Definition of sand filter in English:
A filter used in water purification and consisting of layers of sand arranged with coarseness of texture increasing downward.
- In the NEF test, a 25 mm thick layer of the core material (the base soil) is compacted in a 100 mm diameter steel mould, above the layer of the sand filter to be tested (the test filter).
- The second filter is a slow sand filter with grains of 250 microns.
- Rest the sand bed for four months or treat the bottom layer of the sand filter with hydrogen peroxide, delivered up through the discharge pipe to oxidize the iron sulfide crust.
Definition of sand filter in:
- British & World English dictionary