COVERED AND UNCOVERED

COMPLETE SYSTEM

Use

Rainwater runoff treatment system for outdoor yard sized

considering a rainfall of 400 l/s*ha and able to convey the

equivalent flow of rainwater (5 mm in 15 minutes as per

Regional Reg. Lombardy no. 4 of 24/03/06) to the oil selection

compartment for drain into the public sewer.

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 pipe that from the selection tank, which leads to the grease

trap is positioned with respect to the bypass pipe in such a way

that it only unloads the flow equal to the rainwater (the first 5

mm of rainwater evenly distributed over the entire drainage area

served by the drainage network); the flow rate that exceeds that

of the rainwater is conveyed through the bypass pipe directly into

the final receptor.

The wastewater, loaded with oils/hydrocarbons, which overflows

in the grease trap statically, is separated by gravity.

The rainwater, once treated, is passed through an inspection well

into the final receptor.

Maintenance

To maintain the proper operation of the plant the flowing controls

must be carried out every six months:

•

the level of the inert substances in the selection tank;

•

the level of the inert substances in the grease separator;

•

the level of oil/hydrocarbons in the grease separator;

If an excessive amount of sludge (inert) is found in the various

tanks proceed to its removal.

If an excessive amount of oil/hydrocarbons are found in the

grease separator, proceed to their elimination.

Specification Item

Supply of rainwater treatment plant (5 mm) for paved surfaces of....

m

2

and suitable for the drain of treated water into public sewers; this

system consists of the following artefacts:

•

flow-splitting chamber suitable to send the rainwater to the

grease separator and send the waters from secondary rainfall,

through bypass piping directly to the receiving body of the water;

•

Grease separator where the physical separation of oils and

hydrocarbons by flotation will take place.

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.

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