STC_Tech_manual_January2008_Canada_r4 STC 2000 Stormceptor Technical Manual Canada
User Manual: STC 2000
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Technical Manual
TM
Stormceptor Design Notes
•
Only the STC 300i is adaptable to function with a catch basin inlet and/or inline pipes.
•
Only the Stormceptor models STC 300i to STC 6000 may accommodate multiple inlet pipes.
Inlet and outlet invert elevation differences are as follows:
Inlet and Outlet Pipe Invert Elevations Differences
Inlet Pipe Configuration
STC 300
STC 750 to STC 6000
STC 9000 to STC 14000
Single inlet pipe
75 mm
25 mm
75 mm
Multiple inlet pipes
75 mm
75 mm
Only one inlet pipe.
Maximum inlet and outlet pipe diameters:
Inlet/Outlet
Configuration
Inlet Unit
STC 300i
In-Line Unit
STC 750 to 6000
Series*
STC 9000 to 14000
Straight Through
24 inch (600 mm)
42 inch (1050 mm)
60 inch (1500 mm)
Bend (90 degrees)
18 inch (375 mm)
33 inch (825 mm)
42 inch (1050 mm)
•
The inlet an din-line Stormceptor units can accommodate turns to a maximum of 90 degrees.
•
Minimum distance from top of grade to invert is 1.2 m
•
Submerged conditions. A unit is submerged when the standing water elevation at the proposed
location of the Stormceptor unit is greater than the outlet invert elevation during zero flow
conditions. In these cases, please contact your local Stormceptor representative and provide the
following information:
• Top of grade elevation
• Stormceptor inlet and outlet pipe diameters and invert elevations
• Standing water elevation
•
Stormceptor head loss, K = 1.3
For technical assistance and pricing, please contact:
Imbrium Systems Inc.
Tel: 800-565-4801
www.imbriumsystems.com`
Design Worksheet
PROJECT INFORMATION
Date:
Total Drainage Area:
hectares
Project Number:
Impervious
%
Project Name:
Upstream Quantity Control (A2):
YES
NO
City/Town:
Is the unit submerged (C4):
YES
NO
Development Type:
Describe Land Cover:
Province:
Describe Land Use:
A. DESIGN FOR TOTAL SUSPENDED SOLIDS
REMOVAL
Units are sized for TSS removal. All units are designed for spills
capture for hydrocarbon with a specific gravity of 0.86.
A1. Identify Water Quality Objective:
Desired Water Quality
Objective:
% Annual TSS
Removal
A2. If upstream quantity control exists, identify stage storage and
discharge information:
Elevation
Storage
Discharge
3
(m)
(ha-m)
(m /s)
Permanent
Water Level
5 year
10 year
SUMMARY OF STORMCEPTOR REQUIREMENTS FOR TSS
REMOVAL
Stormceptor Model:
Annual TSS Removed:
%
Annual Runoff Captured:
%
B. STORMCEPTOR SITING CONSIDERATIONS
B1. Difference Between Inlet and Outlet Invert Elevations:
In-line
Series
Number of
Inlet Unit
STC 750 to
STC 10000 to
Inlet Pipes
STC 300
STC 6000
STC 14000
25 year
One
75 mm
25 mm
75 mm
100 year
>1
75 mm
75 mm
N/A
A3. Select Particle Size Distribution:
□ Fine Distribution
□ Coarse Distribution
Particle Size
Distribution
Particle Size
Distribution
um
%
um
%
20
20
150
60
60
20
400
20
150
20
2000
20
400
20
2000
20
□
User Defined Particle Size Distribution
Identify particle size distribution
(please contact your local Stormceptor representative)
Particle Size
Distribution
Specific Gravity
um
%
B2. Other considerations:
Minimum Distance
1.2 m
From Top of Grade to
Invert Elevation
The inlet and in-line Stormceptor units
Bends:
can accommodate turns to a maximum
of 90 degrees
Yes for Inlet and In-Line Stormceptor
Multiple Inlet Pipe:
Units. Please contact your local affiliate
for more details
Only the STC 300 can accommodate a
Inlet Covers
catch basin frame and cover.
B3. Standard maximum inlet and outlet pipe diameters:
In-line
Series
Inlet/Outlet
Inlet Unit
STC 750 to
STC 10000 to
Configuration
STC 300
STC 6000
STC 14000
Straight
600 mm
1050 mm
2400 mm
Through
Bend
450 mm
825 mm
1050 mm
Please contact your local Stormceptor representative for larger pipe diameters.
A4. Enter all parameters from items A1 to A3 into PCSWMM for
Stormceptor to select the model that meets the water quality
objective.
B4. Submerged conditions:
A unit is submerged when the standing water elevation at the proposed
location of the Stormceptor unit is greater than the outlet invert
elevation during zero flow conditions. In these cases, please contact
your local Stormceptor representative for further assistance.
