scholarly journals Unknown Inputs Nonlinear Observer for an Activated Sludge Process

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Feten Smida ◽  
Taoufik Ladhari ◽  
Salim Hadj Saïd ◽  
Faouzi M’sahli
Keyword(s):  
Activated Sludge ◽  
High Gain ◽  
The Other ◽  
Nonlinear Observer ◽  
Dynamics Simulation ◽  
Activated Sludge Process ◽  
Unknown Inputs ◽  
Simulation Results ◽  
Economic Concentration ◽  
Substrate Concentrations

This paper deals with the jointly estimation problem of unknown inputs and nonmeasured states of one altering aerated activated sludge process (ASP). In order to provide accurate and economic concentration measures during aerobic and anoxic phases, a cascade high gain observer (HGO) approach is developed. Only two concentrations are available; the other process’s states are assumed unavailable. The observer converges asymptotically and it leads to a good estimation of the unavailable states which are the ammonia and substrate concentration, as well as a quite reconstruction of the unknown inputs, which are the influent ammonia and the influent substrate concentrations. To highlight the efficiency of the proposed HGO with this MIMO system’s dynamics, simulation results are validated with experimental data.

Unknown Inputs Observer-Based Output Feedback Predictive Controller for an Activated Sludge Process

2018 ◽  
Vol 66 (4) ◽  
pp. 556-568
Author(s):  
Feten Smida ◽  
Taoufik Ladhari ◽  
Salim Hadj Saïd ◽  
Faouzi M'sahli
Keyword(s):  
Activated Sludge ◽  
Output Feedback ◽  
Activated Sludge Process ◽  
Unknown Inputs ◽  
Predictive Controller

The roles of microbes in the removal and inactivation of viruses in a biological wastewater treatment system

1996 ◽  
Vol 33 (10-11) ◽  
pp. 243-250 ◽  
Author(s):  
Tae-Dong Kim ◽  
Hajime Unno
Keyword(s):  
Activated Sludge ◽  
The Other ◽  
Virus Concentration ◽  
Activated Sludge Process ◽  
Filter Feeder ◽  
Virus Removal ◽  
First Order ◽  
Second Stage ◽  
Strong Filter ◽  
Model Virus

The objective of this research is to clarify the mechanism for virus removal in an activated sludge process. The roles of microbes, i.e. bacteria, protozoa and metazoa, which form activated sludge were investigated using poliovirus as a model virus. In a bacteria cultures, the virus concentration decreased in the first one hour after which no further decrease was observed. This phenomenon is explained by the interaction of bacterial floc and virus where virus was removed by reversible adsorption. On the other hand, in the mixed culture of bacteria and protozoa, or of bacteria and metazoa, the virus removal process was observed to proceed in two first-order processes. In the first stage, virus was removed from the liquid phase by adsorption onto the floc, whereas in the second stage, virus is removed by predation of the other microbes, i.e. protozoa or metazoa. Moreover, the floc-forming ability and the feeding manner of the microbes strongly affected the virus removal. Especially, a filter feeder microbe was more effective in virus removal than a detritus feeder microbe. Among the microbes used in the experiments, P. erythrophthalma which had a large mouth and a strong filter-feeding ability as well as a high floc-forming ability showed the most efficient virus removal.

An activated sludge process without excess sludge production

1997 ◽  
Vol 36 (11) ◽  
pp. 163-170 ◽  
Author(s):  
Yoshio Sakai ◽  
Tetsuro Fukase ◽  
Hidenari Yasui ◽  
Masahide Shibata
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
The Other ◽  
Aeration Tank ◽  
Activated Sludge Process ◽  
Organic Substances ◽  
Complete Elimination ◽  
Excess Sludge ◽  
Effluent Quality ◽  
Inorganic Substances

An activated sludge process which produces no excess sludge was developed. The process is very simple as a small amount of return sludge is ozonated and then returned to the aeration tank. The ozonation enhances biodegradability of activated sludge, which is biologically oxidized in the aeration tank. A full-scale plant for treating 450m3/d of municipal wastewater was constructed and has been operated successfully for 9 months. The amount of excess sludge eliminated is directly proportional to the amount of ozone dosed to the sludge. At the ozone dosing rate of 0.034 kg/kg-SS, complete elimination of excess sludge has been achieved when 4 times more amount of sludge is ozonated than that of the excess sludge expected in the treatment without ozonation. After 5 months of operation without any withdrawal of excess sludge, small amount of inorganic substances like sand and silt accumulated in the sludge. On the other hand, inert organic substances does not seem to accumulate. As for effluent quality, BOD and nitrogen were kept good. Although effluent SS was 2–15 mg/l higher compared to a control without ozonation, it has been well below the discharge limit.

scholarly journals Robust State Estimation for a Nonlinear Hybrid Model of the Alternating Activated Sludge Process Using Filtered High-Gain Observers

