In
Brief:
| The ESI StormWater Filtration System™ is a patented cassette style filtration system combined with pre-settling sedimentation containment and overflow by-pass protection. Each unit is either standard or custom manufactured for retrofit or specification to fit a specific catch basin or drain invert size. Units are installed into storm drains by removing the grate/cover, installing a high density polyethylene support plate with CleanPass™ overflow tubes to alleviate flooding concerns and a DryDrain to eliminate ponding which can contribute to bacterial or larval growth. Finally one or more fully loaded filtration canisters are situated into the plate. Water flow enters the unit and sediment and debris settle onto the plate and away from the filter. Water then rises up past the canister’s soft rubber ring and enters the diversion lid which processes the water via gravity feed through the filtration media inside the canister. The filter system’s media utilizes a proprietary blend of hydrophobic cellulose material. Manufacturer claims TSS removals of greater than 95% and effective removal of additional pollutants including suspended and emulsified hydrocarbons (oils, grease, and fuels), phosphorus, nitrogen, volatile organic compounds, PCBs, and various organically bound heavy metals (i.e. lead, copper, zinc, chromium) from stormwater, wash-water and wastewater, while allowing the cleansed water to pass through quickly and safely to be reused or discharged. Media formulations that kill bacterial and/or remove dissolved heavy metals are also available.
Manufacturer claims that a properly maintained unit will achieve substantial reductions of contaminants from entering receiving waters. This particular system is designed to trap contaminants contained in the "first flush" from storm events while allowing overflow protection to eliminate any chance of flooding during heavy wet weather events. To accomplish this, the filtration chamber is designed to handle 40 - 50 GPM through the media chamber, effectively handling up to ½" of rain per hour in a properly designed storm drain. Higher flows from high intensity wet weather events are diverted to the CleanPass™ overflow tubes which are designed to evacuate excessive storm surges and thus prevent flooding while capturing the majority of contaminant loadings from impervious surfaces.
Manufacturer claims that ESI StormWater Filtration Systems™ can be installed at a fraction of the cost of conventional oil-water separators and other BMPs. Installation is purported to be inexpensive as the system can be retrofitted into existing storm drains as well as specified into new or re-development projects. The system designed to be installed in such a manner as to eliminate two potential problems: “streaming”, in which the intended polluted water flows past the filter, and a raised grate which causes a trip hazard.
The ESI StormWater Filtration System™ can be used as a pre-treatment device when used in conjunction with groundwater infiltration systems, detention facilities, water retention systems and oil/grit separators. It can also be utilized as a post-treatment device in wet pond risers. The application of the ESI StormWater Filtration System™ for compact project sites may eliminate the need to set aside land for detention basins or for using traditional, often expensive oil-water separators, where land use is minimal such as in urban settings.
As with any system, the unit must be maintained on a regular schedule to prevent saturation of the filter media by contaminants and impediment from sedimentation and debris buildup. Maintenance is purported to be simple and quick - accomplished by vacuuming sediment loadings from the support plate and replacing the filter(s). With surface access there is no confined space entry. It is recommended that filters be changed every 6 - 10 months depending on the application. Disposal of the spent media in a typical application may be accomplished through placement into lined landfills, as the filter media is non-leaching. Always ensure compliance with all local regulations prior to disposal. |
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