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Case Study- Chemical Free Iron Removal.


Author: Helmut Dresselhaus – Pacific Water Technology – Brisbane

Date: 26/08/2018




 Pacific Water Technology recently commissioned a new commercial water treatment facility for bore water to produce high quality water destined for the water bottling plants in Queensland.  The innovative technology employed is leading edge, and has delivered excellent results.   The project included the complete scope from equipment design, supply of equipment and storage tanks, as well as commissioning and process optimisation.   

 In order to ensure that the good properties of this water is maintained during storage,   the 316 Stainless Steel tanks from Select Water Tanks provided the cost effective solution.  The water bottlers require very strict water quality standards, both in regards to chemical and microbiological standards exceeding Australian Drinking Water Guidelines.  The best technology and equipment was therefore selected to ensure optimum results are delivered. A secondary concern was the formation of bromate due to the ozone oxidation of bromide. Due the low levels of bromide (less than 30 ppb) there was undetectable levels of bromate.

The table below compares the results of ozonation vs aeration of the water, both delivering results well within the required tolerances.  There was some evidence of perhaps ozone oxidation causing some manganese to go back into solution, however this can be remedied by reducing the ozone dose. In conclusion the implementation of either air or ozone in conjunction of Nanobubble technology delivered excellent results in removing iron and manganese and producing water with an excellent flavour and aesthetic profile.








IC001 Bromate mg/l <0.01 <0.01
I.619 Total Dissolved Solids mg/l 250 260
5.308 Manganese as Mn mg/l 0.013 0.001
5.308 Iron as Fe mg/l 0.0052 0.036






The importance of in- situ Legionella testing is becoming increasingly more relevant for all medical  and facilities and nursing homes.  Traditional laboratory testing  can deliver inaccurate results not to mention long delays before the results are known . Rapid Legionella testing can mitigate those risks and  by being able to  get the results within half an hour and hence immediately enable staff to take remedial action.

More reasons below why traditional lab culture testing is loosing its relevance.  


Time’s Up on Lab Culture!


8 reasons why the ‘Gold Standard’ for Legionella testing cannot protect you, your employees or your customer’s from Legionnaire’s Disease.



Legionella is a water-borne bacterium that thrives in man- made water systems. When the bacteria are inhaled by humans, in the form of water droplets and aerosols, it can lead to fatal outbreaks of Legionnaires Disease.

Statistics show that cases of Legionnaires Disease are increasing rapidly each year and that many cases of this fatal infection are going undiagnosed .

The lab culture method is often described as the ‘Gold Standard’ for Legionella testing and is sometimes required by law. However, the accuracy of results is dangerously low when compared with other methods.


Here are 8 reasons why the lab culture method simply isn’t good enough to protect you, your staff and the public from Legionnaires Disease…


 In general, water samples aren’t tested on-site and must be sent to a laboratory for testing.


1. Sample Damage in the Transportation Process

The sample must not be exposed to excessive heat or other radiation, and paperwork must be meticulous to ensure that the test results reflect the sample submitted.

  1. In many cases, with courier-shipped samples, it’s very difficult to guarantee that best practice has been followed and that the sample hasn’t been altered
  2.  Other bacteria in the sample can dominate Legionella en route and use the resources available.
  3.  This can result in a diminished or weakened population of Legionella.

Problem – Guess what? Legionella in the sample can die en route and lead to a false negative result or a low CFU result.



Acid and Heat Treatment

2. Once in the lab, samples can be treated.

The ISO standard specifies acid and heat treatment to kill bacteria that could dominate the culture test and prevent Legionella from being detected .

Problem – Guess what? It can also kill some of the Legionella in the sample and lead to a false negative result or a low CFU result.

 3. Lab Culture Cannot Detect Viable but Non-Culturable Bacteria

Legionella, when shocked due to temperature, biocide,lack of nutrients, or other stress, can enter a Viable but Non-Culturable (VBNC) State.

In this state, the bacteria are still highly dangerous but the lab culture test will NEVER detect them as they cannot be cultured 

Problem – You’ve guessed it! Once again, the lab test result can be highly misleading and again this could lead to a false negative result or a low CFU result.

