Benchmark simulation model no 2: general protocol and exploratory case studies

2007 ◽  
Vol 56 (8) ◽  
pp. 67-78 ◽  
Author(s):  
U. Jeppsson ◽  
M.-N. Pons ◽  
I. Nopens ◽  
J. Alex ◽  
J.B. Copp ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Simulation Model ◽  
Wastewater Treatment Plants ◽  
Control Strategies ◽  
Integrated Control ◽  
Ring Test ◽  
Anaerobic Sludge ◽  
Reject Water ◽  
Whole Plant ◽  
Wide Range

Over a decade ago, the concept of objectively evaluating the performance of control strategies by simulating them using a standard model implementation was introduced for activated sludge wastewater treatment plants. The resulting Benchmark Simulation Model No 1 (BSM1) has been the basis for a significant new development that is reported on here: Rather than only evaluating control strategies at the level of the activated sludge unit (bioreactors and secondary clarifier) the new BSM2 now allows the evaluation of control strategies at the level of the whole plant, including primary clarifier and sludge treatment with anaerobic sludge digestion. In this contribution, the decisions that have been made over the past three years regarding the models used within the BSM2 are presented and argued, with particular emphasis on the ADM1 description of the digester, the interfaces between activated sludge and digester models, the included temperature dependencies and the reject water storage. BSM2-implementations are now available in a wide range of simulation platforms and a ring test has verified their proper implementation, consistent with the BSM2 definition. This guarantees that users can focus on the control strategy evaluation rather than on modelling issues. Finally, for illustration, twelve simple operational strategies have been implemented in BSM2 and their performance evaluated. Results show that it is an interesting control engineering challenge to further improve the performance of the BSM2 plant (which is the whole idea behind benchmarking) and that integrated control (i.e. acting at different places in the whole plant) is certainly worthwhile to achieve overall improvement.

An Integrated Dynamic Model and Control System for Activated Sludge Wastewater Treatment Plants Part II — Control Systems

1989 ◽  
Vol 24 (4) ◽  
pp. 497-522 ◽  
Author(s):  
Zdenko Vitasovic ◽  
John F. Andrews
Keyword(s):  
Process Control ◽  
Activated Sludge ◽  
Dynamic Model ◽  
Flow Rate ◽  
Wastewater Treatment Plants ◽  
Control Strategies ◽  
Integrated Control ◽  
Field Studies ◽  
Pump Station ◽  
And Control

Abstract Part I of this paper has presented an integrated dynamic model for the activated sludge process consisting of a mixture of standard engineering equations and theoretical mechanistic models. In this, Part II of the paper, the integrated model is used in computer simulations to explore process dynamics and integrated control strategies. The interactions of six individual controllers: DO, MCRT, the STOUR profile, settler flow, the compressor, and a pump station have been studied as well as interactions between plant components and design and operation. Among these interactions are those between fluctuations in the influent flow rate and the solids-liquid separator and STOUR in each portion of the biological reactor. The use of a variable volume biological reactor is proposed to damp the effects of flow rate fluctuations on the separator and thus improve effluent quality. Estimation of the STOUR profile and its use in process control is proposed for producing a sludge with more consistent settling characteristics. It is proposed that the use of separator flow control, air flow rate distribution, and step feed capabilities for process control be further explored by field studies for possible incorporation in new plant designs.

OPTIMIZING OPERATION OF WASTEWATER TREATMENT PLANTS BY OFFLINE AND ONLINE COMPUTER SIMULATION

1994 ◽  
Vol 30 (2) ◽  
pp. 165-174 ◽  
Author(s):  
Ralf Otterpohl ◽  
Thomas Rolfs ◽  
Jörg Londong
Keyword(s):  
Computer Simulation ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Historical Analysis ◽  
Computer Work ◽  
Biological Phosphorus Removal ◽  
Wide Range

Computer simulation of activated sludge plant for nitrogen removal has become a reliable tool to predict the behaviour of the plant Models including biological phosphorus removal still require some practical experience but they should be available soon. This will offer an even wider range than today's work with nitrogen removal. One major benefit of computer simulation of wastewater treatment plants (WTP) is the optimization of operation. This can be done offline if hydrographs of a plant are collected and computer work is done with “historical” analysis. With online simulation the system is fed with hydrographs up to the actual time. Prognosis can be done from the moment of the computer work based on usual hydrographs. The work of the authors shows how accuratly a treatment plant can be described, when many parameters are measured and available as hydrographs. A very careful description of all details of the special plant is essential, requiring a flexible simulation tool. Based on the accurate simulation a wide range of operational decisions can be evaluated. It was possible to demonstrate that the overall efficiency in nitrogen removal and energy consumption of ml activated sludge plant can be improved.

