Dissolved oxygen microelectrode measurements to develop a more sophisticated intermittent aeration regime control strategy for biofilm-based CANON systems

2019 ◽  
Vol 365 ◽  
pp. 165-174 ◽  
Author(s):  
Weigang Wang ◽  
Yayi Wang ◽  
Xiaodong Wang ◽  
Yao Zhang ◽  
Yuan Yan
Keyword(s):  
Dissolved Oxygen ◽  
Control Strategy ◽  
Intermittent Aeration ◽  
Oxygen Microelectrode ◽  
Microelectrode Measurements

Estimation of oxygen transfer rate in sequencing batch reactor

1996 ◽  
Vol 34 (3-4) ◽  
pp. 413-420
Author(s):  
Y. C. Liao ◽  
D. J. Lee
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Oxygen Transfer Rate ◽  
Intermittent Aeration ◽  
Transient Effects ◽  
Operational Parameters ◽  
Transient Model

Transient model of oxygen transfer rate in a sequencing batch reactor is derived and solved numerically. The dissolved oxygen response under several conditions is analyzed. Effects of operational parameters and liquid bath height are studied. When with short, intermittent aeration periods, the transient effects on oxygen transfer rate may be substantial and should be taken into considerations. An example considering bioreaction is also given.

Rule based control of a periodic activated sludge process

1998 ◽  
Vol 38 (3) ◽  
pp. 281-289 ◽  
Author(s):  
S. Isaacs ◽  
D. Thornberg
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Control Strategy ◽  
Periodic Operation ◽  
Rule Based ◽  
Criterion Functions ◽  
Strategy Performance ◽  
Working Region ◽  
And Control ◽  
Selection Of

A rule based control strategy for automatically adjusting phase lengths and aeration intensity for an activated sludge nutrient removal process based on a periodic operation is examined using simulations based on the Activated Sludge Model No. 1. The strategy is based on four criterion functions, two which determine the switching of the roles of two nitrifying/denitrifying reactors and two which adjust the dissolved oxygen setpoint levels in the two reactors as functions of ammonia and nitrate concentrations. Trajectory plots of reactor concentrations in the ammonia-nitrate plane are shown to be a useful means of visualizing process and control performance. Together, the trajectories from a working region in the ammonia-nitrate plane, the size and location of which can to some extent be predetermined by selection of the criterion functions. The presented results include the influence of one of the criterion functions on control strategy performance, how an incompatibility between two criterion functions can lead to unsymmetric reactor loading, and the effect of allowing simultaneous nitrification and denitrification during nitrifying periods by reducing the dissolved oxygen level as ammonia is consumed.

Effect of dissolved oxygen concentration on the biofilm and in situ analysis by fluorescence in situ hybridization (FISH) and microelectrodes

2003 ◽  
Vol 47 (1) ◽  
pp. 49-57 ◽  
Author(s):  
A. Jang ◽  
P.L. Bishop ◽  
S. Okabe ◽  
S.G. Lee ◽  
I.S. Kim
Keyword(s):  
In Situ Hybridization ◽  
Dissolved Oxygen ◽  
Nitrifying Bacteria ◽  
Dry Density ◽  
Ammonia Oxidizing Bacteria ◽  
Biofilm Thickness ◽  
Experimental Findings ◽  
And Control ◽  
Microelectrode Measurements

A better understanding of microbiology and ecology of nitrifying bacteria in inner biofilms is an important part of improving process performance and control. Microelectrodes and fluorescent in situ hybridization (FISH) in biofilm research have been used to investigate the spatial distributions of various microbial activities in biofilms and have led to new experimental findings as well as modifications of the homogeneous assumptions in the biofilm kinetic models. The objective of this study is to try the combination of two methods, both FISH and microelectrode measurements, and to provide reliable and in situ information on nitrifying bacterial activity in biofilms. The characteristics of biofilm developed on tygon slides were different according to the change of dissolved oxygen (DO). When the DO increased from 2 to 10 μg DO/L, the rate of the biofilm thickness increased and its dry density changed from 50-70 to 25-90 mg/cm3. Ammonia oxidizing bacteria were not uniformly distributed in biofilm, and were found at the deeper layer where oxygen is depleted, they were detected primarily in the upper and middle layers of the biofilm.

Design of a generalized predictive controller for a biological wastewater treatment plant

2016 ◽  
Vol 73 (8) ◽  
pp. 1986-2006 ◽  
Author(s):  
M. Sadeghassadi ◽  
C. J. B. Macnab ◽  
D. Westwick
Keyword(s):  
Wastewater Treatment ◽  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Control Strategy ◽  
Treatment Plant ◽  
Effective Control ◽  
Activated Sludge Process ◽  
Measured Variable ◽  
Penalty Term ◽  
Predictive Controller

This paper presents a generalized predictive control (GPC) technique to regulate the activated sludge process found in a bioreactor used in wastewater treatment. The control strategy can track dissolved oxygen setpoint changes quickly, adapting to the system uncertainties and disturbances. Tests occur on an Activated Sludge Model No. 1 benchmark of an activated sludge process. A T filter added to the GPC framework results in an effective control strategy in the presence of coloured measurement noise. This work also suggests how a constraint on the measured variable can be added as a penalty term to the GPC framework which leads to improved control of the dissolved oxygen concentration in the presence of dynamic input disturbance.

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