Installing filters for water treatment purification

Filters, the simplest water-treatment devices, can be used wither alone or in conjunction with a water softener.  When used with a softener, a larger filter is usually installed in the line ahead of the water softener to screen out particles that might otherwise clog it; a smaller filter, like a charcoal-type, is placed near the outlet to be filtered.

Common filter units include sand filters, neutralizing filters and oxidizing filters.  The sand filter simply traps suspended particles of salt, algae and organic material.  Neutralizing filters containing marble or limestone chips that react with the carbonic acid and weaken it, but they are not as effective as a chemical feeder for strongly acidic water.  Oxidizing filters use manganese-treated sand to remove larger amounts of iron from water than a water softener can handle, and are also effective in reducing hydrogen sulfide.

Each of these filters must be back-flushed frequently to remove trapped particles.  Neutralizing and oxidizing filters must also be replenished a couple of times a year with new core material, while the core of a charcoal filter must be replaced at least every six months so that any bacteria in the water cannot feed and multiply on the organic material that the filter traps.

The most sophisticated treatement device is the reverse-osmosis purifier.  This unit removes hardness minerals, salt and suspended particles in one process by forcing the water under pressure into a thin membrane through which only pure water can pass.  The unwanted materials remain on one side of the membrane and are drained from the unit through a waste outlet.  Its capacity is low, and it is attached under the sink or lavatory to provide drinking and cooking water from a single tap.