scholarly journals Evaluating the performance of a simple phenomenological model for online forecasting of ammonium concentrations at WWTP inlets

2020 ◽  
Vol 81 (1) ◽  
pp. 109-120 ◽  
Author(s):  
Luca Vezzaro ◽  
Jonas Wied Pedersen ◽  
Laura Holm Larsen ◽  
Carsten Thirsing ◽  
Lene Bassø Duus ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Control Strategies ◽  
Integrated Control ◽  
Model Performance ◽  
Forecast Model ◽  
Flow Sensors ◽  
Sewer Systems ◽  
Wastewater Systems ◽  
Water Quality Forecasting ◽  
Modelling Approach

Abstract A simple model for online forecasting of ammonium (NH4+) concentrations in sewer systems is proposed. The forecast model utilizes a simple representation of daily NH4+ profiles and the dilution approach combined with information from online NH4+ and flow sensors. The method utilizes an ensemble approach based on past observations to create model prediction bounds. The forecast model was tested against observations collected at the inlet of two wastewater treatment plants (WWTPs) over an 11-month period. NH4+ data were collected with ion-selective sensors. The model performance evaluation focused on applications in relation to online control strategies. The results of the monitoring campaigns highlighted a high variability in daily NH4+ profiles, stressing the importance of an uncertainty-based modelling approach. The maintenance of the NH4+ sensors resulted in important variations of the sensor signal, affecting the evaluation of the model structure and its performance. The forecast model succeeded in providing outputs that potentially can be used for integrated control of wastewater systems. This study provides insights on full scale application of online water quality forecasting models in sewer systems. It also highlights several research gaps which – if further investigated – can lead to better forecasts and more effective real-time operations of sewer and WWTP systems.

Evaluation of plant-wide WWTP control strategies including the effects of filamentous bulking sludge

2009 ◽  
Vol 60 (8) ◽  
pp. 2093-2103 ◽  
Author(s):  
Xavier Flores-Alsina ◽  
Joaquim Comas ◽  
Ignasi Rodríguez Roda ◽  
Manel Poch ◽  
Krist V. Gernaey ◽  
...  
Keyword(s):  
Simulation Model ◽  
Control Strategies ◽  
Plant Performance ◽  
Water Control ◽  
Reference Case ◽  
Filamentous Bulking ◽  
Reject Water ◽  
Consequent Reduction ◽  
On Line ◽  
Waste Flow

The main objective of this paper is to evaluate the effect of filamentous bulking sludge on the predicted performance of simulated plant-wide WWTP control strategies. First, as a reference case, several control strategies are implemented, simulated and evaluated using the IWA Benchmark Simulation Model No. 2 (BSM2). In a second series of simulations the parameters of the secondary settler model in the BSM2 are automatically changed on the basis of an on-line calculated risk of filamentous bulking, in order to mimic the effect of growth of filamentous bacteria in the plant. The results are presented using multivariate analysis. Including the effects of filamentous bulking in the simulation model gives a—more realistic—deterioration of the plant performance during periods when the conditions for development of filamentous bulking sludge are favourable: compared to the reference case where bulking effects are not considered. Thus, there is a decrease of the overall settling velocity, an accumulation of the total suspended solids (TSS) in the middle layers of the settler with a consequent reduction of their degree of compaction in the bottom. As a consequence there is a lower TSS concentration in both return and waste flow, less biomass in the bioreactors and a reduction of the TSS removal efficiency. The control alternatives using a TSS controller substantially increase the food to microorganisms (F/M) ratio in the bioreactor, thereby reducing both risk and effects of bulking sludge. The effects of ammonium (NH4+), nitrate (NO3−) and reject water control strategies are rather poor when it comes to handling solids separation problems.

WWTP dynamic disturbance modelling–an essential module for long-term benchmarking development

2006 ◽  
Vol 53 (4-5) ◽  
pp. 225-234 ◽  
Author(s):  
K.V. Gernaey ◽  
C. Rosen ◽  
U. Jeppsson
Keyword(s):  
Activated Sludge ◽  
Simulation Model ◽  
Control Strategies ◽  
Monitoring Methods ◽  
Dynamic Disturbance ◽  
Model File ◽  
Disturbance Model ◽  
Holiday Effects ◽  
Biological Nitrogen

