What is a major source of treatment associated with a soil absorption system (SAS)?

Filtration is a major source of treatment associated with a soil absorption system (SAS) because it is the primary mechanism through which contaminants are removed from wastewater as it passes through the soil. When effluent enters the soil, it is subjected to a variety of physical, chemical, and biological processes that work together to purify the water.

As wastewater infiltrates the soil, larger particles are filtered out by the soil matrix. The various soil layers provide a physical barrier that traps these particles, while also allowing water to flow through. Additionally, the microorganisms present in the soil play a critical role in breaking down organic materials and pathogens, further contributing to the treatment process. The microbial action and process of filtration work in tandem to ensure that the effluent is treated effectively before it reaches the groundwater or surrounding environment.

Other processes like evaporation, precipitation, and aeration may play roles in the broader context of hydrological cycles or soil health, but they are not primary treatment mechanisms within the typical functions of a soil absorption system. Filtering is essential in preventing the contamination of groundwater and ensuring that treated effluent meets safety standards for environmental discharge.