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

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.

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

Water Science & Technology ◽

10.2166/wst.2007.604 ◽

2007 ◽

Vol 56 (8) ◽

pp. 67-78 ◽

Cited By ~ 130

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.

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Model Based On-Line Control of Sewer Systems

Water Science & Technology ◽

10.2166/wst.1993.0649 ◽

1993 ◽

Vol 28 (11-12) ◽

pp. 87-98

Author(s):

Jörgen Bo Nielsen ◽

Sten Lindberg ◽

Poul Harremöes

Keyword(s):

Real Time ◽

Software Package ◽

Control Strategies ◽

Forecast Model ◽

Central Feature ◽

Real Time Control ◽

Sewer System ◽

Model Based ◽

Sewer Systems ◽

On Line

A new software package has been developed for use in real-time control of the flow in combined sewer systems (CSS). A central feature of the new package is forecast modelling of the flows and volumes in the sewer system. Based upon the forecast model predictions, an expert system or an optimisation module determines the set-points for all regulators in the system. The new software package includes a comprehensive tool-set for use in the design of on-line control systems, including a model-based real-time simulator, which can be applied in the testing of control strategies. The first practical application of the software package for a sewer system in the city of Aalborg is described.

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Parameter optimisation of real-time control strategies for urban wastewater systems

Water Science & Technology ◽

10.2166/wst.2001.0408 ◽

2001 ◽

Vol 43 (7) ◽

pp. 139-146 ◽

Cited By ~ 3

Author(s):

M. Schütze ◽

D. Butler ◽

M. B. Beck

Keyword(s):

Parameter Estimation ◽

Real Time ◽

Control Algorithm ◽

Optimization Problem ◽

Control Strategies ◽

Integrated Control ◽

Urban Wastewater ◽

Real Time Control ◽

Time Control ◽

Wastewater Systems

Real-time control (RTC) of wastewater systems has been a topic of research and application for over two decades. Attempts so far have mainly focused on one of the parts of the urban wastewater system: either the sewer system, or the treatment plant or the river. Approaches to integrate these subsystems and considering them jointly for control purposes have been pursued only recently. Control of the system aims at pursuing one (or several concomitant) objectives, which are expressed, for example, in terms of overflow volumes, loads, effluent concentrations, receiving water quality or monetary costs, to name just a few. This paper provides a general and formal definition of the problem to define a real time control algorithm for a given urban wastewater system. A general mathematical optimization problem is formulated, which describes the task of finding an (in some sense) optimum control algorithm. Since this optimization problem is, in the general case, highly non-linear with only limited information available about the objective function itself, optimization methods appropriate for this type of problem are identified. Here, the similarity of the problem to find a control algorithm and of the parameter estimation problem common in mathematical modelling becomes apparent. Hence, methods (and problems encountered) in parameter estimation can be transferred to the problem of determining optimum RTC algorithms. This parallelism is outlined in the paper. As an application of the parameterisation and optimization of control strategies, integrated control of an urban wastewater system is discussed. Since the analysis of integrated control as just described poses certain requirements on a simulation engine, a novel modelling tool, called SYNOPSIS, is utilized here. This simulation tool, comprising of modules simulating water quantity and quality processes in all parts of the urban wastewater system, is embedded into a suite of optimization procedures. An integrated RTC algorithm for the urban wastewater system is formulated, the parameters of which are optimized using various global optimization routines. Comparison of their efficiency indicates good performance for the Controlled Random Search and for the genetic algorithms. The findings suggest that integrated control can indeed lead to an increase in performance of the urban wastewater system. These results appear to be encouraging and justify further work. Areas for further development are identified in the final section of the paper.

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Impacts of onsite greywater reuse on wastewater systems

Water Science & Technology ◽

10.2166/wst.2017.057 ◽

2017 ◽

Vol 75 (8) ◽

pp. 1862-1872 ◽

Cited By ~ 6

Author(s):

Roni Penn ◽

Manfred Schütze ◽

Jens Alex ◽

Eran Friedler

Keyword(s):

Urban Areas ◽

Process Model ◽

Field Experiments ◽

Wastewater Treatment Plants ◽

Domestic Wastewater ◽

Sewer Systems ◽

Case Study Site ◽

Wastewater Systems ◽

Greywater Reuse

Together with significant water savings that onsite greywater reuse (GWR) may provide, it may also affect the performance of urban sewer systems and wastewater treatment plants (WWTPs). In order to examine these effects, an integrated stochastic simulation system for GWR in urban areas was developed. The model includes stochastic generators of domestic wastewater streams and gross solids (GSs), a sewer network model which includes hydrodynamic simulation and a GS transport module, and a dynamic process model of the WWTP. The developed model was applied to a case study site in Israel. For the validation of the sewer simulator, field experiments in a real sewer segment were conducted. The paper presents the integration and implementation of these modules and depicts the results of the effects of various GWR scenarios on GS movement in sewers and on the performance of the WWTP.

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

Water Quality Research Journal ◽

10.2166/wqrj.1989.031 ◽

1989 ◽

Vol 24 (4) ◽

pp. 497-522 ◽

Cited By ~ 1

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.

