Fluoride At low concentrations, Dissolved from rocks In most New Zealand fluoride is beneficial to and soil, particularly source waters, fluoride but at higher levels it can be in geothermal areas. concentrations are too low damaging to health. to be beneficial and some communities adjust the fluoride level. Hardness Hard water is water that Dissolved If any treatment were to contains high levels of (usually limestone) be undertaken, a small calcium and manganese and soil. water supply would ions. It becomes difficult to probably use the ion lather with soap, and scale exchange process. can form on the inside of kettles and hot water cylinders. It is not a health concern but can make the water less palatable. New Zealand waters are not usually hard. This is why they are often aggressive. Iron Iron is an element whose Dissolved rocks, Aeration followed by compounds can cause especially in bore filtration is usually reddish-brown colouration of water. effective in removing iron. the water and can give it a Sometimes increasing the metallic taste. Iron can be pH, chemical oxidation present in the source water followed by filtration, and it can also dissolve out greensand filters or ion of steel pipes when the water exchange is used. is aggressive. Often water coming from a bore source is low in oxygen and, when it comes into contact with air, the iron oxidises and forms reddish brown particles in the water. Manganese Manganese is an element Dissolved rocks and Normally, chemical whose compounds can soil. oxidation followed by cause brown/black stains on filtration, greensand filters laundry and can give water or ion exchange is used. an unpleasant taste. High levels of manganese can be harmful to health. Nitrate At high levels nitrate can Fertilisers, animal The ion exchange methemoglobinemia, a run-off, raw sewage process is normally used disease that is particularly or treated effluent. but this is very expensive toxic to babies. Surface and difficult. Usually a waters are usually low in new source is nitrate but high levels can occur in groundwater.
Fluoride At low concentrations, fluoride is beneficial to but at higher levels it can be damaging to health. Dissolved from rocks and soil, particularly in geothermal areas. In most New Zealand source waters, fluoride concentrations are too low to be beneficial and some communities adjust the fluoride level. Hardness Hard water is water that contains high levels of calcium and manganese ions. It becomes difficult to lather with soap, and scale can form on the inside of kettles and hot water cylinders. It is not a health concern but can make the water less palatable. New Zealand waters are not usually hard. This is why they are often aggressive. Dissolved (usually limestone) and soil. If any treatment were to be undertaken, a small water supply would probably use the ion exchange process. Iron Iron is an element whose compounds can cause reddish-brown colouration of the water and can give it a metallic taste. Iron can be present in the source water and it can also dissolve out of steel pipes when the water is aggressive. Often water coming from a bore source is low in oxygen and, when it comes into contact with air, the iron oxidises and forms reddish brown particles in the water. Dissolved rocks, especially in bore water. Aeration followed by filtration is usually effective in removing iron. Sometimes increasing the pH, chemical oxidation followed by filtration, greensand filters or ion exchange is used. Manganese Manganese is an element whose compounds can cause brown/black stains on laundry and can give water an unpleasant taste. High levels of manganese can be harmful to health. Dissolved rocks and soil. Normally, chemical oxidation followed by filtration, greensand filters or ion exchange is used. Nitrate At high levels nitrate can methemoglobinemia, a disease that is particularly toxic to babies. Surface waters are usually low in nitrate but high levels can occur in groundwater. Fertilisers, animal run-off, raw sewage or treated effluent. The ion exchange process is normally used but this is very expensive and difficult. Usually a new source is
treatment-options-small-drinking-water-supplies-jan14.docx