 4.Artificially Created Environment

Legionella Pneumophila which accounts for most cases of Legionnaires’ Disease worldwide  is a parasite of amoeba. It replicates within the amoeba until it exhausts its resources, then shifts to a lower metabolic state, grows a flagellum, exits the amoeba and uses the flagellum to swim looking for another host.

Lab culture tests do not use amoeba so the reproduction process is not natural or optimal for Legionella to grow.

Problem –  Once again the lab test result can be highly misleading and again this could lead to a false negative result or low CFU result.

 5. Lab Culture Only Detects Part of the Legionella Bacterium Lifecycle

Only certain phases of the Legionella lifecycle are easily replicable via lab culture. Therefore, the success of the lab culture test is at least partially dependent on the lifecycle phase of the bacteria present in the sample, at the time of testing.

The most hazardous phase (referred to as the motile phase), is the phase in which Legionella can infect human lungs. Ironically, this phase cannot be easily replicated via the culture method because the bacteria is not in a naturally replicative state.

Problem – Laboratory testing methods can be highly inaccurate, arguably dangerously so. Yet again the results from a lab can be misleading and false negatives and low CFU results can occur.

 6.Lab Culture is Just TOO SLOW!

With all lab culture tests there is a typical 10-14 day wait for results. Therefore, the test is always providing a historical view of the system being tested .

Legionella populations in man-made water systems can multiply to dangerous levels in just a few days.

That leaves up to 14 days of opportunity for the bacteria to infest the water system and infect you, your employees and the public!

Problem – A negative result may provide a false sense of security and a positive result may be delivered FAR too late – this is a huge risk to staff, customer and general public health!

 7.Lab Culture Testing Achieves Low Recovery Rates – That’s a Fact!

The recovery rate illustrates the percentage of positive samples which are successfully detected by a testing method.

The recovery rate of lab testing can be dangerously low, for the

reasons stated above, and even the ISO standard document only states recovery rates of “>64%”. That’s up to nearly 36% inaccuracy[8]!

However, despite variable and low recovery rates, the lab culture method is still considered the ‘Gold Standard’ in the industry. Confused? So are we!

Problem – False negatives are a serious problem for Lab Culture techniques – even for ISO accredited labs. Not only is the method slow, it can also be inaccurate!

 8.Inefficient Information and Audit Trail

Lab culture testing typically provides a written report, which is sent back to the customer following the 10-14 day testing period. This will have to be interpreted and the information passed on to a duty holder or other risk management professional in order for the required action to take place.

Problem – This adds further delay and increases risk!


Suprised? Check out our sources!


[1] Cdc.gov. (2018). Legionella | Surveillance and Reporting | Legionnaires | CDC. [online] Available at: https://www.cdc.gov/legionella/surv- reporting.html [Accessed 23 Apr. 2018]


[2] McCoy, W., Chen, K., Neville, M., Devender, S., Downes, E., Leonidas, L., Cain, M. and Sherman, D. (2012). Inaccuracy in Legionella tests of building water systems due to sample holding time. Water Research, [online] 46(11), pp.3497-3506. Available at: https://www.sciencedirect.com/science/article/pii/S0043135412002369 [Accessed 17 Apr. 2018].


[3] Lee, J., Lai, S., Exner, M., Lenz, J., Gaia, V., Casati, S., Hartemann, P., Lück, C., Pangon, B., Ricci, M., Scaturro, M., Fontana, S., Sabria, M., Sánchez, I., Assaf, S. and Surman-Lee, S. (2011). An international trial of quantitative PCR for monitoring Legionella in artificial water systems. Journal of Applied Microbiology, [online] 110(4), pp.1032-1044. Available at: https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2672.2011.04957.x [Accessed 17 Apr. 2018].


[4] Dietersdorfer, E., Kirschner, A., Schrammel, B., Ohradanova-Repic, A., Stockinger, H., Sommer, R., Walochnik, J. and Cervero-Aragó, S. (2018). Starved viable but non-culturable (VBNC) Legionella strains can infect and replicate in amoebae and human macrophages. Water Research. [online]  Available   at:   https://www.sciencedirect.com/science/article/pii/S0043135418300721  [Accessed  17  Apr.  2018].


