A Microprocessor-based Estimation and Control System for the Activated Sludge Process

1983 ◽  
Vol 16 (14) ◽  
pp. 111-119
Author(s):  
A. Holmberg
Keyword(s):  
Control System ◽  
Activated Sludge ◽  
Activated Sludge Process ◽  
Estimation And Control ◽  
And Control

System Identification and Control of the Activated Sludge Process by Use of a Statistical Model

1989 ◽  
Vol 21 (10-11) ◽  
pp. 1161-1172 ◽  
Author(s):  
M. Hiraoka ◽  
K. Tsumura
Keyword(s):  
Control System ◽  
System Identification ◽  
Statistical Model ◽  
Activated Sludge ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Ar Model ◽  
Diurnal Changes ◽  
Activated Sludge Process ◽  
And Control

The authors have been developing a hierarchical control system for the activated sludge process which consists of an upper level system controlling long-term seasonal variations, a control system of intermediate level aiming at optimization of the process and a control system of lower level controlling diurnal changes or hourly fluctuations. The control system using the multi-variable statistical model is one of the most appropriate control systems based on the modern control theory, for applying the lower level control of the activated sludge process. This paper introduces our efforts for developing the reliable data acquisition system, the control experiments applying the AR-model, one of the statistical models which were conducted at a pilot plant and present studies on the system identification and control at a field sewage treatment plant.

Multivariable modeling and control of an activated sludge process

1998 ◽  
Vol 37 (12) ◽  
pp. 149-156 ◽  
Author(s):  
Carl-Fredrik Lindberg
Keyword(s):  
Activated Sludge ◽  
Nitrate Concentration ◽  
State Space Model ◽  
Activated Sludge Process ◽  
Invariant State ◽  
Linear Quadratic ◽  
Modeling And Control ◽  
Space Model ◽  
And Control ◽  
Time Invariant

This paper contains two contributions. First it is shown, in a simulation study using the IAWQ model, that a linear multivariable time-invariant state-space model can be used to predict the ammonium and nitrate concentration in the last aerated zone in a pre-denitrifying activated sludge process. Secondly, using the estimated linear model, a multivariable linear quadratic (LQ) controller is designed and used to control the ammonium and nitrate concentration.

Automatic control for DO and pH in the activated sludge process in a coke wastewater treatment plant

1998 ◽  
Vol 37 (12) ◽  
pp. 141-148 ◽  
Author(s):  
B. K. Lee ◽  
S. W. Sung ◽  
H. D. Chun ◽  
J. K. Koo
Keyword(s):  
Wastewater Treatment ◽  
Control System ◽  
Activated Sludge ◽  
Automatic Control ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Pi Controller ◽  
Activated Sludge Process ◽  
Set Point ◽  
Coke Wastewater

The objective of this study is to develop an automatic control system for dissolved oxygen (DO) and pH of the activated sludge process in a coke wastewater treatment plant. A discrete type autotuned proportional-integral (PI) controller using an auto-regressive exogenous (ARX) model as a process model was developed to maintain the DO concentration in aerators by controlling the speed of surface aerators. Also a nonlinear pH controller using the titration curve was used to control the pH of influent wastewater. This control system was tested in a pilot scale plant. During this pilot plant experiment, there was small deviation of pH and the electric power consumption of surface aerators was reduced up to 70% with respect to the full operation when the DO set point was 2 mg/l. For real plant operation with this system, the discrete PI controller showed good tracking for set point change. The electricity saving was more than 40% of the electricity consumption when considering surface aerators. As a result of maintaining the DO constantly at the set point by the automatic control system, the fluctuation of effluent quality was decreased and overall improvement of the effluent water quality was achieved.

Simultaneous Removal of Nitrogen and Phosphorus in Intermittently Aerated 2-Tank Activated Sludge Process Using DO and ORP-Bending-Point Control

1993 ◽  
Vol 28 (11-12) ◽  
pp. 513-521 ◽  
Author(s):  
Kousei Sasaki ◽  
Yasuji Yamamoto ◽  
Kazushi Tsumura ◽  
Shigeru Hatsumata ◽  
Masahiro Tatewaki
Keyword(s):  
Control System ◽  
Activated Sludge ◽  
Phosphorus Uptake ◽  
Material Balance ◽  
Phosphorus Release ◽  
Test Plant ◽  
Activated Sludge Process ◽  
Time Sharing ◽  
Nitrogen And Phosphorus ◽  
Time Control

The 2-tank intermittent aeration method is an anaerobic-aerobic activated sludge process of time-sharing type in which 2 complete mixing reaction tanks are connected in series, and aeration and agitation are periodically repeated in each tank. We have developed a new control system for the process which can secure anaerobic, anoxic and aerobic conditions through a combination of DO and ORP-Bending-point (corresponding to termination of denitrification) emergence time control. In the 1st tank, nitrification and phosphorus uptake occur in the aeration period, followed by denitrification and phosphorus release in the agitation. The 2nd tank performs nitrification and phosphorus uptake in the aeration and denitrification in the agitation. One cycle of aeration and agitation is approximately 2 hours. This control system was applied to the test plant (influent flow rate: 225 I/day) for two months under the conditions of HRT 16 hours and temperature 20 ±2 °C. We achieved stable and high removal ratios: TOC 94.9 %, T-N 89.4 %, and T-P 95.5 %. We also investigated the mechanisms of nitrogen and phosphorus removal and their material balance.

Intelligent control system based on blackboard concept for wastewater treatment processes

1998 ◽  
Vol 37 (12) ◽  
pp. 77-85 ◽  
Author(s):  
T. Ohtsuki ◽  
T. Kawazoe ◽  
T. Masui
Keyword(s):  
Wastewater Treatment ◽  
Control System ◽  
Activated Sludge ◽  
Intelligent Control ◽  
Software Agents ◽  
High Rate ◽  
Target System ◽  
Activated Sludge Process ◽  
Intelligent Control System ◽  
Treatment Processes

An intelligent control system for wastewater treatment processes has been developed and applied to fullscale, high-rate, activated sludge process control. In this control system, multiple software agents that model the target system using their own modeling method collaborate by using data stored in an abstracted database named ‘blackboard’. The software agents, which are called ‘expert modules’, include a fuzzy expert system, a fuzzy controller, a theoretical activated sludge model, and evaluators of raw data acquired by various online sensors including a respirometer. In this paper, the difficulties of controlling an activated sludge system by using a single conventional strategy are briefly reviewed, then our approach to overcome these difficulties by using multiple modeling methods in the framework of an ‘intelligent control system’ is proposed. Case studies of applications to a high-rate activated sludge process that treats BOD and nitrogen of human excrement are also presented.

Dynamics and control of an activated sludge process as a mixed culture system

AIChE Journal ◽  
1984 ◽  
Vol 30 (3) ◽  
pp. 368-376 ◽  
Author(s):  
Takeichiro Takamatsu ◽  
Suteaki Shioya ◽  
Hirokazu Kurome
Keyword(s):  
Activated Sludge ◽  
Mixed Culture ◽  
Culture System ◽  
Activated Sludge Process ◽  
Dynamics And Control ◽  
And Control
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