www.imbriumsystems.com
STORMCEPTOR® QUOTATION AND ORDER FORM
Quotation No:
Date:
Project Information:
Contractor Information
Project Number:
Contact Name:
Project Name:
Company:
Closing Date:
Phone No:
Jobsite Address:
Fax No:
Municipality:
E-mail:
Consultant Information:
Owner Information (Required for Maintenance):
Contact Name:
Contact Name:
Company:
Company:
Phone No:
Phone No:
Fax No:
Fax No:
E-mail:
E-mail:
Land Use (Check one):
□ Commercial
□ Gas Station
□ Street
□ Residential
□ Government
□ Transportation
□ Industrial
□ Other
□ Military
STORMCEPTOR INFORMATION
Structure No.:
Top of Grate Elev.:
Outlet Invert Elev.:
Outlet Pipe Material:
Inlet invert Elev.:
Inlet Pipe Material:
INLET SYSTEM
STC 300
STORMCEPTOR MODEL REQUIRED (circle model number)
IN-LINE SYSTEM
SERIES SYSTEM
STC 750
STC 1000 STC 1500
STC 9000
STC 11000
STC 2000 STC 3000 STC 4000
STC 14000
STC 5000 STC 6000
Downstream Unit
Upstream Unit
Outlet
Pipe
Outlet
Pipe
Show Orientation of Inlet Pipe
Show Orientation of Inlet Pipe
Inlet
Pipe
Show Orientation of Outlet Pipe on
Downstream Unit
Please complete the attached form and fax to (416) 960-5637 or your local manufacturer
www.imbriumsystems.com
Technical Manual
Table of Content
1. About Stormceptor .......................................................................................................... 1
1.1.
1.2.
1.3.
Distribution Network ............................................................................................................... 1
Patent Information .................................................................................................................. 2
Contact Imbrium Systems ...................................................................................................... 2
2. Stormceptor Design Overview........................................................................................ 2
2.1.
Design Philosophy ................................................................................................... 2
2.2.
Benefits .................................................................................................................... 3
2.3.
Environmental Benefit .............................................................................................. 3
3. Key Operation Features .................................................................................................. 4
3.1.
Scour Prevention...................................................................................................... 4
3.2.
Operational Hydraulic Loading Rate ........................................................................ 4
3.3.
Double Wall Containment ........................................................................................ 5
4. Stormceptor Product Line............................................................................................... 5
4.1.
4.2.
4.3.
4.4.
Stormceptor Models ............................................................................................................... 5
Inline Stormceptor .................................................................................................................. 5
Inlet Stormceptor .................................................................................................................... 6
Series Stormceptor................................................................................................................. 7
5. Sizing the Stormceptor System ...................................................................................... 8
5.1.
5.2.
PCSWMM for Stormceptor................................................................................................... 10
Sediment Loading Characteristics ....................................................................................... 10
6. Spill Controls.................................................................................................................. 11
6.1.
6.2.
Oil Level Alarm ..................................................................................................................... 11
Increased Volume Storage Capacity.................................................................................... 12
7. Stormceptor Options ..................................................................................................... 12
7.1.
7.2.
7.3.
7.4.
7.5.
7.6.
7.7.
7.8.
7.9.
7.10.
Installation Depth / Minimum Cover ..................................................................................... 12
Maximum Inlet and Outlet Pipe Diameters........................................................................... 12
Bends ................................................................................................................................... 13
Multiple Inlet Pipes ............................................................................................................... 14
Inlet/Outlet Pipe Invert Elevations ........................................................................................ 14
Shallow Stormceptor ............................................................................................................ 15
Customized Live Load.......................................................................................................... 15
Pre-treatment ....................................................................................................................... 15
Head loss.............................................................................................................................. 15
Submerged ........................................................................................................................... 15
8. Comparing Technologies .............................................................................................. 16
8.1.
8.2.
8.3.
8.4.
Particle Size Distribution (PSD)............................................................................................ 16
Scour Prevention.................................................................................................................. 17
Hydraulics............................................................................................................................. 17
Hydrology ............................................................................................................................. 17
9. Testing ............................................................................................................................ 18
10. Installation ...................................................................................................................... 18
10.1.
10.2.
Excavation ............................................................................................................................ 18
Backfilling ............................................................................................................................. 19
11. Stormceptor Construction Sequence .......................................................................... 19
12. Maintenance ................................................................................................................... 19
12.1.
12.2.
12.3.
12.4.
12.5.
12.6.
Health and Safety................................................................................................................. 19
Maintenance Procedures ..................................................................................................... 19
Submerged Stormceptor ...................................................................................................... 21
Hydrocarbon Spills ............................................................................................................... 21
Disposal................................................................................................................................ 21
Oil Sheens ............................................................................................................................ 21
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Technical Manual
1.
About Stormceptor
The Stormceptor® (Standard Treatment Cell) was developed by Imbrium™ Systems to
address the growing need to remove and isolate pollution from the storm drain system before
it enters the environment. The Stormceptor STC targets hydrocarbons and total suspended
solids (TSS) in stormwater runoff. It improves water quality by removing contaminants
through the gravitational settling of fine sediments and floatation of hydrocarbons while
preventing the re-suspension or scour of previously captured pollutants.
The development of the Stormceptor STC revolutionized stormwater treatment, and created
an entirely new category of environmental technology. Protecting thousands of waterways
around the world, the Stormceptor System has set the standard for effective stormwater
treatment.
1.1. Distribution Network
Imbrium Systems has partnered with a global network of affiliates who manufacture and
distribute the Stormceptor System.
Canada
Ontario
Hanson Pipe & Precast Ltd
888-888-3222
www.hansonpipeandprecast.com
Québec
Lécuyer et Fils Ltée
(800) 561-0970
www.lecuyerbeton.com
New Brunswick /
Prince Edward Island
Strescon Limited
(506) 633-8877
www.strescon.com
Newfoundland / Nova
Scotia
Strescon Limited
(902) 494-7400
www.strescon.com
Western Canada
Lafarge Canada Inc.
