Chemical Engineering 140 September 14, 2015
Problem Set #4
16. 4.2
17. 4.6
18. 4.16
19. 4.19
20. To provide fresh water in arid areas, seawater can be desalinated by reverse osmosis
(RO). As the population of California rises and more years of draught occur, there is
active consideration of building reverse-osmosis desalination units along the coast (such
as San Diego county). The current cost of desalination by reverse osmosis is listed as
around $ 3.50 / 1000 gal1.
a. Explain how desalination by reverse osmosis works and why is it expensive.
b. Assume that all water for crop irrigation in California is supplied by RO
desalination. How much would this cost expressed as a fraction of the current
Sate budget?
1. www.livescience.com/environment/070625_desalination_membranes.html
