Did you know we have biofilm in our infiltration pond? The biofilm is part of the rock chamber.В The rock chamber is the base of our infiltration cell although we previously called it an infiltration pond. A perforated tile was put into our cell. This was surrounded with several inches ofВ 1″ clear wash rock. Attached to this rock is a biofilm. Biofilm is a bacteria that extracts and digests harmful pollutants,В such as gasoline, oil or other harmful pollutants that come from vehicles, and refreshes the water before it goes back into the ground. Biofilm will not live in a pool of water but will survive our typical rainfalls of up to 1 1/4 inches. As the water passes the biofilm, the pollutants are stripped from the water and then this clear water continues into the aquafer or what we consider below ground.