[5] Kuroki, T., Amemura-Maekawa, J., Ohya, H., Furukawa, I., Suzuki, M., Masaoka, T., Aikawa, K., Hibi, K., Morita, M., Lee, K., Ohnishi, M. and Kura, F. (2017). Outbreak of Legionnaire’s Disease Caused by Legionella pneumophila Serogroups 1 and 13. Emerging Infectious Diseases, [online] 23(2), pp.349-351.  Available  at:  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5324795/  [Accessed  17  Apr.  2018].


[6] Price, C., Richards, A., Von Dwingelo, J., Samara, H. and Abu Kwaik, Y. (2013). Amoeba host-Legionellasynchronization of amino acid auxotrophy and its role in bacterial adaptation and pathogenic evolution. Environmental Microbiology, [online] 16(2), pp.350-358. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3946891/ [Accessed 17 Apr. 2018].


[7] Osha.gov. (2003). Legionnaires’ Disease eTool: Water Sampling Guidelines. [online] Available at: https://www.osha.gov/dts/osta/otm/legionnaires/sampling.html [Accessed 23 Apr. 2018].


[8] Water quality — Enumeration of Legionella. (2017). ISO International Standard, (11731).



Are you interested in the latest technologies in Legionella testing industry? Contact us on:


Email us: sales@pacificwater.com.au

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Dechlorination of town water  bottling plant in Stapylton – Queensland

Chlorination is a common method to maintain water, such as drinking water and swimming pool water, biologically safe. It is used to destroy pathogenic micro-organisms, to oxidise taste/odour-forming compounds, and to form a disinfectant residual. The use of chlorine in these applications can lead to the formation of disinfection by-products (DBP) such as the trihalomethanes (THMs), haloacetic acids. In addition to toxicity of THMs in drinking water, they can give a taste in beer, bottled water  or soft drinks in the brewing and bottling industry.


Nanofiltration Plant Brisbane – Waste Water Treatment and Remediation

Nanofiltration Plant – Waste Water Treatment 

Emerging Contaminants Removal

Pacific Water Technology supplied and installed  a Nanofiltration plant for removal of  perfluorinated compounds from contaminated groundwater and industrial effluent  at a site in Brisbane.   The membrane filtration plant was locally assembled in Brisbane and supplied at short notice.      The plant is capable of dealing with a wide range of  feed water qualities, and has the capability of Clean-In-Place to recover  permeate flow.  The plant has a dual membrane array, allowing one  membrane array to be cleaned in place, whilst the other continues to treat the contaminated influent ,thereby minimising downtime.


Rainwater Harvesting and Filtration

Rainwater  Harvesting and Filtration

Many Australians rely on rainwater as their water supply for their daily needs. The general public perception is that rainwater is safe to drink. In most areas of Australia, the risk of illness arising from consumption is relatively low, providing it is visually clear, has little taste or smell and, importantly, the storage and collection of rainwater is via a well maintained tank and roof catchment system.

Australian Households using rainwater.

Source ABS 2010


This water may be used as if it was potable water and sometimes without any filtration and disinfection.   That the water comes from the skies and is always safe to drink, is a fallacy.   As the rainwater is harvested on the roof, any organic and inorganic material including faecal matter is collected into the rainwater tank.  Live animals may also get trapped in the tank and drown providing a source of nutrients and high risk of bacterial contamination.   Algae can also grow where the water is exposed to sunlight.   Most tanks will also contain mosquito larvae which feed on the organic nutrients collected in the tank.

Odours from sediments and slimes are the most commonly reported. Sediment can accumulate in the bottom of tanks that have not been cleaned frequently enough. In warm to hot weather, anaerobic conditions can develop, leading to growth of microorganisms that produce sulphides, with a distinctive sewage or rotten egg-like smell. Listed below are some water parameters that can impact your water quality:

pH levels in rainwater are normally below 7 and considered acidic. This is because carbon dioxide from the atmosphere is absorbed which in turn converts to carbonic acid.  In plastic tanks the pH will remain acidic  and can corrode copper plumbing and brass fittings.  Also see : http://www.abc.net.au/local/stories/2010/11/24/3075218.htm

 If the rainwater is stored in concrete tanks the acidic water will cause lime from the concrete to leach into the water. 

