Question 1

What is filter sand?

Accepted Answer

A washed, dried and closely sized sand used as the filtering bed in water and wastewater treatment. It is specified by effective size and uniformity coefficient.

Question 2

What do effective size and uniformity coefficient mean?

Accepted Answer

Effective size is the sieve opening that ten percent of the sand passes; it governs what the bed captures. Uniformity coefficient is the sixty percent passing size divided by the effective size; a low value means a uniform bed that filters and backwashes evenly.

Question 3

Why must filter sand be dried and sized?

Accepted Answer

Only a dry sand can be screened into the narrow fraction a filter specification requires, because moist sand clumps and blinds the screen. Washing first removes the silt and clay that would otherwise enter the treated water.

Question 4

Can you supply support gravel as well as filter sand?

Accepted Answer

Coarser fractions up to 6 mm can be supplied for support layers beneath the filter bed.

Question 5

Do you supply pool filter sand?

Accepted Answer

Yes. Swimming pool sand filters use a closely sized sand within the specialty range. Contact us with the filter manufacturer’s specification.

Question 6

How is filter sand ordered?

Accepted Answer

By effective size and uniformity coefficient, or by sieve band, together with the tonnage for each layer and the delivery location.

Question 7

Is the filter sand washed?

Accepted Answer

Yes. It is washed to remove silt and clay before being dried and sized, so that no fines are carried into the treated water or blind the bed.

Question 8

Do you supply media for industrial and irrigation filters?

Accepted Answer

Yes. Closely sized fractions within the 0.3 mm to 6 mm range are supplied for industrial process water, irrigation and aquaculture filtration.

Water Filtration

Overview