pH Correction Tanks

pH Correction – pH is a measure of the degree of acidity of the water. It is measured on a scale of 0-14 pH units, with low numbers being acidic, 7 being neutral and higher values being classed as alkaline. Many waters are a few units either side of neutral – the regulatory standard for pH in drinking water is within a range between 6.5 and 9.5.  Many water supplies derived from source in peaty upland areas, will be slightly acidic due to dissolved organic

The pH of the water, in itself, is not usually a significant issue – where it can become a problem is where metal plumbing is installed, such as copper piping or galvanized tanks. The acidic water can gradually dissolve the metals, leading to leaks and significant concentrations of the metals in the water itself, potentially at levels harmful to health.  More commonly, staining of sanitary ware and fittings can occur. Where properties contain old lead pipes, the health aspect becomes even more relevant, as significant concentrations of lead in water can result from relatively small
lengths of lead plumbing.

The simplest method of elevating pH is to pass the water through a filter bed of alkaline granular material.  Such filters are referred to as pH correction filters or neutralizing filters. The alkaline media is usually
calcium carbonate or magnesium oxide, or a combination of both. The materials are processed to render them more suitable for water treatment use, and several proprietary brands of pH correction media are available.
These neutralizing media, or a blend, will often be used to fill a sediment filter shell. On most supplies, pH correction will usually take place after other filtration stages but prior to UV disinfection. This is probably correct,
but in such circumstances, sediment from the pH filter can cause fouling of the UV lamp. If this is the case, a further small filter may be required prior to the UV system. There should be no metal pipework between the pH
filter and the UV system to avoid metal deposition on the lamp. If Chlorine disinfection is used, careful thought needs to be given to the siting of any pH correction as higher pH renders disinfection less effective.

pH Correction – System Design

When designing a pH correction system for a small water supply, care must be given to sizing and residence times. If filters are undersized and contact times insufficient, the pH will not be sufficiently elevated, however, if the
water spends too much time in contact with the media it may become too alkaline, with other quality complications. Different media have differing levels of activity, so care must be taken to achieve the correct blend
and on-site pilot trials may be advisable. Particular difficulties can arise where a property is only used intermittently through the year, meaning that at certain times, water can spend long periods in contact with the
media. Competent specialist advice should be sought.  As a chemical reaction takes place between the water and the media in the neutralizing filter, the media gradually gets used up over time. This means that monitoring of the filter is required and replenishment of the media needs
to take place from time to time. If media is simply topped up periodically there is a risk that insoluble deposits will accumulate in the filter and gradually reduce its performance. Therefore, it is good practice to occasionally take the filter off line, clean it out and completely replenish the media.

Enduramaxx pH Correction Tanks

Enduramaxx work with a number of water treatment installers and offer a number of water treatment tanks, brine tanks and cat5 break tanks for systems.

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