Centralized PI Controller design for Activated Sludge Process

2021 ◽  
Author(s):  
Sanjith S. Anchan ◽  
Chinta Sankar Rao
Keyword(s):  
Activated Sludge ◽  
Controller Design ◽  
Pi Controller ◽  
Activated Sludge Process

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.

Improvement of ammonia removal in activated sludge process with feedforward-feedback aeration controllers

2006 ◽  
Vol 53 (4-5) ◽  
pp. 125-132 ◽  
Author(s):  
Darko Vrečko ◽  
Nadja Hvala ◽  
Aljaž Stare ◽  
Olga Burica ◽  
Marjeta Stražar ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Pilot Plant ◽  
Pi Controller ◽  
Ammonia Removal ◽  
Activated Sludge Process ◽  
Aerobic Reactor

In the paper three linear aeration controllers that can be easily implemented are presented and evaluated on the activated sludge process pilot plant. Controllers differ according to the information that is used about the process, which can be oxygen in the last aerobic reactor, ammonia in the last aerobic reactor and ammonia in the influent. The aeration controllers that are addressed are: oxygen cascade PI controller, ammonia cascade PI controller and ammonia feedforward-cascade PI controller. Experiments show that, in comparison with the oxygen cascade PI controller, the ammonia cascade PI controller allows better control of effluent ammonia and airflow savings of around 23%, while the ammonia feedforward-cascade PI controller gives the best reduction of ammonia peaks and can save up to 45% of the airflow.

Iterative design of a nitrate controller using an external carbon source in an activated sludge process

1998 ◽  
Vol 37 (12) ◽  
pp. 95-102 ◽  
Author(s):  
Pericles R. Barros ◽  
Bengt Carlsson
Keyword(s):  
Carbon Source ◽  
Activated Sludge ◽  
High Performance ◽  
Controller Design ◽  
Wastewater Treatment Plants ◽  
Design Procedure ◽  
Pole Placement ◽  
Activated Sludge Process ◽  
Suggested Approach ◽  
External Carbon Source

More stringent effluent and cost requirements are increasing the need for better control of wastewater treatment plants. In an activated sludge process, the nitrogen removal efficiency may be improved by adding an external carbon source. In this paper, automatic control of the nitrate level by regulating external carbon flow is discussed. More specifically, an iterative tuning procedure for the controller is outlined. Iterative controller design schemes aim at tuning high performance controllers of low complexity using closed loop data. The basic strategy used in this paper is an iterative pole placement controller design procedure. The suggested approach is compared with conventional design in a simulation study.

Improvement of Activated Sludge Process Using Enhanced Nonlinear PI Controller

2014 ◽  
Vol 39 (8) ◽  
pp. 6575-6586 ◽  
Author(s):  
S. I. Samsudin ◽  
M. F. Rahmat ◽  
N. A. Wahab ◽  
M. C. Razali ◽  
M. S. Gaya ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Pi Controller ◽  
Activated Sludge Process

Improving oxygen concentration control in activated sludge process with estimation of respiration and scheduling control

2006 ◽  
Vol 53 (4-5) ◽  
pp. 283-291 ◽  
Author(s):  
S. Gerkšič ◽  
D. Vrečko ◽  
N. Hvala
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Oxygen Concentration ◽  
Pi Controller ◽  
Activated Sludge Process ◽  
Dissolved Oxygen Concentration ◽  
Integral Control ◽  
Process Dynamics ◽  
On Line ◽  
The Cost

The paper presents an efficient and simple model-based method of on-line estimation of respiration from the current values of dissolved oxygen concentration and airflow signals. Fast estimation of respiration is important because respiration appears as the most important disturbance signal in the control of dissolved oxygen concentration, and could therefore be used for improving control efficiency. A parameter scheduling PI (proportional and integral) control scheme is proposed, where the estimated respiration signal is used for scheduling of the PI controller parameters, by using local linearization of the process dynamics. The performance of the scheduling controller is compared to a conventional PI controller in simulation using the COST simulation benchmark, and experimentally on an activated sludge process pilot plant.

Nonlinear and set-point control of the dissolved oxygen concentration in an activated sludge process

1996 ◽  
Vol 34 (3-4) ◽  
pp. 135-142 ◽  
Author(s):  
Carl-Fredrik Lindberg ◽  
Bengt Carlsson
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Oxygen Concentration ◽  
Controller Design ◽  
Ammonia Concentration ◽  
Pilot Scale ◽  
Process Efficiency ◽  
Activated Sludge Process ◽  
Dissolved Oxygen Concentration ◽  
Set Point

Control of the dissolved oxygen concentration (DO) in an activated sludge process is of considerable importance because of economy and process efficiency. A strategy for designing a nonlinear DO controller was developed. The basic idea was to take the nonlinear oxygen transfer function into account in the controller design. Simulations illustrated that a nonlinear DO controller outperforms a standard PI controller. This was also confirmed in a pilot-scale plant experiment. A supervision (set-point) controller for the DO is also outlined. Initial simulations showed promising results where the aeration system is used more efficiently and the effluent ammonia concentration could be maintained low.

Improvement of Activated Sludge Process Using a Nonlinear PI Controller Design via Adaptive Gain

2016 ◽  
Vol 14 (1) ◽  
pp. 407-416 ◽  
Author(s):  
P. A. López-Pérez ◽  
M. I. Neria-González ◽  
R. Aguilar-López
Keyword(s):  
Steady State ◽  
Controller Design ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Pi Controller ◽  
Control Law ◽  
Activated Sludge Process ◽  
Recirculation Flow ◽  
Control Scheme ◽  
Do Concentration

AbstractThe goal of this work was to design an adaptive nonlinear proportional–integral (PI) controller to regulate the dynamics of an aerobic wastewater bioreactor, providing a mathematical sketch of proof of the convergence of the control scheme. Adequate operating regions were determined and the corresponding steady-state points were studied via phase portrait and bifurcation analysis. The proposed controller was applied to a wastewater treatment plant to regulate dissolved oxygen (DO) concentration and, indirectly, the concentration of chemical oxygen demand (COD) in the bioreactor; the recirculation flow rate was considered as the manipulated variable. The implementation was based on the mathematical bioreactor’s model, which was experimentally verified; it describes COD dynamics, DO, biomass, recirculation biomass concentrations, and temperature. The obtained results, via numerical simulations, showed that the proposed control law is able to control DO concentration; this control exhibited better performance in comparison to a linear one.

Sign in / Sign up

Export Citation Format

Share Document