HomeMy Public PortalAbout460955iTI 5D
February 16, 2012
Metropolitan
St. Louis Sewer
District
2350 Market Street
St. Louis, MO 63103-2555
(314) 768-6200
David S Schuster
A.S.P. Enterprises
1099 Cassens Industrial Ct.
Fenton, MO 63026
RE: Nutrient Separating Baffle Box: St. Louis MSD Submission
Redevelopment Use Level (RUL) Approval within the District
Dear Mr. Schuster,
The Metropolitan St. Louis Sewer District has reviewed your application regarding the
Nutrient Separating Baffle Box (NSBB) for use as a Best Management Practice for
Stormwater Management. The District is pleased to provide Redevelopment Use Level
(RUL) approval for use of the Nutrient Separating Baffle Box as a stand-alone water
quality BMP, subject to the following provisions:
• The NSBB is approved for use on redevelopment sites less than 5 acres. This
approval is based on compliance with requirements listed in MSD's Proprietary
Water Quality Products and the MSD's Stormwater Management Program (Rev.
Jan. 2009). Proprietary devices should be treated as a supplementary (rather than
a primary) means of meeting small MS 4 requirements.
• The NSBB must be sized to capture all floatable trash and free oil, and remove
80% of total suspended solids for the OK-110 particle size distribution at the site
water quality flow -rate (WQf). Procedures for calculating WQf are provided in
Appendix D.10 of the Maryland Stormwater Design Manual (2000). Table 1
provides a list of approved models and their respective instantaneous peak
treatment WQf.
Table 1: Nutrient Separating Baffle Box Approved Models and Peak WOf
NSBB Model
Treatment Flow
NSBB-2-4
0.11 cfs
NSBB-3-6
0.25 cfs
NSBB-3-8
0.33 cfs
NSBB-4-8
0.44 cfs
NSBB-5-10
0.69 cfs
NSBB-6-12
1.00 cfs
NSBB-8-14
1.56 cfs
NSBB-8-16
1.78 cfs
NSBB-10-16
2.22 cfs
NSBB-12-20
3.33 cfs
" T h e N S B B s h o u l d b e c o n f i g u r e d i n a n o f f - l i n e l a y o u t . I n m o s t c a s e s t h e B M P
w i l l n o t n e e d t o s t o r e t h e w a t e r q u a l i t y v o l u m e ( W Q v ) u p s t r e a m o f t h e u n i t .
" A l l d e v i c e s s h a l l p r o v i d e a m i n i m u m s e d i m e n t s t o r a g e c a p a c i t y o f 1 0 c u b i c f e e t .
" A l l p r o p r i e t a r y l i d s a n d c o v e r s s h o u l d b e c a p t i v e c o m p o n e n t s . T h e m i n i m u m s i z e
a c c e s s h o l e i s 3 0 i n c h e s i n d i a m e t e r .
" P r o j e c t s p e c i f i c d e s i g n c a l c u l a t i o n s a n d m a i n t e n a n c e p l a n s f u r n i s h e d b y S u n t r e e
T e c h n o l o g i e s m u s t b e i n c l u d e d w i t h i n t h e p r o j e c t '