PRODUCT: Underground Sandfilters

Precast concrete underground sandfilters, also known as DC sandfilters, are watertight structures that are used in situations where the difference in elevation between finished grade and invert out is 8’-5” or greater. This structure can be used in an online or offline situation. This product comes in 10’-0” wide by 8’-0” tall sections with lengths of 8’-0” and 5’-0”. It also has internal baffle walls to create a sediment chamber, permanent pool, filter chamber and clearwell. The baffle walls are also used to trap floating debris and oils, and provide an overflow weir allowing extreme flows to bypass when used in an online system. These structures come standard with a 4’-0” x 4’-0” hatch opening over the filter chamber and a 3’-0” diameter manhole opening over the sediment and clearwell chambers. These structures are designed to have a minimum of 6” and a maximum of 8’-0” of earth cover over the outside top slab. For availability and ease of installation, this product is equipped with recessed panels on all sides of end sections that can be removed for pipe penetrations.

It is required that this product be installed upon a level base to insure proper sheet-flow over the filter media. To accommodate sloped grades, grade rings are used to bring manhole covers and hatches to grade. These structures may also be installed in parallel to accommodate site conditions.