Take a look at our stormwater quality units designed to address various challenges in runoff treatment. Feel free to examine our .dwg and .pdf plan files of our models.
Silt Prison 160D
Silt Prison 160R
Silt Prison 160DP
The Storm Water Buffer Zone’s The SiltPrison filtering membrane is composed of composite woven monofilament thread. The SiltPrison is able to stand up to high pressure flows during the heaviest of rain events.
Installation Requirements:
SBZ units are set by drainage contractor in conjunction with other drainage manholes and piping in accordance with city or state specifications with regard to base and backfill materials, compaction, and other tolerances. Stormwater quality internal parts are installed by precaster prior to delivery. The SBZ system will operate as a high capacity construction phase BMP immediately after included frame and grate are installed.
Maintenance Requirements:
Stormwater Buffer Zone is cleaned by removing the street level inlet grate, removing and emptying the StormBrake gross pollutant trash strainer, and then removing material from the manhole sump using the same method and equipment that is used to clean standard catch basins. It is recommended that every maintenance procedure be recorded in the maintenance log for the site regardless of whether the unit is in construction period or post construction period use. Construction Period: Monthly visual inspection, and brushing off, or hosing off of treatment skirt from street level if needed, plus emptying the strainer of leaf litter, etc while removing it to see skirt. Removal of sediment from the manhole by vactor is not needed unless sediment level reaches treatment skirt, but recommended to be annually otherwise during construction period, or at the end of the construction period. Post Construction Period or Permanent Use: Annual inspection, Biannual cleanout(vactoring): Annual Maintenance; (but every four or six months during the first year): to include visual inspection of strainer and treatment skirt, emptying the strainer of leaf litter, trash, etc (all considered solid waste) while removing it to treat skirt, spraying off or brushing off underside of the treatment skirt, inspecting and recording sediment depth in manhole (if inspection is between cleanouts, or the depth prior to cleanout if unit is being vactored).
Design Methodology:
The treatment skirts (tent filters) has multiple regions with each region having a nominal flow rate that is higher than an adjacent relatively lower region. The lower regions with a relatively lower nominal flow rate can provide a high degree of filtration for the runoff from small storm events. For larger storm events, as the rate of runoff entering a storm drain catch basin exceeds the rate at which water is filtered through the lower regions with a lower nominal flow rate, the level of water on the inlet side of the filters increases bringing the higher regions with a relatively higher nominal flow rate into operation. These higher regions with a higher nominal flow rate provide less filtration but greater flow capacity than the lower regions with a lower nominal flow rate. As the surface level of the water is rising, the distance between the more turbulent surface level and the volatile silt on the bottom of the catch basin increases and can provide an increasing buffer zone as flow through the overall system increases.