Abstract: A drainwater treatment system positionable within the vertical passageway of a drainage system utilizes a catch basin for accepting drainwater which flows downwardly into the drainage system and a filter-supporting section disposed alongside the catch basin. The filter-supporting section accepts drainwater which flows therein from the catch basin and permits drainwater to flow downwardly therethrough. First and second filters containing a hydrophobic material are positioned within the filter-supporting section for filtering contaminants from the drainwater flowing downwardly therethrough, and an overflow is associated with the catch basin and the filter-supporting section through which drainwater is permitted to exit the treatment system and bypass the first and second filters when the flow rate of drainwater into the system exceeds the rate at which drainwater is permitted to flow downwardly through the first and second filters.

Abstract: A drainwater treatment system positionable within a horizontal flow passage of a drainage system utilizes a partition which divides the flow passage into an upstream chamber and a downstream chamber. In addition, a mid-panel is supported within the upstream chamber for dividing the interior of the upstream chamber into an upper section and a lower section so that the drainwater enters the upper section before entering the lower section through a first opening provided in the mid-panel. A conduit is also joined between a second opening provided in the mid-panel and the opening of the partition for conducting drainwater from the lower section of the upstream chamber to the downstream chamber so that the drainwater which enters the upper section and then into the lower section is decelerated to flow conditions at which debris and suspended are permitted to separate and settle from the drainwater before being conducted from the lower section and into the downstream chamber through the conduit.