Pretreatment - Filtration devices and practices

Filtration pretreatment practices include proprietary and non-proprietary devices that remove particles by filtration or sieving through media (gravel, sand or other), vegetation, geotextile or fabric material, metal or plastic screen, or other material. The filtration devices presented in this table are classified as pretreatment due to the nature of the filtration, placement in the treatment train, or built-in additional pretreatment mechanisms. The filtration methods are widely varied from biological to mechanical. They seek to remove not only larger sediments and debris, but also heavy metals, nutrients, and other fine contaminants. The natural or engineered biological systems are, by nature, above ground.

System Design

Some filtration pretreatment methods require a larger footprint than other pretreatment options due to the slower flow through rate and surface-area-based effectiveness. Most drainage area references refer to impervious area.

System and Component Sizing

Sizing is largely based on drainage area and estimated runoff volumes for different design storms or intensities. Most important for the sizing is the anticipated frequency of operation and maintenance as well as protection of downstream BMPs and receiving water. Some devices have “enhancements” that can provide treatment mechanisms beyond the primary pretreatment mechanism. These can provide an additional level of treatment such as filtration, skimming (in addition to settling or screening), chemical treatment/sorption, or biodegradation. This is denoted by the Y or N in the table indicating this ability to perform additional mechanisms.

Links to tables with information on filtration

Below are links to several tables containing information on filtration. To see all tables on a single page, link here. To see the information in a single spreadsheet click on the following link: [[File:]]

• Filtration - pollutant removal information
• Filtration - system design information
• Filtration - system and component sizing
• Filtration - installation and maintenance recommendations

Related pages

• Pretreatment selection tool
• Overview and methods of pretreatment
• Overviews for different types of pretreatment practices
  • Overview for pretreatment settling devices
  • Overview for pretreatment screens
  • Overview for pretreatment vegetated filter strips
• Information for specific types of pretreatment practices
  • Design, construction, operation and maintenance specifications for pretreatment vegetated filter strips
  • Pretreatment - Hydrodynamic separation devices
  • Pretreatment - Screening and straining devices, including forebays
  • Pretreatment - Above ground and below grade storage and settling devices
  • Pretreatment - Filtration devices and practices
  • Pretreatment - Other pretreatment water quality devices and practices

To see the above pages as a single page, link here

Pretreatment sizing for basins and filters strips

Guidance for managing sediment and wastes collected by pretreatment practices

Tables

• Pretreatment tables - link to tabled information for pretreatment practices
• Hydrodynamic separator tables
• Screening and straining devices tables
• Above ground and below grade storage and settling tables
• Filtration tables
• Other water quality devices tables

Other information and links

• Pretreatment - Additional considerations
• Case studies for pretreatment
• References for pretreatment
• Links for pretreatment
• Definitions for pretreatment
• Supporting material for pretreatment
• Photo gallery for pretreatment