Brackish Groundwater



Trailblazer Technologies (Pty) Ltd

Box 680, Featherbrooke, 1746, South Africa.

E-mail:; Tel: +27 82 925 2823; Fax: +27 86 648 2810

Brackish water is a massive resource in many dry parts of the world which has now been made usable due to the KNEW process being able to extract the dissolved salts at an affordable cost. Seawater and brackish water near the coasts may be economically converted to pristine water by using reverse osmosis because the concentrated brine may be returned to the sea but inland this luxury does not exist so any process to remove the dissolved solids will have to convert these salts into usable products to avoid the very costly storage of these troublesome brines.

In the KNEW process the brackish water from rivers or underground aquifers is filtered to remove coarse particles and pumped through an ion exchange battery to remove all the dissolved ions leaving a purified water for agricultural or household use.

The ionex battery is regenerated with dilute nitric acid for the cation resin bank and ammonia solution for the anion resin bank. The nitrate blend is treated with sodium carbonate to cause all the multi-charged cations to precipitate and to be separated for use in agriculture as a soil ameliorant. The residual sodium nitrate solution is mixed with an equimolal amount of potassium chloride and evaporated with the result that the least soluble salt – sodium chloride – crystallizes out and is separated pure and dried for supply to the chlor-alkali industry. The residual liquor is cooled to produce a pure crystalline potassium nitrate which is separated and dried for supply to horticulture as a primary fertilizer. Another option is to use vegetable ash which has a very high potassium carbonate content as a raw material to precipitate out the multi-charged elements giving an even more economic route to the formation of this...