(888) 422-4022
www.lafargepipe.com
British Columbia
Langley Concrete Group
(604) 533-1656
www.langleyconcretegroup.com
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Technical Manual
1.2. Patent Information
The Stormceptor technology is protected by the following patents:
•
•
•
•
•
•
•
•
•
•
•
•
•
Australia Patent No. 693,164 • 707,133 • 729,096 • 779401
Austrian Patent No. 289647
Canadian Patent No 2,009,208 •2,137,942 • 2,175,277 • 2,180,305 • 2,180,383 •
2,206,338 • 2,327,768 (Pending)
China Patent No 1168439
Denmark DK 711879
German DE 69534021
Indonesian Patent No 16688
Japan Patent No 9-11476 (Pending)
Korea 10-2000-0026101 (Pending)
Malaysia Patent No PI9701737 (Pending)
New Zealand Patent No 314646
United States Patent No 4,985,148 • 5,498,331 • 5,725,760 • 5,753,115 • 5,849,181 •
6,068,765 • 6,371,690
Stormceptor OSR Patent Pending • Stormceptor LCS Patent Pending
1.3. Contact Imbrium Systems
Contact us today if you require more information on other products:
Imbrium Systems Inc.
2 St. Clair Ave. West
Suite 2100
Toronto, On M4V 1L5
T 800 565 4801
info@imbriumsystems.com
www.imbriumsystems.com
2.
Stormceptor Design Overview
2.1. Design Philosophy
The patented Stormceptor System has been designed focus on the environmental objective
of providing long-term pollution control. The unique and innovative Stormceptor design allows
for continuous positive treatment of runoff during all rainfall events, while ensuring that all
captured pollutants are retained within the system, even during intense storm events.
An integral part of the Stormceptor design is PCSWMM for Stormceptor - sizing software
developed in conjunction with Computational Hydraulics Inc. (CHI) and internationally
acclaimed expert, Dr. Bill James. Using local historical rainfall data and continuous simulation
modeling, this software allows a Stormceptor unit to be designed for each individual site and
the corresponding water quality objectives.
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Technical Manual
By using PCSWMM for Stormceptor, the Stormceptor System can be designed to remove a
wide range of particles (typically from 20 to 2,000 microns), and can also be customized to
remove a specific particle size distribution (PSD). The specified PSD should accurately
reflect what is in the stormwater runoff to ensure the device is achieving the desired water
quality objective. Since stormwater runoff contains small particles (less than 75 microns), it is
important to design a treatment system to remove smaller particles in addition to coarse
particles.
2.2. Benefits
The Stormceptor System removes free oil and suspended solids from stormwater, preventing
spills and non-point source pollution from entering downstream lakes and rivers. The key
benefits, capabilities and applications of the Stormceptor System are as follows:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Provides continuous positive treatment during all rainfall events
Can be designed to remove over 80% of the annual sediment load
Removes a wide range of particles
Can be designed to remove a specific particle size distribution (PSD)
Captures free oil from stormwater
Prevents scouring or re-suspension of trapped pollutants
Pre-treatment to reduce maintenance costs for downstream treatment measures (ponds,
swales, detention basins, filters)
Groundwater recharge protection
Spills capture and mitigation
Simple to design and specify
Designed to your local watershed conditions
Small footprint to allow for easy retrofit installations
Easy to maintain (vacuum truck)
Multiple inlets can connect to a single unit
Suitable as a bend structure
Pre-engineered for traffic loading (minimum CHBDC)
Minimal elevation drop between inlet and outlet pipes
Small head loss
Additional protection provided by an 18” (457 mm) fiberglass skirt below the top of the
insert, for the containment of hydrocarbons in the event of a spill.
2.3. Environmental Benefit
Freshwater resources are vital to the health and welfare of their surrounding communities.
There is increasing public awareness, government regulations and corporate commitment to
reducing the pollution entering our waterways. A major source of this pollution originates from
stormwater runoff from urban areas. Rainfall runoff carries oils, sediment and other
contaminants from roads and parking lots discharging directly into our streams, lakes and
coastal waterways.
The Stormceptor System is designed to isolate contaminants from getting into the natural
environment. The Stormceptor technology provides protection for the environment from spills
that occur at service stations and vehicle accident sites, while also removing contaminated
sediment in runoff that washes from roads and parking lots.
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Technical Manual
3.
Key Operation Features
3.1. Scour Prevention
A key feature of the Stormceptor System is its patented scour prevention technology. This
innovation ensures pollutants are captured and retained during all rainfall events, even
extreme storms. The Stormceptor System provides continuous positive treatment for all
rainfall events, including intense storms. Stormceptor slows incoming runoff, controlling and
reducing velocities in the lower chamber to create a non-turbulent environment that promotes
free oils and floatable debris to rise and sediment to settle.
The patented scour prevention technology, the fiberglass insert, regulates flows into the
lower chamber through a combination of a weir and orifice while diverting high energy flows
away through the upper chamber to prevent scouring. Laboratory testing demonstrated no
scouring when tested up to 125% of the unit’s operating rate, with the unit loaded to 100%
sediment capacity (NJDEP, 2005). Second, the depth of the lower chamber ensures the
sediment storage zone is adequately separated from the path of flow in the lower chamber to
prevent scouring.
3.2. Operational Hydraulic Loading Rate
Designers and regulators need to evaluate the treatment capacity and performance of
manufactured stormwater treatment systems. A commonly used parameter is the
“operational hydraulic loading rate” which originated as a design methodology for wastewater
treatment devices.
