Simple control strategies of methanol dosing for post-denitrification

1998 ◽  
Vol 38 (3) ◽  
pp. 291-297 ◽  
Author(s):  
N. Puznava ◽  
S. Zeghal ◽  
E. Reddet
Keyword(s):  
Control Strategies ◽  
Operating Cost ◽  
Feed Water ◽  
Effluent Quality ◽  
Second Stage ◽  
Point Tracking ◽  
Regulatory Constraints ◽  
Operation Costs ◽  
Line Measurement ◽  
On Line

The objective of this work is to propose a simple but efficient way of controlling the carbon addition for the post-denitrification process in order to comply with regulatory constraints and optimize operating cost. A Biostyr® pilot column filled with polystyrene beads was used for the experiments. In order to simulate a secondary treated water from a nitrifying stage with a carbon source addition, the feed water was composed of river water dosed with nitrates, phosphates and methanol. Methanol was added initially with no control (at different constant rates) and in a second stage with different control strategies based on the on-line measurement of inlet and/or outlet nitrate concentrations. This simple dosing mode proved to be very efficient in set-point tracking to ensure the effluent quality and in minimizing the methanol addition (up to 20% less methanol consumption), thus optimizing operation costs.

Control Strategies for a Highly Loaded Biological Ammonia Elimination Process

1993 ◽  
Vol 28 (11-12) ◽  
pp. 531-538 ◽  
Author(s):  
B. Teichgräber
Keyword(s):  
Closed Loop ◽  
Control Strategies ◽  
Level Control ◽  
Sludge Dewatering ◽  
Loop Control ◽  
Reject Water ◽  
Line Measurement ◽  
Control Pattern ◽  
On Line ◽  
Treatment Facilities

A nitrification/denitrification process was applied to reject water treatment from sludge dewatering at Bottrop central sludge treatment facilities of the Emschergenossenschaft. On-line monitoring of influent and effluent turbidity, closed loop control of DO and pH, and on-line monitoring of nitrogen compounds were combined to a three level control pattern. Though on-line measurement of substrate and product showed substantial response time it could be used to operate nitrification/denitrification within process boundaries.

Aeration control on a nitrifying biofilter system by using on-line analyzers

2000 ◽  
Vol 41 (4-5) ◽  
pp. 369-374
Author(s):  
N. Puznava ◽  
D. Thornberg ◽  
P. Magnin ◽  
E. Reddet
Keyword(s):  
Process Control ◽  
Dissolved Oxygen ◽  
Large Scale ◽  
Air Flow ◽  
Ammonia Concentration ◽  
Effluent Quality ◽  
Operation Costs ◽  
New Process ◽  
On Line ◽  
Rainy Days

Two new ways of controlling the aeration in nitrifying biofilters, by measuring on-line dissolved oxygen and ammonia concentration in the effluent of the filter, are compared to the standard control using time tables with constant air flow. Both on pilot and large scale, the new process control concepts proved to be very efficient in optimizing operation costs for aeration (up to 70% during rainy days) and to guarantee a demanded effluent quality.

Real-time expert system control of anaerobic digestion

1994 ◽  
Vol 30 (12) ◽  
pp. 21-29 ◽  
Author(s):  
D. P. Chynoweth ◽  
S. A. Svoronos ◽  
G. Lyberatos ◽  
J. L. Harman ◽  
P. Pullammanappallil ◽  
...  
Keyword(s):  
Expert System ◽  
Control Strategy ◽  
Control Strategies ◽  
System Control ◽  
Potential Contribution ◽  
Adaptive Optimization ◽  
Line Measurement ◽  
On Line ◽  
Methane Production Rate ◽  
Abnormal Performance

The objective of this research was to develop on-line measurement and feed-back control strategies for evaluation and optimization of a glucose-fed CSTR digester. Using methane yield as a direct on-line measurement, a model and algorithm were developed and applied for feed-back control and adaptive optimization of the digester for temperature. The model and algorithm were modified and integrated into an expert system to use methane production rate and dilution rate to automatically detect and recover digester abnormal performance resulting from underloading, overloading, and addition of an inhibitor (phenol). On-line fluorometric measurement of NADH, which is a measurement of overall microbial activity, was evaluated for its potential contribution to this control strategy.

Fuzzy control of nitrogen removal in predenitrification process using ORP

2005 ◽  
Vol 52 (12) ◽  
pp. 161-169 ◽  
Author(s):  
Y. Peng ◽  
Y. Ma ◽  
S. Wang ◽  
X. Wang
Keyword(s):  
Fuzzy Control ◽  
Control Strategies ◽  
Integrated Control ◽  
Experimental Investigations ◽  
Carbon Addition ◽  
Effluent Quality ◽  
Optimal Value ◽  
On Line ◽  
New Applications ◽  
And Control

In order to meet increasingly stringent discharge standards, new applications and control strategies for the sustainable removal of nitrogen from wastewater have to be implemented. In the past years, numerous studies have been carried out dealing with the application of fuzzy logic to improve the control of the activated sludge process. In this paper, fuzzy control strategies of predenitrification systems are presented that could lead to better effluent quality and, in parallel, to a reduction of chemicals consumption. Extensive experimental investigations on lab scale plant studies have shown that there was excellent correlation between nitrate concentration and ORP value at the end of the anoxic zone. Results indicated that ORP could be used as an on-line fuzzy control parameter of nitrate recirculation and external carbon addition. The optimal value of ORP to control nitrate recirculation and external carbon addition was −86±2mV and −90±2mV, respectively. The results obtained with real wastewater also showed the good performance and stability of the fuzzy controllers independently from external disturbances. The integrated control structure of nitrate recirculation and external carbon addition in the predenitrification system is also presented.

