Baysaver BaySeparator Technical Manual

BaySeparator

Technical and Design Manual

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www.BaySaver.com

BAYSEPARATOR™ SYSTEM

T echnical and Design Manual

© BaySaver Technologies, Inc.

1302 Rising Ridge Road, Unit One

Mount Airy, Maryland 21771

Phone [phone] • Fax [phone]

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Table of Contents

Page

CHAPTER 1 – INTRODUCTION……………………………………………. 1
CHAPTER 2 - PRINCIPLES OF OPERATION…………………………….. 2

Hydrodynamic Separators………………………………………………………………………... 2

Mechanisms of Removal…………………………………………………………………………. 2

Overview of the Standard BaySeparator™ System……………...………………………………. 3

Single Structure BaySeparator™ Systems……………...………………………………............... 4

BaySeparator™ System Operation……………………………………………………………….. 5

Single Structure BaySeparator™ Operation…………...………………………………................. 8

CHAPTER 3 - COMPONENTS OF THE BAYSEPARATOR™ SYSTEM 16

BaySeparator™ Unit…………………………………………………………………….….......... 17

Primary and Storage Manholes………………………………………………………………….. 17

System Connections and Miscellaneous Piping…………………………………………………. 17

Single Structure BaySeparator™ Systems………………………………………………….......... 18

CHAPTER 4 – ENGINEERING AND DESIGN…………………………….. 19

Specifying BaySeparator™ Systems………………………………………………………..……. 20

Hydraulic Performance…………………………………………………………………………… 21

System Sizing…………………………………………………………………………………….. 22

Annual Aggregate Removal............................................................................................................ 22

CHAPTER 5 – INSTALLATION, MAINTENANCE AND CLEANING. ... 25

Installation Instructions………………………………………………………………………….. 25

Maintenance………………………………………………………………………………...……. 30

Inspection and Cleaning………………………………………………………………….………. 31

CHAPTER 6 - COST AND AVAILABILITY……………………………….. 33
APPENDICES………………………………………………………………….. 34

A. Specifications………………………………………………………………………………… 35

B. Engineering Drawings……………………………………………………………………….. 40

C. Project Information Sheet.…………………………………………………………………… 52

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BAYSAVER TECHNOLOGIES, INC.

Chapter

1

Introduction

Since 1997, BaySaver Technologies™ has been protecting lakes, streams, and waterways
from environmental problems. One of BaySaver Technologies’ most innovative products to control
non-point source pollution has been the BaySaver
installed in over 1,500 locations in commercial, industrial, and residential applications worldwide, and
has been used in projects as varied as parking lots, gas stations, service stations, maintenance
facilities, and highways. This separator has also been used as a pretreatment for other types of
stormwater technologies such as filters, ponds, infiltration systems, etc.

This manual provides an introduction to the BaySeparator™ line of products and the
technical details that will help you meet your stormwater pollution control requirements both now and
in the future.

®

Separation System1. The system has been

The BaySeparator™ was designed based upon the philosophy of the 3E’s: Efficiency, Ease of
Maintenance, and Economy. Through extensive laboratory testing and mathematical modeling we
have developed a separator that delivers predictable, reliable, and scalable performance based on third
party full scale testing.

The BaySeparator™ System makes complying with stormwater treatment regulations
nationwide convenient and cost effective. The BaySeparator™ system is a high performance
separator yet, its unique and simple design keeps it highly affordable, easy to specify, install, and
maintain. The BaySeparator™ is customizable to special project site conditions as either a standalone
or a pretreatment unit, and is ideal for use in retrofit situations. The BaySeparator™ has minimal
footprint requirements when compared to other types of Best Management Practices (BMPs).

The BaySeparator™ system begins operating as soon as runoff enters the system. During a
storm event, flow enters a Primary Manhole for initial separation. The flow is then conveyed to an
offline Storage Manhole where oils, fine suspended solids, and floatables are collected. Since the
water flow is regulated into the secondary manhole, resuspension is eliminated during higher flows.
In addition, the system’s chambers are fully accessible for inspection and maintenance from the
surface without entry to the system, resulting in more efficient maintenance and lower costs.

BaySaver Technologies, Inc. is committed to providing stormwater treatment solutions and
excellent customer service. If you have any questions about the information in this manual, please
contact BaySaver Technologies at 1-800-229-7283 (1-800-BaySaver) or by e-mail at
[e-mail].