Operational hydraulic loading rate may be calculated by dividing the flow rate into a device by
its settling area. This represents the critical settling velocity that is the prime determinant to
quantify the influent particle size and density captured by the device. PCSWMM for
Stormceptor uses a similar parameter that is calculated by dividing the hydraulic detention
time in the device by the fall distance of the sediment.
vSC =
H
θH
=
Q
AS
Where:
vSC = critical settling velocity, ft/s (m/s)
H = tank depth, ft (m)
θ H = hydraulic detention time, ft/s (m/s)
Q = volumetric flow rate, ft3/s (m3/s)
AS = surface area, ft2 (m2)
(Tchobanoglous, G. and Schroeder, E.D. 1987. Water Quality. Addison Wesley.)
Unlike designing typical wastewater devices, stormwater systems are designed for highly
variable flow rates including intense peak flows. PCSWMM for Stormceptor incorporates all
of the flows into its calculations, ensuring that the operational hydraulic loading rate is
considered not only for one flow rate, but for all flows including extreme events.
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Technical Manual
3.3. Double Wall Containment
The Stormceptor System was conceived as a pollution identifier to assist with identifying illicit
discharges. The fiberglass insert has a continuous skirt that lines the concrete barrel wall for
a depth of 18 inches (406 mm) that provides double wall containment for hydrocarbons
storage. This protective barrier ensures that toxic floatables do not migrate through the
concrete wall and the surrounding soils.
4.
Stormceptor Product Line
4.1. Stormceptor Models
A summary of Stormceptor models and capacities are listed in Table 1.
Table 1. Canadian Stormceptor Models
Stormceptor
Model
Total Storage
Volume
Imp. Gal (L)
Hydrocarbon Storage
Capacity
Imp. Gal (L)
Maximum Sediment
Capacity
Imp. Gal (L)
STC 300i
STC 750
STC 1000
STC 1500
STC 2000
STC 3000
STC 4000
STC 5000
STC 6000
STC 9000
STC 10000
STC 14000
470 (1 775)
895 (4 070)
1,070 (4 871)
1,600 (7 270)
2,420 (6 205)
3,355 (15 270)
4,450 (20 255)
5,435 (24 710)
6,883 (31 285)
9,758 (44 355)
10,734 (48 791)
14,610 (66 410)
66 (300)
46 (915)
46 (915)
46 (915)
636 (2 890)
636 (2 890)
739 (3 360)
739 (3 360)
864 (3 930)
2,322 (10 555)
2,322 (10 555)
2,574 (11 700)
319 (1 450)
660 (3 000)
836 (3 800)
1,365 (6 205)
1,300 (7 700)
1,694 (11 965)
3,627 (16 490)
4,606 (20 940)
5,927 (26 945)
7,255 (32 980)
8,230 (37 415)
11,854 (53 890)
NOTE: Storage volumes may vary slightly from region to region. For detailed information, contact your
local Stormceptor representative.
4.2. Inline Stormceptor
The Inline Stormceptor, Figure 1, is the standard design for most stormwater treatment
applications. The patented Stormceptor design allows the Inline unit to maintain continuous
positive treatment of total suspended solids (TSS) year-round, regardless of flow rate. The
Inline Stormceptor is composed of a precast concrete tank with a fiberglass insert situated at
the invert of the storm sewer pipe, creating an upper chamber above the insert and a lower
chamber below the insert.
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Technical Manual
Figure 1. Inline Stormceptor
Operation
As water flows into the Stormceptor unit, it is slowed and directed to the lower chamber by a
weir and drop tee. The stormwater enters the lower chamber, a non-turbulent environment,
allowing free oils to rise and sediment to settle. The oil is captured underneath the fiberglass
insert and shielded from exposure to the concrete walls by a fiberglass skirt. After the
pollutants separate, treated water continues up a riser pipe, and exits the lower chamber on
the downstream side of the weir before leaving the unit. During high flow events, the
Stormceptor System’s patented scour prevention technology ensures continuous pollutant
removal and prevents re-suspension of previously captured pollutants.
4.3. Inlet Stormceptor
The Inlet Stormceptor System, Figure 2, was designed to provide protection for parking lots,
loading bays, gas stations and other spill-prone areas. The Inlet Stormceptor is designed to
remove sediment from stormwater introduced through a grated inlet, a storm sewer pipe, or
both.
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Technical Manual
Figure 2. Inlet Stormceptor
The Inlet Stormceptor design operates in the same manner as the Inline unit, providing
continuous positive treatment, and ensuring that captured material is not re-suspended.
4.4. Series Stormceptor
Designed to treat larger drainage areas, the Series Stormceptor System, Figure 3, consists of
two adjacent Stormceptor models that function in parallel. This design eliminates the need for
additional structures and piping to reduce installation costs.
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Technical Manual
Figure 3. Series System
The Series Stormceptor design operates in the same manner as the Inline unit, providing
continuous positive treatment, and ensuring that captured material is not re-suspended.
5.
Sizing the Stormceptor System
The Stormceptor System is a versatile product that can be used for many different aspects of
water quality improvement. While addressing these needs, there are conditions that the
designer needs to be aware of in order to size the Stormceptor model to meet the demands
of each individual site in an efficient and cost-effective manner.
