First Defense
®
Operation and Maintenance Manual
First Defense
®
Operation and Maintenance Manual
Hydro International
(Stormwater), 94 Hutchins Drive, Portland ME 04102
Tel: (207) 756-6200 Fax: (207) 756-6212 Web: www.hydro-int.com
I. First Defense
®
by Hydro International
Table of Contents
3
First Defense
®
by Hydro International
- Introduction
- Operation
- Pollutant Capture and Retention
4
Model Sizes & Configurations
- First Defense
®
Components
5 Maintenance
- Overview
- Maintenance Equipment Considerations
- Determining Your Maintenance Schedule
6
Maintenance Procedures
- Inspection
- Floatables and Sediment Clean Out
8
First Defense
®
Installation Log
9
First Defense
®
Inspection and Maintenance Log
COPYRIGHT STATEMENT:
The contents of this manual, including the graphics contained herein, are intended for the use of the recipient to whom the
document and all associated information are directed. Hydro International plc owns the copyright of this document, which is supplied in confidence. It
must not be used for any purpose other than that for which it is supplied and must not be reproduced, in whole or in part stored in a retrieval system or
transmitted in any form or by any means without prior permission in writing from Hydro International plc. First Defense
®
is a trademarked hydrodynamic
vortex separation device of Hydro International plc. A patent covering the First Defense
®
has been granted.
DISCLAIMER:
Information and data contained in this manual is exclusively for the purpose of assisting in the operation and maintenance of Hydro
International plc’s First Defense
®
. No warranty is given nor can liability be accepted for use of this information for any other purpose. Hydro International
plc has a policy of continuous product development and reserves the right to amend specifications without notice.
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Introduction
The First Defense
®
is an enhanced vortex separator
that combines an effective and economical stormwater
treatment chamber with an integral peak flow bypass. It
efficiently removes total suspended solids (TSS), trash and
hydrocarbons from stormwater runoff without washing out
previously captured pollutants. The First Defense
®
is available
in several model configurations (refer to
Section II. Model
Sizes & Configurations
, page 4) to accommodate a wide
range of pipe sizes, peak flows and depth constraints.
Operation
The First Defense
®
operates on simple fluid hydraulics. It is self-
activating, has no moving parts, no external power requirement
and is fabricated with durable non-corrosive components.
No manual procedures are required to operate the unit and
maintenance is limited to monitoring accumulations of stored
pollutants and periodic clean-outs. The First Defense
®
has
been designed to allow for easy and safe access for inspection,
monitoring and clean-out procedures. Neither entry into the
unit nor removal of the internal components is necessary for
maintenance, thus safety concerns related to confined-space-
entry are avoided.
Pollutant Capture and Retention
The internal components of the First Defense
®
have been
designed to optimize pollutant capture. Sediment is captured
and retained in the base of the unit, while oil and floatables
are stored on the water surface in the inner volume (Fig.1).
The pollutant storage volumes are isolated from the built-in
bypass chamber to prevent washout during high-flow storm
events. The sump of the First Defense
®
retains a standing
water level between storm events. This ensures a quiescent
flow regime at the onset of a storm, preventing resuspension
and washout of pollutants captured during previous events.
Accessories such as oil absorbent pads are available for
enhanced oil removal and storage. Due to the separation
of the oil and floatable storage volume from the outlet, the
potential for washout of stored pollutants between clean-outs
is minimized.
• Inlet options include surface grate or multiple inlet pipes
•
Integral high capacity bypass conveys large peak flows without
the need for “offline” arrangements using separate junction
manholes
• Proven to prevent pollutant washout at up to 500% of its
treatment flow
•
Long flow path through the device ensures a long residence
time within the treatment chamber, enhancing pollutant settling
•
Delivered to site pre-assembled and ready for installation
Advantages
• Stormwater treatment at the point of entry into the drainage line
•
Sites constrained by space, topography or drainage profiles
with limited slope and depth of cover
•
Retrofit installations where stormwater treatment is placed on or
tied into an existing storm drain line
•
Pretreatment for filters, infiltration and storage
Applications
Oil
Max Oil
Storage Depth
Sediment
Storage
Sediment
Fig.1 Pollutant storage volumes in the First Defense
®
.
