Unformatted text preview: by passing through a porous material. This medium may be sand, anthracite diatomaceous earth, or a finely woven fabric. Different Types of Filtration
Is a form of filtration whose primary objective is the removal of microorganisms (phytoplanktons, zooplankton and microscopic debris).A filtering medium consisting of a finely woven stainless steel fabric is normally used.
Diatomaceous Earth Filters
First used extensively during the World War II to provide water to military units in the field within a short period of time. The filter medium is supported on a fine metal screen, a porous ceramic material, or a synthetic fabric known as septum. Pressure Filters
Pressure Filters have a media (sand, anthracite or calcite) and underdrains contained in a steel tank. Water is pumped through the filter under pressure and the media washed by reversing flow through the bed, flushing impurities. Step 6:D i s i n f e c t i o n , Step 6:
Fluoridation, Acidity Correction The final chemicals are added at this point. A small amount of chlorine (or another disinfecting chemical) is added to kill any remaining germs and to keep the water safe as it travels to the public. In some places disinfection is the only treatment given. In some areas, fluoride is also added to assist with dental health protection. In some areas other chemicals are added at this point to correct the acidity of the water again. The purpose of disinfecting drinking water is to destroy organisms that cause diseases in man. F l u o r i d a t i o n = most public water supplies add fluoride ion to achieve an optimum level as a public health insurance. Medical studies have also indicated that fluoride...
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