What role do bacteria play in a septic system?

Bacteria play a crucial role in the functioning of a septic system by breaking down solid waste and treating sewage. In the septic tank, anaerobic bacteria help decompose organic matter, converting solids into liquids and gases. This biological process is essential for the effective operation of the system, as it reduces the volume of waste and makes it easier for the effluent to be further treated by the soil in the drain field.

While other options mention processes related to septic systems, they do not accurately reflect the primary function of bacteria. For instance, filtering toxins from water is more associated with the physical and chemical mechanisms of the septic system and the surrounding soil, rather than the biological activity of bacteria. Accumulating solid waste contradicts the essential operation of bacteria, which is to break it down instead. Regulating water temperature is not a function associated with septic system bacteria and does not contribute to the treatment process. Thus, the primary role of bacteria in a septic system centers on their ability to break down waste effectively.