Calcite filters are recommended for an appropriate treatment of acidic water.


Turbidity is the measure of relative clarity of a liquid. It is an optical characteristic of water and is an expression of the amount of light that is scattered by material in the water when a light is shined through the water sample. The higher the intensity of scattered light, the higher the turbidity. Material that causes water to be turbid include clay, silt, finely divided inorganic and organic matter, algae, soluble colored organic compounds, and plankton and other microscopic organisms.


Tannins are a natural organic material that can be the byproducts of nature’s fermentation process, be created as water passes through decaying vegetation in the gutters. This can cause water to have a faint yellow to tea-like colour, and can cause yellow staining on fabrics, fixtures, china and laundry.

Rainwater in its natural state, is very close to de-ionised but after passing over the  roof, conductivity levels can be elevated due to contaminants that may be dissolved in  the rain water.

In its natural state rainwater is very soft and ideal for washing and laundry and  under some conditions for hot water systems.  The water also has a low alkalinity and that combined with soft water and low pH results in the rain water causing corrosion and that includes copper plumbing .

Total Suspended Solids .

Suspended solids refers to small solid particles which remain in suspension in water as a colloid or due to the motion of the water. It is used as one indicator of water quality.  A colloid is a solution that has particles ranging between 1 and 1000 nanometers in diameter, yet are still able to remain evenly distributed throughout the solution.

Coliform Colony Counts 
The most basic test for bacterial contamination of a water supply is the test for total coliform bacteria. Total coliform counts give a general indication of the sanitary condition of a water supply

Prevention is better than cure

There are a number of steps that can be taken by the householder to ensure good quality rainwater.

Gutter Guard

Gutter Guard or mesh can help prevent  leaves and other organic  matter from reaching the rainwater tank.

First Flush diverters

Are readily available from hardware stores, or can easily made up yourself.

Regular tank cleaning and inlet screen filter maintenance.

Effective filtration and disinfection.

Effective filtration and UV Disinfection will provide you with safe drinking water

The filtration steps should comprise at  least of a 10 micron sediment filter, followed by an antibacterial silver impregnated activated carbon filter and final UV disinfection step.

For higher flow rates we recommend automated backwash filters. Zeolite and activated glass media filters are very effective in removing suspended solids.  Activated Carbon filters can remove dissolved organics and any bad odours and taste. An occasional backwash will ensure that any colloidal or organic material is removed It is very important to use silver impregnated carbon or antibacterial carbon, as organics trapped in the organic matrix can aggravate the problem. 

Environmental factors

Environmental Factors should also be considered.  Any dust that is blown onto your roof may end up in your water tank.  This  may include dust from a mine ,  agricultural activity that could include pesticides and fertilisers.  If the water runs off old asbestos roofing, or is in contact with plumbing that contains lead solder are factors that should be considered as well.

Water Testing

Water testing should be carried out at least once a year to see what contaminants are present. There are easy DIY test kits which can provide an indication of whether your rainwater is not contaminated.

complete water testing for your home


Rainwater harvesting has become an important factor in conserving our most precious resource. More than ever, Australians are relying on rainwater as their potable water supply.  Preventative Maintenance is an important factor in ensuring a safe water supply. Preventing organic and inorganic matter from getting into the tank can reduce the risk of bacterial contamination, algae growth and reduce the amount of suspended and colloidal material in your water tank. Sediment and carbon filtration  followed by ultraviolet disinfection are highly recommended to ensure a safe source of drinking water. Calcite filter should also be considered to ensure that the water is not corrosive, and will cause corrosion to your plumbing.



Removal of iron from borewater – Case Study Blenners Transport -Darra QLD

Iron removal filters have become an important water treatment process  for providing clean and safe drinking water in Australia. Small amounts of iron are frequently present in water because iron is  naturally present in the soil and because corrosive water will pick up iron from unprotected  ferrous pipes. The presence of iron in water is considered objectionable because it imparts a brownish /orange colour to laundered goods and affects the taste of beverages such as tea and coffee. Some bore waters however could contain very high levels (>100mg/L). There is no health related guideline value for iron. However, for aesthetic reasons (taste and staining) the concentration of iron in drinking water should not exceed 0.3mg/L.

