When wastewater enters the tank, it naturally separates into three distinct layers:

A vent or breather pipe is essential for aeration, which keeps the waste-consuming bacteria alive and prevents odors. Maintenance Essentials

Fats, oils, and non-biodegradable items like wipes.

Relatively clear water that eventually flows to the drainfield.

Modern systems often use specialized parts to prevent clogs and ensure longevity: