Brackish Water Treatment

Brackish water is water that is more saline than fresh water, but not as much as seawater. It can come from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. Certain human activities can also produce brackish water, in particular certain civil engineering projects such as dikes and the flooding of coastal marshland to produce brackish water pools for freshwater prawn farming. Brackish water is also the primary waste product of the salinity gradient power process. Because brackish water is hostile to the growth of most terrestrial plant species, without appropriate management it is damaging to the environment.

brackish water treatment

Technically, brackish water contains between 0.5 to 30 grams of salt per litre—more often expressed as 0.5 to 30 parts per thousand (ppt or ‰). Thus, brackish covers a range of salinity regimes and is not considered a precisely defined condition. It is characteristic of many brackish surface waters that their salinity can vary considerably over space and/or time.

Reverse Osmosis systems can be used to remove both salts and organic materials from brackish water, enabling communities with limited fresh water to increase potable water for their inhabitants. Long lasting, highly efficient membranes reduce demineralization and desalination costs

For the preservation of the effectiveness and life span of a Reverse Osmosis (RO) installation, a sufficient pre-treatment is required. A proper selection of pre-treatment methods for feed water will improve affectivity and extend the life span of the system by preventing or minimizing biofouling, scaling and membrane plugging.

To perform an uninterrupted and reliable pre-treatment of the feed water a special approach is used. A pre-treatment that is not geared to the installation may cause a system overload. When this occurs the system parts need cleaning much more often to restore productivity and salt retention. Cleaning costs, system performance and standstill time are very significant in that situation.
The kind of pre-treatment system that is used greatly depends on feed water quality. Consequentially, sufficient feed water pre-treatment is dependent on:

When the source of the feed water that needs treatment is specified, a complete and exact water analysis is performed. This action is an important step for the design of a pre-treatment system and the entire Reverse Osmosis system, because this often determines the type and size of the pre-treatment.