What is a water softener?
The idea of a water softener is simple. The actual magnesium and calcium ions within the water will be exchanged with sodium ions. Since sodium does not really pass through out in pipes or respond negatively with detergent, both of the issues of hard water are generally eliminated. To accomplish the ion replacement, the water in the house carries on through a bed of compact plastic beads or through the use of a chemical matrix called Zeolite. The beads associated with Zeolite are blanketed with sodium ions. As the water runs past the sodium ions, that they exchange places with the calcium and magnesium ions. Subsequently, the particular beads or Zeolite contain nothing but calcium and magnesium and no salt, at this point they stop softening the water. It's then time to regenerate the beads of Zeolite.
Regeneration will involve treating the beads or Zeolite in a flow of sodium ions. Salt is Sodium Chloride, so the water softener blends up an extremely strong brine solution and flushes it through the Zeolite or beads (this is why you load up a water softener with salt). The actual powerful brine displaces all the magnesium and calcium that has accumulated in the Zeolite or beads and replaces it once again with sodium. The remainder brine plus all of the magnesium and calcium is flushed out by means of a drainpipe. Regeneration can make plenty of salty water- something like 25 gallons (95 litres).
What type of salt may I use for my water softener?
Regarding water softening, three types of salt are generally offered: -
Rock salt
Solar salt
Evaporated salt
Rock salt in the form of mineral develops naturally within the ground. It can be obtained from underground salt deposits by traditional mining techniques. It includes between ninety-eight and ninety-nine % sodium chloride and a water insolubility degree of about .5-1.5%, deliver primarily calcium sulphate. It's most important component is calcium sulphate.
Solar salt as a natural product is gathered predominantly through evaporation of seawater. Its content has eighty five percent sodium chloride. It's got a water insolubility level of less than .03%. It's usually solid in crystal form and at times solid in pellets.
Evaporated salt is obtained by means of mining underground sodium deposits of dissolving salt. The moisture is then evaporated, making use of energy from natural gas or coal. Evaporated salt is made up of somewhere between 99.6 - 99.99% sodium chloride.
Rock salt contains a lot of matter that's not water-soluble. Consequently, the conditioning reservoirs need to be cleaned much more frequently. Rock salt is cheaper than evaporated salt and solar salt, although reservoir cleansing may consume a lot of time and energy.
Solar salt consists of a bit more water-insoluble material than evaporated salt. Whenever you make any decision concerning what salt to use, consideration should be assigned to how much salt is needed, how often the softener might need a cleanout, as well as the softener design. if salt usage is low; the products could possibly be used alternatively. If salt application is high, insoluble salts will increase faster when using solar salt. Furthermore, the actual reservoir will need much more regular cleaning. Therefore, evaporated salt is to be advised.
It is generally not bad for blend salts in the water softener, but you'll find kinds of softeners which are suitable for specific water softening products. When using different systems, these softeners won't perform well. Mixing evaporated salt with rock salt isn't recommended as this may block the softener reservoir. It is strongly recommended that you permit your unit to go empty of one particular type of salt before including another to prevent the likelihood of any issues.
Salt is usually added onto the reservoir throughout regeneration of the softener. The more frequently a softener is regenerated, the greater often salt needs to be applied. Usually water softeners are examined monthly. To assure a satisfactory production of soft water, the salt water needs to be maintained at least half-full at all times.
When salt starts working in a water softener, it needs a little residence period within the reservoir because the salt is dissolving slowly. Whenever one instantaneously begins regeneration after placing the salt to reservoir, the water softener might not operate according to standards. In the event that water softening doesn't occur, it could also suggest softener failure or even a issue with the salt that's applied.
What exactly is a simplex water softener?
A simplex water softener consists of one vessel that contains ion exchange resin. As soon as the iron exchange resins are depleted, the water softener will go into the regeneration sequence. During the regeneration sequence which will take about two hours, there won't be any water passed through the softener in order to service. If the water softener is time controlled, you'll be able to set the regeneration time to 3am when there is ordinarily no requirement for water. If the water softener is a water meter controlled product, it's harder to gauge exactly what time the water softener will regenerate. If a steady supply of softened water is necessary, you should install a duplex water softener.
