M-GB - First Rain Water Treatment Plants
M.GB. srl has studied a special type of treatment device able to treatment the only first rain waters and to dispose the following ones directly into the final discharge.
Squares, car- parks, iron open storage, car breakers etc, are continuously and constantly dirtied by sands, oils and greases of the parked vehicles, by metallic elements depots, by motor percolates . Owing to rain , such substances are conveyed to the discharge.
These substances are a dangerous pollution source and therefore must be removed before waters are discharged. For such a reason, European standards impose the treatment of the first rain waters.
The “ first rain waters” are called all the meteoric storm water resulting from the first 5mm of rain equally fallen on the drained surface equipped with draining net. To calculate the flow rate the above mentioned value has to occur in 15 minutes; the influx coefficients to the net are considered
To calculate the flow rates, it is considered that such value is verified in 15 minutes; the afflux coefficients are assumed equal to 1 for the surfaces which are covered, stone pavement or waterproofed and 0.3 for each type of permeability surfaces, by excluding the cultivated surfaces.
The treatment cycle foresees the following phases :
- De sldge and storage (in decantation basins)
- De oiling
- Physical-chemical treatment made of :
- Reaction group
- Accelerated sedimentation in tube nest
- Absorption on activated carbon column
- Sludge extraction
Used materials are :
- Reinforced concrete
- Stainless steel