PCSWMM for Stormceptor is the support tool used for identifying the appropriate
Stormceptor model. In order to size a unit, it is recommended the user follow the seven
design steps in the program. The steps are as follows:
STEP 1 – Project Details
The first step prior to sizing the Stormceptor System is to clearly identify the water quality
objective for the development. It is recommended that a level of annual sediment (TSS)
removal be identified and defined by a particle size distribution.
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Technical Manual
STEP 2 – Site Details
Identify the site development by the drainage area and the level of imperviousness. It is
recommended that imperviousness be calculated based on the actual area of
imperviousness based on paved surfaces, sidewalks and rooftops.
STEP 3 – Upstream Attenuation
The Stormceptor System is designed as a water quality device and is sometimes used in
conjunction with onsite water quantity control devices such as ponds or underground
detention systems. When possible, a greater benefit is typically achieved when installing a
Stormceptor unit upstream of a detention facility. By placing the Stormceptor unit upstream of
a detention structure, a benefit of less maintenance of the detention facility is realized.
STEP 4 – Particle Size Distribution
It is critical that the PSD be defined as part of the water quality objective. PSD is critical for
the design of treatment system for a unit process of gravity settling and governs the size of a
treatment system. A range of particle sizes has been provided and it is recommended that
clays and silt-sized particles be considered in addition to sand and gravel-sized particles.
Options and sample PSDs are provided in PCSWMM for Stormceptor. The default particle
size distribution is the Fine Distribution, Table 2, option.
Table 2. Fine Distribution
Particle Size
Distribution
Specific Gravity
20
60
150
400
2000
20%
20%
20%
20%
20%
1.3
1.8
2.2
2.65
2.65
If the objective is the long-term removal of 80% of the total suspended solids on a given site,
the PSD should be representative of the expected sediment on the site. For example, a
system designed to remove 80% of coarse particles (greater than 75 microns) would provide
relatively poor removal efficiency of finer particles that may be naturally prevalent in runoff
from the site.
Since the small particle fraction contributes a disproportionately large amount of the total
available particle surface area for pollutant adsorption, a system designed primarily for
coarse particle capture will compromise water quality objectives.
STEP 5 – Rainfall Records
Local historical rainfall has been acquired from the U.S. National Oceanic and Atmospheric
Administration, Environment Canada and regulatory agencies across North America. The
rainfall data provided with PCSMM for Stormceptor provides an accurate estimation of small
storm hydrology by modeling actual historical storm events including duration, intensities and
peaks.
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Technical Manual
STEP 6 – Summary
At this point, the program may be executed to predict the level of TSS removal from the site.
Once the simulation has completed, a table shall be generated identifying the TSS removal of
each Stormceptor unit.
STEP 7 – Sizing Summary
Performance estimates of all Stormceptor units for the given site parameters will be displayed
in a tabular format. The unit that meets the water quality objective, identified in Step 1, will be
highlighted.
5.1. PCSWMM for Stormceptor
The Stormceptor System has been developed in conjunction with PCSWMM for Stormceptor
as a technological solution to achieve water quality goals. Together, these two innovations
model, simulate, predict and calculate the water quality objectives desired by a design
engineer for TSS removal.
PCSWMM for Stormceptor is a proprietary sizing program which uses site specific inputs to a
computer model to simulate sediment accumulation, hydrology and long-term total
suspended solids removal. The model has been calibrated to field monitoring results from
Stormceptor units that have been monitored in North America. The sizing methodology can
be described by three processes:
1. Determination of real time hydrology
2. Buildup and wash off of TSS from impervious land areas
3. TSS transport through the Stormceptor (settling and discharge) The use of a
calibrated model is the preferred method for sizing stormwater quality structures for
the following reasons:
a. The hydrology of the local area is properly and accurately incorporated in the
sizing (distribution of flows, flow rate ranges and peaks, back-to-back storms,
inter-event times)
b. The distribution of TSS with the hydrology is properly and accurately considered
in the sizing
c. Particle size distribution is properly considered in the sizing
d. The sizing can be optimized for TSS removal
e. The cost benefit of alternate TSS removal criteria can be easily assessed
f. The program assesses the performance of all Stormceptor models. Sizing may be
selected based on a specific water quality outcome or based on the Maximum
Extent Practicable
For more information regarding PCSWMM for Stormceptor, contact your local Stormceptor
representative, or visit www.imbriumsystems.com to download a free copy of the program.
5.2. Sediment Loading Characteristics
The way in which sediment is transferred to stormwater can have a considerable effect on
which type of system is implemented. On typical impervious surfaces (e.g. parking lots)
sediment will build over time and wash off with the next rainfall. When rainfall patterns are
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Technical Manual
examined, a short intense storm will have a higher concentration of sediment than a long
slow drizzle. Together with rainfall data representing the site’s typical rainfall patterns,
sediment loading characteristics play a part in the correct sizing of a stormwater quality
device.
Typical Sites
For standard site design of the Stormceptor System, PCSWMM for Stormceptor is utilized to
accurately assess the unit’s performance. As an integral part of the product’s design, the
program can be used to meet local requirements for total suspended solid removal. Typical
installations of manufactured stormwater treatment devices would occur on areas such as
paved parking lots or paved roads. These are considered “stable” surfaces which have non –
erodible surfaces.
Unstable Sites
While standard sites consist of stable concrete or asphalt surfaces, sites such as gravel
parking lots, or maintenance yards with stockpiles of sediment would be classified as
“unstable”. These types of sites do not exhibit first flush characteristics, are highly erodible
and exhibit atypical sediment loading characteristics and must therefore be sized more
carefully. Contact your local Stormceptor representative for assistance in selecting proper
unit size for such unstable sites.
