HomeMy Public PortalAboutAquaSwirlXCL_ApprovalLetter_020723February 7, 2023
AquaShield, Inc
Mr. Mark Miller
2733 Kanasita Dr, Ste 111
Chattanooga, TN 37343
RE: AquaSwirl XCelerator Treatment System
Redevelopment Use Level (RUL) Approval within the District
Dear Sir,
The Metropolitan St. Louis Sewer District (MSD) is pleased to
provide RUL approval for the use of the AquaSwirl XCelerator HDS
unit as a stand-alone water quality BMP, subject to the following
provisions:
• The XCelerator is only approved for use on public highway and
roadway projects, and for redevelopment sites less than 5
acres. This approval is based upon compliance with
requirements listed in MSD's Proprietary Water Quality
Products and the MSD's Stormwater Management Program (Revised
Jan. 2009).
• The XCelerator must be sized such that the Maximum Treatment
Flow Rate (MTFR) for the unit exceeds the Water Quality flow
rate calculated for the unit's tributary area. The
XCelerator's approved MTFRs will be those shown in Table 1
below, to match the certified flow rates provided by the New
Jersey Department of Environmental Protection (NJDEP).
Procedures for calculating the Water Quality flow rate are
provided in Appendix D.10 of the Maryland Stormwater Design
Manual (2000).
Metropolitan
St. Louis Sewer
District
2350 Market Street
St. Louis, MO 63103-2555
(314) 768-6200
Table 1: XCelerator Models and Approved MTFRs
Model Manhole
Diameter (ft)
MTFR (cfs)50% Max.
Sediment
Storage
Volume (ft3)
XC-4 4.5 1.86 7.95
XC-5 5.5 2.78 11.88
XC-6 6.5 3.88 16.59
XC-7 7.5 5.17 22.09
XC-8 8.5 6.64 28.38
XC-9 9.5 8.29 35.44
XC-10 10.5 10.13 43.30
XC-11 11.5 12.15 51.94
XC-12 12.5 14.35 61.36
XC-13 13 15.53 66.37
The XCelerator will be configured as an off-line unit,
downstream from a diversion manhole. In most cases, the BMP
will be installed without the need to store the Water Quality
volume upstream of the unit.
All devices shall provide a minimum sediment storage capacity
of 10 cubic feet.
All proprietary lids and covers should be captive components.
The minimum size access hole is 30 inches in diameter.
Confined space entry shall not be a requirement for routine
maintenance. No special tools or attachments should be
required to provide for routine maintenance with a vacuum
pumping truck.
A reinforced concrete pad shall be placed over the entire
XCelerator when subject to H-20 (or greater) traffic loading.
The pad shall extend not less than 12 inches beyond the
outside diameter of the XCelerator. A professional engineer
shall provide final approval of the design of the concrete
pad and the calculations must be included in the submittal.
Traffic rated foundry rims and covers must be installed such
that no contact is made between the HOPE access riser and the
cast iron frame.
Project specific design calculations and maintenance plans
furnished by the manufacturer must be included within the
project's Stormwater Management Facilities Report prepared by
the consulting engineer.
The initial installation of the XCelerator within the MSD
will be subject to the following additional requirements:
1) A manufacturer's or vendor's representative must be
onsite during the proprietary BMP installation to
ensure the product's installation requirements are
met.
2) Shop drawings indicating flow lines, weirs, pipe
inverts, etc will be required prior to installation.
3) The manufacturer or vendor must arrange for an as-
built survey of the proprietary BMP to be performed
by a Missouri-registered Professional Land Surveyor
once the device has been installed.
4) The manufacturer or vendor must perform quarterly
inspections of the proprietary BMP during its first
year of operation, which will include visual
inspections and qualitative analysis of the BMP' s
sediment removal. MSD requests to be invited to these
inspections to further enhance familiarity and
understanding of the device.
5) Formal reports shall be submitted to MSD, including
the as-built drawings and quarterly inspection
reports. The reports shall include summaries,
photographs of the structure, outfall conditions,
etc. The reports shall also evaluate the level of
the Owner's adherence to the approved maintenance
plan, and offer suggestions for any areas of
improvement.
MSD reserves the ability to withdraw or modify this approval based
on subsequent information, including information indicating that
this BMP does not satisfy MSD rules, requirements, or construction
specifications.
Sincerely,
Curtis Zurliene, PE
Civil Engineer (BMP Committee Chairman)
Engineering / Development Review
Metropolitan St. Louis Sewer District