ICA and me--a subjective review.

ICA - instrumentation, control and automation - is a hidden technology. It is ubiquitous in all industrial processes, including water and wastewater treatment systems. Still, as long as everything works fine, it is not noted but when things go wrong it will be observed. ICA has now about forty years of history in water and wastewater systems and is well recognized. One early attitude was that ICA will be a necessary burden to be added to a plant in order to correct for a poor design. However, the key reason for ICA is the fact that all processes are subject to disturbances, externally via the wastewater influent, from the customers in a water supply system, or from operations in one unit process that will propagate as a disturbance to another unit within a plant. This paper is an attempt to describe the development of ICA in water and wastewater systems. Most of it is based on personal experiences with all their limitations. No single paper can fairly describe the development that is documented in thousands of research papers, practiced by so many operators and process engineers and implemented in so many treatment systems. Still, the hope is that the paper can give a flavour of the most important ingredients of this fascinating development.