What is a duplex water softener?
A duplex water softener consists of a pair of vessels that contain ion exchange resin, when the first column of resin has depleted and goes into regeneration, the 2nd column goes into service. This maintains soft water to service all the time. Duplex water softeners usually are water meter controlled however in some instances, duplex water softeners could be time clock controlled.
What is water-softening resin?
Throughout the softening process, water is passed by means of a column of ion exchange resin. The calcium and magnesium ions existing within the water are exchanged on the resin beads for an equivalent quantity of sodium ion. The softened water exiting the water softener is considerably higher in sodium than the raw water. This basically is “The ion exchange process”.
The actual exchange of hardness for sodium is not perfect or total. A small amount of ‘hardness’ ordinarily passes throughout the softener in the treated water. Nevertheless, screening of the softened water discharging from a properly operating softener unit for hardness during this period will most likely not identify the trace quantity of hardness. Eventually, more and more hardness will escape within the water and may be detected using a typical hardness test kit. At some stage, it will be important to rejuvenate or regenerate the resin so that the quality of the softened water may be maintained with the required standard.
Regeneration of the resin is achieved by transferring a solution of salt (Brine or Sodium Chloride) through the resin to displace the calcium and magnesium ions that have been taken up through the resin beads in the water. The sodium in the brine replaces the calcium and magnesium ions on the resin. When this method is complete, the resin may be used again for softening water.
Commonly, the more efficiently the brine can be used, the greater efficiently the hardness is displaced from the resin. For more challenging functions for example softening boiler water, more brine has to be used. This is to minimise the quantity of resin that is left within the resin when the softener is brought back into service. If insufficient brine is employed, hardness leakage from the softener will likely be higher.
Water softening resin selection
Many different ion exchange resins can be used for water softening. They're the center in the water softener. Whenever hard water which contains calcium and magnesium (the key hard water constituents) passes through a bed of resin, calcium and magnesium are removed from the water. Together these types of impurities are referred to as the total hardness (TH) of the water.
Depending on the accuracy and reliability needed, the water hardness may be tested by trillion or by the simpler dropper bottle test. The effect for the total hardness test can be as either parts per million (PPM) of hardness, or grains per gallon (GPG) and even milligrams per litre (MD/L), in most cases expressed as Calcium Carbonate (CaCO3). (Grains per US Gallon x 17.118 = parts per million).
Household water containing less than 1 grain per gallon, or (17.1ppm total hardness as CaAo3) is generally regarded as being soft water. However, water for industrial or commercial use (e.g.- boiler feed water or other more demanding applications) may require the water hardness to be decreased to under 1ppm total hardness.
In both cases, similar conditioning processes may be used. To achieve the lower lever of complete hardness needed for the industrial application, the design for the industrial and commercial units will probably be more stringent.
Along with elliminating hardness from water, ion exchange resins will also clear away soluble iron from the water. It is therefore vital that you test water for presence and quality of soluble iron. Traditional resins are actually limited to a maximum of 3ppm of soluble iron. The resin are usually applied to get rid of a higher amount of iron providing steps are used to make certain iron fouling does not occur. Iron fouling might take place by removal of the iron ahead of the water has been fed through the resin or through the use of a resin-cleaning chemical substance during the regeneration process.
What is ion exchange?
Most typical ion exchange systems use a Zeolite resin bed and exchange unwanted ions (Ca 2 and Mg 2 ) with benigin (soap friendly) sodium or potassium ions. This is the popular water softener. A far more rigorous form of ion exchange swaps hydrogen (H ) ions for unwanted cations and hydroxide (OH-) ions for unwanted anions. The result is H OH- - > H 2 O. this technique is recharged with hydrochloric acid and sodium hydroxide. The results is effectively deionised water.What is a brine tank?
The brine tank is a tank where the salt is held and mixed in order to produce a brine solution for the water softener to regenerate.
