Water runoff from parking lots and roadways creates a real risk of soil and ground water pollution. Rainwater pounding the roadways and running off their surface can be laden with hydrocarbons and sludges that cannot be discharged directly into the natural surroundings. This requires a water treatment system.

The hydrocarbon trap separates the hydrocarbons which remain suspended in road runoff water...

		The hydrocarbon trap separates the hydrocarbons which remain suspended in road runoff water. The trap often has a deslimer, which settles the sludge particles and stops them in the trap. The separator works thanks to the different densities that water, sludges and hydrocarbons have. The polluted water enters the deslimer compartment of the trap, and the sludge, which is heavier than water, settles here. The hydrocarbons, which are lighter than water, rise to the surface and are trapped in a retention chamber. The treated water evacuates through an orifice at the bottom of the separator, to avoid carrying along the suspended hydro carbons. The size of the hydrocarbon trap is based on the amount of road surface to be treated. For optimal treatment of roadway runoff, the separator must be maintained at least once a year. Maintenance, which should be done by a specialised firm, entails cleaning and rinsing the trap which could otherwise reach its limit and pollute the site itself. To mitigate this risk, it is strongly recommended that the trap be equipped with an automatic shutoff point. In the event of saturation, the shutter closes the drainage hole before the hydrocarbons spill over and out.