Water ◽

Activated Sludge ◽

Klebsiella Oxytoca ◽

Settling Tank ◽

Oxygen Demand ◽

Volume Index ◽

High Concentration ◽

Olive Mill Waste Water ◽

Rhizopus Sp ◽

Olive Mill

Abstract This study aims to investigate the feasibility of treating olive mill waste water (OMWW) by activated sludge pilot (AS) after its high dilution (1%) by urban waste water (UWW) and to study the effect of polyphenol compounds on the biomass during the treatment. Specific oxygen uptake rate (SOUR), mixed liquor volatile suspended solids (MLVSS), chemical oxygen demand (COD) and total polyphenols, were followed up over 100 days. In spite of the polyphenols' high concentration (up to 128 mg·L−1), successful biomass growth of 7.12 g MLVSS.L −1 and activity were achieved. Most of the bacteria (Pseudomonas sp., Klebsiella oxytoca, Citrobacter fereundii, Escherichia coli and Staphylococcus sp.) and fungi (Trichoderma sp., Rhizopus sp., Aspergillus niger, Penicillium sp., Fusarium sp., Alternaria) identified in the aerobic basin during the stabilization stage were known to be resistant to OMWW and showed effective adaptation of the biomass to polyphenols in high concentration. COD and polyphenols were highly eliminated (90%, 92% respectively). The sludge volume index in the pilot settling tank was almost constant at around 120 mL.g −1. This suggests the possibility of managing OMWW by simple injection at a given percentage in already functioning conventional AS treating UWW.

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Intensification of Activated Sludge Waste Water Treatment

Water Science & Technology ◽

10.2166/wst.1986.0302 ◽

1986 ◽

Vol 18 (7-8) ◽

pp. 307-311 ◽

Cited By ~ 1

Author(s):

A. Donáth-Jobbágy ◽

J. Káimán ◽

R. Hajós

Keyword(s):

Waste Water ◽

Activated Carbon ◽

Water Treatment ◽

Activated Sludge ◽

Waste Water Treatment ◽

Settling Tank ◽

Pure Oxygen ◽

Pollution Level ◽

Reactor Volume ◽

Sludge Waste

The efficiency of two possible intensification methods of activated sludge waste water treatment (pure oxygen activation and activated carbon addition) were compared. Experiments were carried out in laboratory scale equipment with variable reactor volume (maximum capacity 20,0 dm3, settling tank vol. 15 dm3). In order to detect even minor differences, we operated completely identical units in parallel runs, with one representing a traditional system as reference. A model sewage of industrial character, diluted milk, was used as influent and in the course of activated carbon intensification experiments an anion-active detergent was added as a poorly biodegradable model material to be removed mainly by adsorption. Reactor loads were gradually increased - from low values to overloading - by decreasing the dilution of milk or by reducing reactor volume. The effects of different intensification methods on the effluent pollution level (COD value and anion-active detergent content) and on the settling properties of sludge were examined as a function of loading. The efficiency of both intensification methods was found to be increasing with increasing loading. Comparison of the two systems showed activated carbon intensification to be more efficient in the removal of soluble COD and extremely useful in the elimination of a poorly biodegradable material.

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Ocena wpływu systemu technologicznego oczyszczania ścieków na charakterystykę osadu czynnego

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska ◽

10.22630/pniks.2017.26.3.37 ◽

2017 ◽

Vol 26 (3) ◽

pp. 383-393

Author(s):

Izabela Płonka ◽

Barbara Pieczykolan

Keyword(s):

Activated Sludge ◽

Municipal Wastewater ◽

Settling Tank ◽

Operating Conditions ◽

Volume Index ◽

Technological Systems ◽

Tank System ◽

Bioreactor System ◽

Secondary Settling ◽

Biological Methods

Biological methods are used for treatment of municipal wastewater. These processes can be conducted in various kinds of technological systems. In the paper the comparison of characteristic of activated sludge from two types of technological systems is shown. A flow bioreactor with secondary settling tank (system I) and sequential bioreactor (system II) were used. The study showed, that more favorable operating conditions of activated sludge were in the SBR reactor. The activated sludge in SBR reactor had better sedimentary properties, as indicated by values of sludge volume index and flocs’ sizes. This can be connected with the fact that sludge in SRB reactor is not pumped (what occurs in flow systems). Therefore the sludge is not subjected to unfavorable conditions during hydraulic transport (flocs do not undergo the dispersion). Moreover the values of flocs’ sizes, respiratory activity and specific surface area of sludge from II system were higher in comparison with system I.

