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.

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.

Control Systems for the Activated Sludge Process Part I — Modelling

1989 ◽  
Vol 24 (4) ◽  
pp. 479-496 ◽  
Author(s):  
Zdenko Vitasovic ◽  
John F. Andrews
Keyword(s):  
Activated Sludge ◽  
Distribution System ◽  
Control Strategies ◽  
Integrated Model ◽  
Activated Sludge Process ◽  
Supply And Distribution ◽  
Air Supply ◽  
Pump Station ◽  
And Control ◽  
Liquid Separator

Abstract An integrated dynamic model and control system are presented for the activated sludge process. The integrated model is comprised of separate models for the influent pump station, air supply and distribution system, biological reactor, and solids-liquid separator. The models for the pump station and for the air supply and distribution system were based on those for a full-scale plant, the Sagemont plant, Houston, Texas, and use standard engineering equations. The models for the biological reactor and solids-liquid separator are more research oriented and were obtained primarily from the literature. Predictions using these models are therefore expected to be more qualitative than quantitative. The integrated model will be used in part II of the paper to explore process control strategies by computer simulation.

Optimization and Control Petroleum Refinery Wastewater Treatment Systems — Status, Trends and Needs

1989 ◽  
Vol 24 (3) ◽  
pp. 463-477
Author(s):  
Stephen G. Nutt
Keyword(s):  
Wastewater Treatment ◽  
Process Control ◽  
Petroleum Refinery ◽  
Control Strategies ◽  
Refinery Wastewater ◽  
Statistical Process ◽  
Petroleum Refinery Wastewater ◽  
Optimization And Control ◽  
And Control ◽  
Wastewater Treatment Systems

Abstract Based on discussions in workshop sessions, several recurring themes became evident with respect to the optimization and control of petroleum refinery wastewater treatment systems to achieve effective removal of toxic contaminants. It was apparent that statistical process control (SPC) techniques are finding more widespread use and have been found to be effective. However, the implementation of real-time process control strategies in petroleum refinery wastewater treatment systems is in its infancy. Considerable effort will need to be expended to demonstrate the practicality of on-line sensors, and the utility of automated process control in petroleum refinery wastewater treatment systems. This paper provides a summary of the discussions held at the workshop.

scholarly journals Evidence of Neospora caninum exposure among native Korean goats (Capra hircus coreanae)

2014 ◽  
Vol 59 (No. 12) ◽  
pp. 637-640 ◽  
Author(s):  
BY Jung ◽  
SH Lee ◽  
D. Kwak
Keyword(s):  
Neospora Caninum ◽  
Control Strategies ◽  
Integrated Control ◽  
Protozoan Parasite ◽  
Capra Hircus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Caninum Infection ◽  
One Year ◽  
And Control

Neospora caninum is a protozoan parasite that causes abortion in ruminants, including goats. The objective of the present study was to determine the seroprevalence of N. caninum in native Korean goats (Capra hircus coreanae). A commercial enzyme-linked immunosorbent assay kit was used to analyse 464 serum samples for the presence of N. caninum antibodies. Four samples (0.9%, 95% confidence intervals – CI: 0.0–1.7) were found to be positive for N. caninum antibodies. The seroprevalence was analysed according to age (less than to one year, young; more than or equal one year, adult; and unknown), sampling season (April to September, warm; October to March, cold), and region (northern, central, and southern). However, there were no statistically significant differences in seroprevalence according to age, season, and region (P > 0.05). This is the first report on the seroprevalence of N. caninum in native Korean goats. The results of this study indicate a nationwide distribution of N. caninum among goats, with a relatively low prevalence. Therefore, the implementation of integrated control strategies as well as measures for prevention and control of N. caninum infection among goats is recommended.

Growth, Reproductive Potential, and Control Strategies for Deeproot Sedge (Cyperus entrerianus)

2012 ◽  
Vol 26 (1) ◽  
pp. 122-129 ◽  
Author(s):  
Charles T. Bryson ◽  
Richard Carter
Keyword(s):  
Growth Rate ◽  
Field Study ◽  
Control Strategies ◽  
Reproductive Potential ◽  
Field Studies ◽  
Growth Chamber ◽  
Chamber Studies ◽  
Growth Chamber Studies ◽  
And Control ◽  
Achene Production

Greenhouse, growth chamber, and field studies were conducted at Stoneville, MS, in 2000 to 2008, to determine the growth rate, reproductive and overwintering potential, and control of deeproot sedge. In growth chamber studies, deeproot sedge growth rate (ht) and plant dry wt were greatest at 25/35 C (night/day temperatures), when compared with regimes of 5/15, 15/25, and 20/30 C. Based on the average number of scales (fruiting sites per spikelet), spikelets per inflorescence, and culms per plant, deeproot sedge reproductive potential was 2.6-, 6.2-, and 17.4-fold greater than Surinam, green, and knob sedges, respectively. A single deeproot sedge plant produced an average of 85,500 achenes annually. Mowing at 15-cm ht weekly prevented achene production but did not kill deeproot sedge plants. The average number of inflorescences produced on mowed plants was 1.2 to 4 times greater in 2- and 1-yr-old deeproot sedge plants, respectively, when compared with unmowed plants. Mature deeproot sedge achenes were produced between monthly mowings. In a 3-yr field study, glyphosate, glufosinate, hexazinone, and MSMA provided more than 85% control of deeproot sedge, and above the soil, live deeproot sedge plant dry wt was reduced by 50, 64, 68, 72, 86, and 93% by dicamba, halosulfuron-methyl, MSMA, hexazinone, glufosinate, and glyphosate, respectively. All (100%) deeproot sedge plants 1 yr old or older overwintered at Stoneville, MS, at 33°N latitude.

