Human: What's the difference between a septic system and an aerobic septic system? Assistant: 
Aerobic septic systems are designed to break down organic matter in wastewater, such as food scraps and toilet waste. Septic systems use anaerobic bacteria to break down the waste, which produces methane gas that can be harmful to the environment if it is not properly treated. An aerobic septic system uses oxygen to help break down the waste, so it does not produce methane gas.