HydroION® Base Exchange Water Softening
80 Fully WRAS Approved Models Available
High efficiency strong acid cation exchange resin of high quality mono-spherical grade
Independently tested to both BS EN 14743:2005 + A1:2007 and DIN 19636-100:2008-02
BIM models available
Automatic Regeneration Chlorinator
Automatic Refresh Mode
High Brining Rates Available for Specialist Applications (Cooling tower, humidifiers, etc.)
Integrated low brine alarm available with BMS functionality
Water softening by the method of ‘base exchange’ or ‘ion exchange’ can be an extremely effective method of scale control for many systems. In particular this technique is useful where a permanent softening effect is required or is indeed critical for the operation for some downstream process such as the use of a reverse osmosis machine or a steam generator, for example.
The Base Exchange Water Softening Process
This process has many names and is also often referred to as salt regenerative water softening or ion exchange water softening. This is a chemical process and this is the key differentiator from the physical water conditioning process. The process works by swapping the mineral salts naturally present in the water, responsible for causing hard water, with other minerals that cannot lead to scale formation and thus the water is ‘softened’. Because the water is chemically modified and this is outside the control of the regulated water treatment works, the Drinking Water Inspectorate (for England and Wales) recommend that this water is not considered to be of potable quality and that a supply of untreated mains water must be made available in the premises. There are however many potential benefits for the water softening process and Hydrotec has developed class leading equipment, the HydroION® range to provide this where desirable.
Hard water – or water that can lead to scale formation in water systems, contains the mineral salts of calcium and magnesium (which are naturally present in water, the amount will vary from location to location, depending on the source of the water). When dissolved in water, these minerals form ‘ions’ which are charged particles, calcium and magnesium will always have a positive charge (known as cations) and other ions such as bicarbonates, chlorides and sulphates will always have a negative charge (known as anions).
At the heart of the water softener is an ‘ion exchange resin’, which has the ability to ‘swap’ or ‘exchange’ ions. In this case the undesirable ions of calcium and magnesium become attached to the resin beads and sodium ions are released to replace them. For every resin there is a an ‘exchange capacity’ or finite amount of ions it can exchange, once the resin has been exhausted it must be regenerated so that the process can begin again. To effect the regeneration the resin must be contacted with a very high level of sodium containing water, this is created by the dissolving of common salt (sodium chloride) in a brine bin, which can be periodically flushed over the exhausted resin. Hence the process uses salt as a regenerant.
The amount of salt used during the regeneration is governed by the amount and type of resin, the ‘salting rate’ of the resin and the amount of water that can be produced from it (between regenerations). HydroION® water softeners employ only high quality ‘mono-spherical’ resins, this means that we have been able to lower the salt usages very substantially resulting in the most economic operation (i.e. lowest salt use) for this type of water softener, reducing the impact on the environment and providing a low cost of operation. Typically there are two basic types of water softener, Simplex or Duplex models. Simplex units employ just one resin vessel and are ideal where the demand is discontinuous and the units can be sized to regenerate during a regular period of zero demand (such as during the night for a school application). Duplex units as the name suggest employ two resin vessels, each should be capable of serving the full process requirement and these will operate in the duty / standby mode. Here one vessel will be in service and will allow a period when the other can regenerate, once the first vessel is exhausted the vessels are changed over automatically, allowing the continued production of fully softened water, without interruption to supply.
Advanced Features of the HydroION Water Softener Range
As for all products in our range, Hydrotec take a holistic approach to water treatment and are acutely aware of the inseparable relationship of scale control and biological control treatment regimes. With water softeners it is possible for the resin bed over a period of time to provide a habitat for bacteria, this is naturally unwelcome, as some bacteria can lead to system damage and some can be hazardous to health. To prevent this being a problem HydroION® water softeners are equipped with both a Regeneration Chlorinator and Water Refresh (on Duplex units).
The regeneration chlorinator produces a small amount of free chlorine automatically, during each regeneration (without the need for any additional chemicals or chemical handling) which disinfects the resin bed on each regeneration cycle, this helps to maintain the resin bed in a biologically clean condition and reduce the areas in which potentially harmful bacteria may live.
The water refresh mode is possible as a direct result of the HydroION®’s unique control system. In a duplex plant, when water demand is low the possibility of water stagnation in the offline vessel can increase significantly. To prevent this, the control system continuously monitors the offline vessel and if it is found to be offline for a period of more than 12 hours it will automatically bring the offline unit into service (briefly) and thus avoid water stagnating in the offline vessel. This is particularly important where the softener vessels are located in a warm plant room, which could more readily lead to the growth of undesirable bacteria. The initiation of the regeneration process is typically either via the water meter (monitoring process flow) or on a timer basis. Within the HydroION® range it is possible to supplement these control technologies with an electronic hardness monitoring system, for critical applications.
The microprocessor based softener control system, controls all functions of the HydroION® units, records key process data, interfaces with BMS systems if required and can even predict when a unit service is required. In addition to the standard range of plant, Hydrotec are able to offer fully bespoke solutions through our HydroION® AS range, particularly suited to high flow rate or high volume demand systems, a small domestic range and also our mobile range, particularly suited to the charging of closed circuit systems.
The HydroION® range should be considered where:
- The water quality would indicate that scale formation is likely
- Potable water is not required
- Specialist applications are to be served
- Reverse osmosis plant (use high salting rate)
- Cooling towers
- Combi ovens, pressure steamers
- Laundry equipment
- Steam generators (use high salting rate)
- Compliance with the HSE’s Approved Code of Practice, L8, for the control of legionnaires disease is required
- Compliance with building regulations is required
- Value for money treatment is desirable
- Low energy consumption is needed
- There is the desire to protect high value capital assets from scale formation
- There is a need to maintain the performance of water heating equipment to maintain fuel bills and carbon emissions at the lowest possible levels
- BMS connectivity is required
- Routine maintenance is possible and a supply of tablet salt is available. Your Hydrotec technical representative will be pleased to provide additional information on all aspects of the operation of the HydroION® range and assist in the complete water treatment design of your project.