The Reverse Osmosis Pretreatment System (ROPT) consists of several tanks, beginning with a mechanically agitated pH and ORP adjustment tank. In this tank, the pH is adjusted to an appropriate level so the Langlier Index is correct, and the ORP can be adjusted to ensure that all free chlorine is destroyed prior to the Reverse Osmosis (RO) unit. In this same tank, anti-scaling chemistry is added on a volumetric basis to assist in the prevention of scale formation within the RO membranes.
The water then overflows to a lift tank. This tank acts as a reservoir for the RO feed pump. The RO lift tank contains level controls that prevent the RO feed pump from running out of water preventing the tank from overflowing.
A control system, based on a Siemens PLC, controls all the functions of the ROPT system.
The reaction tank contains a Brawn mixer and GLI probes for pH and ORP signals. The pH and ORP signals are displayed on the GLI transmitters in the control panel. The output signals from the GLI transmitters will control the addition of acid and SBS to maintain the proper settings. Anti-scale chemistry is added volumetrically. All additions are made by LMI pumps.