2025 Nelsen Corporation Catalog - Catalog - Page 120
4 Garnet
Resins, Media & Chemicals
Garnet
Garnet is a high hardness, high density granular filter media. It
is normally used as the lower (final) filtration layer of a multi-bed
Downflow filtration system. Called Multi-Media or Mixed Media
filtration, the high density small grain size of Garnet solves a
major filtration problem. In a single media granular filter such as a
sand filter, the material will hydraulically classify during backwash
according to granule size, the smallest rinsing to the top. When
water flows downward through the sand, the fine particles at the top
of the bed do most of the straining of the sediment. The solids form
a cake on the surface with filtration typically taking place in the top
few inches. As the cake forms, the filtration becomes finer and head
loss increases exponentially in time.
The ideal situation would be to have the large grains of media at the
top to trap the large solids and a uniformly decreasing grain size in
the direction of fluid flow with the small grains at the bottom to do
the final polishing. The penetration of the solids through the entire
bed allows increased solids storage, longer filter runs and higher
filtration rates.
A properly designed multi-media system will maintain its unique
inverse void gradation and provide superior performance even
after long periods of use in backwash. This stable condition of
large grains above finer ones is achieved by the use of materials of
different sizes and specific gravities. Garnet with its high specific
gravity of 4.0 forms the lower fine grain layer, its 0.3 mm effective
size can filter down to the 10-20 micron range. Filter sand (e.s. =0.5
mm) and Anthracite (e.s. = 0.9 mm) or Filter-Ag can form the larger
less dense layers.
See Technical Section for Multi-Media Loading Capacities
Multi-Media filtration technology is applicable to both water and
waste water treatment. Custom designed filters with varying filter
bed configurations can be designed to meet specific needs. For
the majority of municipal and industrial water supply applications, a
filter bed composed of 55 percent low-density material, 30 percent
medium density material, and 15 percent high-density material is
recommended. Garnet sized per requirements, is the ideal high
density material.
#8 Garnet at 150 lb./ft.3 is a good choice for support beds when
using other high density filtration media such as high purity Flomag.
Advantages:
• High specific gravity allows unique filter designs. In combination
with other filter media both higher flow rates, higher loadings and
better filtration can be achieved.
• High hardness reduces attrition and provides for years of
reliable service.
• An excellent support bed for other high density media.
Physical Properties:
Color ............................................................ Light tan to reddish purple
Type........................................................................................Almandite
Crystal System............................................................................... Cubic
Fracture ......................................................................... Sub-conchoidal
Hardness .....................................................................7.5 (Moh’s Scale)
Specific Gravity ................................................................................. 4.0
Density ..........................................................................120 - 150 lbs/ft3
Free Silica.......................................................................................None
Garnet mineral sand manufactured by
International Garnet Co., Inc. is classified by
Underwriters Laboratories Inc.® in Accordance
with Standard NSF/ANSI/CAN 61
Garnet
A high-hardness, high-density filter material used in multi-media filters. Recommended as a support bed
for other materials such as filter sand, anthracite, Corosex, etc.
Pallet quantity - 70 bags per pallet
GAR8-50
#8, .38 Cu Ft Bag (50 lb.)
GAR8-50-BOX
#8, .38 Cu Ft Box (50 lb.)
GAR12-50
GAR12-50-BOX
#8 - 12, .38 Cu Ft Bag (50 lb.)
#8 - 12, .38 Cu Ft Box (50 lb.)
GAR30/40-50
GAR30/40-50-BOX
#30-40, .36 Cu Ft Bag (50 lb.)
#30-40, .36 Cu Ft Box (50 lb.)
GARNET #8
4 - 18
GARNET #8 - 12
For more information visit – NelsenCorp.com • NelsenWaterSolutions.com • VESTAwater.com
All prices and products subject to change without notice. ©Nelsen Corporation
GARNET #30 - 40