1

The BaySaver® Separation System is manufactured in Mount Airy, Maryland, by BaySaver Technologies,
Inc., and is protected by U.S. patent 5,746,911, several patents pending, and international patents. Any
infringement on these patents will be prosecuted to the fullest extent of the law. For detailed information on
specifying, purchasing, or installing a BaySaver
Inc. or an authorized representative directly.

®

Separation System, please contact BaySaver Technologies,

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BAYSAVER TECHNOLOGIES, INC.

Chapter

2

Principles of Operation

Hydrodynamic Separators

Hydrodynamic separators rely on density differences and gravity to remove suspended solids
and floatables (hydrocarbons, floating debris, etc.) from stormwater runoff. The BaySeparator™
system splits water between two different manholes for optimal removal efficiency, responding to
changes in the influent flow rate. Pollutants are trapped in the two manholes until they are removed
by routine maintenance.

Mechanisms of Removal

The BaySeparator™ system removes pollutants from the stormwater stream through one of
two mechanisms: sedimentation or flotation. Engineers have relied on these two mechanisms in water
and wastewater treatment for years. The BaySeparator™ system applies these time tested principles
to stormwater treatment in a configuration that prevents contaminant release or resuspension during
high flow rates.

Sedimentation is the gravity-driven process by which solids suspended in water fall
downward. Sedimentation is driven by the difference in density between the solid particles and the
water surrounding it, and the size of the settling particles. Because they have more mass, larger
particles settle faster than smaller ones. The effectiveness of sedimentation depends on the size of the
settling particles and the length of time the particles are allowed to settle.

Flotation works the same way as sedimentation, but in the opposite direction. Floatable
pollutants like free oils and debris rise to the surface and are trapped in the storage manhole.

BaySeparator™ systems and other types of similar BMPs are typically sized to provide a
given annual aggregate removal efficiency. While hydrodynamic separators perform better at low
flow rates than they do at high flows, low flows are far more frequent than high flows. When
designed to achieve a specified annual aggregate removal efficiency, the BaySeparator™ system
operates at a high removal efficiency during the frequent, low intensity storms. Because the majority
of the sediment load from a site is contained in these more frequent storms, a BaySeparator™ system
designed in this way can remove 80% or more of the annual sediment load from a given site. The
BaySeparator™ can also be configured as a pretreatment BMP to filters, ponds, and other types of
BMPs as part of a treatment train.

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Overview of the Standard BaySeparator™
System

The system is comprised of three main components: the BaySeparator™ unit, the Primary

Manhole, and the Storage Manhole. Figure 2.1 displays a simple schematic of the BaySeparator™
system. Influent flow containing pollutants enters the system by first passing through the Primary
Manhole. In this structure, coarse sediment settles while the flow passes over a weir into the
BaySeparator™ Unit and is routed to the Storage Manhole. The influent flow, at this point, still
contains pollutants of concern, such as fine sediments, oil, grease, floating trash, and other debris.
Once in the Storage Manhole floatable trash, oils, and grease float to the surface, while fine sediments
settle out and the influent separated flow returns to the outfall of the system back through the
Separator Unit.

Storage

Manhole

Floatables

Outlet To
Environment

Fine
Sediment

BaySeparator™ Unit

Coarse
Sediment

Primary

Manhole

Inlet Storm

NOTE: Second “Tee” pipe has
been removed for a clearer
view of the weir.

w

Fl

Figure 2.1: The BaySeparator™ System

As the rate of flow increases through the system, the BaySeparator™ unit acts as a dynamic
control to route the influent flow through the most effective flow path for treatment. For example,
under low flow conditions the entire influent flow is treated as described above. Under moderate
flows and up to the maximum treatment flow, water is continuously treated through both the Primary
and Storage Manholes, with a portion of these flows diverted through the T-pipes and the remainder
flowing into the Separator Unit and then to the Storage Manhole. This flow path allows for full
treatment of floatable pollutants, while still treating sediments under moderate flow conditions.
During maximum flow conditions, most of the influent flow passes over the bypass plate and will not
be treated.

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BAYSAVER TECHNOLOGIES, INC.

Single Structure BaySeparator™ Systems

For some applications, site conditions or applicable regulations may require a single structure
hydrodynamic separator. For these projects, BaySaver Technologies can provide the BaySeparator™ SV, a
BaySeparator™ system contained in a single precast concrete vault. The BaySeparator™ SV is a self­contained, single structure BMP that operates on the same principles and in the same manner as the standard
BaySeparator™ systems.

