HomeMy Public PortalAbout333136Metropolitan
St. Louis Sewer
District
2350 Market Street
St. Louis, MO 63103-2555
(314) 768-6200
October 5, 2009
Mr. Alex Weisz
Regulatory Compliance Coordinator
BaySaver Technologies, Inc.
1302 Rising Ridge Road
Mount Airy, MD 21771
RE: Baysaver Technologies BayFilter System: St. Louis MSD Submission
Redevelopment Use Level (RUL) + Provisional Use Level (PUL) Approval within District
Dear Sir:
The Metropolitan St. Louis Sewer District (MSD) has reviewed your application regarding the
BayFilter for use as a Best Management Practice for stoiniwater management. MSD is pleased to
provide Redevelopment Use Level (RUL) + Provisional Use Level (PUL) approval for use of the
BayFilter as a stand-alone water quality BMP, subject to the following provisions.
• The BayFilter is approved for use on redevelopment sites of any size. This approval is based
on compliance with requirements listed in MSD's Proprietary Water Quality Products and the
MSD's Stoiniwater Management Program (Rev. Jan. 2009). Proprietary devices should be
treated a?supplementary (rather thana primary) means of meeting small MS 4
requirements.
• Proposed uses and designs of the device must be in general confotniance with the infoiniation
and methodologies provided in BayFilter's application dated January 18, 2009.
• The use of buried filters shall be avoided on residential type projects.
• The BayFilter must be sized to capture all floatable trash and free oil, and remove 80% of the
total suspended solids for the site Water Quality Volume (WQv). Procedures for calculating
WQ„ are provided in Volume I of the Maryland Stoiniwater Design Manual (2000). All units
shall be installed with adequate storage to treat 75% of the WQv.
• The peak inflow is limited to 30 gallons per minute (gpm) for each BayFilter cartridge.
• The BayFilter cartridge shall have an annual sediment removal of no more than 150 pounds
(lbs) at 30 gpm or 300 lbs at 15 gpm. Cartridges shall be designed to operate at 34 inches of
head above the outlet and use a sand perlite media mix.
• BayFilter systems must provide a minimum of 7 square feet of settling area for every BayFilter
cartridge.
• The device must be configured so that the filter vault is closed off from the outfall. All units
including pretreatment, should be configured in an off-line layout.
• Adequate pretreatment shall be provided in all site designs in this case this will likely include
BaySeparator unit. No reduction in the number of filter cartridges shall be made for the
installation of pretreatment. The BaySeparator shall be sized to remove 50% of the TSS (ok
110 PSD) at the water quality flowrate (WQf).
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