Modelling Simulation and Control of an Existing Activated Sludge Wastewater Treatment Process

1976 ◽  
Vol 11 (1) ◽  
pp. 108-121
Author(s):  
N. Thérien ◽  
P. Harrington
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Flow Rate ◽  
Treatment Plant ◽  
Organic Substrate ◽  
Activated Sludge Process ◽  
Two Phase ◽  
Wastewater Treatment Process ◽  
Wastewater Stream ◽  
And Control

Abstract The dynamic response of the activated sludge process in the wastewater treatment plant of the Centre Hospitalier Universitaire de Sherbrooke was analysed with respect to large disturbances in both the flow rate and the quality of wastewater entering the plant. A mass balance conducted for the organic substrate and biomass entering and leaving the process led to a model consisting of two separate differential equations in terms of BOD and VSS with a two-phase bio-kinetic relationship for the reaction term. Predictions of the model for BOD and VSS variations in time were compared to experimental observations at the plant. A model using mean daily values for VSS and expressed in terms of BOD for the stream flowing out the clarifier unit in response to flow rate and BOD cyclic fluctuations of the entering wastewater stream to the process was found apt at describing the time at which BOD peaks in the process effluent occurred as well as predicting the magnitude of these peaks. The dynamic behaviour of the activated sludge process has been simulated for periods of one to several days using this model. Its use in predicting appropriate control action in time in order to improve the treatment efficiency is also indicated.

scholarly journals A Software Emulator for the Modelling and Control of an Activated Sludge Process in a Wastewater Treatment Plant

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2054
Author(s):  
Dan Selișteanu ◽  
Ion-Marian Popescu ◽  
Monica Roman ◽  
Constantin Șulea-Iorgulescu ◽  
Sorin Mehedințeanu
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Software Tool ◽  
Open Architecture ◽  
Software Systems ◽  
Activated Sludge Process ◽  
And Control ◽  
Software Emulator

The design and implementation of a simulator, as a real-time application, for a complex process from the biological treatment stage of a wastewater treatment plant (WWTP), is addressed. More precisely, this emulator was achieved as a software tool that can be later integrated into a more complex SCADA (supervisory control and data acquisition) system of the WWTP Făcăi, Romania. The basic idea is to implement and validate a reduced-order model of the activated sludge process (ASP), initially simulated in the Matlab/Simulink environment (The MathWorks, Inc., Natick, MA, USA). Moreover, an advanced multivariable adaptive control scheme of the ASP is addressed. This software tool can be made to work in parallel with the evolution of the process and can have as input signals measured directly at the process level, possibly following parametric or model adaptations. The software emulator is developed in the LabWindows/CVI programming environment (National Instruments), which offers low-level access to hardware or software systems that have minimal open-architecture facilities. This environment provides versatile drivers and software packages that can facilitate the interaction with software tools developed within some earlier SCADA systems. The structure and the graphical interface of the emulator, some functionalities, experiments, and evolution of main variables are presented.

scholarly journals Treatment of slaughterhouse wastewater using an activated sludge/contact aeration process

2003 ◽  
Vol 47 (12) ◽  
pp. 285-292 ◽  
Author(s):  
C.-K. Chen ◽  
S.-L. Lo
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Biological Treatment ◽  
Treatment Plant ◽  
Aeration Tank ◽  
Activated Sludge Process ◽  
Two Phase ◽  
Slaughterhouse Wastewater ◽  
Aeration Process ◽  
Biological Treatment System

This study combines a two-phase biological treatment system of activated sludge/contact aeration process by adding biological contact filters into the rear sector of the activated sludge aeration tank of the slaughterhouse wastewater treatment plant. This system keeps the advantages of complete mixing of substrates and microorganisms and flexible operation of the activated sludge process, and increased biological phase, less sludge, process stability and good settleability of sludge of the contact aeration process. This system could avoid the defects of sludge bulking, increased sludge production and difficult operation of the activated sludge process, and system clogging and rigid operation of the contact aeration process. Because suspended microorganisms are flowing into the contact aeration system, which then degrade or suspend within the biological contact filters after being adsorbed by the fixed biological film, on which partial bio-solids will act as seeding microorganisms. Suspended microorganisms and the dropped biological film will settled in the secondary settling tank, then reflux into the activated sludge aeration tank. The partial dropped biological film will decompose in the activated sludge aeration tank to achieve the function of decreasing sludge. Large specific gravity and good settling ability of biofilm sludge will provide better effluent quality. It has been proven through a practical experiment at a slaughterhouse wastewater treatment plant in Taiwan, that the activated sludge process effluent COD value of 150-200 mg/L and SS value of 80-100 mg/L were decreased to around 40 mg/L and 22 mg/L, respectively, after changing its system to the two-phase biological treatment system of activated sludge/contact aeration process.