The most economical way of removing iron from water is by aeration (dissolved iron is oxidised and precipitates out of solution as rust Fe2O3). Iron dissolved in groundwater delivered via irrigation systems can produce unsightly rust stains on buildings, paths, fences and plants in many areas, especially on the Perth coastal plain. It may also stain clothes washed in iron-rich water and plumbing fixtures such as basins and toilet bowls. These rust stains resist cleaning with soaps, detergents and bleach.  The iron can also foul membrane systems, and it is imperative to remove the iron prior to membrane filtration. 

DMI-65 is an extremely powerful catalytic water filtration media that is designed for the removal of iron and manganese in aqueous solutions (water) without the need for potassium permanganate regeneration. The unique microporous structure of DMI-65 efficiently removes dissolved iron to the almost undetectable levels as low as 0.001 ppm and manganese to 0.001 ppm. DMI-65 acts as an oxidation catalyst with immediate oxidation and filtration of the insoluble precipitates derived from this oxidation reaction. DMI-65 can also remove Arsenic, Aluminium and other heavy metals and Hydrogen Sulphide under certain conditions.  The removal of iron is based on the oxidation reaction that converts ferrous soluble iron into insoluble ferric hydroxide which precipitates in crystalline form aggregates of size from 3 nanometres and larger. The aggregates coagulate in larger flocks and are retained in the catalytic bed.

In order for this oxidation reaction to proceed unimpeded, a continuous source of nascent oxygen is required. This is facilitated by the dosage of Sodium Hypochlorite solution (typically 12.5%) and maintain a free residual chlorine content during normal operation and also during backwash.

An example is demonstrated below .

Removal of iron using DMI 65

Bore water with iron content of 2.8 ppm iron, 0.2 ppm Manganese was to be used as cooling water for a refrigeration system at a transport company. Service flow is 120 litres per minute, and filtered water is stored in a large storage tank. 

The solution proposed was a DMI-65 twin filter system with 293 Magnum Control Head, where the flow is split to supply equal flow to each filter. This solution would then allow the 21” vessels to be backwashed at the required flow rate of 120 litres per minute.

Bore water Before and after filtration

Another issue that is sometimes associated with iron is low pH.  In cooling water applications, neutral pH or higher than 7 is required to reduce the corrosiveness of the water. The total alkalinity was also  less than 40 ppm therefor causing a negative Langelier saturation index. This alone may not indicate that the water is corrosive, however in this instance it may be necessary to increase the pH without adding hardness to the water. This is achieved by dosing for instance with soda ash. In this example chlorine was dosed at approximately 3 mg/l to achieve  free chlorine level of >0.2 mg/l downstream of the iron removal filters.   The final iron content (total) was below 0.01 ppm.

In this example the dosing of Sodium Hypochlorite is preferred as that will also  have a secondary function as a biocide in cooling water. Cooling water towers can be ideal breeding grounds for biological growth, including algae, bacteria, sulphate-reducing bacteria, protozoa, and fungi. If not properly controlled, these organisms will form a layer of bio-slime that acts as a natural adhesion surface for scale formation, resulting in increased corrosion rates, restricted water flow, and reduced system efficiency.  


Pacific Water  also utilises alternative Manganese Dioxide Media that only requires aeration  to regenerate  the media and oxidise the dissolved iron.   The options include Birm and also  MediaPlus ; both chemical free options for treating iron and manganese in bore water.  More:

Chemical free iron removal




Citric Acid Uses

Citric Acid Uses 

Citric acid is a weak organic acid that is produced as a white crystalline powder. It is a natural food preservative that is also used to add an acidic, or sour taste to foods and soft drinks. In biochemistry, it is important as an intermediate in the Krebs (citric acid) cycle and therefore occurs in the metabolism of virtually all living things. Citric acid can also be used as an environmentally benign cleaning agent. It is also commonly used in the food industry as a preservative and also acidity regulator.

