◆ Filter Sand

In terms of sand filtration (rapid/slow filtration), the maintenance of filter largely depends on the property and particle size. Therefore, the selection of quality of filter sand is very important. The property, size, quality and conformity play important role to satisfy JWWA standards

Only 10% of natural sand can be used for rapid filtration. The sand for rapid filtration also accounts for only 30% in natural sand, because the uniform particle size, which is sieved by the advanced technique, is required. NIHON GENRYO provide the cutting-edge technology to produce the products for rapid and slow filtration for more than 75 years. Our original sieving, physical and chemical tests are held according to our strict standards to provide high-quality filter media in the market.

■ Standards for selection under JWWAA-103 and results of our filter sand tests(extract)

	JWWA A-103 Quality regulations	JWWA A-103 2006 tests results(Our Plant)
Turbidity	30 degree or below	10 degree
Specific gravity	2.57-2.67	2.64
Ignition loss	0.75% or below	0.40%
Attrition rate	3.0% or below	0.40%
Hydrochloric acid solubility	3.5% or below	0.30%