Two membrane systems are under consideration for treating cooling tower blowdown to reduce its volume. A low-pressure seawater reverse osmosis (SWRO) system will operate at 500 psi and produce 720,000...

Two membrane systems are under consideration

for treating cooling tower blowdown to reduce its

volume. A low-pressure seawater reverse osmosis

(SWRO) system will operate at 500 psi and produce

720,000 gallons of permeate per day. It will

have a fixed cost of $465 per day and an operating

cost of $485 per day. A higher-pressure SWRO

system operating at 800 psi will produce 950,000

gallons per day at a cost of $1280 per day. The

fixed cost of the high-pressure SWRO system will

be only $328 per day because fewer membranes

will be required. How many gallons of blowdown

water will require treatment each day for the two

systems to break even?