INTRODUCTION.
The following document is a brief outline on water problems that are typical to New Zealand. The information contained here does not pretend to give a comprehensive study on each item rather than to give you a brief outline on the item, which may help you in discussions with your customer. Please contact Aqua Dynamics for a more detailed outline of these problems.
BACTERIA, E COLI, CYSTS AND VIRUSES.
Perfectly safe water can change in the blink of an eye to become microbiologically unsafe for humans. This is due to infestation primarily from faecal matter that introduces E Coli, Giardia and a whole host of other nasties to the water. Very few natural water sources are free from contamination of this nature. In the very worst cases drinking this water can result in death but generally causes sickness to people who drink this water. Infestation of this water is generally from birds or animals fouling the waterways or depositing onto roofs. The New Zealand drinking water standard for E Coli in potable water is zero and recently the same standard has been applied to Dairy Sheds. Many of these sheds are supplied by rain fed tank water or streams and this water should generally be considered to be contaminated. The same should be said for rain fed or stream water-supplying houses with their water. To quote a Government scientist the writer recently had discussions on this matter about, “if they drink untreated rain or river water they should not bother washing their hands after they go to the toilet”. Enough said.
Treatment.
Aqua Dynamics offers a wide range of systems to treat this water. However, generally we suggest an Ultra Violet sterilisation system as a minimum.
pH AND ACIDIC WATER.
The lower the pH of water the more acidic it becomes. pH is at a neutral level when it’s reading is between 7.0 and 8.0. Water with a pH below 7.0 is generally acidic and as such aggressive towards plumbing fittings. A sure sign of this is blue/green staining occurring on whiteware which is actually copper from the plumbing fittings that has been eaten away by the acidic water.
Rainwater generally has a low pH. As the rain falls through the atmosphere it absorbs carbon dioxide and after it hits the ground this continues as it absorbs carbon dioxide from decaying vegetation. This absorption of carbon dioxide reacts with the water to form an acid called carbonic acid, which in turn causes the water to be aggressive toward fittings.
Treatment.
This is relatively easy to correct by installing a pH Neutralising filter. Aqua Dynamics offers a full range of options on the units with varying flow rates and backwashing options.
HARDNESS
Water is considered hard when magnesium and calcium are present in the water. When water is hard it cannot react to soap i.e. it is difficult to get soap to lather, it also causes scale build up inside of the pipework with the eventual result of the flow through these pipes being restricted. Hard water also shows when the water temperature is elevated by forming scale. This does shorten the life of hot water cylinders and heating elements such as in the kettle. Other symptoms are, scale in the toilet and on recently washed windows, and it is very hard to get the clothes clean in the washing machine, as the washing powder will not lather.
Treatment.
Aqua Dynamics offers a wide-ranging variety of Water Softeners. We offer Electromechanical heads with 12-day clocks or the full Electromechanical heads. We have all sizes of tanks and heads for these units and are able to cater for any flow rate you may require.
IRON AND MANGANESE IN BORE WATER
Soluble iron is commonly found in bore water in this New Zealand. This iron is usually in a soluable state when it first comes from the ground but in very short order it oxidises and the water turns a reddy brown colour. This stains plumbing fittings and causes build up inside the pipework. It also causes the water to have a horrible taste. This is a common problem in rural areas and the treatment of iron does depend on many different things and every application has to be treated on an individual basis. Generally speaking the soluable iron is oxidised to a precipitated state where it is removed from the water. This may be accomplished by an ion exchange system such as in a water softener or other oxidisation methods may be used. Another common system is aeration into the tank and removal by way of a sand filter. Iron and manganese removal can be tricky and each application is different.
TURBIDITY
This is a general term for suspended matter such as decaying organic matter in water that may make the water appear dirty or cloudy. There are many things that can cloud water such as clay, iron, sand etc. This is measured on water tests by an NTU reading that is a unit that measures the reflection of light off particles suspended in the water. High levels of turbidity can reduce the effectiveness of disinfection procedures for water such as Ultra Violet sterilisation.
Treatment.
There are many ways to remove turbidity from water starting with simple cartridge filtration all the way through to automatic backwashable multi media sand filters. Again all such cases should be treated on their individual merit from either a water sample or a water test result.
FLUORIDE
Fluorides are soluble salt compounds that occur in New Zealand water supplies. Municipal supplies of water have Fluoride added to the water to prevent tooth decay. However there are people that do object to the presence of Fluoride in the water and will ask for it to be removed.
Treatment.
Reverse Osmosis will remove Fluoride but also there are Fluoride specific cartridges available form Aqua Dynamics that will fit easily into an under bench filter unit to remove the fluoride form the water.
HYDROGEN SULPHIDE (ROTTEN EGG SMELL)
Hydrogen Sulphide is a flammable poisonous gas which is produced in water as a result of decomposing organic matter present in the tanks. It is generally noticed by the smell of rotten eggs and foul taste. It can also result in tarnishing of polished metals and is toxic to aquarium fish life. It is more apparent during the warmer times of the year.
Treatment.
Generally if Hydrogen Sulphide is present the best idea is to dump the water in the tank and get the tank cleaned out thoroughly. Some form of disinfection should then be installed to prevent this from occurring again. Again each case is different. Please contact us for a recommendation.
NITRATES
Nitrates are not good to be present in water. In high concentrations they can be dangerous to young children causing a blue tinge to the skin because of a decreased ability of the blood to carry oxygen. Nitrates present in water may also indicate the presence of bacteria.
Treatment.
Nitrate specific cartridges are available from Aqua Dynamics. Reverse Osmosis is also an effective way to remove nitrates from water supplies.
SILICA
Silica is formed inside the earths crust by the erosion of rocks and sand and may be present in water although not always visible to the human eye. It forms on containers and can block treatment screens in things such as Water Softeners. It is also hard to remove when it has been allowed to build up inside pressure tanks and boilers etc. It has been known to cause major problems with water supplies and is quite difficult to remove (although not impossible) as the general treatment for this type of thing, Multi Media sand filtration, does struggle as using sand to remove sand does not always work correctly. However if you have a Silica problem please contact us at Aqua Dynamics and we will design a system for you.
COPPER
Copper is not naturally present in New Zealand water supplies that often. Occasionally it is detected when the water source is near a copper mine or such like, but generally it is seldom found naturally. Copper however is generally found in water where the pH of the water is low (see pH chapter above) and this acidic aggressive water has eroded the copper plumbing fittings present. This is generally characterised by blue/green staining of the whteware in the house. Copper in water is toxic to fish and does make the water taste somewhat bitter.
LEAD
The same occurs for lead which again is very rarely found naturally occurring in New Zealand water supplies. If lead is present in water it is generally from lead or soldered fittings being eroded by acidic aggressive water as above.
