A filtration device is a proprietary practice designed to remove oil, grease, sediments, trash, and other debris from stormwater by passing them through a media filter. They are most often used for commercial or industrial redevelopment applications where other management practices are not practical. In high flow situations, the volume of water may exceed the capacity of the filter chamber and stormwater may bypass the device without treatment.

Advantages

• Widely applicable
• Requires minimal land areas
• Compatible with most storm drain systems
• Can be used to meet redevelopment requirements

Disadvantages

• Limited effectiveness with large storm events
• Does not reduce peak flows
• Requires frequent maintenance
• Expensive

These devices are available in a wide array of configurations from a variety of vendors and should be custom designed to meet the individual needs of the site. At a minimum, they shall be designed to treat the first ½ inch of runoff from the site and provide the necessary sediment reduction. The filters must remain effective for at least a year, before replacement is required.

• Installation should follow all manufacturers’ specifications
• Device must be water tight to prevent groundwater pollution
• Maintenance access must be provided

Maintenance activities should follow the manufacturers’ recommendations and specifications. However, additional maintenance requirements may be required and are listed below.

• Oil and grease filters should be inspected regularly to ensure that the practice is functioning properly
• All accumulated oil, grease, sediment and other debris should be disposed of properly

Companies have the option to submit their devices for County approval. As of June 11, 2018 the following products have been reviewed and approved for meeting sediment control and oil and grease removal standards.

StormFilter
Contech Engineered Solutions
9025 Centre Pointe Drive
West Chester, OH 45069
1-800-338-1122

Up-Flo Filter
Hydro International
94 Hutchins Drive
Portland, ME, ME 04102
1-207-756-6200

WinSLAMM must be used to determine the sediment removal efficiency of these devices.

• DNR Proprietary Stormwater Filtration Devices Technical Standard 1010