DESIGN PLANNING WASTEWATER TREATMENT PLANT OF NATA DE COCO INDUSTRY WITH THE ACTIVATED SLUDGE PROCESS

2016 ◽  
Vol 9 (2) ◽  
Author(s):  
Dinda Rita K. Hartaja ◽  
Imam Setiadi
Keyword(s):  
Waste Water ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Waste Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Appropriate Technology ◽  
Waste Water Treatment Plant ◽  
Activated Sludge Process ◽  
High Level

Generally, wastewater of nata de coco industry contains suspended solids and COD were high, ranging from 90,000 mg / l. The high level of of the wastewater pollutants, resulting in nata de coco industry can not be directly disposed of its wastewater into the environment agency. Appropriate technology required in order to process the waste water so that the treated water can meet the environmental quality standards that are allowed. Designing the waste water treatment plant that is suitable and efficient for treating industrial wastewater nata de coco is the activated sludge process. Wastewater treatment using activated sludge process of conventional (standard) generally consists of initial sedimentation, aeration and final sedimentation.Keywords : Activated Sludge, Design, IPAL

Rehabilitation and Upgrading of the Beni Suef City Wastewater Treatment Plant

1990 ◽  
Vol 22 (7-8) ◽  
pp. 131-138
Author(s):  
Ahmed Fadel
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Primary Treatment ◽  
High Rate ◽  
Shock Load ◽  
Economic Evaluations ◽  
Activated Sludge Process ◽  
Trickling Filter

Many of Egypt's cities have existing treatment plants under operation that have been constructed before 1970. Almost all of these treatment plants now need rehabilitation and upgrading to extend their services for a longer period. One of these plants is the Beni Suef City Wastewater Treatment Plant. The Beni Suef WWTP was constructed in 1956. It has primary treatment followed by secondary treatment employing intermediate rate trickling filters. The BOD, COD, and SS concentration levels are relatively high. They are approximately 800, 1100, and 600 mg/litre, respectively. The Beni Suef city required the determination of the level of work needed for the rehabilitation and upgrading of the existing 200 l/s plant and to extend its capacity to 440 l/s at year 2000 A description of the existing units, their deficiencies and operation problems, and the required rehabilitation are presented and discussed in this paper. Major problems facing the upgrading were the lack of space for expansion and the shortage of funds. It was, therefore, necessary to study several alternative solutions and methods of treatment. The choice of alternatives was from one of the following schemes: a) changing the filter medium, its mode of operation and increasing the number of units, b) changing the trickling filter to high rate and combining it with the activated sludge process, for operation by one of several possible combinations such as: trickling filter-solids contact, roughing filter-activated sludge, and trickling filter-activated sludge process, c) dividing the flow into two parts, the first part to be treated using the existing system and the second part to be treated by activated sludge process, and d) expanding the existing system by increasing the numbers of the different process units. The selection of the alternative was based on technical, operational and economic evaluations. The different alternatives were compared on the basis of system costs, shock load handling, treatment plant operation and predicted effluent quality. The flow schemes for the alternatives are presented. The methodology of selecting the best alternative is discussed. From the study it was concluded that the first alternative is the most reliable from the point of view of costs, handling shock load, and operation.

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.

Operational Results of the Wolfsburg Wastewater Treatment Plant

1992 ◽  
Vol 25 (4-5) ◽  
pp. 203-209 ◽  
Author(s):  
R. Kayser ◽  
G. Stobbe ◽  
M. Werner
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nitrogen Content ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Phosphate Removal ◽  
Total Nitrogen Content ◽  
Activated Sludge Process

At Wolfsburg for a load of 100,000 p.e., the step-feed activated sludge process for nitrogen removal is successfully in operation. Due to the high denitrification potential (BOD:TKN = 5:1) the effluent total nitrogen content can be kept below 10 mg l−1 N; furthermore by some enhanced biological phosphate removal about 80% phosphorus may be removed without any chemicals.

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.

Sensitivity of Effluent Variables in Activated Sludge Process

2017 ◽  
Vol 13 (2) ◽  
Author(s):  
B Vivekanandan ◽  
K Jeyannathann ◽  
A. Seshagiri Rao
Keyword(s):  
Activated Sludge ◽  
Flow Rate ◽  
Oxygen Transfer Rate ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Maximum Flow ◽  
Activated Sludge Process ◽  
Flow Conditions ◽  
Treated Effluent ◽  
Influent Flow

Abstract The quality of a treated effluent changes when there is a sudden variation in the influent flow to the wastewater treatment plant during dry, rain, and storm weather conditions. In this study, various influent flow conditions in an activated sludge process are considered that affect the sensitivity of effluent variables such as chemical oxygen demand (COD), biological oxygen demand (BOD), nitrate nitrogen (SNO), ammonical nitrogen (SNH), and total nitrogen (TN) with respect to varying internal recycle flow rate (Qa), sludge recycle flow rate (Qr), sludge wastage flow rate (Qw) and oxygen transfer rate co-efficient of aerobic tanks (KLa(3,4,5)). The analysis has been carried out based on benchmark simulation model no.1 (BSM 1) plant layout which comprises of two models namely activated sludge model no.1 (ASM 1) and simple one dimensional (Simple 1-D) Takacs model. Based on the present analysis, it is observed that the changes in influent flow rate have larger impact on the effluent variables. This variation can be subdued by introducing additional tanks to smoothen the perturbations or using internal recycle rate from the fifth tank in order to maintain the flow around the optimal influent flow rate. The sludge wastage rate has a greater impact on all effluent variables except nitrogenous variables during maximum flow conditions.

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