FILTERMEDIA

Filtration of various components from water is a complex issue. There are four different media used for most instances: sand, nutrifil, basalt and zeotlite. These can be used seperately or mixed to improve the whole filteration process.

Sand has traditionally been used to extract turpidity and iron from water but tends to fall down on other impurities. Sand does not absorb or react with impurities but because of its sharp edges it blocks larger particles from its progress so backflushing has to stir up and unblock the structure of the sand to release and remove the particles. Sand therefore does not require frequent changing to remain an effective media.

Nutrifil is used for the removal of low levels of iron and to help improve PH imbalance. Nutrifil is made of dolomite limestone granules with a very high surface area. This means that a relatively small amount of the media - typically 15-30kgs - will neutralise typical household and farm flow rates. The media slowly disolves and therefore is topped up to the original level (typically every 2-3mths).

Basalt is a porous volcanic rock which can be used for the removal of iron, manganese and turpidity.

Zeolite has become a very useful media in that it can be used to remove iron, ammonia, manganese and turpidity. Zeolite is high in Aluminium Silicate which also has a useful effect on improving the PH balance of water. Zeolite works by absorbing impurities and also blocking particle progress through the media. While backflushing may remove particles of impurity from Zeolite it is not as efficient at removing the absorbed impurity. Zeolite as a media requires changing annually.