Low-flow-contaminant-adsorbing system

Abstract

A structure for use with low flow stormwater drainage includes a two-piece outer cylindrical housing and a removable inner cylindrical flow cartridge containing a replaceable filter media. The housing consists of a sealed basin with a removable lid. The cartridge is suspended within the housing by an open tubular mechanical support extending downward from the housing lid. The bottom of the cartridge is above the bottom of the housing. The cartridge has a permeable screened bottom and a screened orifice at the top where the open tubular support attaches. An inlet into the housing accepts fluid flow transverse to the vertical axis of the cartridge at a depth location near the cartridge vertical midpoint. In operation, hydrostatic head pressure forces stormwater flow into the housing where primary separation of insoluble contaminants occurs. Contaminants with a density less than water remain inside the housing but outside the cartridge at a depth near the housing lid. Contaminants with a density substantially greater than water remain inside the housing but outside the cartridge at a depth near the housing bottom. The separated stormwater flows through the cartridge bottom permeations, upward through the filter media where secondary treatment occurs then out the open tubular support. Secondary treatment removes targeted dissolved and suspended contaminants through adsorption and filtration.