How does the filter remove contaminants?
Throughout the system, contaminant removal is occurring by sedimentation, filtration, adsorption and chemical transformation.
Water enters the structure through the inlet pipe attached to a 90° bend in the interior, and is forced into a centrifugal swirl pattern above the hydrodynamic separator and below the porous concrete filter. Due to the unique inlet design, hydrodynamic separation occurs in a controlled space, where settleable and suspended solid pollutants fall through the center opening of the hydrodynamic separator via gravity. This sedimentation falls through the opening into the quiet water below the hydrodynamic separator, where previously deposited sediment remains undisturbed in the sediment catchment sump.
Head pressure drives the influent waters up through the porous filter. During treatment, unsettled smaller particles remain in the centrifugal swirl pattern under the filter, where they slowly attach to the underside, or find their way into the pores of the filter, becoming trapped. Dissolved particles come in contact with the internal surface area of the filter and adsorb to the filter. A chemical transformation occurs and the particles form an insoluble compound and precipitate out. As the storm event subsides, much of the particulate gravitates out of the filter and into the sediment catchment sump.
Sediments are removed from storm water in two steps based on particle size and weight. Cyclonic separation occurs as the water is introduced to the structure. Here settleable and larger suspended particles will drop out due to gravity. They are then stored in the sediment catchment sump apart from mainline flow of the ecoStorm® plus. Smaller particles remain in the cyclonic separation chamber or are captured by the aggregate in the porous filter as water is passed through vertically. After the storm event has ended and there is no further upward vertical flow, much of these smaller sediment particles fall out of the filter via gravity and are collected in the sediment catchment sump of the ecoStorm® plus.
Certain dissolved solids will have an affinity for the filter and will accumulate on the surfaces of the filter. This is a physical process that is caused by the surface energy of the dissolved solid and the filter.
Dissolved solids with ionic characteristics (metals) are converted to an insoluble form (particle) by the reaction between the dissolved (soluble) compounds and the alkalinity (increased buffering ability) associated with the filter. These particles are then removed from solution by filtration and subsequent gravitational settling when flow through the filter stops.
ecoStorm plus® - Integrated PLUS Filtration Technology
- Proprietary Information: Patented Design, All Rights Reserved. Royal Environmental Systems, Inc.
- ecoStorm plus (U.S. Pat. No. 7,632,403).