This article looks at some of the applications for citric acid.   Pacific Water Technology supplies the citric acid  as a crystalline powder (anhydrous) or solution with up to 50% concentration.  For specialised applications there is also a high purity solution made up with demineralised water and citric acid.

Some of the applications for citric acid:

Citric Acid for pH control: Citric acid is a weak organic acid and is often favoured for pH control in the food industry.  Some  examples are the poultry industry where chlorination is used in the spin chillers for disinfecting the chicken carcasses. The water has a very high organic load and chlorination can be very ineffective if not carried out at a pH of 6.5.  The reason for this is that the dissociation of the sodium hypochlorite into hypochlorous acid  is only effective at lower pH.  Citric acid can effectively reduce and maintain the pH at levels where chlorination is at its’ most effective without increasing the risk of generating dangerous levels of trihalomethanes and chloramines.

Citric Acid as preservative and food additive:

Citric Acid is commonly use in the food industry as a buffering agent, acidity regulator, preservative and food additive for food, beverages and pharmaceutical products.

In its broadest sense, a food additive is any substance added to food. Legally, the term refers to “any substance the intended use of which results or may reasonably be expected to result — directly or indirectly — in its becoming a component or otherwise affecting the characteristics of any food.”

In most of beverages, citric acid (E 330) is the first choice for use as an acid regulator, as it has several additional benefits, such as enhancing the activity of beneficial antioxidants and adding aroma

Citric Acid as a descaler

Citric acid is a popular environmental friendly descaler  for coffee machines , kettles, shower screens  and other areas that may experience scale build-up. It is also used in industrial scale often in conjunction with other cleaning agents for cleaning RO  and other membranes .   It is also used for descaling heat transfer surfaces in heat exchangers.



The dangers lurking in dam, river or other untreated water supplies

A large proportion of Australians rely on untreated or minimally treated water supplies,  for their daily water requirements.   Recent events have highlighted the dangers of untreated water supplies, even when the water is not consumed.  Naegleria infects people by entering the body when water containing the amoeba goes up the nose. This may occur when people swim, dive or fall into warm freshwater containing Naegleria.  Also see Australian Story .

The dangers lurking in stagnant waters

The dangers lurking in stagnant waters-Source: Wikipedia

Infections have occurred following domestic bathing, for example when young children fall or slip in a bath of water containing Naegleria. The amoebae travel up the nose to the brain where they infect and destroy brain tissue. Naegleria fowleri, also  known as the “brain-eating amoeba“, is a species of  free-living, bacteria-eating amoeba that can be pathogenic, causing a ) brain infection.This microorganism is typically found in bodies of warm freshwater, such as ponds, lakes, rivers, and hot springs. There is no reason why this bacteria could not also be encountered in rain water tanks.

There are other water borne bacteria and viruses as well, and some people may build up some level of immunity  against some of these potentially lethal microbes.    Legionella is just another example of a bacteria, that thrives in warm stagnant water. Rain water that falls from the skies is perceived safe to drink,  and provides a false sense of security- the same applies to dams and rivers that may be located in prestine environments.   Others in the community in particular older people and children may not have the same level of immunity – and it just is not worth it to roll the dice .   The best way to ensure your water supply is safe is to have some levels of filtration and ultraviolet disinfection. UV radiation affects microorganisms by altering the DNA in the cells and impeding reproduction. UV treatment does not remove organisms from the water, it merely inactivates them. The effectiveness of this process is related to exposure time and lamp intensity as well as general water quality parameters.  

Used alone, UV radiation does not improve the taste, odour, or clarity of water. UV light is a very effective disinfectant, although the disinfection can only occur inside the unit. There is no residual disinfection in the water to inactivate bacteria that may survive or may be introduced after the water passes by the light source.  It is therefor necessary to treat the water immediately after it is pumped from the water source, and prior to consumption. Water for recreational use should also be treated. The percentage of microorganisms destroyed depends on the intensity of the UV light,  the contact time, raw water quality, and proper maintenance of the equipment.  Any stagnant water like  inflatable pools may also require supplementary disinfection like chlorination.


