An analogy from everyday life.
If you wanted to make a plate of nachos to eat while watching football on game day. You would assemble the ingredients and put them in the oven, then set a timer for the correct amount of time. You'd sit back down to watch the game until you heard the timer.
It wouldn't work if you had to stand by the oven continually reading a thermometer, adjusting the oven temperature up and down, trying to avoid burning the nachos.
It seems obvious why we automate our home appliances. The same logic should apply to water treatment plants.
Automating coagulant feed guards against:
1) Human error while running jar tests.
2) Over-dosing or under-dosing, which will lead to poor plant performance.
3) Paying for unnecessary chemicals.
(Side note: The current estimate is that water plants overdose, in general , by about 25%.)
The oven analogy is an oversimplification. Our software is significantly more complex than an oven's simple temperature control software. It adjusts for temperature plus pH, organics, electrostatic charge, and turbidity. However, you get the point; it is huge advantage to have both your oven and your water plant automated.