Operation Monitoring of Ultrapure Water Pretreatment System

The most important monitoring item for the effluent (RO feed water) of a pretreatment system is SDI (Sediment Dissolved Intake). For pretreatment systems using deep well water as a source, SDI typically needs to be measured once every 8 hours. For pretreatment systems using surface water as a source, the monitoring frequency should be increased, usually every 2-4 hours. Online automatic SDI analyzers have become available in recent years, offering greater convenience.

If scale inhibitors are used, the scale inhibitor dosing system should be checked regularly. The amount of scale inhibitor added each shift should be recorded and compared with the amount required for the reverse osmosis system's permeate flow rate during that period. If acid is used to adjust the pH value, although automatic acid dosing systems are generally used for control, the pH meter should be calibrated frequently to ensure reliable operation of the acid dosing system.

Other items requiring monitoring include coagulant dosage, multi-media filter and activated carbon filter operating pressure differential, COD and free chlorine concentrations, security filter pressure, and pressure differentials between different sections.

Real-time Computer Monitoring

Reverse osmosis is used in systems such as power plant boiler feedwater treatment and seawater desalination. Real-time computer monitoring employs a distributed control system (DCS) with centralized monitoring and distributed control. The system uses an industrial computer as the operator station, forming a highly reliable and efficient DCS control system. It primarily collects, stores, statistically analyzes, tabulates, and prints relevant analog signals related to water quality, flow rate, water temperature, water pressure, and pH value in real time.