6.
Spill Controls
When considering the removal of total petroleum hydrocarbons (TPH) from a storm sewer
system there are two functions of the system: oil removal, and spill capture.
'Oil Removal' describes the capture of the minute volumes of free oil mobilized from
impervious surfaces. In this instance relatively low concentrations, volumes and flow rates
are considered. While the Stormceptor unit will still provide an appreciable oil removal
function during higher flow events and/or with higher TPH concentrations, desired effluent
limits may be exceeded under these conditions.
'Spill Capture' describes a manner of TPH removal more appropriate to recovery of a
relatively high volume of a single phase deleterious liquid that is introduced to the storm
sewer system over a relatively short duration. The two design criteria involved when
considering this manner of introduction are overall volume and the specific gravity of the
material. A standard Stormceptor unit will be able to capture and retain a maximum spill
volume and a minimum specific gravity.
For spill characteristics that fall outside these limits, unit modifications are required. Contact
your local Stormceptor Representative for more information.
One of the key features of the Stormceptor technology is its ability to capture and retain
spills. While the standard Stormceptor System provides excellent protection for spill control,
there are additional options to enhance spill protection if desired.
6.1. Oil Level Alarm
The oil level alarm is an electronic monitoring system designed to trigger a visual and audible
alarm when a pre-set level of oil is reached within the lower chamber. As a standard, the oil
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Technical Manual
level alarm is designed to trigger at approximately 85% of the unit’s available depth level for
oil capture. The feature acts as a safeguard against spills caused by exceeding the oil
storage capacity of the separator and eliminates the need for manual oil level inspection.
The oil level alarm installed on the Stormceptor insert is illustrated in Figure 4.
Figure 4. Oil level alarm
6.2. Increased Volume Storage Capacity
The Stormceptor unit may be modified to store a greater spill volume than is typically
available. Under such a scenario, instead of installing a larger than required unit,
modifications can be made to the recommended Stormceptor model to accommodate larger
volumes. Contact your local Stormceptor representative for additional information and
assistance for modifications.
7.
Stormceptor Options
The Stormceptor System allows flexibility to incorporate to existing and new storm drainage
infrastructure. The following section identifies considerations that should be reviewed when
installing the system into a drainage network. For conditions that fall outside of the
recommendations in this section, please contact your local Stormceptor representative for
further guidance.
7.1. Installation Depth / Minimum Cover
The minimum distance from the top of grade to the crown of the inlet pipe is 24 inches (600
mm). For situations that have a lower minimum distance, contact your local Stormceptor
representative.
7.2. Maximum Inlet and Outlet Pipe Diameters
Maximum inlet and outlet pipe diameters are illustrated in Figure 5. Contact your local
Stormceptor representative for larger pipe diameters.
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Technical Manual
Figure 5. Maximum pipe diameters for straight through and bend applications.
*The bend should only be incorporated into the second structure (downstream structure) of the
Series Stormceptor System
7.3. Bends
The Stormceptor System can be used to change horizontal alignment in the storm drain
network up to a maximum of 90 degrees. Figure 6 illustrates the typical bend situations for
the Stormceptor System. Bends should only be applied to the second structure (downstream
structure) of the Series Stormceptor System.
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Technical Manual
Figure 6. Maximum bend angles.
7.4. Multiple Inlet Pipes
The Inlet and Inline Stormceptor System can accommodate two or more inlet pipes. The
maximum number of inlet pipes that can be accommodated into a Stormceptor unit is a
function of the number, alignment and diameter of the pipes and its effects on the structural
integrity of the precast concrete. When multiple inlet pipes are used for new developments,
each inlet pipe shall have an invert elevation 3 inches (75 mm) higher than the outlet pipe
invert elevation.
7.5. Inlet/Outlet Pipe Invert Elevations
Recommended inlet and outlet pipe invert differences are listed in Table 3.
Table 3. Recommended drops between inlet and outlet pipe inverts.
Number of Inlet Pipes
Inlet System
Inline System
Series System
1
>1
3 inches (75 mm)
3 inches (75 mm)
1 inch (25 mm)
3 inches (75 mm)
3 inches (75 mm)
Not Applicable
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Technical Manual
7.6. Shallow Stormceptor
In cases where there may be restrictions to the depth of burial of storm sewer systems. In
this situation, for selected Stormceptor models, the lower chamber components may be
increased in diameter to reduce the overall depth of excavation required.
7.7. Customized Live Load
The Stormceptor system is typically designed for local highway truck loading (HS-20 in the
US and CHBDC in Canada). In instances of other loads, the Stormceptor System may be
customized structurally for a pre-specified live load. Contact your local Stormceptor
representative for customized loading conditions.
7.8. Pre-treatment
The Stormceptor System may be sized to remove sediment and for spills control in
conjunction with other stormwater BMPs to meet the water quality objective. For pretreatment
applications, the Stormceptor System should be the first unit in a treatment train. The benefits
of pre-treatment include the extension of the operational life (extension of maintenance
frequency) of large stormwater management facilities, prevention of spills and lower total lifecycle maintenance cost.
7.9. Head loss
The head loss through the Stormceptor System is similar to a 60 degree bend at a
maintenance hole. The K value for calculating minor losses is approximately 1.3 (minor loss
= k*1.3v2/2g). However, when a Submerged modification is applied to a Stormceptor unit, the
corresponding K value is 4.
