Start Date: November 2004
Completion Date: January 2005
Client: AerexÂ® Industries, Inc
AerexÂ® Industries, in an effort to meet the requirements of several forth coming membrane projects, designed and built a pilot unit for testing low to medium TDS brackish water. Overall recoveries of up to 90 percent can be achieved by using raw water blend and concentrate recycle.
The raw water booster pump is designed to be operated when the water source has insufficient pressure to feed the high pressure feed pump and also functions as the membrane cleaning pump. Chemical feed systems have been incorporated into the process design for the addition of acid for pH adjustment and scale inhibitor. Additional pretreatment is provided by the feed water cartridge filter housing in FRP construction, containing (6) 20â€ â€“ 5 micron filters. Panel mounted rotometers have been installed for first and second stage permeates, blend, recycle and concentrate. Flow control valves are included on each of these steams for precise measurement and control.
Instrumentation includes a two-channel pH/ORP monitor/transmitter, a two-channel conductivity monitor/transmitter. Pressure gauges equipped with selector valves are provided to measure the filter inlet and outlet, first and second stage permeate, feed, interstage, and concentrate pressures. For precise control, the unit uses a vertical centrifugal pump in 316 SS construction, controlled by a variable frequency drive. For additional flexibility in pilot testing, the unit has been set up in a 2-2-1-1 array using 4â€-4 element pressure vessels in a wrap around design.
The system is controlled through the use of an Allen-Bradley PLC for normal operation and monitoring the alarm circuits.