General Filter

The support bed is eliminated by the
MULTIBLOCK shield, an HDPE cap
with a unique design that contacts each
side of the block for a secure seal. Further
enhancing the block underdrains structural
integrity, the MULTIBLOCK shield is
secured to each block along the center
and top edge of the block. Some other
block systems use only 2 edge screws
without a center fastener. Two versions of
the MULTIBLOCK shield accommodate
varying filter types. Single or dualmedia
filters use the 500-micron
porosity MS-500 MULTIBLOCK shield,
while Mixed Media filters require the
250-micron design MS-250.
ADDING MULTIWASH? MAXIMIZES
BACKWASH EFFECTIVENESS
The MULTIBLOCK underdrain is
available alone or with other USFilter
equipment, such as the CenTROL?
clustered gravity filter or the MULTIWASH
Filtration Process. Adding
MULTIWASH to a MULTIBLOCK
system allows existing plants to increase
filter backwash cleaning efficiency. This
combination of technologies allows for
sustained simultaneous air/water backwash,
which eliminates the draindown
step, provides vigorous scouring action,
and returns a clean filter bed without
media loss.
The MULTIBLOCK system has been
incorporated into the new ACTIFLOC
pre-engineered water treatment system.
This package plant for hard-to-treat
waters uses the MS-250 MULTIBLOCK
shield to support Mixed Media without a
gravel layer. Whether you need a single
technology, a complete plant or total
system planning, USFilter can provide
everything for water and wastewater
treatment.

MULTIBLOCK DOES:
Retain filter media directly.
Install quickly and easily.
Resist corrosion and calcification.
Allow for easy, effective backwash.
MULTIBLOCK DOESNT:
Require support gravel.
Require frequent cleaning and
maintenance.
Impede process flow.

As part of the USFilter family of products,
the MULTIBLOCK underdrain brings
you more than its own features and
benefits. It brings you the expertise and
single-source convenience of the worlds
largest water treatment company.
Designed for efficient retrofits and
plant expansions, this lightweight, easyto-
handle underdrain is made of highstrength,
corrosion-resistant HDPE. The
MULTIBLOCK design offers you a low
profile (approximately 12''), low maintenance
and low headloss. The MULTIBLOCK
system will support single, dual
or Mixed Media without a gravel layer.
Mixed Media may allow filters to run at
up to 30% higher flow rates, providing
increased plant capacity without the
installation of additional filters.

MULTIBLOCK underdrain is a part of the USFilter family of products. The underdrain has a snap together design for quick and easy installation. The underdrain is equipped with a stainless steel or HDPE "shield" having a unique design that contacts each side of the block for a secure seal. The "shield" is secured to each block along the center and sides of the block with a three-screw hold-down system. The stainless steel Laser Shield media retainer includes openings less than .22 mm and the HPDE Shield has a 500 micron porosity. To increase filter backwash cleaning efficiency, the underdrain can be provided with our MULTIWASH? technology for a simultaneous air/water backwash that provides vigorous scouring action to return a clean filter bed without media loss.

General Filter Underdrain Product Introduction