Instrumentation and Control (C&I)

An integral part of every water treatment plant is a system of flow meters, valves, pumps, level switches, pressure gauges/transmitters, pH electrodes/transmitters, temperature gauges, and analyzers that work together in unison controlled by a Programmable Logic Controller which is the brain of the Water Treatment Plant. This is called Automation and it makes systems inherently more safe because human error is removed from the equation.

Specialists that study instruments and control are called C&I Engineers and PLC programmers are called Systems Engineers.

Trends displaying different parameters in the water treatment process are very important for efficient working and control of the WTP as well as for analyzing events and changes. The results are displayed in the so called Human Machine Interface (HMI).

The most popular PLC program providers are Siemens from Germany, Schneider from France and Allan Bradley and Emerson from the USA.

PLC programs send signals to valves to open and close and to pumps to start and stop depending on specific conditions.

Common instruments for process control in water treatment are:

1. pH and ORP measurement

2. Streaming Current Monitor for monitoring the coagulation step in clarifiers.

3. Turbidity measurement

4. Sludge Level measurements

5. Level sensors both digital and analog

6. Pressure measuremetns

7. Temperature measurement

8. Flow measurement

9. Conductivity measurements

10. Concentration measurement

11. Particle counters

12. Online Silica, Sodium and TOC monitors

Compiled by Rami E. Kremesti M.Sc.