Gravity Sand Filter

Conventional Gravity Filters provide three steps of water treatment comprising of the following:

-and filtration.

Conventional filters are recommended for raw waters with turbidity greater than 5 NTU and/or color greater than 20 TCU.

First, chemicals are quickly mixed into the raw water and then softly mixed in a buffer tank called the flocculation chamber. The main group of chemicals added are referred to as coagulants. Coagulants when mixed with the raw water form precipitates that trap suspended solids such as dirt, bacteria, viruses, and other microorganisms. The detention time in the flocculator which allows precipitates to form and remove the contaminates must be adjusted accordingly with temperature variations

After flocculation, the water flows into the clarifier, a large chamber where the flow velocity of water is diminished. The low velocity lets the particulate matter to settle out of suspension by gravity.

The filter is contained within a filter container, usually made of coated steel, stainless steel or aluminum. Inside the filter container are layers of filter media (sand, anthracite, etc.) and gravel. Below the gravel, a network of pipes makes up the underdrain which collects the filtered water and evenly distributes the backwash water. Backwash troughs help distribute the influent water and are also used in backwashing.

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PROTEC is a privately owned company established in Doha, Qatar engaged in the fields of Engineering, Supply, Construction, Installation, Commissioning, Operation and Maintenance of various types of equipment for the Water, Waste Water, Energy, and Industrial markets.


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