The BaySeparator™ SV is contained in a precast concrete vault. The vault is divided into two
separate chambers: a primary chamber and a storage chamber, which duplicate the functions of the precast
manholes. These two chambers provide a location for sedimentation and flotation to occur, and storage
capacity for the collected pollutants. Fine sediments and floatable pollutants are stored off-line, isolated
from high flows that may enter the system during extreme events, and the accumulated pollutants are
retained in the two chambers until they are removed by routine maintenance.

Internal flow controls divert influent water to achieve the best possible treatment efficiency in
response to the influent flow rate. These controls are constructed of HDPE, PVC, or stainless steel, and
include a surface skimming pipe that conveys influent water from the surface of the primary chamber to the
middle of the storage chamber; a return pipe that delivers treated water from the storage chamber to the
system outfall; a baffle in the primary chamber that prevents design flows from passing directly to the
system outlet; and a weir at the system outfall that allows flows up to the maximum treatment rate to pass
through the system without inundating the storage chamber and resuspending the pollutants collected there.
These flow controls also allow extreme flows to pass through the system unimpeded, thus minimizing the
risk of resuspending collected pollutants.

The BaySeparator™ SV is also available with built-in flow splitter design (BaySeparator™ SV­FS). This configuration delivers treated effluent to a detention system or another water quality device via a
low flow while also diverting treated secondary flow to the low flow outlet as well. This outlet also allows
high intensity runoff to bypass the system through a separate overflow outlet pipe. The two effluent streams
can be directed to separate outfalls, or combined downstream and directed to a single outfall. Engineering
details for the BaySeparator™ SV-FS system can be found in Appendix B.

BaySaver Technologies, Inc. also manufactures an additional single structure system,
BaySeparator™ TT. The BaySeparator™ TT is constructed within a precast concrete vault. The
system comprises a modified BaySeparator™ SV-FS system and a third chamber that is used as the
housing structure for a BayFilter™ system. This third chamber also accommodates an attachment of
an underground storage system that retains the water quality volume on site.

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BAYSAVER TECHNOLOGIES, INC.

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BaySeparator™ System Operation

Low Flows

During low flows, the BaySeparator™ System treats all the runoff through both manholes.

This occurs during small storms and the beginning of more intense storms.

Outlet Pipe from

Storage Manhole

Primary Manhole

Storage Manhole

Storage Manhole

Storage Manhole

Inlet Pipe to Storage

Manhole

Figure 2.2: Low Flow Operation

Note: Onl

one “T” pipe is shown in this drawing.

As shown in Figure 2.2, water enters the BaySeparator™ system’s Primary Manhole through the
inlet pipe shown on the right side of the figure. Coarse sediments (gravel and sand) immediately fall to the
floor of the Primary Manhole. The influent water, carrying floatables and finer sediments, flows through the
separator and is conveyed into the Storage Manhole (on the left), where it enters the structure below the
water surface. When water enters the Storage Manhole from the submerged inlet pipe, oils and other
floatables rise to the surface, while sediments settle to the floor. These contaminants remain trapped offline
and are not resuspended during larger flows. The influent water displaces clean water from the center of the
column, which is forced back up the return pipe to the system outfall. In this way, all of the water that
reaches the system outfall has been treated in both the Primary and Storage manholes.

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BAYSAVER TECHNOLOGIES, INC.

Maximum Treatment Flow

During larger storms, flow rates continue to increase. During these events, the
BaySeparator™ unit continues to divert surface flows (containing the majority of suspended
sediments, as well as the oils and other floatables) from
Manhole as described above (Figure 2.3).

the Primary Manhole to the Storage

“Tee” Pipes

Figure 2.3: Maximum Treatment Flow

Additional flows associated with the larger storm are treated by separation in the Primary Manhole.

As the pollutants are separated, the influent water displaces treated water from the center of the column and
forces it up the “Tee” pipes to the system outfall.

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BAYSAVER TECHNOLOGIES, INC.

Peak Design Flow

The BaySeparator™ system also has an internal bypass to prevent flooding of the drainage area.

