Water Treatment

Bromide Removal

Current legislation requires that bromate in bottled water be controlled at less than 10 ppb. Bromate is formed when ozone is added to bromide-containing water. Continued use of ozone for the production of bottled water is highly desired, due to its proven efficacy and ease of control.

Ion exchange is the ideal technology for removing or reducing trace levels of contaminants in water to acceptable levels. However, for bottled water that is labelled either as “natural,” “spring,” “artesian,” or “mineral” water, the use of standard ion exchange technology is not considered a feasible option. Major changes in the quality of the water occur during the standard ion exchange process that can violate regulations requiring that no significant changes be made to the composition and quality of the water during processing.
By using the ION-IX technology with the Bromide Plus resin in a conditioned form for the specific water to be treated the bromide levels can be reduced whilst producing minimal changes to the composition of the treated water.

No changes occur to the total dissolved solids or the individual cations that are present, such as sodium, calcium and magnesium, since a strong base anion resin is utilized. Changes in concentration of other anions such as chloride, sulphate and bicarbonate are kept to a minimum, typically less than +/- 15% and even lower depending on the specific situation. These variations are minimal to and are considerably lower than the natural seasonal fluctuations that may cause some constituents of the source water to change by 50% or more.

It can be seen that using the technology described above means that the end user only has one process treatment unit and as such no remineralisation would be required.

The bromide removal design will essentially comprise two different options, either with or without conditioning. The conditioning step is designed to minimise the water character changes between the feed and treated water. Depending on the specifics of each individual scheme, this step may not be necessary.

The ION-IX system can be broken up into 6 distinctive zones with each zone operating continuously. The resin is initially loaded with the bromide in the adsorption zone. The adsorption zone consists of 12 IX columns in parallel. The combined output from these 12 columns will be the average of the output from each column and hence any slight changes in the performance of an individual column will very slight. As the valve rotates, the resin that has been saturated with bromide moves into the regeneration zone and at the same time a column containing regenerated resin will move back into the adsorption zone. Any impact of this column movement will be averaged out over all 12 columns.

In the regeneration zone the resin is contacted with Hydrochloric acid over three vessels in series.

After regeneration, the resin requires neutralising with caustic.

Following the neutralisation step the resin undergoes conditioning using a chemical recipe depending on the character of the feed water and the required treated water quality.

Following the conditioning step the resin enters the rinse zone where the vessel is rinsed using bromide free water prior to moving back into the adsorption zone. The rinse zone consists of two vessels arranged in series.

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