Research on Triaxial Linkage and Cut Point Tracking for Automotive Crankshaft Servo Grinder and its Key Technology

2011 ◽  
Vol 66-68 ◽  
pp. 419-423
Author(s):  
Xing Hong Huang ◽  
Xu Hua Pan ◽  
Xing Wu ◽  
Wen Guang Huang
Keyword(s):  
Dynamic Performance ◽  
Machining Accuracy ◽  
Connecting Rod ◽  
Precision Grinding ◽  
Cut Point ◽  
Point Tracking ◽  
Straight Line ◽  
Line Measurement ◽  
Ultra Precision ◽  
On Line

Based on the principle analysis of two-axis linkage and cut point tracking crankshaft servo grinding technology, the principle of triaxial linkage and cut point tracking for crankshaft servo grinding is analyzed and researched on the technological advantages for the neck of crankshaft connecting rod and the spindle neck. Then the dynamic grinding model is established, and the high-precision liquid hydrostatic slide-way technology, high rigidity straight line drive technology and on-line measurement and error compensation technology are employed synthetically to solve the dynamic performance of moving parts for ultra-precision grinding and its influence on the machining accuracy successfully. The problem of using common corundum wheel to process the crankshaft neck and connecting rod efficiently and accurately is conquered.

Model-based evaluation of an on-line control strategy for SBRs based on OUR and ORP measurements

2006 ◽  
Vol 53 (4-5) ◽  
pp. 161-169 ◽  
Author(s):  
Ll. Corominas ◽  
G. Sin ◽  
S. Puig ◽  
A. Traore ◽  
M. Balaguer ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Control Strategy ◽  
Control Strategies ◽  
Mechanistic Model ◽  
Treated Wastewater ◽  
Effluent Quality ◽  
Model Based ◽  
Treatment Technologies ◽  
On Line ◽  
Key Aspects

Application of control strategies for existing wastewater treatment technologies becomes necessary to meet ever-stricter effluent legislations and reduce the associated treatment costs. In the case of SBR technology, controlling the phase scheduling is one of the key aspects of SBR operation. In this study a calibrated mechanistic model based on the ASM1 was used to evaluate an on-line control strategy for the SBR phase-scheduling and compare it with the SBR's performance using no control strategy. To evaluate the performance, reference indices relating to the effluent quality, the required energy for aeration and the treated wastewater volume were used. The results showed that it is possible to maintain optimal SBR performance in the studied system at minimal costs by on-line control of the length of the aerobic and anoxic phases.

Thickness Measurement in the AEM by Macintosh-Based Analysis of Two-Beam Convergent Beam Patterns

1990 ◽  
Vol 48 (2) ◽  
pp. 504-505
Author(s):  
John F. Mansfield ◽  
Douglas C. Crawford
Keyword(s):  
Electron Microscope ◽  
Video Camera ◽  
Thickness Measurement ◽  
Specimen Thickness ◽  
Crystalline Materials ◽  
Beam Dynamic ◽  
Line Measurement ◽  
On Line ◽  
Image Position ◽  
Convergent Beam

A method has been developed that allows on-line measurement of the thickness of crystalline materials in the analytical electron microscope. Two-beam convergent beam electron diffraction (CBED) patterns are digitized from a JEOL 2000FX electron microscope into an Apple Macintosh II microcomputer via a Gatan #673 CCD Video Camera and an Imaging Systems Technology Video 1000 frame-capture board. It is necessary to know the lattice parameters of the sample since measurements are made of the spacing of the diffraction discs in order to calibrate the pattern. The sample thickness is calculated from measurements of the spacings of the fringes that are seen in the diffraction discs. This technique was pioneered by Kelly et al, who used the two-beam dynamic theory of MacGillavry relate the deviation parameter (Si) of the ith fringe from the exact Bragg condition to the specimen thickness (t) with the equation:Where ξg, is the extinction distance for that reflection and ni is an integer.

Automatic buffer capacity based sensor for effluent quality monitoring

1996 ◽  
Vol 33 (1) ◽  
pp. 81-87
Author(s):  
L. Van Vooren ◽  
P. Willems ◽  
J. P. Ottoy ◽  
G. C. Vansteenkiste ◽  
W. Verstraete
Keyword(s):  
Wastewater Treatment ◽  
Buffer Capacity ◽  
Wastewater Treatment Plants ◽  
Data Interpretation ◽  
Full Scale ◽  
Quality Monitoring ◽  
Effluent Quality ◽  
Capacity Curves ◽  
On Line

The use of an automatic on-line titration unit for monitoring the effluent quality of wastewater plants is presented. Buffer capacity curves of different effluent types were studied and validation results are presented for both domestic and industrial full-scale wastewater treatment plants. Ammonium and ortho-phosphate monitoring of the effluent were established by using a simple titration device, connected to a data-interpretation unit. The use of this sensor as the activator of an effluent quality proportional sampler is discussed.

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