What are the THREE layers or zones found in a septic tank?

A septic tank is designed to treat wastewater through a process that separates solid and liquid waste. The three layers or zones found in a septic tank are scum, liquid, and sludge.

In the scum layer, which is the topmost layer, floating materials such as fats, oils, and grease accumulate. This layer is critical as it helps to minimize the odor and keeps the unsightly waste beneath it.

The liquid layer, often referred to as effluent, lies in the middle and consists of mostly clarified wastewater. This layer is essential as it flows to the drain field for further treatment and absorption into the soil.

Finally, the sludge layer comprises heavier solids that settle at the bottom of the tank. This layer contains undigested organic matter and pathogens that can be harmful.

Understanding these layers is crucial for proper septic tank maintenance and function, as each layer plays an important role in the wastewater treatment process and impacts the tank's overall efficacy and longevity.