The natural way to disinfect without chemicals

Contact your local PWT specialist and we can recommend the most suitable disinfection solution for your water requirements.


For more on our range of UV disinfection systems : 

Brochure pacific-water-uv-guard-slt-series-brochure


Water Softeners Commercial Kitchens

Water Softeners  Commercial Kitchens

Pacific Water Technology recently commissioned a new water softener commercial kitchen at Algester Nursing Home to treat the water supply to the commercial kitchen and laundry.   The facility has been struggling with scale build-up inside the hot water systems, steamers and dishwashers .  The problem in particular manifested itself as scale inside the headers clogging up the  steam nozzles. Brisbane water  supply is considered hard and can  reach almost 150 mg/l   CaCO3.   In simple terms , the water contains minerals like calcium and magnesium that become insoluble when heated and drop out of solution as a white deposit( lime build-up) .

Calcium and magnesium ions  (these are both positive ions) in water join with the soap to form as insoluble curd and reduce the effectiveness of the soap as a washing agent. The real problem comes when you try to wash the curd out of the clothes because as an insoluble material it sticks to the fibres of the clothes, does not re-dissolve and is left behind after rinsing.  So you may have added dirt to the clothes (in the form of these insoluble calcium and magnesium compounds) rather than cleaning them. Clothes may feel damp even though they are dry, and do not have a ‘crispness’ after washing. Over time, this soap curd will give a dull yellow colour to white materials.

Increasing your appliance life and eliminating lime deposits

Increasing your appliance life and eliminating lime deposits

In the bath or shower, soap is difficult to get a lather with hardwater and instead of feeling slippery it seems difficult to wash.

Other classification systems are intermediate to the Australian Drinking Water Guidelines (2004)and refer to various scales of total hardness as:

    soft                                        <17 mg/L CaCO3
    slightly hard                     17-60 mg/L CaCO3
    moderately hard              60-120 mg/L CaCO3
    hard                                        120-180 mg/L CaCO3
    very hard                            >180 mg/L CaCO3

An effective way to solve your hard water problem is to remove the hardness ions from your water using an ion exchange  water softener.

How ion exchange water softeners work?

One of the biggest misconceptions about water softeners is that the salt is what softens your water. What actually softens the water are thousands of tiny resin beads within the tank that filter out hard water chemicals. The salt is used to clean the resin beads during a regeneration cycle, allowing the system to continually remove hardness from your water supply.

There are many different types of softeners, each with its own benefits. The method used most often in homes is cation exchange, the principles of which are simple. An ion is an electrically charged atom or group of atoms. A cation is a positively charged ion. The water is softened when the hardness ions (magnesium and calcium) are exchanged for sodium ions. This exchange occurs in a resin bed during the softening cycle.  


Three main parts make up most water softeners:  

  • Resin Tank – Contains the resin bed. 

water softeners commercial kitchens

World class water softening resin for commercial applications

  • Resin Bed – This is made up of tiny bead-like material often made of styrene and divinylbenzene. The beads attract and hold positively charged ions such as sodium, but will exchange them whenever the bead encounters another positively-charged ion such as calcium or magnesium. 


  • Brine Tank – This tank holds the dissolved salt solution that is necessary to regenerate the resin. Regeneration refers to reversing the ion exchange operation. The magnesium and calcium ions are driven off of the resin beads and replaced by positively charged sodium ions. The regeneration occurs when the resin beads are washed with a strong salt water solution. The salt forces the calcium and magnesium ions to be released, and they are then discharged as waste during the backwashing cycle. The beads are ready to once again attract hardness ions from the water. 

    Benefits of Softened Water

    Even for those whose water is slightly hard, significant benefits can result from using softened water:  

    • Water heating efficiencies on systems using softened water may be increased up to 29 percent if heating with gas, and 22 percent if using electricity. (Source: New Mexico State University Study) 

    • The life of the plumbing system may increase because clogging from scale within pipes will be reduced. 

    • Many appliances may last longer and perform better. 

    • Soapy residue on clothes is reduced so they may look and wear better. 

    • Skin and hair can be rinsed more completely, making hair look shinier and skin cleaner. 

