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
Inspection Procedures
1.
Set up any necessary safety equipment around the access
port or grate of the First Defense
®
as stipulated by
local ordinances. Safety equipment should notify passing
pedestrian and road traffic that work is being done.
2.
Remove the grate or lid to the manhole.
3.
Without entering the vessel, look down into the chamber to
inspect the inside. Make note of any irregularities. Fig.4
shows the standing water level that should be observed.
4.
Without entering the vessel, use the pole with the skimmer net
to remove floatables and loose debris from the components
and water surface.
5.
Using a sediment probe such as a Sludge Judge
®
, measure
the depth of sediment that has collected in the sump of the
vessel.
6.
On the Maintenance Log (see page 9), record the date, unit
location, estimated volume of floatables and gross debris
removed, and the depth of sediment measured. Also note
any apparent irregularities such as damaged components or
blockages.
7.
Securely replace the grate or lid.
8.
Take down safety equipment.
9.
Notify Hydro International of any irregularities noted during
inspection.
Floatables and Sediment Clean Out
Floatables clean out is typically done in conjunction with
sediment removal. A commercially or municipally owned sump-
vac is used to remove captured sediment and floatables (Fig.5).
Floatables and loose debris can also be netted with a skimmer
and pole. The access port located at the top of the manhole
provides unobstructed access for a vactor hose and skimmer
pole to be lowered to the base of the sump.
Scheduling
•
Floatables and sump clean out are typically conducted once
a year during any season.
•
Floatables and sump clean out should occur as soon as
possible following a spill in the contributing drainage area.
Recommended Equipment
•
Safety Equipment (traffic cones, etc)
•
Crow bar or other tool to remove grate or lid
•
Pole with skimmer or net (if only floatables are being removed)
•
Sediment probe (such as a Sludge Judge
®
)
•
Vactor truck (flexible hose recommended)
•
First Defense
®
Maintenance Log
Floatables and sediment Clean Out Procedures
1.
Set up any necessary safety equipment around the access
port or grate of the First Defense
®
as stipulated by
local ordinances. Safety equipment should notify passing
pedestrian and road traffic that work is being done.
2.
Remove the grate or lid to the manhole.
3.
Without entering the vessel, look down into the chamber to
inspect the inside. Make note of any irregularities.
4. Remove oil and floatables stored on the surface of the water
with the vactor hose (Fig.5) or with the skimmer or net (not
pictured).
5.
Using a sediment probe such as a Sludge Judge
®
, measure
the depth of sediment that has collected in the sump of the
vessel and record it in the Maintenance Log (page 9).
6.
Once all floatables have been removed, drop the vactor hose
to the base of the sump. Vactor out the sediment and gross
debris off the sump floor (Fig.5).
7.
Retract the vactor hose from the vessel.
8.
On the Maintenance Log provided by Hydro International,
record the date, unit location, estimated volume of floatables
and gross debris removed, and the depth of sediment
measured. Also note any apparent irregularities such as
damaged components, blockages, or irregularly high or low
water levels.
9.
Securely replace the grate or lid.
Fig.4 Floatables are removed with a vactor hose (First Defense
model FD-4, shown).
- Regularly during first year of installation
- Every 6 months after the first year of installation
- Once per year, with sediment removal
- Following a spill in the drainage area
- Once per year or as needed
- Following a spill in the drainage area
Activity
Frequency
Inspection
Oil and Floatables
Removal
Sediment Removal
Maintenance at a Glance
NOTE: For most clean outs the entire volume of liquid does not need to be removed from the manhole. Only remove the
first few inches of oils and floatables from the water surface to reduce the total volume of liquid removed during a clean out.
Fig.5 Sediment is removed with a vactor hose (First Defense
model FD-4, shown).
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