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Design and Operation of Small Wastewater Treatment Plants by the Microbial Film Process

Water Science & Technology ◽

10.2166/wst.1990.0194 ◽

1990 ◽

Vol 22 (3-4) ◽

pp. 139-144 ◽

Cited By ~ 4

Author(s):

S. Iwai ◽

Y. Oshino ◽

T. Tsukada

Keyword(s):

Urban Areas ◽

Wastewater Treatment Plants ◽

Waste Water Treatment ◽

Small Scale ◽

Small Communities ◽

Fishing Villages ◽

Sewer Systems ◽

Water Treatment Plants ◽

History Of ◽

Microbial Film

Although the ratio of sewer systems to population in Japan has been improving in recent years, the construction of sewer systems in small communities such as farming or fishing villages, etc. had lagged behind that of urban areas. However, construction of small-scale sewer systems in farming and fishing villages has been actively carried out in recent years. This report explains the history of the promotion of small-scale sewer systems, why submerged filter beds are being employed in many cases, and introduces the design, operation and maintenance of representative waste-water treatment plants in farming and fishing villages which incorporate de-nitrogen and dephosphorization.

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Pollution based real time control strategies for combined sewer systems

Water Science & Technology ◽

10.2166/wst.1997.0688 ◽

1997 ◽

Vol 36 (8-9) ◽

pp. 331-336 ◽

Cited By ~ 8

Author(s):

Gabriela Weinreich ◽

Wolfgang Schilling ◽

Ane Birkely ◽

Tallak Moland

Keyword(s):

Real Time ◽

Control Strategies ◽

Ammonia Nitrogen ◽

Simple Extension ◽

Real Time Control ◽

Time Control ◽

Sewer Systems ◽

Receiving Waters ◽

Tunnel System

This paper presents results from an application of a newly developed simulation tool for pollution based real time control (PBRTC) of urban drainage systems. The Oslo interceptor tunnel is used as a case study. The paper focuses on the reduction of total phosphorus Ptot and ammonia-nitrogen NH4-N overflow loads into the receiving waters by means of optimized operation of the tunnel system. With PBRTC the total reduction of the Ptot load is 48% and of the NH4-N load 51%. Compared to the volume based RTC scenario the reductions are 11% and 15%, respectively. These further reductions could be achieved with a relatively simple extension of the operation strategy.

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Evaluation of a Distributed Streamflow Forecast Model at Multiple Watershed Scales

Water ◽

10.3390/w12051279 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1279

Author(s):

Tyler Madsen ◽

Kristie Franz ◽

Terri Hogue

Keyword(s):

Local Population ◽

Model Performance ◽

Forecast Model ◽

Hydrologic Model ◽

Laboratory Research ◽

Discharge Data ◽

Distributed Hydrologic Model ◽

Verification Period ◽

Silver Spring

Demand for reliable estimates of streamflow has increased as society becomes more susceptible to climatic extremes such as droughts and flooding, especially at small scales where local population centers and infrastructure can be affected by rapidly occurring events. In the current study, the Hydrology Laboratory-Research Distributed Hydrologic Model (HL-RDHM) (NOAA/NWS, Silver Spring, MD, USA) was used to explore the accuracy of a distributed hydrologic model to simulate discharge at watershed scales ranging from 20 to 2500 km2. The model was calibrated and validated using observed discharge data at the basin outlets, and discharge at uncalibrated subbasin locations was evaluated. Two precipitation products with nominal spatial resolutions of 12.5 km and 4 km were tested to characterize the role of input resolution on the discharge simulations. In general, model performance decreased as basin size decreased. When sub-basin area was less than 250 km2 or 20–40% of the total watershed area, model performance dropped below the defined acceptable levels. Simulations forced with the lower resolution precipitation product had better model evaluation statistics; for example, the Nash–Sutcliffe efficiency (NSE) scores ranged from 0.50 to 0.67 for the verification period for basin outlets, compared to scores that ranged from 0.33 to 0.52 for the higher spatial resolution forcing.

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EFFECTS OF FLORIDA CITRUS PEST CONTROL PRACTICES ON THE CITRUS BLACKFLY (HOMOPTERA: ALEYRODIDAE) AND ITS ASSOCIATED NATURAL ENEMIES

The Canadian Entomologist ◽

10.4039/ent111731-6 ◽

1979 ◽

Vol 111 (6) ◽

pp. 731-734 ◽

Cited By ~ 7

Author(s):

George E. Fitzpatrick ◽

Ronald H. Cherry ◽

Robert V. Dowell

Keyword(s):

Control Strategies ◽

Integrated Control ◽

Biological Control Agents ◽

Chemical Treatments ◽

Chronic Effects ◽

Aleurocanthus Woglumi ◽

Integrated Control Strategies ◽

Florida Citrus ◽

Amitus Hesperidum ◽

Predator Complex

AbstractThe postbloom and summer sprays recommended in Florida commercial citrus cultures for management of insect and mite pests and phytopathogenic diseases caused a significant (P < 0.05) reduction of citrus blackfly, Aleurocanthus woglumi Ashby, infesting urban dooryard citrus. There were no observed adverse chronic effects on populations of the parasite Amitus hesperidum Silvestri, or the predator complex consisting of spiders, chrysopids, and coccinellids attributable to the chemical treatments. The absence of chronic pesticide-induced interference with biological control agents was interpreted as an indication of the potential for development of integrated control strategies against A. woglumi should this insect invade commercial citrus areas in Florida.

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