Chapter 21 - Instrumentation, control-regulation (30 pages)
- 1.Instrumentation and measurements
- 1.1.General
- 1.2.Measurement principles applicable to routine parameters
- 1.2.1.Flow measurements
- 1.2.2.Level measurements
- 1.2.3.Pressure measurements
- 1.2.4.Differential pressure measurements
- 1.2.5.Temperature measurements
- 1.2.6.Stress, mechanical torque measurements
- 1.3.Measurements specific to water treatment
- 1.3.1.Physical sensors
- 1.3.2.Specific water quality analysers
- 1.3.3.Gas analysers
- 1.4.All-or-nothing sensors
- 1.5.Examples of measurement usage in processes
- 1.5.1.Examples of measurement usage in a wastewater treatment plant
- 1.5.2.Examples of measurement usage in a drinking water treatment plant
- 1.5.3.Examples of measurements in sludge treatment
- 2.Real time control
- 2.1.Changes in restrictions applicable to control-regulation systems
- 2.1.1.Drinking water plant
- 2.1.2.Wastewater
- 2.1.3.Sludge treatment
- 2.2.Technologies used
- 2.2.1.Site networks (figure 10)
- 2.2.2.«Thin clients» (see Valenton (France) architecture figures 11 and 12)
- 2.2.3.Ethernet (see Valenton (France) architecture - figures 13 an 14)
- 2.2.4.Object-oriented programming (figure 15)
- 2.2.5.Control-Regulation numerical system or monitoring programmable logic controller solution
- 3.Deferred plant control system
- 3.1.Statements software: Aquacalc
- 3.2.Maintenance
- 3.2.1.Computer aided management and manufacturing program (GMAO)
- 3.2.2.Aquamaint software
- 4.Conclusion
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Introduction
Continuous and automatic treatment process regulation involves the use of analog measurements and of detection values that provides TOR (tout ou rien in French = all or nothing) data. It is very important that we differentiate between these two information modes:
- an analog measurement delivers a signal that is proportional to a measured variable;
- a detection delivers a 0/1 binary status, i.e. a value that has either not been reached or that has been exceeded in relation to a specific set point.
Commonly used measurements and detection systems apply to liquids regardless of their loading (including liquid sludge), liquid reagents, paste-like or dry products (dewatered sludge, dried sludge, powder, ash...), and to gases (process air, foul air, biogas, water vapor...) within the context of plant operation and safety and of the quality of the water produced by the plant.
The first part of this section consists of a list of the principle of measurements used in the water industry; the second provides relevant application examples given by treatment area.