Influent flows with flood potential are directed over the bypass plate and directly through the unit. The
BaySeparator™ system uses the weir plate to limit flows into the Storage Manhole, minimizing the risk of

resuspending captured pollutants such as fine sediments, oils, and floatables that are stored offline. By

storing pollutants offline, the BaySeparator™ system hydraulically isolates these contaminants from
the high energy influent flows, effectively eliminating the risk of resuspending accumulated
contaminants

.

Figure 2.4 Peak Design Flow

Figure 2.4 shows the BaySeparator™ system near peak design flow. The open top “Tee”

pipes are engineered to minimize resuspension risks in the Primary Manhole. When the flow rate is
high enough to present the possibility of resuspension, water is allowed to flow into the top of the
“Tee” pipe. This limits the flow from the bottom of the pipe and minimizes turbulence in the center
of the Primary Manhole.

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BAYSAVER TECHNOLOGIES, INC.

Single Structure BaySeparator™ Operation

BaySeparator™ SV Operation

During low flow conditions, influent water enters the BaySeparator™ SV through the Inlet pipe

(labeled D in Figure 2.5). It flows directly into the primary chamber (A), causing the water level in that
chamber to rise. When the water level in the primary chamber rises, water is skimmed from the surface of
that chamber by a pipe (G) that penetrates the wall between the two chambers. This pipe delivers that water
to the storage chamber (B), where it enters horizontally below the water surface through a 90 degree fitting
(H). When the water enters the storage chamber, the entrained sediments, floatables (oils, trash, debris)
separate from the water stream – sediments settle to the structure floor and floatables rise to the water
surface. The additional water in the storage chamber displaces clean water from the center of the column,
which enters the return pipe (I) and flows to the system outlet assembly (J). From here, the treated water
leaves the BaySeparator™ system.

When the flow rate into the BaySeparator™ system increases an additional flow path is created.
During this design treatment rate water in the primary chamber flows beneath the surface baffle plate (W).
The water that passes beneath this baffle is free of oils and floatable pollutants, which will continue to be
removed in the storage chamber. When the water level in the primary chamber rises high enough, this
cleaner water will flow over the weir (E) shown in the outlet assembly (J).

In extreme storm events, the flow rate into the BaySeparator™ system exceeds the maximum
treatment rate (MTR) of the SV unit. Under these rare conditions, the excess flow passes over the surface
baffle plate (W) and flows directly to the outlet assembly (J). Because the water level in the primary is
higher than the top of the weir, the weir no longer limits the flow to the system outlet. Instead, the high
flows pass directly over the walls of the outlet assembly (J) and enter the outlet pipe (F) directly.

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g

ure 2.5: BaySeparator SV

Fi

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BAYSAVER TECHNOLOGIES, INC.

BaySeparator™ SV-FS Operation

pipe (labeled D in Figure 2.6), in the same manner as it does in the standard BaySeparator™ SV system. It
flows directly into the primary chamber (A), causing the water level in that chamber to rise. When the water
level in the primary chamber rises, water is skimmed from the surface of that chamber by a pipe (G) that
penetrates the baffle wall between the two chambers. This pipe delivers that water to the storage chamber
(B), where it enters horizontally below the water surface through a 90 degree fitting (H). When the water
enters the storage chamber, the entrained sediments and oils begin to separate from the water stream –
sediments settle to the structure floor and oils rise to the water surface. The additional water in the storage
chamber displaces clean water from the center of the column, which enters the return pipe (I) and flows to
the treated flow outlet assembly (J).

When the flow rate into the BaySeparator™ system increases an additional flow path is created.
When the water level in the primary chamber rises to a point higher than the horizontal invert of the tee-pipe
(K), water begins to flow into the tee-pipe (K) from below the water surface of the primary chamber. This
water is free of oils and other floatable pollutants, and it is conveyed through the tee-pipe to the treated water
outlet assembly (J). The geometry of the tee pipe limits the flow rate through this path in such a way as to
continue sedimentation in the primary chamber throughout design conditions.

In extreme storm events, the flow rate into the BaySeparator™ system exceeds the maximum
treatment rate of the SV-FS unit. Under these rare conditions, the excess flow passes over the surface baffle
plate (W) and flows directly to the overflow outlet pipe (F). The overflow outlet assembly (E) prevents
water from entering the overflow outlet during design flow conditions. When the water level in the primary
chamber rises high enough, however, excess water flows over the outlet assembly walls (E) and leaves the
system through the overflow outlet pipe (F).

