The permeate is recycled to the make-up of the cooling water system. This reduces the amount of fresh water make-up requ

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The permeate is recycled to the make-up of the cooling water
system. This
reduces the amount of fresh water make-up required to maintain the
TDS in the
water that enters the cooling tower below 1500 mg/l. Draw a flow
diagram of the
system, draw up a water- and TDS mass balance for the cooling
system
incorporating the permeate recycle and calculate the volume of
make-up required
to maintain the TDS below 1500 mg/l in the system assuming that
conditions of
evaporation and windage losses remain unchanged. The TDS of the
make-up
water is 250 mg/l. (12)