7.10. Submerged
The Submerged modification, Figure 7, allows the Stormceptor System to operate in
submerged or partially submerged storm sewers. This configuration can be installed on all
models of the Stormceptor System by modifying the fiberglass insert. A customized weir
height and a secondary drop tee are added.
Submerged instances are defined as standing water in the storm drain system during zero
flow conditions. In these instances, the following information is necessary for the proper
design and application of submerged modifications:
•
•
•
Stormceptor top of grade elevation
Stormceptor outlet pipe invert elevation
Standing water elevation
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Technical Manual
Figure 7. Submerged Stormceptor
8.
Comparing Technologies
Designers have many choices available to achieve water quality goals in the treatment of
stormwater runoff. Since many alternatives are available for use in stormwater quality
treatment it is important to consider how to make an appropriate comparison between
“approved alternatives”. The following is a guide to assist with the accurate comparison of
differing technologies and performance claims.
8.1. Particle Size Distribution (PSD)
The most sensitive parameter to the design of a stormwater quality device is the selection of
the design particle size. While it is recommended that the actual particle size distribution
(PSD) for sites be measured prior to sizing, alternative values for particle size should be
selected to represent what is likely to occur naturally on the site. A reasonable estimate of a
particle size distribution likely to be found on parking lots or other impervious surfaces should
consist of a wide range of particles such as 20 microns to 2,000 microns (Ontario MOE,
1994).
There is no absolute right particle size distribution or specific gravity and the user is
cautioned to review the site location, characteristics, material handling practices and
regulatory requirements when selecting a particle size distribution. When comparing
technologies, designs using different PSDs will result in incomparable TSS removal
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Technical Manual
efficiencies. The PSD of the TSS removed needs to be standard between two products to
allow for an accurate comparison.
8.2. Scour Prevention
In order to accurately predict the performance of a manufactured treatment device, there
must be confidence that it will perform under all conditions. Since rainfall patterns cannot be
predicted, stormwater quality devices placed in storm sewer systems must be able to
withstand extreme events, and ensure that all pollutants previously captured are retained in
the system.
In order to have confidence in a system’s performance under extreme conditions,
independent validation of scour prevention is essential when examining different
technologies. Lack of independent verification of scour prevention should make a designer
wary of accepting any product’s performance claims.
8.3.
Hydraulics
Full scale laboratory testing has been used to confirm the hydraulics of the Stormceptor
System. Results of lab testing have been used to physically design the Stormceptor System
and the sewer pipes entering and leaving the unit. Key benefits of Stormceptor are:
•
•
•
•
Low head loss (typical k value of 1.3)
Minimal inlet/outlet invert elevation drop across the structure
Use as a bend structure
Accommodates multiple inlets
The adaptability of the treatment device to the storm sewer design infrastructure can affect
the overall performance and cost of the site.
8.4. Hydrology
Stormwater quality treatment technologies need to perform under varying climatic conditions.
These can vary from long low intensity rainfall to short duration, high intensity storms. Since a
treatment device is expected to perform under all these conditions, it makes sense that any
system’s design should accommodate those conditions as well.
Long-term continuous simulation evaluates the performance of a technology under the
varying conditions expected in the climate of the subject site. Single, peak event design does
not provide this information and is not equivalent to long-term simulation. Designers should
request long-term simulation performance to ensure the technology can meet the long-term
water quality objective.
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Technical Manual
9.
Testing
The Stormceptor System has been the most widely monitored stormwater treatment
technology in the world. Performance verification and monitoring programs are completed to
the strictest standards and integrity. Since its introduction in 1990, numerous independent
field tests and studies detailing the effectiveness of the Stormceptor System have been
completed.
•
•
•
•
•
•
•
•
Coventry University, UK – 97% removal of oil, 83% removal of sand and 73% removal
of peat
National Water Research Institute, Canada, - scaled testing for the development of
the Stormceptor System identifying both TSS removal and scour prevention.
New Jersey TARP Program – full scale testing of an STC 750/900 demonstrating
75% TSS removal of particles from 1 to 1000 microns. Scour testing completed
demonstrated that the system does not scour. The New Jersey Department of
Environmental Protection laboratory testing protocol was followed.
City of Indianapolis – full scale testing of an STC 750/900 demonstrating over 80%
TSS removal of particles from 50 microns to 300 microns at 130% of the unit’s
operating rate. Scour testing completed demonstrated that the system does not scour.
Westwood Massachusetts (1997), demonstrated >80% TSS removal
Como Park (1997), demonstrated 76% TSS removal
Ontario MOE SWAMP Program – 57% removal of 1 to 25 micron particles
Laval Quebec – 50% removal of 1 to 25 micron particles
10. Installation
The installation of the concrete Stormceptor should conform in general to state highway,
provincial or local specifications for the installation of maintenance holes. Selected sections
of a general specification that are applicable are summarized in the following sections.
10.1. Excavation
Excavation for the installation of the Stormceptor should conform to state highway, provincial
or local specifications. Topsoil removed during the excavation for the Stormceptor should be
stockpiled in designated areas and should not be mixed with subsoil or other materials.
Topsoil stockpiles and the general site preparation for the installation of the Stormceptor
should conform to state highway, provincial or local specifications.
The Stormceptor should not be installed on frozen ground. Excavation should extend a
minimum of 12 inches (300mm) from the precast concrete surfaces plus an allowance for
shoring and bracing where required. If the bottom of the excavation provides an unsuitable
foundation additional excavation may be required.
