What is considered scum in the context of a septic tank?

In the context of a septic tank, scum refers specifically to the accumulated floating material that consists mostly of grease, oils, and other lighter solids that do not settle. This layer forms at the top of the septic tank and is essential for the functioning of the septic system, as it helps to trap and break down organic matter through anaerobic digestion. The presence of scum is a normal part of the process that occurs within the septic tank, distinguishing it from the solids that settle at the bottom (which form the sludge) and the treated effluent that is ready for absorption into the soil.

Understanding what constitutes scum helps in the management and maintenance of septic systems, ensuring they function effectively and do not cause environmental issues.