2,216
edits
Changes
Jump to navigation
Jump to search
Line 68:
Line 68:
→Types of Treatment Train Designs
These are the most common types of treatment trains. They typically involve installation of one or more [[pretreatment]] devices upstream or at the [[inlet]] of the primary stormwater treatment facility.
These are the most common types of treatment trains. They typically involve installation of one or more [[pretreatment]] devices upstream or at the [[inlet]] of the primary stormwater treatment facility.
[[File:Treatment train air force.JPG|thumb|800px|An example of a stormwater treatment train approach at Tyndall Air Force Base in Florida, in a coastal environment. This example includes source controls of [[bioretention]] parking islands, [[permeable pavement]], and conveyance controls of[[swales]], a natural infiltration basin in a forested woodlot, and end-of-pipe controls of [[dry ponds]], [[constructed wetlands]] and coastal dunes. All of these features help to reduce traditional SWM features' maintenance, treatment and rehabilitation coasts, while also reducing pollutants into the receiving waterbody. (U.S Air Force, 2020)<ref>U.S. Air Force. n.d. LANDSCAPE MASTER PLAN - C. Site Development Criteria. CO4. Stormwater - C04.3.2 Stormwater at Individual Building Sites. Accessed: https://www.tyndallifs.com/images/LMP_pdf/TAFB_Final_LandscapeMasterPlan_2020-09-24_SectionC04.pdf</ref>]]
'''Example''': Runoff into larger treatment practices such as [[bioretention]] or [[stormwater tree trenches]] may be pretreated by [[Inlet sumps: Gallery|concrete sumps]] at [[curb cut]] inlets, [[forebays]] or catch basin inserts, which are designed to capture coarse sediment, debris and trash. Centralizing sediment and trash captured at the inlet or entrance to the facility reduces maintenance by preventing [[filter media]] [[clogging]] and limiting the area over which sediment and trash needs to be removed. In some cases, pre-treatment device clean-outs may be incorporated into existing municipal catch basin cleaning programs.
'''Example''': Runoff into larger treatment practices such as [[bioretention]] or [[stormwater tree trenches]] may be pretreated by [[Inlet sumps: Gallery|concrete sumps]] at [[curb cut]] inlets, [[forebays]] or catch basin inserts, which are designed to capture coarse sediment, debris and trash. Centralizing sediment and trash captured at the inlet or entrance to the facility reduces maintenance by preventing [[filter media]] [[clogging]] and limiting the area over which sediment and trash needs to be removed. In some cases, pre-treatment device clean-outs may be incorporated into existing municipal catch basin cleaning programs.
'''Performance calculation''': If the downstream facility provides filtration, such as [[bioretention]] or [[Infiltration trenches|stone filled trenches]], the overall water quality performance of this facility would not increase with [[pretreatment]] because the coarse sediment and debris captured by the pretreatment device would be removed by the downstream facility even in the absence of pretreatment. The purpose of adding pre-treatment is to prevent clogging or filling and thereby reduce the cost and effort of long term [[Inspections and maintenance|maintenance]] and delay requirements for major facility [[Maintenance, Rehabilitation and Repair|rehabilitation or replacement]].
'''Performance calculation''': If the downstream facility provides filtration, such as [[bioretention]] or [[Infiltration trenches|stone filled trenches]], the overall water quality performance of this facility would not increase with [[pretreatment]] because the coarse sediment and debris captured by the pretreatment device would be removed by the downstream facility even in the absence of pretreatment. The purpose of adding pre-treatment is to prevent clogging or filling and thereby reduce the cost and effort of long term [[Inspections and maintenance|maintenance]] and delay requirements for major facility [[Maintenance, Rehabilitation and Repair|rehabilitation or replacement]].
===2. Treatment trains designed to address one or more design criteria===
===2. Treatment trains designed to address one or more design criteria===