Use
Rainwater runoff treatment system for outdoor paved area sized
considering a rainfall of 400 l/s*ha suitable to convey rainwater
(5 mm in 15 minutes as per Regional Reg. Lombardy no. 4 of
24/03/06) in the storage area to then be degreased prior to the
delivery into the final receptor after a time of ..... h (between 1 and
100 hours) from the end of the rainfall.
The final receptor must be the public sewer.
Operation
The rainwater containing oils, hydrocarbons, suspended solids
and sediment, enter the selection tank where coarse solids
(gravel, crushed rock) decant, ensuring the perfect functioning of
purification in later stages.
The wastewater, free of coarse solids, overflows into the
sedimentation/accumulation sector sized to contain the
rainwater (the first 5 mm of rainfall evenly distributed over the
entire drainage area served by the drainage network as per
Regional Decree of Lombardy no. 62 of 27/05/85).
Once the sedimentation/accumulation sector is filled the return
valve, located upstream of the system, blocks the return of the
water stored, and the wastewater that continues to enter the
selection tank causes the raising of the door in the well so that
the water overflows into the bypass pipe flowing directly into the
final receptor.
The wastewater stored in the sedimentation/accumulation
sector, after being separated from the sedimentable substances
is re-launched to a grease separator using a submersible impeller
electric pump complete with safety float.
The discharge of the sedimentation/accumulation sector takes
place at a distance of 48 hours from the end of the rainfall through
the electric pump triggered by an electronic control unit actuated
by a rain sensor, and its switching off is guaranteed using a
minimum float placed inside the sedimentation/accumulation
sector.
The light liquids (oils and hydrocarbons) in the grease separator
are statically separated by gravity. The grease separator can
be equipped with a floating obstructer, which guarantees
the outgoing flow interruption in case the setting area of the
grease separator has accumulated an excessive amount of oil/
hydrocarbons avoiding, therefore, the drain into the final receptor.
The rainwater, once treated, is passed through an inspection well
into the final receptor.
Maintenance
To maintain the EPRAIN ACC rainwater runoff treatment system
efficient it is necessary to check the following every six months:
•
Check the presence of inert materials (gravel and sand)
inside the selection tank
•
Check for the presence of the sand inside the storage tanks
checking that they do not obstruct the suction port of the
electric pump
•
Check the presence of inert materials and oils inside the
grease separator
•
Verify the correct operation of the inlet valve on the
first
installation
•
Check the electrical connections
Proceed to the drainage in the case of:
•
excessive presence of gravel and sand inside the selection
tank.
•
a level of sand inside the accumulation installations blocking
the mouth of the electric pump.
•
excessive material (sands) inside the grease separator
(about 40 cm of material deposited on the bottom).
In the event of excess oils within the grease separator, proceed to
their removal.
COVERED AND UNCOVERED PAVED AREAS
COMPLETE PLANT
Operation
The rainwater containing oils, hydrocarbons, suspended solids
and sediment, enter the selection tank where coarse solids (gravel,
crushed rock) decant, thus ensuring the perfect functioning of
purification in later stages.
The wastewater, free of coarse solids, overflows into the
sedimentation/accumulation sector sized to contain the rainwater
(the first 5 mm of rainfall evenly distributed over the entire drainage
area served by the drainage network as per
Regional Decree of Lombardy no. 62 of 27/05/85).
Once the sedimentation/accumulation sector is filled the return
valve, located upstream of the system, blocks the return of the water
stored, and the wastewater that continues to enter the selection tank
causes the raising of the door in the well so that the water overflows
into the bypass pipe flowing directly into the final receptor.
The wastewater stored in the sedimentation/accumulation sector,
after being separated from the sedimentable substances is re-
launched to a grease separator using a submersible impeller electric
pump complete with safety float.
The discharge of the sedimentation/accumulation sector takes
place at a distance of 48 hours from the end of the rainfall through
the electric pump triggered by an electronic control unit actuated by
a rain sensor, and the switching off is guaranteed using a minimum
float placed inside the sedimentation/accumulation sector.
The light liquids (oils and hydrocarbons) in the grease separator are
statically separated by gravity.
The grease separator can be equipped with a floating obstructer,
which guarantees the outgoing flow interruption in case the setting
area of the grease separator has accumulated an excessive amount of
oil/hydrocarbons avoiding, therefore, the drain into the final receptor.
The rainwater, once treated, is passed through an inspection well into
the final receptor.
Specification Item
Supply of rainwater treatment plant (5 mm) for paved surfaces of....
m
2
and suitable for the drain of treated water into surface bodies; this
system consists of the following artefacts:
•
flow-splitting chamber suitable to send the rainwater to the
storage tank and send the waters from secondary rainfall,
through bypass piping directly to the receiving body of the water.
•
Storage tank suitable to accommodate a quantity of rain of
height h = 5 mm uniformly distributed throughout the paved
area in question; the water to be treated will be stored inside for
a time t (0-100 hours)
•
The system is equipped with non-return valve that closes the
accumulation when full and an electric pump that after a certain
time t will send the water to a grease separator
•
Grease separator where the physical separation of oils and
hydrocarbons by flotation will take place
•
End of rainfall sensors operate the electric pump, which will
empty the installations after a time t from the end of the weather
event.
•
An electrical system suitable for the management of the plant.
All the artefacts are made of constant thickness polyethylene (12
mm) with the rotational moulding technique and consist of ribs,
which confer resistance for underground use, complete with screw
caps for inspection and relative extensions (50 cm) in diameter from
DN 50 to DN 63.
63
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