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A Combination of the Activated Sludge Process with Fixed Film Biomass to Increase the Capacity of Waste Water Treatment Plants

Water Science & Technology ◽

10.2166/wst.1984.0217 ◽

1984 ◽

Vol 16 (10-11) ◽

pp. 119-130 ◽

Cited By ~ 10

Author(s):

W Hegemann

Keyword(s):

Waste Water ◽

Activated Sludge ◽

Waste Water Treatment ◽

Biomass Concentration ◽

Volume Index ◽

Aeration Tank ◽

Sludge Flocs ◽

Fixed Film ◽

Different Types ◽

Porous Plastic

The volume of the activated sludge aeration tank is influenced by f/m ratio and attainable biomass concentration. Increase of biomass results in smaller tank volume. In case of overloaded plants restoration may be achieved by increase of biomass instead of construction of further tank volume. Pieces of porous plastic media filled into ordinary compressed air aeration tanks may serve as fixed film biomass support. By this method biomass concentration in the tank may be increased to two or three times normal values. At the same time the sludge volume index of the activated sludge flocs still present in the aeration tank is improved. Better sedimentation and thickening of the activated sludge occurs because smaller quantities of flocs are passed to the final clarifiers. Results of tests with different types of waste water in semi-technical scale pilot plants as well as in existing plants of different sizes are presented.

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DESIGN PLANNING WASTEWATER TREATMENT PLANT OF NATA DE COCO INDUSTRY WITH THE ACTIVATED SLUDGE PROCESS

Jurnal Rekayasa Lingkungan ◽

10.29122/jrl.v9i2.1994 ◽

2016 ◽

Vol 9 (2) ◽

Author(s):

Dinda Rita K. Hartaja ◽

Imam Setiadi

Keyword(s):

Waste Water ◽

Wastewater Treatment ◽

Activated Sludge ◽

Waste Water Treatment ◽

Treatment Plant ◽

Water Treatment Plant ◽

Appropriate Technology ◽

Waste Water Treatment Plant ◽

Activated Sludge Process ◽

High Level

Generally, wastewater of nata de coco industry contains suspended solids and COD were high, ranging from 90,000 mg / l. The high level of of the wastewater pollutants, resulting in nata de coco industry can not be directly disposed of its wastewater into the environment agency. Appropriate technology required in order to process the waste water so that the treated water can meet the environmental quality standards that are allowed. Designing the waste water treatment plant that is suitable and efficient for treating industrial wastewater nata de coco is the activated sludge process. Wastewater treatment using activated sludge process of conventional (standard) generally consists of initial sedimentation, aeration and final sedimentation.Keywords : Activated Sludge, Design, IPAL

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An equation for the empirical design of anoxic zones used to eliminate rising sludges at nitrifying activated sludge plants

Water Science & Technology ◽

10.2166/wst.1996.0070 ◽

1996 ◽

Vol 33 (3) ◽

pp. 185-194 ◽

Cited By ~ 1

Author(s):

M. Sarioglu ◽

N. Horan

Keyword(s):

Activated Sludge ◽

Empirical Equation ◽

Nitrate Nitrogen ◽

Critical Concentration ◽

Settling Tank ◽

Limited Information ◽

Batch Experiments ◽

Anoxic Zone ◽

Secondary Settling ◽

Anoxic Zones

Anoxic zones are designed for the removal of nitrogen in nitrifying activated sludge plants. This can be carried out either to achieve a nitrogen discharge consent or to eliminate the problem of rising sludges. The rising sludge problem is mostly encountered in medium and small size plants in warm conditions and there is limited information as to the appropriate design of anoxic zones to protect against rising sludges in the secondary sedimentation tanks. Therefore a series of batch experiments were undertaken in order to establish the critical concentration of nitrate-nitrogen which causes rising sludge in the secondary settling tank and the effect of environmental factors such as temperature (15°C to 30°C) and residual carbon source (100 to 600 mg/1 COD) were examined. Based on the results of these experiments an empirical equation was presented which can be used to size an anoxic zone to eliminate rising sludges. The application of this equation at full-scale plants is discussed.

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