http://sludgehammer.net/
Waste and unoxygenated bacteria are the primary reason for failure of traditional septic systems. When large colonies of these anaerobic bacteria migrate from the septic tank to the disposal field they produce a mucus-like layer of slime, or biomat, which clogs the pores of the soil so air cannot circulate. Additionally, as they grow, this anaerobic bacteria creates large amounts of nitrate, a toxic element when produced in large quantities, which can, over time, seep into the local water table. The usual solution at this point is to pump the waste and clogs from the septic tank and start a new disposal field—costly solutions to a now avoidable situation.