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Afef Boudagga ◽  
Habib Dimassi ◽  
Salim Hadj-Said ◽  
Faouzi M’Sahli
Keyword(s):  
Activated Sludge ◽  
State Estimation ◽  
Estimation Method ◽  
High Gain ◽  
Observer Design ◽  
Measurement Noise ◽  
Observation Error ◽  
Activated Sludge Process ◽  
High Gain Observer ◽  
Nonlinear Hybrid

In this paper, a robust state estimation method based on a filtered high-gain observer is developed for the alternating activated sludge process (AASP) considered as a nonlinear hybrid system. Indeed, we assume that the biodegradable substrate and the ammonia concentrations in the AASP model are unmeasured due to the high cost of their sensors whose maintenance is also very expensive. The observer design is based on the association of the classical high-gain observer and the idea of the application of linear filters on the observation error to deal with measurement noise. It is shown through a Lyapunov analysis that the designed observer ensures the estimation of the unmeasured states (the biodegradable substrate and the ammonia concentrations) based on the measured dissolved oxygen and nitrate concentrations subject to noise. A comparison with the classical high-gain observer is performed via numerical simulations in order to show the robustness of the suggested estimation approach against Gaussian measurement noise.

scholarly journals Observer based robust H∞ fuzzy tracking control: application to an activated sludge process

2021 ◽  
Vol 7 ◽  
pp. e458
Author(s):  
Abdelmounaim Khallouq ◽  
Asma Karama ◽  
Mohamed Abyad
Keyword(s):  
Activated Sludge ◽  
Fuzzy Systems ◽  
Fuzzy Controller ◽  
Sufficient Conditions ◽  
Linear Matrix ◽  
Activated Sludge Process ◽  
Fuzzy Observer ◽  
Control Application ◽  
Takagi Sugeno ◽  
Substrate Concentrations

The design of an observer-based robust tracking controller is investigated and successfully applied to control an Activated Sludge Process (ASP) in this study. To this end, the Takagi–Sugeno (TS) fuzzy modeling is used to describe the dynamics of a nonlinear system with disturbance. Since the states of the system are not fully available, a fuzzy observer is designed. Based on the observed states and a reference state model, a reduced fuzzy controller for trajectory tracking purposes is then proposed. While the controller and the observer are developed, the design goal is to achieve the convergence and a guaranteed H∞ performance. By using Lyapunov and H∞ theories, sufficient conditions for synthesis of a fuzzy observer and a fuzzy controller for TS fuzzy systems are derived. Using some special manipulations, these conditions are reformulated in terms of linear matrix inequalities (LMIs) problem. Finally, the robust and effective tracking performance of the proposed controller is tested through simulations to control the dissolved oxygen and the substrate concentrations in an activated sludge process.

Pilot Regulation to Treat PTA Wastewater

2013 ◽  
Vol 295-298 ◽  
pp. 1115-1119
Author(s):  
Lei Shi ◽  
Xue Tan ◽  
Ya Zong Mai
Keyword(s):  
Activated Sludge ◽  
Manganese Peroxidase ◽  
Terephthalic Acid ◽  
Loading Rate ◽  
Specific Activity ◽  
The Other ◽  
Activated Sludge Process ◽  
Purified Terephthalic Acid ◽  
Functional Strain

In the pilot research for treatment of the purified terephthalic acid (PTA) wastewater with the functional strain Fhhh in the carrier activated sludge process (CASP) effectively, control of the value of COD: TN: TP and the concentrations of Cu, Mn, Se and Zn were conducted to improve the manganese peroxidase (MnP) level. When the value of COD:TN:TP was 100:0.36:0.15 and the concentrations of Cu, Mn, Se and Zn were 0.54, 5.07, 0.00 and 0.08mg/L, the specific activity value of MnP reached a higher level being 689 units while the sludge loading rate was 1.09 d-1. This value of the sludge loading rate was those of 4-7fold of the other processes reported. The data suggested that improving MnP level could enhance the degradability for Fhhh. And the potentials for Fhhh in the PTA wastewater CASP will be also discussed in this paper.

Simulation and Optimization of Compound A2/O Treatment Process Based on Model ASM3

2013 ◽  
Vol 726-731 ◽  
pp. 2389-2393
Author(s):  
Xiao Hu ◽  
Yong Xiang Zhang ◽  
Yi Fan Wang ◽  
Shuo Jia Peng
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Process Design ◽  
Treatment Process ◽  
Reflux Ratio ◽  
Activated Sludge Process ◽  
Compound A ◽  
Simulation And Optimization ◽  
Simulation Results ◽  
Removal Efficiencies

Introduction is given to the content of activated sludge model No.3 (ASM3). The simulation program which based on the integration of ASM3 and Anaerobic Digestion Model was used to simulate A2/O with AquaMats Process. The predicted results of effluent COD, NH3-N and NO3-N accorded with the actuality. The removal efficiency of TP was quite low when sludge return rate was 100%. Based on this condition, the improved scheme which adjusts sludge reflux ratio to 60% was put forward and simulated. Process was optimized depending on the simulation results and the removal efficiencies of COD, NH3-N and TP reached to 83.1%, 98.75 and 24.01%. It is verified that ASM3 can be used as the platform of activated sludge process design.

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