What are features of having a domestic water softener?
Combined with obvious advantages that softened water has on a household (less dependence on soaps and chemicals, healthier hair and skin, protection of water using equipment) there's also several great advantages which could in turn save money.
Possessing soft water saves people money. Whenever your water is soft, you can use much less soap and fewer cleaning goods. Your budget will automatically reflect the cost savings.
Your plumbing will last longer. Hard water could potentially cause a build up of scales from an accumulation of mineral deposits. With time, plumbing can clog, water flow can diminish and water pressure can be reduced. This doesn’t happen with soft water. Soft water is reduced mineral content, consequently doesn’t leave deposits in the pipes.
Your hot water heater will last longer. Scale and lime increase created by minerals won't occur if the water is soft. This concludes to a prolonged life of your own hot water heater. Another benefit is by preventing deposits in your hot water heater, it will cost approximately 20% less to warm the water that your family will use. At the end of a year, these savings can really accumulate.
Most water utilizing devices lasts longer. From your coffee pot to your humidifier, soft water inhabits an accumulation of minerals and contributes life to these products.
What is softened water?
Softened water is water which has a low calcium and magnesium content. Normal water hardness typically indicates less than 100 ppm or 6 grains, also water which has gone through a water softener. Pools and spas should not be filled up with soft water from your softener. Water with less than 100 ppm of hardness needs to be increased to a minimum of 150 to 200 ppm utilizing calcium chloride
What is hard water?
Many of us call water ‘hard’ if it contains a lot of calcium or magnesium dissolved within it. Domestically, hard water causes TWO complications.
It can cause scale to create in the inside pipes, water heaters kettles and so forth. The calcium and magnesium precipitate out on the water and sticks to items. Ultimately, pipes may become entirely clogged.
It reacts with cleaning soap to create a sticky scum and so decreases soaps ability to form lather.
To fix all the complications of hard water, it is crucial to either filter the water by distillation or reverse osmosis. These processes will remove the magnesium and calcium from the water. The outcome of this would be achieving a production of soft water. An alternative option is filtration. Although affective, filtration would be extremely costly to use throughout the household on a regular basis.
What else will a water softener remove?
Water softeners will remove nearly all the calcium and magnesium from the raw water during the softening process. Softeners will also remove up to 10 ppm of iron and manganese. Water supplies with high levels of iron and manganese (greater than 10 ppm) may need pre-treatment to prolong the lifespan of a water softener.
How long will water softeners last?
A quality water softener, such as the softeners available from Industrial Water Equipment LTD can last for tens of years. However, it is usual to replace the ion exchange resins within the water softener once they have been exhausted. This is usually between 4 and 7 years, depending on the incoming water hardness and other variable factors.
Do water softeners need to be serviced?
It is usual to get water softeners serviced every year for domestic water softeners and twice a year for industrial water softeners.
How may the operation of your water softener be tested?
There is wide range of water hardness kits are available from Industrial Water Equipment LTD.
Disinfection treatment explained
Under certain conditions when contaminated water sources in particular are being fed to ion exchange systems the resins may become fouled either with bacteria or algae.
Where contamination of resin beds is observed the following procedures can be considered:
Peracetic acid
Peracetic acid, a derivative of hydrogen peroxide, displays an incredibly wide bandwidth of attack against microbes.
Research has shown that peracetic acid could be used to an ever-increasing degree in the field of human medicine because of its bacterial, fungicidal, spo-ricidal and anti-virus action.
Due to the wide spectrum of attack peracetic acid has been shown to be very suitable for a wide bandwidth disinfectant for deionsers. (Result of work done by Degussa Technical Applications Department in conjunction with Chemiewerk Homburg).
Using a peracetic acid solution of strength .2% (in water, with a reaction time of 1 hour), -a slime concentration of 104 -1 05/ml- including mould-was reduced to almost zero. The short rinsing time after using peracetic acid is of importance (typically about 45 minutes or 10-15BV).
In addition towards the excellent disinfection action, peracetic acid (according to experiments) has a minimal effect on the ion- exchange properties of cation or anion resins.
