The Glasgow WTP control system was designed as a conventional computer control system to run the plant automatically with manual adjustment and override features. The plant may be operated up to 21 hours per day (assuming MARCO operates 3 hours per day) but will normally be staffed on an 8 to 12 hour per day schedule. A second shift with minimum staff may be needed during peak demand periods in the summer months. During non-staffed hours, critical treatment processes are monitored and alarmed. A computer auto-dialer system is in place for alarm conditions.
The main plant controller, or main terminal unit (MTU), monitors plant functions and provides a user interface in the form of a desktop computer in the office of the WTP. Control of most major plant equipment is performed at local panels near the equipment. The desktop computer provided the human machine interface (HMI). Programmable logic controllers (PLCs) perform the logic required to operate the equipment at the plant.