In areas with a high water table, continuous dewatering may be required to ensure that the
excavation is stable and free of water.
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Technical Manual
10.2. Backfilling
Backfill material should conform to state highway, provincial or local specifications. Backfill
material should be placed in uniform layers not exceeding 12 inches (300mm) in depth and
compacted to state highway, provincial or local specifications.
11. Stormceptor Construction Sequence
The concrete Stormceptor is installed in sections in the following sequence:
1. Aggregate base
2. Base slab
3. Lower chamber sections
4. Upper chamber section with fiberglass insert
5. Connect inlet and outlet pipes
6. Assembly of fiberglass insert components (drop tee, riser pipe, oil cleanout port
and orifice plate
7. Remainder of upper chamber
8. Frame and access cover
The precast base should be placed level at the specified grade. The entire base should be in
contact with the underlying compacted granular material. Subsequent sections, complete with
joint seals, should be installed in accordance with the precast concrete manufacturer’s
recommendations.
Adjustment of the Stormceptor can be performed by lifting the upper sections free of the
excavated area, re-leveling the base and re-installing the sections. Damaged sections and
gaskets should be repaired or replaced as necessary. Once the Stormceptor has been
constructed, any lift holes must be plugged with mortar.
12. Maintenance
12.1. Health and Safety
The Stormceptor System has been designed considering safety first. It is recommended that
confined space entry protocols be followed if entry to the unit is required. In addition, the
fiberglass insert has the following health and safety features:
•
•
•
Designed to withstand the weight of personnel
A safety grate is located over the 24 inch (600 mm) riser pipe opening
Ladder rungs are provided for entry into the unit, if required
12.2. Maintenance Procedures
Maintenance of the Stormceptor system is performed using vacuum trucks. No entry into the
unit is required for maintenance (in most cases). The vacuum service industry is a wellestablished sector of the service industry that cleans underground tanks, sewers and catch
basins. Costs to clean a Stormceptor will vary based on the size of unit and transportation
distances.
The need for maintenance can be determined easily by inspecting the unit from the surface.
The depth of oil in the unit can be determined by inserting a dipstick in the oil
inspection/cleanout port.
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Technical Manual
Similarly, the depth of sediment can be measured from the surface without entry into the
Stormceptor via a dipstick tube equipped with a ball valve. This tube would be inserted
through the riser pipe. Maintenance should be performed once the sediment depth exceeds
the guideline values provided in the table 4.
Table 4. Sediment Depths indicating required servicing.
Sediment Depths Indicating Required Servicing *
Sediment Depth
inches (mm)
Model (CAN)
300i
9 (225)
750
9 (230)
1000
11 (275)
1500
16 (400)
2000
14 (350)
3000
19 (475)
4000
16 (400)
5000
20 (500)
6000
17 (425)
9000
16 (400)
10000
20 (500)
14000
17 (425)
* based on 15% of the Stormceptor unit’s total storage
Although annual servicing is recommended, the frequency of maintenance may need to be
increased or reduced based on local conditions (i.e. if the unit is filling up with sediment more
quickly than projected, maintenance may be required semi-annually; conversely once the site
has stabilized maintenance may only be required every two or three years).
Oil is removed through the oil inspection/cleanout port and sediment is removed through the
riser pipe. Alternatively oil could be removed from the 24 inches (600 mm) opening if water is
removed from the lower chamber to lower the oil level below the drop pipes.
The following procedures should be taken when cleaning out Stormceptor:
1.
2.
3.
4.
5.
Check for oil through the oil cleanout port
Remove any oil separately using a small portable pump
Decant the water from the unit to the sanitary sewer, if permitted by the local
regulating authority, or into a separate containment tank
Remove the sludge from the bottom of the unit using the vacuum truck
Re-fill Stormceptor with water where required by the local jurisdiction
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Technical Manual
12.3. Submerged Stormceptor
Careful attention should be paid to maintenance of the Submerged Stormceptor System. In
cases where the storm drain system is submerged, there is a requirement to plug both the
inlet and outlet pipes to economically clean out the unit.
12.4. Hydrocarbon Spills
The Stormceptor is often installed in areas where the potential for spills is great. The
Stormceptor System should be cleaned immediately after a spill occurs by a licensed liquid
waste hauler.
12.5. Disposal
Requirements for the disposal of material from the Stormceptor System are similar to that of
any other stormwater Best Management Practice (BMP) where permitted. Disposal options
for the sediment may range from disposal in a sanitary trunk sewer upstream of a sewage
treatment plant, to disposal in a sanitary landfill site. Petroleum waste products collected in
the Stormceptor (free oil/chemical/fuel spills) should be removed by a licensed waste
management company.
12.6. Oil Sheens
With a steady influx of water with high concentrations of oil, a sheen may be noticeable at the
Stormceptor outlet. This may occur because a rainbow or sheen can be seen at very small oil
concentrations (<10 ppm). Stormceptor will remove over 98% of all free oil spills from storm
sewer systems for dry weather or frequently occurring runoff events.
The appearance of a sheen at the outlet with high influent oil concentrations does not mean
the unit is not working to this level of removal. In addition, if the influent oil is emulsified the
Stormceptor will not be able to remove it. The Stormceptor is designed for free oil removal
and not emulsified conditions.
21
Appendix 1
Stormceptor Drawings
Contact
800 565 4801
www.imbriumsystems.com
TM
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