Stormwater Filter Accommodates Shallow Installations

New filter eliminates bacteria and viruses under flowing stormwater conditions.

Installing large, vertical vault stormwater filtration devices in relatively flat terrain with minimal elevation fall has always been difficult.

When faced with that problem in a large, mixed-use development in Southern California, Katchall Stormwater Filtration Systems LLC used a Jensen Precast vault and developed the Kleerstream antimicrobial filtration chamber, a shallow-draft, reinforced concrete unit that requires less excavation, accommodates minimal elevation differences, and eliminates bacteria and viruses under flowing stormwater conditions.

“In a conventional filtration device, the inlet and outlet pipe elevations are usually at least two to three feet apart,” notes Kip Searcy, CEO. “With the Kleerstream unit, the elevations can be as little as 12 inches between the pipes, so you’re no longer faced with how to get a site to drain properly if each unit requires a 2- to 3-foot drop in pipe elevations. We took the same basic principles being used for vertical devices and made them function in a horizontal plane.”

The self-contained structures use two-stage filtration. First, hydrodynamic separation removes solids larger than 100 microns. Then the stormwater passes through a series of antimicrobial filtration weir walls that remove suspended solids, hydrocarbons, nutrients, and heavy metals to less than 50-micron levels, and kill 99.99 percent of bacteria and viruses with less than one-second contact time.

There are seven H-20-rated chambers, each able to accommodate several different pipe diameters. The smallest unit (Model 120) is 4 1/2-feet-wide by 6 1/2 feet long by 4 feet deep with a 35-square-foot footprint. It filters up to 3,410 gpm, and retains about 1.5 cubic yards of solid waste material.

“You can literally place this unit only one foot under a street and hook it up to the storm drainage conveyance pipes,” Searcy says. “The bottom of the vault is only five feet below the street surface — that’s huge in terms of minimizing the cost of excavations and disposal of waste products.”

The largest (Model 200) is 8-feet-wide by 40-feet-long by 6-feet-deep and has a 340-square-foot footprint. It filters up 55,000 gpm. “Every unobstructed square foot of antimicrobial filtration media can filter 180 gpm,” Searcy says. The chambers work as inline filtration systems or as off-line (first flush) systems, and can handle flows even during 25- to 50-year storms. For information: 866/528-2425;


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