Retrofitting activated sludge systems to intermittent aeration for nitrogen removal

2002 ◽  
Vol 46 (8) ◽  
pp. 75-82 ◽  
Author(s):  
O. Hanhan ◽  
N. Artan ◽  
D. Orhon
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Design Procedure ◽  
Intermittent Aeration ◽  
System Operation ◽  
Conceptual Approach ◽  
Available Nitrogen ◽  
Model Simulations ◽  
Activated Sludge Systems

The paper provides the basis and the conceptual approach of applying process kinetics and modelling to the design of alternating activated sludge systems for retrofitting existing activated sludge plants to intermittent aeration for nitrogen removal. It shows the significant role of the two specific parameters, namely, the aerated fraction and the cycle time ratio on process performance through model simulations and proposes a way to incorporate them into a design procedure using process stoichiometry and mass balance. It illustrates the effect of these parameters, together with the sludge age, in establishing the balance between the denitrification potential and the available nitrogen created in the anoxic/aerobic sequences of system operation.

Differences in nitrification potential between fully aerobic and nitrogen removal activated sludge systems

2002 ◽  
Vol 46 (1-2) ◽  
pp. 297-304
Author(s):  
G.J. Hatziconstantinou ◽  
A. Andreadakis
Keyword(s):  
Activated Sludge ◽  
Decay Rate ◽  
Nitrogen Removal ◽  
Nitrogen Loss ◽  
Performance Evaluations ◽  
Available Nitrogen ◽  
Nitrification Potential ◽  
Autotrophic Biomass ◽  
Heterotrophic Biomass ◽  
Activated Sludge Systems

Experimental observations made on two pilot plants, showed that nitrogen removal activated sludge systems, operating under favourable conditions, seem to develop increased nitrification potential compared to fully aerobic systems under similar conditions. This increased potential, which cannot be detected by simple nitrification performance evaluations, is attributed to higher autotrophic populations sustained – developed in similar systems employing anoxic reactors or phases. A reduced autotrophic decay rate under anoxic conditions as reported by some researchers, seems to play a significant role in such a response, most likely together with a more efficient use of available nitrogen for additional nitrifying microorganisms production, resulting from a reduced nitrogen loss to autotrophic biomass maintenance needs and heterotrophic biomass synthesis requirements.

scholarly journals Characteristics of N2O Emission and Nitrogen Removal at A DO Controlled Intermittent Aeration Activated Sludge Process.

1998 ◽  
Vol 34 (2) ◽  
pp. 1-14 ◽  
Author(s):  
YUZURU KIMOCHI ◽  
YUHEI INAMORI ◽  
NOBORU FURUYA ◽  
TOICHI EBISUNO ◽  
MASATOSHI MATSUMURA
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
N2o Emission ◽  
Activated Sludge Process ◽  
Intermittent Aeration

Nitrogen removal in activated sludge systems including denitrification in secondary clarifiers

1994 ◽  
Vol 30 (6) ◽  
pp. 101-111 ◽  
Author(s):  
H. Siegrist ◽  
W. Gujer
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Retention Time ◽  
Secondary Clarifier ◽  
Solids Retention Time ◽  
Solids Retention ◽  
Activated Sludge Systems

Denitrification in the secondary clarifier can contribute substantially to the nitrogen removal of activated sludge systems. This is illustrated on two treatment plants with different secondary clarifier systems. A model to estimate denitrification capacity and to design activated sludge systems for nitrogen removal is developed and verified with data from two treatment plants. The model includes denitrification in the secondary clarifier, wastewater composition (soluble readily biodegradable COD, particulate degradable COD), oxygen input into the anoxic volume, temperature, and solids retention time (SRT). The influence of aerated grit chambers and primary sedimentation on denitrification is discussed.

Mechanism and design of intermittent aeration activated sludge process for nitrogen removal

2011 ◽  
Vol 46 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Oytun Hanhan ◽  
Güçlü Insel ◽  
Nevin Ozgur Yagci ◽  
Nazik Artan ◽  
Derin Orhon
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Activated Sludge Process ◽  
Intermittent Aeration
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