TREATMENTS FOR RAIN AND STORM WATERS -
Large square oil interceptors

This type of oil/grease intercepting tank for large paved parking areas is characterised by the fact that it treats the amount of rain and storm waters and it transports through a floodway the excess oil and sludge to the drain.

They are made of one or more tanks for sludge sedimentation and resting and at least one tank for oil trapping with an intermediate division inlet and outlet siphon drain and oilproof and waterproof cushions.

The tanks are made by our technical office on the base of specific hydraulic calculations, according to each specific problem and considering the load and intensity of rain water following tabular references.

The result is assured by the retention time, by the siphon drains and by the intermediate wall put in the central area of the oil interceptor close to which the oil floats to the surface (to increase the result some oil-absorbing cushions are installed in the intercepting chamber).

This sort of treatment doesn’t utilize pumps, sensors and electric boards. As a consequence there is no energy consumption.

Since the tanks have a floodway system, the system is not affected by the intensity of the rain and it is thus able to treat from a few litres per second up to big quantities. Moreover unlike the tanks for the first rain waters, the system can also treat and separate the oily and sedimentable substances of a following rain fall. This is particularly useful if there is the possibility of accidental spills of oily substances during the atmospheric event.

 

TANKS FOR FIRST RAIN MADE ACCORDING TO THE REGIONAL LAW n.62 of 27.05.1985 of LOMBARDIA REGION

The modular or monolithic tanks of first rain are used to collect the first 5 mms of the catchment area uniformly distributed on the surface. These tanks store the polluted water and avoid that it is carried directly to the rain water outlet.

The stored water in the tank is disposed of through a drain pump to the city drainage system, or it is treated in proper systems according to the polluting substances it contains such as separating systems and/or physical-chemical systems if the water contains mineral oils, surface oils, sedimentable solids, heavy metals etc...

The introduction of the first rain water in the urban systems, should take place within 24-48 hours after the end of the atmospheric phenomenon always according to the instructions of the Body that manages the drainage system. During the rainfalls the urban depuration systems must already dispose the water coming from the mixed drainage systems. If not they would finish up treating quantities bigger than their treatment capacity.

This system consists of a modular or monolithic pre-fabricated tank which is internally separated by a divider and likely by other holding tanks of equal sizes, until the achievement of the established storage volume.

The main module has an electronic device which is situated at the inlet which signals the beginning and the end of a rainfall. After a pre-established time from the beginning of the rainfall the electronic device activates a pump which unloads the water, stored up to that moment into the drainage system or a following depuration system.