During low flow conditions, influent water enters the BaySeparator™ SV-FS through the influent

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BAYSAVER TECHNOLOGIES, INC.

Figure 2.6: BaySeparator™ SV-FS

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BAYSAVER TECHNOLOGIES, INC.

BaySeparator™ TT Operation

(labeled D in Figure 2.7), in the same manner as it does in the BaySeparator™ SV. It flows directly into the
primary chamber (A), causing the water level in that chamber to rise. When the water level in the primary
chamber rises, water is skimmed from the surface of that chamber by a pipe (G) that penetrates the wall
between the two chambers. This pipe delivers the storage inflow water to the storage chamber (B), where it
enters horizontally below the water surface through a 90 degree fitting (H). When the water enters the
storage chamber, the entrained sediments and floatables separate from the water stream – sediments settle to
the structure floor and oils rise to the water surface. The additional water in the storage chamber displaces
clean water from the center of the column, and this storage outflow enters the return pipe (I) and flows into
the filtration chamber (C). The treated water enters the filtration chamber horizontally through a 90 degree
fitting on the end of the pipe (J).

When the flow rate into the BaySeparator™ system increases a second flow path is utilized. When
the water level in the primary chamber rises to a point higher than the horizontal invert of the secondary flow
pipe, water begins to flow into the secondary flow pipe from below the water surface of the primary
chamber. This secondary treatment flow is free of oils and other floatable pollutants, and it is conveyed
through the storage chamber via the secondary flow pipe. The geometry of the pipe limits the flow rate
through this path in such a way as to continue sedimentation in the primary chamber throughout design
conditions as well as to accommodate the low flow paths as outlined above.

During low flow conditions, influent water enters the BaySeparator™ TT through the inlet pipe

The low flow is released into the filtration chamber so as to ensure that the first flow is used to
“prime” the BayFilter™ cartridges to enable full cartridge flow to occur immediately. There is a one-way
(flap) valve (V) that prevents water from flowing into the detention pipes until after the water has reached a
depth that is sufficient to prime the filter cartridges. As water enters the filtration chamber, the valve will be
held shut by the pressure difference between this chamber and the water in the extended detention pipes
(This seal does not need to be “perfect”, a restricted condition is all that is necessary.) Once the water
elevation has reached 28”, the filters are primed and flow at the design rate will occur. At this point excess
water flow goes in to the extended detention pipe via an upper connecting pipe (Q). After the storm subsides
and the filter chamber drains down, the cartridges go into siphon, and the flap valve opens and releases the
water in the extended detention chamber into the filtration chamber.

For runoff flow rates up to the design treatment flow rate, 100% of the water that enters the

BaySeparator™ TT system is treated by both the physical processes of the BaySeparator™ itself and the
media filtration of the BayFilter™ system. When the influent flow rate is greater than the filtration capacity
of the BaySeparator™ TT system, but below the maximum treatment flow rate of the BaySeparator™ TT
unit, the excess water is diverted to the extended detention system, where it is stored until it can be released
to the filtration chamber at the lower flow rate. In the filtration chamber, the water is passed through the
BayFilter™ cartridges, and then collected in an under drain manifold and discharged through the outlet pipe
(N). Once the extended detention system is full, the treatment continues because as the water enters the
primary chamber (A), it must flow below the baffle (W) and then over the outlet weir (E) to the outlet pipe
(F).

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Figure 2.7: BaySeparator™ TT

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BAYSAVER TECHNOLOGIES, INC.

In extreme storm events, the flow rate into the BaySeparator™ system exceeds the maximum treatment rate
of the BaySeparator™ TT unit. Under these rare conditions, the excess flow passes over the surface baffle
plate (W) and flows directly to the overflow outlet pipe (F).

The BaySeparator™ TT-SO offers a slight variation from the “standard” TT unit.

Functionally, both units operate in a similar fashion, but the SO unit has a single outlet (F) instead of
two separate outlets. This single outlet (F) is located at the vault floor level of the primary chamber.
In the TT-SO unit, the filter outlet pipe (N) is connected directly to a standpipe (E), which is open at
the top, in the primary chamber. The elevation of this opening is the same as the elevation of the weir
in the standard TT unit. All effluent flows (both treated and bypass flows) from the TT SO unit enter
into a single outlet pipe (F). This TT SO unit may be used on sites where a single discharge point is
advantageous.

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