If peracetic acid can be used as a disinfectant the next procedure should be followed for both cation and anion resin:-
Ensure anion resins are fully exhausted as peracetic acid performs best at a pH below 8.
Make up one bed volume (BV)* of peracetic acid solution containing .2% peracetic acid.
Inject 1 BV of disinfectant at a flow rate of SBV/h, with displacement discharged to drain.
When all of the peracetic acid has been injected close all valves and retain the disinfectant not less than ONE HOUR to soak the resin and pipe work.
Execute a displacement rinse using raw water for at least 60 at 5BV/h, then a fast flush for Half an hour. Regenerate the resins once and return the unit to service.
Formaldehyde
If formaldehyde is to be used as disinfectant the next procedure should be followed:-
Make up 3BV* of formaldehyde solution containing .5% formaldehyde. Commercial formaldehyde (called formalin) contains 40% formaldehyde and should therefore be diluted approximately 80 times. Alternatively arrange the regenerant injection system to supply a solution of injection strength .5%. The ion exchange plant manufacturer provides advice regarding how this can be accomplished.
Inject 1 BV of disinfectant at a flow rate of 5BV/h discharging to drain.
If possible, drain down the unit to a level about SOmm above the resin surface.
Inject a second BV of disinfectant on the same rate and retain in the unit for a period with a minimum of eight hours and preferably in the unit overnight. Formaldehyde should be detectable by smell at any drain valve.
Flush the machine to drain using raw water until no formaldehyde is detectable along at the drain by Schiffs Test.
Regenerate the resins TWICE (double regeneration) and return the unit to service.*1 BV = 1 litre per litre of resin.
Sodium hypochlorite
Availability
One of the most convenient packout of sodium hypochlorite is in the form of small carboys/containers.
Preparation
For resin sterilisation a 1% available chlorine solution should be used. That is obtained by diluting the commercially available hypochlorite.
Treatment Procedure
The column should be regenerated with brine before treatment so that you can convert all resin to the depleted form (a double or triple regeneration is usually required). It needs to be ensured particularly that cation resin is fully depleted before treatment so that there is no chance of production of chlorine gas.
The minimum volume of solution required to treat the bed is 3 bed volumes (i.e. 3 times the resin volume installed in the unit).
The first bed volume needs to be passed over the bed at normal regeneration flow rate or approximately 4 bed volumes per hour (4BV/h).
A portion of the second bed volume needs to be retained within the bed, but for no more than 2 hours.
The third bed volume should be passed throughout the bed at the same rate as the first bed volume.
The sodium hypochlorite should now be displaced at a rate of approximately 4BV/h with softened water and then rinsed thoroughly to drain to get rid of any trace of sodium hypochlorite. At least 8-10 bed volumes will be required. The resin should be triple regenerated before returning to service.
Caution
It should be noted that this type of treatment might cause slight decrosslinking of the resin matrix and so frequent remedies are not advised. The procedure is not suitable for phenolic, polycondensation, and chelate resins.
In the case of anion resins, the oxidising effect of the sodium hypochlorite is on the amine groups and therefore disinfection in sodium hypochlorite should only be considered in extreme cases and then only on a once off basis.
Please note:
Suitable safety precautions should be taken when using sodium hypochlorite and drains into which the waste is discharged should be free from acids or other chemicals that may react adversely with the dilute hypochlorite discharge.Iron and magnesium explained
Introduction
Iron can be present in several different forms in water. For example in the case of un-aerated borehole water iron can be present in the ferrous state (Fe ) but on oxidation it is converted into the ferric form (Fe ).
Iron can also be complexed with organic matter; in that case it is present as an anionic complex.
Normally iron within the ferric state is removed by cation resin operated either within the sodium or hydrogen forms.
In the case of hydrogen form cation resin representing the very first stage of the demineralisation system the iron is taken off water but eluted on regeneration with mineral acid. With softening resin the specific situation is different, as the ion exchange resin removes the iron from the water however the regeneration procedure using brine does not elute the accumulated iron from your resin throughout the regeneration cycle. Consequently the iron accumulates on the resin from cycle to cycle and steadily causes progressive iron fouling.