scholarly journals Research of Jiles-Atherton Dynamic Model in Giant Magnetostrictive Actuator

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Yongguang Liu ◽  
Xiaohui Gao ◽  
Chunxu Chen
Keyword(s):  
Mathematical Model ◽  
Dynamic Model ◽  
Control Strategies ◽  
Structural Parameters ◽  
Hysteresis Loops ◽  
Structural Dynamic ◽  
Magnetostrictive Actuator ◽  
Output Characteristics ◽  
And Control ◽  
Minor Hysteresis Loops

Due to the existence of multicoupled nonlinear factors in the giant magnetostrictive actuator (GMA), building precise mathematical model is highly important to study GMA’s characteristics and control strategies. Minor hysteresis loops near the bias magnetic field would be often applied because of its relatively good linearity. Load, friction, and disc spring stiffness seriously affect the output characteristics of the GMA in high frequency. Therefore, the current-displacement dynamic minor loops mathematical model coupling of electric-magnetic-machine is established according to Jiles-Atherton (J-A) dynamic model of hysteresis material, GMA structural dynamic equation, Ampere loop circuit law, and nonlinear piezomagnetic equation and demonstrates its correctness and effectiveness in the experiments. Finally, some laws are achieved between key structural parameters and output characteristics of GMA, which provides important theoretical foundation for structural design.

scholarly journals Grinding in Ball Mills: Modeling and Process Control

2012 ◽  
Vol 12 (2) ◽  
pp. 51-68 ◽  
Author(s):  
Vladimir Monov ◽  
Blagoy Sokolov ◽  
Stefan Stoenchev
Keyword(s):  
Process Control ◽  
Control Strategies ◽  
Grinding Process ◽  
Ball Mills ◽  
Modeling And Control ◽  
Energy Models ◽  
And Control

Abstract The paper presents an overview of the current methodology and practice in modeling and control of the grinding process in industrial ball mills. Basic kinetic and energy models of the grinding process are described and the most commonly used control strategies are analyzed and discussed.

scholarly journals Aeration control – a review

2013 ◽  
Vol 67 (11) ◽  
pp. 2374-2398 ◽  
Author(s):  
L. Åmand ◽  
G. Olsson ◽  
B. Carlsson
Keyword(s):  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Control Strategies ◽  
Pilot Scale ◽  
Special Focus ◽  
Municipal Wastewater Treatment ◽  
Optimal Controllers ◽  
Municipal Wastewater Treatment Plants ◽  
And Control ◽  
Published Research

This review covers automatic control of continuous aeration systems in municipal wastewater treatment plants. The review focuses on published research in the 21st century and describes research into various methods to decide and control the dissolved oxygen (DO) concentration and to control the aerobic volume with special focus on plants with nitrogen removal. Important aspects of control system implementation and success are discussed, together with a critical review of published research on the topic. With respect to DO control and determination, the strategies used for control span from modifications and developments of conventional control methods which have been explored since the 1970s, to advanced control such as model-based predictive and optimal controllers. The review is supplemented with a summary of comparisons between control strategies evaluated in full-scale, pilot-scale and in simulations.

Anthelmintic resistance and novel control options in equine gastrointestinal nematodes

Parasitology ◽  
2018 ◽  
Vol 146 (4) ◽  
pp. 425-437 ◽  
Author(s):  
Ali Raza ◽  
Abdul Ghaffar Qamar ◽  
Khizar Hayat ◽  
Shoaib Ashraf ◽  
Andrew R. Williams
Keyword(s):  
Anthelmintic Resistance ◽  
Early Stage ◽  
Control Strategies ◽  
Field Studies ◽  
Gastrointestinal Nematodes ◽  
Feed Additives ◽  
Macrocyclic Lactones ◽  
Fecal Egg Count ◽  
Worm Control ◽  
And Control

AbstractControl of equine nematodes has relied on benzimidazoles (BZs), tetrahydropyrimidines and macrocyclic lactones. The intensive use of anthelmintics has led to the development of anthelmintic resistance (AR) in equine cyathostomins and Parascaris equorum. Field studies indicate that BZ and pyrantel resistance is widespread in cyathostomins and there are also increasing reports of resistance to macrocyclic lactones in cyathostomins and P. equorum. The unavailability of reliable laboratory-based techniques for detecting resistance further augments the problem of nematode control in horses. The only reliable test used in horses is the fecal egg count reduction test; therefore, more focus should be given to develop and validate improved methodologies for diagnosing AR at an early stage, as well as determining the mechanisms involved in resistance development. Therefore, equine industry and researchers should devise and implement new strategies for equine worm control, such as the use of bioactive pastures or novel feed additives, and control should increasingly incorporate alternative and evidence-based parasite control strategies to limit the development of AR. This review describes the history and prevalence of AR in equine nematodes, along with recent advances in developing resistance diagnostic tests and worm control strategies in horses, as well as giving some perspective on recent research into novel control strategies.

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