    • Film on tubs and shower tiles may be reduced, as will scratching to bathroom fixtures and sinks. 

    Pacific Water Technology is located in Brisbane and we supply water softeners across Australia for comemercial and industrial applications.


10 Things to consider when buying a residential reverse osmosis system


Buying a new water purifier or reverse osmosis system for your home can be simplified if you get in prepared with the necessary knowledge. Before buying a new unit consider this:

1.Any RO system should comprise of at least three pre-filter stages – one sediment pre-filter rated at 5 microns, and two granular activated carbon filters. The granular activated carbon filters should ideally be catalytic carbon to remove chloramines.

filters three stage

2. The pre-filters are an important part of your Reverse Osmosis Filter, the sediment filter protects the carbon filters, and the carbon filters protect the reverse osmosis membrane, which is prone to oxidation damage from chlorine or chloramine.  Chloramines are a combination of ammonia with chlorine. Unlike straight chlorine, which dissipates fairly quickly when exposed to air, chloramines remain in the water. Chloramines are very difficult to remove from your water supply.Chloramine_Diagram


3.Ensure that your RO membrane is from a reputable company like DOW TFC membranes, and should be at least 50 GPD( gallons per day).

dow membrane tfc

4.Be wary of any salesman that tells you that they have a pure water to waste water ratio of 1:1 . The ratio is more likely going to be 1:3 or 1:5 (pure:waste) . This ratio is necessary to ensure continuous high performance of your RO membrane, and helps flush contaminants from the tiny pores(0,0001 microns) which otherwise can get clogged.  This ratio is also dependent on a number of factors including water quality.  High dissolved solid content like for instance hard water, will require a higher flush rate. A  flow restrictor by-pass is also recommended as that will help clean out the membrane surface by initiating a high flow.

comparative sizing

5.Residential RO membranes can only be used for town water supply i.e. chlorinated water with relatively low dissolved solid content. They should not be used for river, dam or rain water.  Special membranes are required for brackish and seawater and they require significantly different configurations to suit the increased osmotic pressure caused by the increased salinity.  Seawater which has a salt content of above 35,000 ppm would require at least 24 Bar just to overcome the osmotic pressure. Residential RO systems should be operated at pressures of 300 to 800 kPa( 3-8 Bar)- low water pressure means you would require a booster pump with your RO system, which is normally just a add-on.

6.The purified water from your reverse osmosis system is slightly acidic as the water is devoid of any minerals and the remaining CO2 gas in the water causes the slight acidic conditions. Hence we recommend a mineral or alkaline stage that does two things; it provides minerals back into the water (Calcium, Magnesium, etc) and also increases the ph to levels above 8. The added minerals will also help provide buffering capacity to the water.


7.Reverse osmosis systems are the best purifier to remove fluoride from water. The level of fluoride added is typically 0.5 ppm .  Activated carbon does not remove fluoride, activated alumina and ion exchange resins with fluoride specific ions can, but require significant contact time.  They also become saturated and to find out when that happens can be rather expensive. Measuring residual fluoride in water in the parts per billion range is very expensive- and the filter sales people know that. It is therefore better to rely on reverse osmosis filters, as the method of removal is by size exclusion. The size of the fluoride ion is larger than the tiny pores of a membrane which are only 0.0001 microns.

8.There are three options for RO systems ; Tank option ,direct flow option and also units that automatically fill up a portable reservoir . A buffer tank with a bladder provides adequate flow when you want to fill up a glass.  Ensure the tank is manufactured from food grade approved materials.  Direct flow units are also popular but to be practical should produce at least 400 GPD of purified water.  Automatic RO systems like the Astroboy, are becoming very popular as they allow the portable container to be taken anywhere, or positioned into a water dispenser.


9.A final stage carbon polishing filter is also recommended to ensure there is no residual taint as a result of water sitting in the line or the storage tank

10.Quick change cartridges are becoming very popular, as they require very little effort to replace and no tools.  Remember be very diligent about changing cartridges- as that will ultimately ensure consistent good quality water and ensure your reverse osmosis membrane will last at least 3 years.


 purepro quick chnage

Nominal impurity removal characteristics of TFC RO membrane



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