Boron removal from seawater reverse osmosis permeate

Boron removal from seawater reverse osmosis permeate utilizing selective ion exchange resin


Abstract
A minimum of boron in irrigation water is required for certain metabolic activities, but if its concentration is
only slightly higher, plant growth will exhibit effects of boron poisoning, which are yellowish spots on the leaves
and fruits, accelerated decay and ultimately plant expiration. Seawater in general contains relatively high
concentration of boron: 4 to 5 ppm. The Red Sea water utilized as feed for the Eilat desalination plant contains
4.7 ppm boron falling within the above range. When acidified as a part of pre-treatment, the boron is in the form
of boric acid, manifesting poor trans-membrane rejection of 65%. In the Eilat desalination plant the result has
been 1.8 ppm of boron concentration in the permeate, a level by far higher than the allowance of the standards. A
process based on the selective removal of boron with resin has been evolved. The pilot plant tests allowed an
accurate cost assessment for the removal of boron in the range of 4 to 6 US cents per cubic meter of permeate,
dependent on the cost of the resin, the chemicals, and the operation and maintenance.
Keywords: Boron; Selective ion exchange resin