What is the purpose of subsurface disposal?

The purpose of subsurface disposal is specifically to apply sewage effluent beneath the ground surface. This method is primarily used in septic systems, where treated wastewater is distributed through a network of perforated pipes buried underground. The soil acts as a natural filter, helping to further treat the effluent as it percolates through the soil layers. This underground application minimizes the risk of surface contamination and helps maintain a safe environment while protecting water sources.

In contrast, storing sewage above ground does not align with the function of subsurface disposal, as it would pose significant health risks and environmental hazards. Discharging treated sewage into rivers is a different method altogether, typically seen in larger treatment facilities rather than residential septic systems. Creating a pond for sewage treatment is also a separate process that may be used in some systems but does not reflect the core principle of subsurface disposal focused on underground effluent application.