In the case of iron being present as organo/iron complexes the complex exists as an anion and is particularly therefore taken off solution through the anion resin.
Because the anion resin is being regenerated with caustic soda, whilst the organic matter might be substantially removed each regeneration cycle, the iron is retained to the resin. The accumulation of iron on the resin causes the anion resin to become iron fouled.
It is recommended that where the iron content of water is greater than .5ppm some form of pre-treatment is used in order to reduce the iron level down to less than .1 ppm.
Remedial Action
Cation Resin
When utilizing sulphuric acid constantly while iron exists within the feedwater some accumulation of iron on the resin might occur causing a reduction in performance.
In these cases, treatment with hydrochloric acid should be considered providing the internal construction on the units and attendant piping make this possible.
In the case of accumulation of iron on Base Exchange softening resin, again either hydrochloric acid or sodium dithionite treatment might be considered.
Sodium dithionite treatment
Sodium dithionite is really a powerful reducing agent and when applied to an iron fouled resin bed will reduce any ferric iron given to the soluble ferrous form. Thus the bed can be freed from iron during a standard aqueous cycle.
We would recommend the following process of applying the sodium dithionite to a resin bed: -
The sodium dithionite needs to be added to water (and not the reverse) in order to form a 4% solution.
Caution should be shown when mixing the sodium dithionite because strong fumes of an obnoxious nature are evolved during the mixing process. Sufficient solution ought to be mixed so that when placed on the resin bed there is sufficient to fully immerse the whole of the resin. The resin should be agitated so that the sodium dithionite solution is evenly distributed throughout the bed.
Air should not be used for agitation purposes, as this will tend to oxidise the sodium dithionite.
The dithionite should be allowed to keep in contact with the resin bed for no less than 3 hours but 6 hours if at all possible.
After this period drain and rinse the unit thoroughly in a down flow fashion after pressuring the unit after which backwash for a full 30 minutes in order to remove any extraneous matter.
After this particular last procedure the unit ought to be regenerated in the normal way prior to it being returned to service.
Because of the relative instability of sodium dithionite solution a technique utilising sodium tripolyphosphate has been found to be much more effective than using sodium dithionite alone.
In this instance the solution should consist of 2% sodium dithionite 2% sodium tripolyphosphate. The resultant solution retains its iron removal power for a period of up to sixteen hours because of its greater stability.
In instances where a preventive procedure may be considered we would recommend the addition of a 1 gram of sodium dithionite to every 100 grams of sodium chloride used through the regeneration sequence.
However, we would emphasise that this same precaution should be utilized both the preventing of oxidation of the sodium dithionite by addition immediately prior to brine injection and also in the method of addition to brine solution.
The general characteristics of sodium dithionite together with the precautionary procedures are as follows: -
Characteristics of sodium dithionite
Sodium dithionite will decompose under the influence of heat or moisture. For this reason sodium dithionite should be kept in sealed watertight containers and stored in a cool dry place. Under such conditions this material can be stored over a pro- longed period with negligible loss in activity. Care should be exercised in handling sodium dithionite since, on contact with water; this product decomposes quite rapidly forming gases that can ignite spontaneously.
For this reason Sodium Dithionite is classified as a flammable solid and is shipped under the appropriate caution label. Because on the above mentioned, any material which is spilled should be promptly cleaned up and the site washed with copious amounts of water. Partially used containers represent a definite fire hazard.
When fighting a sodium dithionite fire the burning material should be deluged with water since too little water may be worse than none at all. Carbon dioxide and dry fire extinguishers are valueless since the product provides for its own oxygen for combustion.
Caution
Full details on the recommended procedure for storing and handling sodium dithionite should be obtained from the supplier and these recommendations strictly adhered to so as to ensure full compliance with local Health and Safety Regulations.
