PRODUCT: Perimeter Sandfilters

Precast concrete Perimeter sandfilters, also known as Delaware sandfilters, are watertight structures that are used in situations where the difference in elevation between finished grade and invert out is 8’-5” or less. This structure can be used in an online or offline situation. This product comes in 10’-0” section lengths with two 4’-0” wide side-by-side chambers and the common wall having flow ports to accommodate either 3’ or 2’ filter media. It also has internal baffle walls to create a clearwell, trap floating debris and oils, and provide an overflow weir allowing extreme flows to bypass. These structures are designed to be flush with finished-grade with removable top slabs or optional accessories which include grates and concrete slabs with inspection covers. For availability and ease of installation, this product is equipped with recessed panels on all sides 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, RES offers the option of sloping the top of the sandfilter to either a 3.13% or 5.21% grade with the minimum height from finished-grade to invert out of 5’-11” and a maximum height of 8’-5”. These structures may also be installed in parallel to accommodate site conditions.