The purification center has three operators on duty 10 hours a day every day of the year. Additionally, plant supervisor and maintenance personnel are on-call during non-business hours. The purification center is computer operated and the operators are responsible for monitoring all plant functions, inspecting all equipment and facilities, and following up on any problems. Water quality is monitored by computers and people, and together they monitor multiple parameters, such as pH, oxygen concentrations, etc. For many of the water quality parameters, the system provides computer alarms when water quality parameters are outside acceptable limits so that they can be remedied as soon as possible. There are also alarms for mechanical or electrical failures.