Hydrochloric acid treatment
In many instances it is not possible to treat softening resins with hydrochloric acid in situ because on the materials of construction on the softening unit.
However, where it is possible, 6% hydrochloric acid should be utilised and three bed volumes applied retaining the middle bed volume in contact with the resin for a period in excess of two hours (warming to 40'C is beneficial).
The resin should then be regenerated twice with 10% brine solution, before putting back into service.
Organic fouling explained
Introduction
It is well known that anion resins are susceptible to fouling by the humic and fulvic acids sometimes found in surface waters. These organic species, because of the relatively large molecular weights, become trapped within the resin matrix (to a greater or lesser degree depending upon the resin) and specific procedures have to be employed to cause recovery of the original ion exchange properties on the resin.
The symptoms of organic fouling include long rinse requirements, poor capacity and, in the case of strong base resins, higher silica leakage.
Treatment
The most common forms of treatment involve the use of brine solution; the procedure is as follows: -
The resin should be treated at the end of the normal exhaustion cycle.
Three bed volumes of 10% w/v brine solution containing 2% w/v caustic soda should be prepared.One bed volume should be introduced into the ion exchange unit at a flow rate not exceeding 2 BV's per hour followed by a second bed volume -this second bed volume should be retained in the unit for as long as possible, but at least 4 hours. Some agitation, if possible, should be employed periodically throughout the retention period.
At the end on the retention period the last bed volume of brine should be passed through the resin at a rate of 1 BV per hour and the resin thoroughly rinsed with clean water until free from brine.
The resin should be subject to at least two complete regeneration cycles before being put back on line.
N.B. Brine at minimum 35°C should be employed or preferably as high as 60°C so as to produce a better organic elution effect.
Iron/Organic Complexes
This subject is covered to some extent in the section on iron fouling.
Occasionally the presence of iron is detected on the anion resin. This can arise from an iron/organic complex being present in the raw feed water. In these cases, it is advisable to consider treatment of the anion resin with 6% hydrochloric acid immediately after the brine treatment.
The procedure that should be followed is similar to that given for brining. It is extremely important that all traces of hydrochloric acid are removed from the unit before introduction on the caustic soda regenerant.
It is important to ensure that the materials of construction are suitably resistant to hydrochloric acid.Which minerals cause water hardness?
The most common are magnesium, manganese and calcium
Why is hard water a problem?
For many uses, hard water is not a concern, although there are equally as many scenarios that hard water will be become a problem. One problem is a reaction soap has with hard water. The reaction causes the soap to form a scum that will result to all sorts of problems. Among which is the scum not washing off your body properly, resulting in clogged pores. This could then lead onto skin irritation, particularly when the service user already is affected with skin irritations like eczema. Another problem that occurs with the use of hard water is the prevention of soaps to create a lather, hard water tries to avoid this process, therefore service users find themselves using twice as much soap, whether is be washing the car, washing clothes or washing themselves. The obvious problem to this is that it's not cost effective.
Can Industrial Water Equipment test my water?
Yes, please see water analysis link
What should be done if water is found to be hard?
Although considered a luxury, treating water that's not above 3GPG hard isn't necessary. It's going to provide extra comfort when bathing or shaving but the cost of the instillation won't be saved from the running on the system. Alternatively, water that is found to be over 3 GPG would benefit from receiving treatment from the water conditioner. This is because the effects of the hard water being softened would be extremely noticeable. Another advantage is that the savings that the water conditioner would generate would cover the cost of the installation.
What should I look for in a water conditioner?
Firstly you need to determine the required volume on the water conditioner and the resin. You need to ensure that the resin will be enough for your daily water usage. The average water usage for a household is 87 gallons per day per person. Another thing to look for in a water conditioner is the method in which you want to recharge the unit. There are several options. The most common of which is to recharge by a time clock. This method relies upon a calculation of how much water you are going to use throughout a day, then the information will be programmed into the timer resulting in the timer knowing when it needs to recharge. It will be set to recharge at a certain day or certain time of day. In theory this works, but any changes to your routine can result in wasted salt and water or running out of softened water. |