Seawater desalination for agriculture by integrated forward and reverse
osmosis: Improved product water quality for potentially less energy
abstract
Seawater desalination for agricultural irrigation will be an important contributor to satisfying growing
water demands in water scarce regions. Irrigated agriculture for food production drives global water
demands, which are expected to increase while available supplies are further diminished. Implementation
of reverse osmosis, the current leading technology for seawater desalination, has been limited in
part because of high costs and energy consumption. Because of stringent boron and chloride standards
for agricultural irrigation water, desalination for agriculture is more energy intensive than desalination
for potable use, and additional post-treatment, such as a second pass reverse osmosis process, is
required. In this perspective, we introduce the concept of an integrated forward osmosis and reverse
osmosis process for seawater desalination. Process modeling results indicate that the integrated
process can achieve boron and chloride water quality requirements for agricultural irrigation while
consuming less energy than a conventional two-pass reverse osmosis process. The challenges to further
development of an integrated forward and reverse osmosis desalination process and its potential
benefits beyond energy savings are discussed.