Intensive use of the benchmark simulation model No. 1 (BSM1), a protocol for objective comparison of the effectiveness of control strategies in biological nitrogen removal activated sludge plants, has also revealed a number of limitations. Preliminary definitions of the long-term benchmark simulation model No. 1 (BSM1_LT) and the benchmark simulation model No. 2 (BSM2) have been made to extend BSM1 for evaluation of process monitoring methods and plant-wide control strategies, respectively. Influent-related disturbances for BSM1_LT/BSM2 are to be generated with a model, and this paper provides a general overview of the modelling methods used. Typical influent dynamic phenomena generated with the BSM1_LT/BSM2 influent disturbance model, including diurnal, weekend, seasonal and holiday effects, as well as rainfall, are illustrated with simulation results. As a result of the work described in this paper, a proposed influent model/file has been released to the benchmark developers for evaluation purposes. Pending this evaluation, a final BSM1_LT/BSM2 influent disturbance model definition is foreseen. Preliminary simulations with dynamic influent data generated by the influent disturbance model indicate that default BSM1 activated sludge plant control strategies will need extensions for BSM1_LT/BSM2 to efficiently handle 1 year of influent dynamics.

Dissolved and colloidal organic nitrogen removal from wastewater treatment plants effluents and reject waters using physical–chemical processes

2014 ◽  
Vol 70 (3) ◽  
pp. 561-568 ◽  
Author(s):  
K. Czerwionka ◽  
J. Makinia
Keyword(s):  
Activated Sludge ◽  
Organic Nitrogen ◽  
Wastewater Treatment Plants ◽  
Exchange Process ◽  
Cation Exchange Resin ◽  
Chemical Processes ◽  
Biological Nutrient Removal ◽  
Reject Water ◽  
Physical Chemical ◽  
Low Efficiency

Four physical–chemical processes were compared in terms of the efficiencies of dissolved and colloidal organic nitrogen (DON and CON) removal from the secondary effluents (SE) and reject water from full-scale biological nutrient removal activated sludge systems. Adsorption on activated carbon was most efficient and allowed removal from the SE of up to 80% and 100% of DON and CON, respectively. High efficiencies of DON removal from SE (up to 55%) were also obtained when using coagulation with iron(III) chloride and calcium hydroxide at final pH = 11.0–11.5. The efficiency of DON removal from thickening waste activated sludge (TWAS) reject water, obtained using coagulation with iron(III) chloride, was comparable with the efficiency for the SE. The efficiency of this process with regard to the sludge digester liquors (SDL) was significantly higher, i.e., 65–70% for both DON and CON. The ion exchange process with strongly acidic cation exchange resin (without pH correction) resulted in a relatively small efficiency of DON removal (<15%), and negligible efficiency of CON removal (<10%). Furthermore, ultrafiltration (0.015 μm) of SE and TWAS reject water resulted in a relatively low efficiency of DON removal (10–13% and 10–20% respectively). Ultrafiltration was found to be more effective for DON removal from SDL (41–68%).

Development of an operational performance indicator system for activated sludge wastewater treatment plants

2015 ◽  
Vol 10 (4) ◽  
pp. 860-871
Author(s):  
Glenn T. Gordon ◽  
Brian P. McCann
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Performance Indicator ◽  
Wastewater Treatment Plants ◽  
Indicator System ◽  
Municipal Wastewater Treatment ◽  
Water Utility ◽  
Stakeholder Consultation ◽  
Wide Range

Sustainable operation, optimisation and performance evaluation of municipal wastewater treatment plants (WwTPs) in Ireland is topical due to the transfer of water and wastewater operational and capital delivery functions from 34 local authorities to a single national water utility in Ireland. This paper describes the development process of a sustainable optimisation indicator (SOI) system for small-to-medium sized activated sludge (AS) WwTPs using a stakeholder-based approach. The SOI system provides a framework of indicators for performance assessment to facilitate continuous sustainable performance improvement of AS WwTP operations. The findings from plant optimisation and stakeholder consultation studies and the mechanism for their contribution to the development of the SOI system indicators and framework are presented. The proposed system is applicable to wide range of stakeholders for the sustainable and improved monitoring, operation and management of AS WwTPs.

Operating space diagrams: a tool for designers of wastewater treatment plants

2001 ◽  
Vol 44 (2-3) ◽  
pp. 69-76 ◽  
Author(s):  
L. N. Hopkins ◽  
P. A. Lant ◽  
R. B. Newell
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Control Strategies ◽  
Design Stage ◽  
Operating Space

Recent years have seen the introduction of new and varied designs of activated sludge plants. With increasing needs for higher efficiencies and lower costs, the possibility of a plant that operates more effectively has created the need for tools that can be used to evaluate and compare designs at the design stage. One such tool is the operating space diagram. It is the aim of this paper to present this tool and demonstrate its application and relevance to design using a simple case study. In the case study, use of the operating space diagram suggested changes in design that would improve the flexibility of the process. It also was useful for designing suitable control strategies.

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