Your septic system separates floatable matter, such as grease and oils, from solids and digests organic matter from the wastewater. A soil-based system discharges the liquid, called effluent, from your septic tank into various perforated pipes found buried in chambers, a leach field or other specific units made to release the effluent slowly into the soil. Ways things get into your septic tank include: Waste like diapers, cigarette butts and coffee grounds that slowly decompose or don't get flushed down drains completely. Synthetic fiber lint flows from washing machines. The bacteria in the drain and tank septic field are unable to break it down. Garbage disposers, used heavily, can send too much solid waste into your septic system. Shrubs and tree roots can clog a drain field, causing damage.