Coagulation Controller – CoagSense
The CoagSense uses a range of sensors (including existing site sensors) that can be added to a central controller (analyser). The controller then takes those signals, manipulates them and produces a signal that controls the dosing of a coagulant. These are:
Flow – Used to increase or decrease the coagulant dose proportionally to the flow.
Raw Water pH – Perhaps the single most important parameter affecting coagulation, Pi uses an extremely fast responding, reliable, solid polymeric junction pH sensor to alarm if the pH moves outside a predetermined range or preferably to control the pH of raw water on a separate PID loop.
Coagulant Water pH – Used to alarm if the pH goes outside the predetermined range for optimum control.
UV254 – During periods of low turbidity and high SUVA¹, optimal organics and therefore THM removal can be achieved using feed forward control from a UVA signal.
Raw Water Turbidity – When turbidity is high, UVA sensors become swamped and no longer effectively measure organics. During these periods another basis for control is often preferable and this can potentially be turbidity.
Streaming Current – With the right water conditions and/or coagulant, streaming current feedback control can offer the simplest and most reliable coagulation control. Installed in over 5000 plants worldwide, streaming current monitors can offer a robust and cost effective solution. Understanding the relationship between pH and streaming current is essential for the successful implementation of a streaming current based coagulation controller. Streaming current measures all variables that affect charge neutralisation, a key aspect of coagulation. If not used for control, a streaming current monitor can be extremely useful as a coagulation monitor, continuously monitoring for changes in any aspect of coagulation, including changes in water chemistry, coagulant make up and the dosing region such as the pump output.
References: 1. Edzwald, J. K. & Kaminski, G. S. A simple method for plant water optimisation and operation of coagulation. (American Water Works Association, 2007).
- Configured and optimised for each site
- Stable and reliableOnline free chlorine analyser
- Excellent process control
- Can interpret UV254, streaming current, pH, turbidity and flow
- Profibus, Modbus and TCP comms to SCADA
- Help and consulting available